Class ZTX^"^! Book.._^LA4S"_ %ri^lrtN"J_a^Q_ COK^'HrCilT OEPOSfT FOOD INSPECTION'' and ANALYSIS FOR THE USE OF PUBLIC ANALYSTS, HEALTH OFFICERS, SANITARY CHEMISTS, AND FOOD ECONOMISTS BY ALBERT E. LEACH, S.B. Late Chief of the Denver Food and Drug Inspection Laboratory, Bureau of Chemistry, U. S. Department of Agriculture; Late Chief Analyst of the Massachusetts State Board of Health REVISED AND ENLARGED BY ANDREW L. WINTON, Ph.D., Formerly Chief of the Chicago Food and Drug Laboratory, Bureau of Chemistry, U. S. Department of Agriculture; Formerly in Charge of the^ A nalytical Laboratory, Connecticut Agricultural Experiment Station FOURTH EDITION TOTAL ISSUE, EIGHT THOUSAND NEW YORK JOHN WILEY & SONS, Inc. London: CHAPMAN & P a : T Limited 1920 Copyright, 1904, 1909. BY ALBERT E. LEACH. First Edition Entered at Stationers' HalL COYRIGHT, I913. 1920. BY Mrs. MARTHA T. LEACH. hvw -^ «^'^^ PRESS Ol' BRAUNWURTH ti CO. BOOKBINDERS AND PRINTERS BROOKLYN, N. Y. l\ (e)nLA5R54 48 ,-;ul ^/ PREFACE TO FOURTH EDITION. The present revision has been carried out after a thorough search of the literature. A large amount of new material has been added or substituted for that in previous editions and the size of the book increased by 90 pages. While a somewhat different arrangement of the chapters may seem more logical, it was decided to retain the old order to which those who have hitherto used the book have become accustomed. The lists of references at the end of the chapters, which never aspired to be complete bibhographies, have been dropped and more attention has been given to footnote references. The reviser is indebted for criticisms and notes to many friends, especially the following: Prof. E. H. Farrington, Prof, E. S. Guthrie, and Dr. L. L. Van Slyke (dairy products). Prof. H. S. Grindley (meat), Mr. F. C. Atkinson, Mr. Carl S. Miner, and Prof. Harry Snyder (cereal products), Mr. M. C. Albrech, Mr. F. M. Boyles, and Mr. A. E. Paul (spices), Mr. H. S. Bailey, Prof. E. F. Ladd, and Dr. David Wesson (oils). Dr. C. S. Browne, Mr, A. Hugh Bryan, Dr. W. D. Home, and Mr. W. E. Rice (sugar), Mr. H. M. Loomis and Mr. W. E. Mathewson (colors), and Dr. A. R. Albright (flavoring extracts). A special feature is a final chapter by Prof. Gerald L. Wendt, on the determination of acidity by the hydrogen electrode, a method which seems destined to play an important part in food analysis. So far as possible original papers have been consulted, but whenever this was not possible owing to the war or other conditions the abstracts in the Experiment Station Record and Chemical Abstracts have proved invaluable. A. L. W. Wilton Conn., January, 1920. V PREFACE TO FIRST EDITION. In the preparation of the present work, the requirements of the public analyst are mainly kept in view, as well as of such officials as naturally cooperate with him in carrying out the provisions of the laws dealing with the suppression of food adulteration in states and municipalities. To this end special prominence is given to the nature and extent of adul- teration in the various foods, to methods of analysis for the detection of adulterants, and to some extent also to the machinery of inspection. While the analyst may not in all cases have directly to deal with the minuticB of food inspection, his work is so closely allied therewith that this branch of the subject is of vital interest and importance to him. Indeed, in many smaller cities one official often has charge of the entire work, combining the duties of both inspector and analyst. Endeavor has been made, furthermore, to deal with the general com- position of foods, and to give such analytical processes as are likely to be needed by the sanitary chemist, or by the student who wishes to determine the proximate components of food materials. It has been thought best to include brief synopses of processes of manufacture or preparation of certain foods and food materials, in cases where impurities might be suggested incidental to their preparation. In view of the fact that Massachusetts was the pioneer state to adopt, over twenty years ago, a practical system of food and drug inspection, and for many years was the only state to enjoy such a system, no apology is perhaps needed for more frequent mention of Massachusetts methods and customs than those of many other states, in which the food laws are now being enforced wiih equal zeal and efficiency. Considerable attention has been paid in the following pages to the use of the microscope in food analysis. Of the figures in the text illus- vii Viii PREFACE. trating the microscopical structure of powdered tea, coffee, cocoa, and the spices, fifteen have been reproduced from the admirable drawings of Dr. Josef Moeller, of the University of Graz, Austria. Acknowledg- ment is gratefully given Dr. Moeller for his kind consent to their use. The photomicrographs in half-tone, forming the set of plates at the end of the volume, were all made in the author's laboratory, and may be divided into three classes: ist, illustrations of powdered pure foods and food products, as well as of powdered adulterants; 2d, types of adulterated foods, chosen from samples collected from time to time in the routine course of inspection; and 3d, photographs of permanently mounted sections of foods and adulterants. While recent works covering the whole field of general food analysis are comparatively few, the number of treatises, monographs, government bulletins, and articles scattered through the journals, dealing with special subjects relative to food and its inspection, is surprisingly large, and from a painstaking review of these much information has been culled, for which it has been the author's intention at all times to give credit. Special mention should here be made of the valuable publications of the U. S. Department of Agriculture, both the bulletins issued from Washington, and those from the various experiment stations, an ever- increasing number of which are becoming engaged in human food work. The author has freely drawn from these sources, and especially from the data and material furnished by his coworkers in the recent and still pending labor of preparing food methods for the Association' of Official Agricultural Chemists, and he wishes to extend his thanks to all of them for their assistance. Appreciation is also expressed for the care and discrimination shown by Mr. L. L. Poates in the preparation of the cuts. Thanks are especially due to Mr. Hermann C. Lythgoe, Assistant Analyst of the Massachusetts State Board of Health, for his invaluable cooperation, and to Dr. Thomas M. Drown for helpful hints and suggestions. Boston, Mass., July i, 1904. TABLE OF CONTENTS. CHAPTER I. Food Analysis and Official Control i- Introductory, i. Food Analysis from the Dietetic Standpoint, 2. Commercial Food Analysis, 3. Systematic Food Inspection; Functions of the Official Analyst; Standards of Purity; Nature of Analytical Methods, 3-5. Adulteration of Food, 5. Misbranding, 6. A Typical System of Food Inspection, 6-9. Practical Enforcement of Food Laws; Publication; Notification; Prosecution, 10. CHAPTER II. The Laboratory and its Equipment 12-27 Location, 12. Floor; Lighting; Ventilation; Benches, 13. Hoods, 14. Sinks and Drains, 15. Gas; Electricity; Steam, 17. Suction and Blast, 18. Apparatus, 18-24. Reagents, 24. Equivalents of Standard Solutions, 25-26. Indicators, 27. CHAPTER III. Food, its Functions, Proximate Components, and Nutritive Value 28-40 Nature and General Composition of Food; Fats, 28. Proteins; Classification of Nitrogenous Bodies, 29-34. Proteins, their Subdivisions, Occurrence, and Characteristic Tests, 29. Amino Acids, etc., 34- Bases; Alkaloids; Nitrates; Ammonia; Lecithin; Cyan Compounds, 35. Carbohydrates and their Classi- fication, 35-38. Organic Acids; Mineral or Inorganic Materials; Fuel Value of Food, 38. Calorimeters, 38-40. CHAPTER IV General Analytical Methods 41-67 Proximate Analysis; Expression of Results, 41-42. Preparation of Sample, 43. , Specific Gravity; Methods and Apparatus, 43-48. Freezing Point; Moisture, 49-50. Ash, 51. Extraction with Volatile Solvents, 52-56. Extraction with Immis- cible Solvents, 57. Nitrogen, 58-62. Protein and Amino Acid Nitrogen; Carbo- hydrates; Poisons, 63. Arsenic, 63-66. Colorimetric Analysis; Colorimeter, 66. Tintometer, 67. ix X TABLE OF CONTENTS. CHAPTER V PAGE The Microscope in Food Analysis 68-85 Microscopical vs. Chemical Analysis; Technique of Food Microscopy, 68. Apparatus and Accessories, 69-71. Preparation of Vegetable Foods for Micro- scopical Examination, 72. Microscopical Diagnosis, 73. Vegetable Tissues and Cell Contents, under the Microscope, 74-77. Microscopical Reagents, 77-80. Pho- tomicrography; Appurtenances and Methods, 80-85. Microchemical Reactions, 81. CHAPTER VI. The Refractometer 86-107 Types, 86. Butyro-refractometer, 87. Refractometer Heater, 88. Manipula- tion, 88-90. Equivalents of Refractive Indices and Butyro-refractometer Read- ings, 91-92. Temperature Correction, 93. Abbe Refractometer, 94. Construc- tion; Manipulation, 95-97. Immersion Refractometer, 97-98. Manipulation, 99-101. Equivalents of Refractive Indices and Immersion Refractometer Read- ings, 102-105. Strength of Solutions by Refractometer, 106. Temperature Cor- rections, 107. CHAPTER VII. Milk and Milk Products 108-204 Milk; Composition; Characteristics; Acidity; Microscopy, 108. Color; Fat; Lactose, 109. Proteins and other Nitrogenous Bodies, 109-110. Citric Acid; Other Organic Constituents; Enzymes, no. Composition of Milk, 111-112. Composition of Ash, 112-113. Milk of Different Animals; Fore Milk and Strip- pings, 113. Colostrum, 114. Composition as related tv. Stage of Lactation, Age, Breed, Feed, etc., 114-116. Frozen Milk; Fermentations of Milk, 116. Analysis of Milk; Sampling, 117. Specific Gravity, 118-120. Total Solids, 119-121. Ash, 121. Fat, by Extraction, by Centrifugal, and by Refractometric Methods, 121-131. Proteins; Casein, 132. Albumin; Other Nitrogenous Bodies, 133. Milk Sugar, by Optical Methods, 134-136, by Fehling's Solution, 136-138. Relation between the Various Milk Constituents; Calculation by Formulae, 138-141. Acidity, 140, Modified Milk and its Preparation, 142-144. Milk Adulteration and Inspection; Milk Standards, 144-146. Forms of Adul- teration, and Variation in Standard, 146-147. Rapid Approximate Methods of Examination, 148. Examination of Milk Serum; Constants, 149-154. Freezing Point, 153. Systematic Routine Examination, 154. Analytical Methods for Solids, Fat, and Ash, 155-158. Added Foreign Ingredients, 158. Coloring Matters and their Detection, 159-162. Preservatives, their Relative Efficiency and their Detection, 162-171. Added Cane Sugar, Starch, and Condensed Skimmed Milk, 171. Analysis of Sour Milk, 172. Homogenized Milk, 172. Analysis, 173. Pasteurized Milk; Enzyme Tests, 173-174. Fermented Milk; Kumiss, 174. Mazun; Analysis, 175. Condensed Milk; Composition, Standards, Adulteration, 175-178. Methods of Analysis, 178-183. Calculation of Fat in Original Milk, 183. Milk Powder, 184. Analysis, 185. TABLE OF CONTENTS. xi PAGE Cream; Composition, Standards, Adulterants, 186-187. Analytical Methods, 187-190. Ice Cream; Standards, 191. Classification, Ingredients, 192. Methods of Analysis, 193-196. Cheese; Composition, Varieties, 196-197. Standards; Adulteration, 198. Analytical Methods, 199-203. Protein Preparations; Casein, 203. Lactalbumin, 204. CHAPTER VIII. Flesh Foods 205-266 Meat; Structure and Components, 205-206. Proximate Composition of the Common Meats, 207-212. Meat Inspection, 207. Standards, 213. Preserva- tion; Storage, 214. Curing, 215. Antiseptics, 216. Drawn vs. Undrawn Poultry; Spoilage, 217. Effect of Cooking, 217-218. Canned Meats, 218-219. Sausages 220-222. Analytical Methods; Water, 223. Fats, 224. Nitrogenous Bodies, 225-230. Ash; Acidity, 230. Starch, 231. Horseflesh, 232. Glycogen, 233-236. Biological Tests for Horseflesh, 236. Sugars, 237. Preservatives, 238-240. CoLi- ing Matter, 240-241. Frozen Meat, 241. Meat Extracts; Manufacture, 242. Constituents, 243. Meat Juices, 244. Peptones and Seasonings, 245. Composition of Extracts, etc., 246-249. Bouillon Cubes, 250-251. Yeast Extracts, 252. Standards for Extracts, etc., 252-253. Analytical Methods, 253. Water; Ash; Fat; Nitrogen, 253. Nitrogenous Bodies, 253~257. Acidity, 257. Sugars; Glycerol; Preservatives, 258. Gelatin, 258. Fish; Structure; Composition, 259-261. Crustaceans and Mollusks, 262. Canned, Salted and Smoked Fish, 263. Floating of Shellfish, 264. Preservatives in Fish and Oysters; Colors, 265. Concentrated Foods for Armies and Campers, 265-266. CHAPTER IX Eggs 267-279 Nature; Weight, 267. Composition, 268. Shell; Membrane; Egg White, 269. Constituents, 270. Egg Yolk, 270. Constituents, 271-272. Grades of Eggs; Preservation, 272. Cold Storage, 273. Spoilage, 274. Frozen Eggs, 275. Desic- cated Eggs, 276. Analytical Methods, 276-278. Lecithin; Preservatives, 278. Egg Substitutes, 278-279. Custard Powders, 279. CHAPTER X. Cereals and their Products, Legumes, Vegetables, and Fruits 280-377 Composition of Cereals, Vegetables, Fruits, and Nuts, 280-284. Methods of Proximate Analysis, 285-288. Carbohydrates of Cereals, 288. Starch: Detec- tion, Varieties, Classification, Microscopical Examination, 288-292. Starch Determination, 292-293. Sugars, 293. Cellulose, 294. Pentosans, 294-304. Carbohydrates of Cereals, 304-305. Proteins of Cereals and Vegetables, 305-309. Proteins of Wheat, 307-309. Proteins of Other Cereals and Vegetables, 309. Ash, 310. Scheme for Ash Analysis, 311-313. Sulphur, 313. Chlorine, 314. Microscopy of Cereal Products, 314-320. xii TABLE OF CONTENTS. PAGE Flour; Milling; Composition, 320-321. Graham Flour, 322. Flour of Other Cereals, 323. Damaged Flour; Ergot, 323. Adulteration, 324-327. Alum; Bleaching, 325. Inspection and Analysis; Fineness; Color, 326-327. Absorp- tion, and Dough Tests, 327. Expansion of Dough; Baking Tests, 328-330. Ash, 330. Gluten; Gliadin, 331. Glutenin, etc., 332. Acidity; Improvers, 333. Bleaching; Nitrites, 334-335. Chlorine, 335. Bamihl Test, 336. Corn Meal; Manufacture, 337. Composition; Spoilage; Acidity, 338. Bread; Composition; Varieties, 338-340. Water; Acidity, 340. Fat; Yeast Foods, 341. Alum; Wrapping; Cake, 342. Analytical Methods, 343. Compo- sition of Cake, 343. Leavening Materials; Yeast, 343. Compressed Yeast; Dry Yeast, 344. Com- position, 345. Starch in Compressed Yeast; Microscopy, 346. Carbon Dioxide, 347- Chemical Leavening Materials, 348. Baking Powders; Classification, 349. Composition, 350-351. Adulteration, 351. Cathartics in Residue; Alum Salts; Analytical Methods; Sodium Bicarbonate, 352. Cream of Tartar, 353. Carbon Dioxide, 353-356. Tartaric Acid, 356-359. Starch, 360. Alumina; Lime; Potash; Soda, 361. Phosphoric Acid; Sulphuric Acid; Ammonia; Arsenic; Lead, 362. Semolina and Edible Pastes, 363. Macaroni, etc.; Noodles, 364. Adulteration, 365. Analytical Methods; Lecithin-Phosphoric Acid, 366. Colors, 366-369. Cereal Breakfast Foods; Nature and Composition, 369-371. Infants' and Invalids' Foods, 371. Preparation, 372. Composition, 373. Dia- betic Foods, 373-375- Analytical Methods, 375-377. CHAPTER XI. Tea, Coffee, and Cocoa 378-421 Tea; Varieties; Method of Manufacture, 378. Compositions, 379-381. Analyt- ical Methods, 381. Protein; Ash; Essential Oil; Insoluble Leaf, 382. Extract, 383. Tannin, 383-385. Theine, or Caffeine, 385-387. Facing, 387. Spent Leaves; Foreign Leaves, 388. Stems and Fragments, 389. Astringents; Tea Tablets, 390. Microscopy, 391. Coffee; Nature; Constituents, 392. Composition, 393-395. Substitutes and Adulterants, 395. Analytical Methods, 395. Caffetanic Acid, 395-396. Caffeine; Adulteration, 397. Imitation Coffee; Coloring; Glazing; Methods, 398. Micros- copy, 399. Chicory; its Microscopical Structure, 400-402. Composition of Chicory, and its Detection in Coffee, 402-403. Date Stones, 403. Hygienic Coffee, 404-405. Substitutes, 406. Cocoa and Cocoa Products, 406. Manufacture, 407. Composition, 407-409. Theobromine and Nitrogenous Substances; Pentosans, 410. Milk Chocolate; Compounds, 410. Analytical Methods; Moisture; Ash, 411. Protein; Casein, 412. Theobromine and Caffeine, 413. Crude Fiber; Reducing Matters, 414. Starch; Pentosans; Sucrose; Lactose, 415. Cocoa Red, 416. Adulteration, and Standards, 417. Addition of Alkali; Microscopy, 418-419. Cocoa Shells; Added Starch, Sugar, Fat and Colors, 420-421. ♦ TABLE OF CONTENTS. xiii CHAPTER XII. PAGE Spices 422-485 Nature; Adulteration; General Methods of Proximate Analysis, 422. Moisture; Ash, 423. Ether, and Alcohol Extract; Nitrogen, 424. Starch; Crude Fiber; Volatile Oils, 425. Microscopy, 426. Spice Adulterants, 426-427. Cloves; Composition, 426-429. Tannin, 429. Microscopy, 430-431. Stand- ards; Adulterants; Clove Stems; Exhausted Cloves, 432. Cocoanut Shells, 433. Allspice; Nature, 434. Composition; Tannin, 435. Microscopy, 436-437. Standards; Adulteration, 438. Cassia and Cinnamon; Nature, 438-439. Composition, 439-440. Microscopy, 440-442. Standard; Adulterants; Foreign Bark, 442. Pepper; Nature, 442. Composition, 443-446. Nitrogen Determination, 446. Piperin, 447. Microscopy, 447-449. Standards; Adulteration, 449. Pepper Shells and Dust, 449. Olive Stones, 450. Buckwheat, 451. Long Pepper, 452. Red Pepper (Cayenne, Paprika, etc.); Nature, 452-453. Constituents, 454. Composition, 455-458. Microscopy, 458-460. Adulteration, 460-462. Added Oil in Paprika, 461. Ginger; Nature, 462. Composition, 463-464. Exhausted Ginger, and its Detection, 464-465. Microscopy, 465. Standards; Adulteration, 466. Turmeric; Nature; Composition, 467. Microscopy, 468. Mustard; Nature, 469-470. Composition, 471-473. Analytical Methods; Potassium Myronate; Sinapin Thiocyanate; Myrosin; Volatile Oil, 473-474. Microscopy, 475. Standards; Adulteration, 476. Wild Mustard, 476-477. Coloring Matter, 478. Prepared Mustard; Composition, Adulteration, 478-479. Analytical Methods, 479. Nutmeg and Mace; Nature, 480. Composition of Nutmeg, 480-481. Micros- copy, 481. Standards; Adulteration, 482. Composition of Mace, 482-483. Microscopy; Standards; Adulteration, 484. Bombay or Wild Mace and its Detection; Macassar Mace, 484-485. CHAPTER XIII. Edible Oils and Fats 486-585 Constituents; Solubihties, 486. Fatty Acids, 486-487. Saponification, 487. Hydrogenation; Analytical Methods; Judgment of Purity, 488. Rancidity; Filter- ing; Weighing; Measuring, 489. Specific Gravity, 490-492. Viscosity, 492. Refraction, 493-495. Melting Point, 496-497. Reichert-Meissl Process for Volatile Fatty Acids, 497-499. Polenske Number, 499-500. Soluble and Insol- uble Fatty Acids, 501-503. Saponification Number, 503-504. Iodine Absorption Number; Hiibl Method, 504-507. Hanus Method, 50S. Wijs Method, 509. Bromine Absorption Number, 509-510. Thermal Tests, 510. Maumene Test, 511. Bromination Test, 511-514. Acetyl Value, 514-516. Valenta Test, 516. Elaidin Test, 517. Free Fatty Acids, 518. Titer Test, 518-520. Unsaponifiable Matter, 520. Cholesterol and Phytosterol, 520-521. Separation and Crystallization, 522-525. Bomer Phytosterol Acetate Test, 525-526. Paraffin; Microscopy, 527. Constants of Edible Oils and Fats, 527-529. Olive Oil; Source, 530. Nature; Composition; Substitutes, 531. Standards, 531-532. Tests for Adulteration, 532-535. Cottonseed Oil; Source; Nature; Composition, 535. Standards; Bechi Test, 536. Halphen Test, 537, Sesame Oil, 537. Adulterants; Tocher xiv TABLE OF CONTENTS. Test; Baudonin Test; Vlllavechia and Fabric Test, 538. Rape Oil, 539. Mustard Oil; Charlock Oil, 540. Corn Oil, 541. Sitosterol, 542. Peanut Oil; Composi- tion; Standards; Adulterants, 542. Renard Test, 543-544. Bellier Test, 544- 545. Soy Oil, 545. Composition; Tests, 546. Linseed Oil, 547. Poppyseed Oil, 547. Sunflower Oil, 547-548. Rosin Oil, 548-549. Cocoanut Oil, 549. Palm Kernel Oil; Cocoa Butter; Tallow, 550. Butter, 551. Composition, 551-552. Effects of Feeding; Analytical Methods, 552. Water, 553-555. Fat; Casein, 555. Ash; Lactose; Salt; Standards, 556. Colors, 557-559. Preservatives, 560-562. Reno\ated or Process Butter, 563. Oleomargarine, 563. Oleo Oil, 564. Coloring; Detection of Palm Oil, 565. Adulterants, 566. Healthfulness; Distinction from Butter, 567-571. Distinguish- ing Tests for Butter, Process Butter, and Oleomargarine, 571. Foam Test, 572, Milk Test, 573. Curd Tests, 574. Microscopical Examination, 574-576. Nut Butter, 576. Lard; Nature, 577. Constants, 578. Effects of Feeding; Oily Hogs; Standards; Lard Oil, 579. Compounds; Substitutes; Adulterants, 580-582. Analytical Methods, 582. Beef Fat, 582-583. Various Oils-,. Nickel in Hydrogenated Sub- stitutes, 584. Paraffin, 585. CHAPTER XIV. Sugar and Saccharine Products 586-681 Nature; Classification, 586. Cane Sugar; Standard, 587. Sugar Cane; Manu- facture of Cane Sugar, 588. Composition of Cane Sugar Products, 589. Sugar Beet; Manufacture of Beet Sugar, 590. Refining Sugar; Maple Products, 591. Com- position, Standards, and Adulteration of Maple Products, 592-594. Sorghum, 595. Grape Sugar; Levulose, 596. Malt Sugar; Dextrin; Commercial Glucose, 597- 598. Standards and Healthfulness of Glucose; Milk Sugar, 599. Raffinose, 600. Polariscope, 600. Saccharimeter, 600-606. Comparison of Scales and Normal Weights, 606. Specific Rotary Powers, 607. Birotation, 608. ! Analysis of Cane Sugar and its Products; Tests for Sucrose, 608. Moisture; Ash; Non-sugars, 609. SucroseDeterminationby Polariscope, 610-613. Inversion; Clerget's Formula, 611. Detection and Determination of Invert Sugar; Ultra- marine in Sugar, 613. Copper Reduction, 614. Volumetric Feliling Process, 615-617. Gravimetric Fehling Methods, 617. Defren-O'Sullivan Method, 618- 621. Munson and Walker Method, 622-631. Allihn Method, 632-634. Elec- trolytic Apparatus, 634-637. Meissl and Hiller Invert Sugar Method, 637-641. Sucrose Determination by Fehling Solution, 642. Analysis of Molasses and Syrups, 642. Solids; Ash; Polarization, 643-650. Double Dilution Method of Polarizing; Raffinose Determination, 650. Adultera- tion of Molasses and Standards, 651. Glucose Determination, 651-654. Ashing Saccharine Products, 654. Tin Determination, 655. Separation and Determination of Various Sugars, 655, 656. Analysis of Maple Products; Moisture, 656. Ash; Malic Acid Value, 657. Lead Number, 658. Hortvet Number, 659-660. Sy's Method, 660. Snell Elec- trical Conductivity Method, 661. Analysis of Glucose; Polarization Formulae, 661-662. Dextrin; Ash; Sulphurous Acid; Arsenic, 663. Honey; European; Canadian, 664. American; Hawaiian, 665-666. Cuban; Mexican; Haitian, 667. Adulteration, 668-669. TABLE OF CONTENTS. XV PAGE Analysis of Honey; Moisture, 670. Ash; Polarization; Reducing Sugar; Levulose, 671. Dextrose; Sucrose; Dextrin, 672. Acids; Glucose, 673. Invert Sugar; Distinction of Honeydew from Glucose, 674. Beeswax, 675-676. Confectionery; Standard; Adulteration; Colors, 677. Analytical Methods; Mineral Matter; Lead Chromate, 678. Ether Extract; Paraffine, 679. Starch- Polarization, 680 Alcohol; Colors; Arsenic, 681. CHAPTER XV. Alcoholic Beverages 682-787 Alcoholic Fermentation, 682. Alcoholic Liquors and State Control, 683. Liquor Inspection, 684-686. Analytical Methods Common to all Liquors; Specific Gravity, 686. Detection and Determination of Alcohol, 686-689. Alcohol Tables, 690-703! The Ebullioscope, 704-705. Extract; Ash; Artificial Sweeteners, 706. Fermented Liquors; Cider, 707. Manufacture, 707-708. Composition, 708-711. Adulteration, 711. Perry, 712. Wine; Manufacture, 713. Classification; Varieties, 714-715- Constituents, 715-716. Composition, 716-718. Standards, 716-720. Adulteration, 720. Plastering; Cane Sugar, 721. Watering, 722-723. Fortification, 723-724. Pomace Wine; Piquette, 724. Various Adulterants; Fruit Wines, 725. Analytical Methods; Extract; Acidity, 726. Volatile Acidity, 726, 731- Extract Table, 727-729- Tartaric Acid, 731-732. Lactic Acid, 732-733! Sugars; Glycerol, 734. Sulphates; Chlorides; Nitrates; Tannin, 735. Foreign Colors, 736-737- Malt Liquors; Beer; Malting, 738. Brewing; Varieties of Beer and Ale, 739. Composition, 740-741- Malt and Hop Substitutes, 741. Adulteration and Standards, 742-743- Malted vs. Non-malted Liquors, 743-744. Malt vs. Substi- tutes, 744-745- Preservatives; Arsenic; Temperance Beers, 746. Analytical Methods; Alcohol, 747. Extract, 747-755- Original Gravity, 754-756. Sugars; Dextrin; Glycerol, 756. Acids; Proteins; Phosphoric Acid, 757. Carbon Dio.xide, 758. Bitter Prmciples, 759-760. Arsenic, 760; Malt Extract, 761-762. Distilled Liquors, 762. Standards for Spirits, 763. Fusel Oil, 763-764. Whiskey, 764. Manufacture, 764-765- Standards, 765-767. Composition, 767-770! Adulteration, 770-771- Brandy, 771. Manufacture, 771. Composition; Stand- ards, 772. Adulteration, 773. Rum; Composition; Standards, 774-775. Gin; Composition, 776. Analytical Methods; Extract; Acids; Esters; Aldehydes! 777- Furfural, 778. Fusel Oil, 778-781. Methyl Alcohol, 781-784. Caramel! 784-785. Opalescence Test, 785. Liqueurs and Cordials, 786. Composition; Analytical Methods, 787. CHAPTER XVI. V^^^^^^ 788-811 Acetic Fermentation; Varieties of Vinegar, 788. Manufacture, 789. Compo- sition, 790. Cider Vinegar, 790-791- Wine Vinegar, 792. Malt Vinegar, 792- 793- Spirit, Glucose, and Molasses Vinegars, 794. Wood Vinegar; Analytical Methods; Density; Extract; Ash; Phosphoric Acid, 795. Nitrogen; Acidity, 796. Alcohol; Mineral Acids, 797-798. Malic Acid, 798. Lead Precipitate, 799! Acid Potassium Tartrate; Sugars, 800-801. Pentosans, 801. Glycerol, 801-803. Adulteration of Vinegar; Standards, 803-804. Artificial Cider Vinegar, 805. xvi TABLE OF CONTENTS. PAGE Character of Residue and Ash, 805-806. Character of Sugars, 807. Glycerol, 808. Direct Tests, 808-809. Composition of Artiucial Cider Vinegars, 809. Detection of Adulterants, and Metallic Impurities, 810-81 1. CHAPTER XVII. Artificial Food Colors 812-875 Extent of Use; Objectionable Features, 812. Toxic Effects, 813-814. Harm- ful and Harmless Colors, 815. Mineral Colors; Detection, 816. Lakes; Detection, 817. Vegetable and Animal Colors, 817. Dyeing Tests; Reactions on Fiber, 818-819. Extraction with Immiscible Solvents, 818-820. Reactions in Aqueous Solution and with Sulphuric Acid, 820-823. Special Tests; Orchil; Logwood; Turmeric; Caramel, 821. Indigo; Cochineal, 824. Coal-tar Colors, 824. Allowed Colors, 825-826. Examination of Coal-tar Food Colors, 826. Analytical Schemes, 827. Rota Scheme, 827-832. Separa- tion and Identification of Allowed Colors, 833-836. Quantitative Separation of Acid Colors, 836-839. Analysis of Colors, 839. Spectroscopic Examination, 840. Detection of Coal Tar Colors in Foods, 840. Basic and Acid Dyes; Wool Dyeing Methods, 841-842. Extraction with Amyl Alcohol, 843. Extraction with Acetic Ether; Separation with Ether; Extraction of Dried Residues, 844. Special Tests, 844-845. Loomis Scheme, 845-852. Reactions of Dry Colors or Dyed Fibers, 853. Mathewson's Tables, 854-858. Mathewson Method for Separation by Immiscible Solvents and Identification, 859-867. Mathewson's Tables, 868-875. CHAPTER XVIII. Food Preservatives 876-904 Preservation of Food, 876. Regulation of Antiseptics, 877. Commercial Food Preservatives, 878-879. Formaldehyde, 879. Determination in Preservatives, 880. Detection in Food, 881-882. Determination, 883. Boric Acid, 883. Deter- mination in Preservatives, 884-885. Detection in Foods, ^885-886. Determina- tion, 886-887. Salicylic acid, 887. Detection, 8S8-889. Determination, 890. Benzoic Acid; Sodium Benzoate, 890. Detection, 891-893. Determination, 893- 896. Sulphurous Acid, 896. Detection; Determination, 897-898. Formic Acid, 898. Detection, 899. Determination, 900-901. Fluorides, Fluosilicates, Fluo- borates, 901. Detection, 902. Beta-Naphthol; Detection, 903. Asaprol or Abrastol, 903. Detection, 904, CHAPTER XrX. Artificial Sweeteners 905-910 Extent of Use; Saccharin, 905. Detection of Saccharin, 906-907. Deter- mination, 907-908. Dulcin; Detection, 90S 909. Determination of Dulcin, 909-910. Glucin, 910. TABLE OF CONTENTS. xvii CHAPTER XX. PAGE Flavoring Extracts and their Substitutes 911-956 Vanilla Extract, 911. Vanilla Bean, 911-912. Composition, 912. Vanillin; Exhausted Vanilla Beans; Preparation of Vanilla Extract, 913. Composition of Vanilla Extract, 914-916. Tonka Bean; Coumarin; Standards; Adulteration of Vanilla Extract, 917. Artificial Extracts, 918. Analytical Methods; Detection of Artificial Extracts, 919. Determination of Vanillin and Coumarin, 920-923. Tests for Coumarin, 923-924. Vanillin and Coumarin under the Microscope, 924. Normal Lead Number, 925. /Vcetanilide, 925-926. Glycerol; Alcohol; Caramel, 926. Acidity; Colors, 927. Lemon Extract, 927. Standards, 927-928. Adulteration, 928-929. Analytical Methods, 929. Determination of Lemon Oil, 929-932. Alcohol, 932. Total Aldehydes, 933-934. Citral, 934-935. Methyl Alcohol, 935. Colors; Solids; Ash, 936. Glycerol; Examination of Lemon Oil, 937. Constants of Lemon and other Oils, 938. Citral, Citronellal, and other Adulterants, 938-939. Lemon Oil; Analytical Methods: Density; Refraction; Rotation, 939. Citral; Aldehydes; Physical Constants, 940. Pinene; Alcohol, 941. Orange Extract; Standards, 941-942. Analytical Methods, 942. Almond Extract; Oil of Bitter Almonds, 942. Benzaldehyde; Standards; Adulteration, 943. Analytical Methods; Determination of Benzaldehyde, 944-945. Nitro- benzol; Distinction and Separation from Benzaldehyde, 945-946. Artificial Benzal- dehyde; Alcohol; Hydrocyanic Acid, 946. Wintergreen Extract; Standards; Adulteration, 947. Determination of Wintergreen Oil; Peppermint Extract; Peppermint Oil, 948. Standards; Analytical Methods, 949. Spearmint Extract, 949. Spice Extracts; Standards, 949-951. Analytical Methods, 951-953. Rose Extract; Standards; Determination of Rose Oil, 953. Imitation Fruit Flavors, 954-956. Determination of Esters, 956, CHAPTER XXI. Vegetable and Fruit Products 957-1020 Canned Vegetables and Fruits; Method of Canning, 957-958. Composition, 959. Decomposition; Swells; Springers, 960. Metallic Impurities, 961. Action of Fruit Acids on Tin Plate, 961-964. Action of Fruits and Vegetables on Differ- ent Weights of Tin Coating, 964-965. Salts of Lead, 965. Salts of Zinc, 966. Salts of Copper, 967-968. Salts of Nickel, 968. Toxic Effects of Metallic Salts; Preservatives, 969. Soaked Goods; Analytical Methods; Gases from Spoiled Cans, 970. Drained Solids, 971. Tin and Lead in Tin Plate and Alloy, 972. Tin, Copper, Lead, Zinc, and Nickel, 973-977. Ketchup; Standards, 977. Process of Manufacture; Composition, 978. Decayed Material; Refuse, 978-980. Foreign Pulp; Preservatives; Colors, 980. Analytical Methods; Solids; Sand, 981. Sugars; Citric Acid, 982. Lactic Acid, 983. Micro- scropy, 984. Pickles, 984. Composition, 985. Adulteration; Horseradish, 986. Preserves; Fruit Butter, 986. Mince Meat; Pie Filling, 987. Maraschino Cher- ries, 988-989. Jams and Jellies, 989. Composition; Adulteration, 990-993. Compounds; Imitations, 994-995. .'Vnalytical Methods, 995. Solids; Ash; Acidity, 996. XVlll TABLE OF CONTENTS. Protein, 997. Sugars, 997-999. Glucose; Dextrin, 999. Alcohol Precipitate; Colors, 1000. Preservatives; Sweeteners; Starch; Gelatin, looi. Agar-agar; Apple Pulp; Fruit Tissues, 1002. Dried Fruits, 1002. Lye Treatment; Sulphuring, 1003. Moisture; Spoilage; Zinc, 1004. Fruit Juices; Composition, 1004. Grape Juice, 1005. Sweet Cider, 1006. Lime Juice, 1006-1007. Analytical Methods; Acidity, 1007. Tartaric and Malic Acids, 1008-1009. Citric Acid, 1009-1010. Fruit Syrups, loio-ioii. Non-Alcoholic Carbonated Beverages; Soda Water, loii. Syrups, 1012. Bottled Beverages, 1012-1013. Sweeteners; Acids; Preservatives, 1013. Colors, Foam Producers; Habit-forming Drugs, 1014. Analytical Methods, 1014. Solids; Ash; Acids; Sugars; Flavors; Colors; Preservatives; Sweeteners; Alcohol, 1015. Saponin, 1015-1017. Caffein; Cocaine, loi 7-1020. CHAPTER XXn. Determination of Acidity by Means of the Hydrogen Electrode 1021-1039 Practical Value, 1021. Principle of Method, 1022-1023. Theory of Method, 1024. Apparatus, 1025-1026. Hydrogen Electrode, 1027. Calomel Electrode, 1028. Electrical Instruments, 1029. Titration, 1030. Typical Curves, 1030-1033. Titration of Milk, 1033-1034. Tea and Coffee, 1035. Acidity of Fruit Juices, 1035-1038. Effects of Ripening, 1038-1039, APPENDIX. The Food and Drugs Act, 1041. The Meat Inspection Law, 1045. TABLE OF CONTENTS xix PLATES I-XL. Photomicrographs of Pure and Adulterated Foods and of Adulterants. Cereals: Barley, I. Buckwheat, II, III. Corn, III, IV. Oat, IV, V. Rice, V, VI. Rye, VI, Vn. Wheat, VIII. Legtimes: Bean, IX. Lentil, IX, X. Pea, X, XL Miscellaneous Starches: Potato; Arrowroot; Tapioca, XII. Turmeric; Sago, XIII. Coffee, XIV, XV. Chicory, XV, XVI. Cocoa, XVI, XVII. Tea, XVIII. Spices: Allspice, XVIII, XIX. Cassia, Cinnamon, XX-XXII. Cayenne, XXII- XXIV. Cloves; Clove Stems, XXIV-XXVII. Ginger, XXVII-XXIX. Mace, XXIX. Nutmeg, XXX. Mustard, XXXI-XXXIII. Pepper, XXXIII-XXXVI. Spice Adulterants: Olive Stones; Cocoanut Shells, XXXVL Elm Bark; Sawdust; Pine Wood, XXXVII. Edible Fats: Pure Butter; Renovated Butter; Oleomargarine, XXXVIII. Lard Stearin, XXXIX. Beef Stearin, XL. PLATE XLI. Minimum Percentages of Alcohol in Wines Corresponding to Halphen Ratios. FOOD INSPECTION AND ANALYSIS. CHAPTER I. FOOD ANALYSIS AND OFFICIAL CONTROL, INTRODUCTORY. The general subject of food analysis, in so far as the public health is concerned, is to be considered from two somewhat different standpoints: first, from the outlook of the government, state, or municipal analyst, whose mission it is to ascertain whether or not the food may properly be con- sidered pure or free from aduUeration; and second, from the point of view of the food economist, whose aim is to determine its actual composition and nutritive value. The one protects against fraud and injury, the other furnishes data for the arrangement of dietaries and for an intelUgent conception of the role which the various nutrients play in the metaboHsm of matter and energy in the body. The two fields are as a rule distinct each from the other, often • involving, in the examination of the food, different methods of procedure. Official Control of Food.— In view of the importance of the consideration of food with reference to its purity, an ever-increasing number of states have realized the necessity of protecting their citizens from the unscrupu- lous manufacturers who in various lines are seeking to produce cheaper or inferior articles of food in close imitation of pure goods. Many of the states have laws in accordance with which the sale of such impure or aduherated foods is made a criminal offense, and some, but not all of these, are provided with public analysts and other officers to enforce these laws and punish the offenders. Numerous communities are awake to the importance of municipal control of such commonly used articles of food as milk, butter, and vinegar, and in many cases have machinery of their own for regulating the sale of these foods. 2 FOOD INSPECTION AND ANALYSIS. Since January i, 1907, the federal government has been actively en- gaged in the enforcement of the national food law of June 30, igo6, through the Bureau of Chemistry of the U. S. Department of Agriculture. In addition to the central laboratories of this Bureau at Washington, a num- ber of branch laboratories have baen established in the principal cities of the United States to enforce the provisions of the national law which regu- lates interstate commerce in foods, as well as their manufacture and sale in the territories and the District of Columbia, and their importation from foreign countries. Food Analysis from the Dietetic Standpoint. — The study of the prin- ciples of dietetics has been given increased attention during the last decade in the curricula of many of the technical schools and colleges. Much has been accomplished by certain of the state experiment stations working as a rule in connection with the United States Department of Agriculture along this line. Investigations of this character are especially valuable, and are indeed rendered necessary by the general tendency of the modern physician to regard the hygienic treatment of disease, especially with reference to the matter of diet, as often of far greater importance than the mere administering of drugs. The food economist studies the varying conditions of age, sex, occupa- tion, environment, and health among his fellow men, with a view to show- ing what foods are best adapted to supply the special requirements of various classes. The quantity and proportion of protein, fat and carbo- hydrates, or of fuel value best suited for the daily consumption of a given class or individual having been determined, dietaries are made up from various food materials to supply the need with reference as far as possible to the taste and means of the consumer. Experiments are made on famihes, clubs, or individuals, representing various typical conditions of life, and extending over a given period, dur- ing which records are kept of the available food materials on hand and received during the term of the experiment, as well as of those remaining at the end. In the case of individuals, additional records may be kept of the amount and composition of the urine and feces. From such data the physiological chemist calculates the amount of nutrients utilized, and studies the metabolism of material in the human body. Up to this point no very extensive apparatus is required, but if in addition the incone and outgo of heat and energy are to be studied, which are important to a complete investigation of the economy of food in the body, the student will require a respiration calorimeter and its appurtc- FOOD ANALYSIS AND OFFICIAL CONTROL. 3 nances. The calorimeter is so constructed that an individual may be confined therein for a term of days under close observation and with carefully regulated conditions. Such an equipment involves a large expenditure and is to be found in but few laboratories. It is not the purpose of the present work to go beyond the strictly chemical or physical processes involved in making the analyses by which the proximate components of the foods are determined. For more com- plete information in the field of dietary studies and the metabolism of matter and energy in the body, the student is referred especially to the investigations of Atwater and his co-workers, as published in the annual reports of the Storrs Experiment Station at Middletown and in the bulle- tins of the U. S. Department of Agriculture, Office of Experiment Stations, also to studies conducted by Benedict of the Carnegie Institution. Commercial Food Analysis. — The proper preparation of food products has long ceased to be carried on by the hap-hazard rule-of-thumb methods that formerly prevailed. Now in the manufacture of many prepared foods and condiments, especially on a large scale, it has become a necessity to use scientific processes, rendered possible only by the employment of skilled chemists. In fact it is coming to be more and more common for food manufacturers to establish chemical laboratories in connection with their works, in the interests both of economy and of improved production. Frequently disputed points arise in the enforcement of the food laws that render the services of the private food analyst of great importance both to manufacturer and dealer. Thus a wide field is open to the analyst of foods outside the domain of the government or state laboratory, either in connection with the large food manufacturing plants directly, or m private laboratories for experimental research, or for analytical control work. SYSTEMATIC FOOD INSPECTION. Functions of the Official Analyst. — The public analyst is employed by city, state, or government to pass judgment on various articles of food taken from the open market by purchase or seizure, either by himself or by duly authorized collectors employed for the purpose. The sole object of his examination is to ascertain whether or not such articles of food con- form to certain standards of purity fixed in some cases by special law, and in others by common usage or acceptance. Such a public analyst need not concern himself with the dietetic value of the food or whether it is of high or low grade. It is for him to determine simply whether it is genuine or 4 FOOD INSPECTION AND ANALYSIS. adulterated within the meaning of the law, and, if adulterated, how and to what extent. Aside from his skill as a chemist, it is often necessary for him to possess other no less important qualifications, chief among which are his ability to testify clearly and concisely in the courts, and to meet at any time the most rigid kind of cross-examination, it being of the utmost importance that he understand thoroughly the nature of evidence. Standards of Purity for Food Products.* — Under an act of Congress approved March 3, 1903, standards of purity for certain articles of food have been established as official standards for the United States by the Secretary of Agriculture. The earlier of these standards were formulated under the Secretary's direction by a committee of the Association of Official Agricultural Chemists. Later, however, a joint committee of that asso- ciation and of the association composed of state and national food officials has had charge of this work and still later a joint committee of these organ- izations and the Bureau of Chemistry. Standards have been adopted, covering the entire range of food products. Nature of the Analytical Methods Employed. — Since usually only a small number of the samples submitted are adulterated, the analyst should, as quickly as possible, separate the pure from the impure, so as to con- centrate his attention on the latter. The nature of the processes by which this is done varies with the foods. Experience soon enables one to judge much by even the characteristics of taste, appearance, and odor, though such superficial indications should be used with discretion. One or two simple chemical or physical tests may often suffice to establish beyond a doubt the purity of the sample, after which no further atten- tion need be paid to it. A sample failing to conform to the tests of a genuine food must be carefully examined in detail for impurities or adulterants. While in most cases usage or experience suggests the forms of adulteration peculiar to various foods, the analyst should be on the alert to meet new conditions constantly arising. His methods are largely qualitative, since technically he need only show in most cases the mere presence of a forbidden in- gredient, though for the analyst's own satisfaction 'he had best deter- mine the amount, at least approximately. In reporting approximate quantitative results in court, especially when they are calculated from assumed or variable factors, or when they are the result of judgment based on the appearance of the food under * U. S. Dept. of Agric, Ofif. of Sec, Circ. 19. FOOD ANALYSIS AND OFFICIAL CONTROL 5 the microscope, the analyst should always be conservative in his figures by expressing the low^est or minimum amount of the adulterant, so as to give the defendant the benefit of any doubt. When exact standards are fixed by law, as in the case of total solids or fat in milk, for example, there is of course great necessity for preciseness in quantitative work. A full analysis of an adulterated food beyond establishing the nature and amount of the adulteration is entirely unnecessar}', and in most instances adds nothing to the strength of a contested case, as twenty years' experience in the enforcement of the food laws in Massachusetts has shown. The responsibility resting upon the analyst is not to be lightly con- sidered, when it. is realized that his judgment and findings constitute the basis on which court complaints are made, and the payment of a fine or even the imprisonment of the defendant may be the result of his report. Therefore he should be sure of his ground, knowing that his results are open to question by the defendant. Where court procedure is apt to be involved, a safe rule is for the analyst to consider himself the hardest person to convince that his tests are unquestionable, making every possible confirmatory test to strengthen his position and consulting all available authorities before expressing his opinion; and finally, after being fully convinced that a sample is adulterated, and having so alleged, let him adhere to his statements and not waver in spite of the most rigid cross- examination to which he may be subjected. While each state or municipality has its own peculiar code of regula- tions and restrictions concerning the duties of the analyst and other officials, these rules are in the main very similar. For instance, it is usually neces- sary, excepting in the case of such a perishable food as milk, for the analyst to reserve a portion of a sample before beginning the analysis, which sample, in the event of proving to be adulterated, shall be sealed, so that in case a complaint is made against the vendor, the sealed sample may, on application, be delivered to the defendant or his attorney. Adulteration of Food. — Except in special cases a food in general is deemed to be adulterated if anything has been mixed with it to reduce or lower its quality or strength; or if anything inferior or cheaper has been substituted wholly or in part therefor; or if any valuable constituent has been abstracted wholly or in part from it ; or if it consists wholly or in part of a diseased, decomposed, or putrid animal or vegetable sub- stance; or if by coloring, coating, or otherwise it is made to appear of greater value than it really is; or if it contains any added poisonous 6 FOOD INSPECTION AND ANALYSIS. ingredient. These provisions briefly expressed are typical of the general food laws adopted by most states and by the government, though the verbiage may differ. Laws covering compound foods and special foods vary widely with the locality. As to the character of adulteration, nine out often adulterated foods are so classed by reason of the addition of cheaper though harmless ingredients added for commercial profit, rather than by the addition of actually poisonous or injurious substances, though occasional instances of the latter are found. Authentic instances of actual danger to health from the presence of injurious ingredients are extremely rare, so that the question of food adulteration should logically be met largely on the ground of its fraudu- lent character. Indeed the commoner forms of adulteration are restricted to a comparatively small number of food products, the most staple articles of our food supply, such as sugar and the cereals, eggs, fresh meat, fresh vegetables and fruit being less often subject to adulteration. Misbranding.—Under the federal food law and the laws of many of the states misbranding constitutes an offense as well as adulteration. By misbranding is meant any untrue or deceptive statement or design on the label of a food package, either regarding the nature of the contents, or of the place of manufacture or name of manufacturer. One of the com- monest forms of misbranding consists in the incorrect statement of weight or measure. Extravagant and untrue claims as to nutritive value have hitherto constituted a frequent form of misbranding. A Typical System of Food Inspection. — The efficiency of a system of public food inspection is greatly enhanced if the business part of the work, including the bookkeeping and attending to the outside public, be done wholly through some person other than the analyst, as, for example, a health officer, to whom the collectors of samples and the analyst may report independently as to the results of their work, and whose duty it is to determine what shall be done in cases of adulteration. In this way the analyst knows nothing of the data of collection nor the name of the person from whom the sample was purchased, so that he can truthfully state in court that his analysis was un4 biased. Suppose, for example, that three collectors are employed to purchase samples of food for analysis, their duties being to visit at irregular intervals different portions of a state or municipality. Each collector keeps a book in which he enters all data as to the collection of the sample, includ- FOOD AN.\LYSIS AND OFFICIAL CONTROL. Fig. I.— Inspectors' Lockers. Insuring safe legal delivery of samples collected by Inree inspectors. Each locker has a door in the rear accessible, from an anteroom, to the in- spector holding key to that locker only. FOOD INSPECTION AND ANALYSIS. &i)o FJD Fio. 2. — Inspectors' Lockers. Front View. The lockers are accessible to the analyst in the laboratory bv a single sUding-sash front, provided with a spring lock. The removable sliding-racks are convenient for returning clean sample bottles. FOOD ANALYSIS AND OFFICIAL CONTROL. 9 ing the name of the vendor, assigning a number to each sample, which number is the only distinguishing mark for the analyst. One collector may use for this purpose the odd numbers in succession from i to 9999, the second the even numbers from 2 to 10,000, while the third may use the numbers from 10,000 up. Each of the two former would begin with a lettered series, as, for instance, A, numbering his samples lA, 3 A, 5 A, 7 A, etc., or 2A, 4A, 6A, etc., till he reached 10,000, then beginning on series B and so on. If the analyst is to be kept in ignorance of the brand or manufacturer in the case of package goods, the collector must remove from the original package sufficient of the sample for the needs of the analyst, and deliver it to the latter in a plain package, bearing simply the name under which the article was sold and the number. Such precau- tions are, however, not always practicable and depend largely on local regulations. The analyst reports the result of the analysis of each sample with the number thereof on a library card, with appropriate blanks both for data of analysis and for data of collection, the latter to be filled by the collector from his book after the analyst has handed in the card with the data of analysis. This system of recording and reporting analyses has been successfully used for years by the Department of Food and Drug Inspection of the Massachusetts State Board of Health. Legal Precautions. — The laboratory of the public analyst should preferably be provided with a locker for each collector, to which access may be had only by that collector and the analyst, so that in the absence of the latter, or when circumstances are such that the samples cannot be delivered to him personally, there may be such safeguards with respect to lock and key as to leave no question in the courts as to safe delivery and freedom from accidental tampering. With such a system it is un- necessary for the collector to place under seal the various samples sub- mitted for analysis. Unless such lockers or their equivalent are employed, it is best to carefully seal all samples. Such a system of lockers for use with three collectors is shown in Figs. I and 2. The same careful attention should afterwards be given to keep the specimens in a secure place both before and during the process of analysis, and to label with care all precipitates, filtrates, and solutions having to do with the samples, especially when several processes are being simultaneously conducted, in order that there may be no doubt whatever as to their identity. The importance of precautions of this kind in connection with court work can hardly be too strongly emphasized. 10 FOOD INSPECTION AND ANALYSIS. Practical Enforcement of the Food Law. — In the case of foods actually found adulterated, there are three practical methods of suppressing their further sale, viz., by publication, by notification, and by prosecution. These may be separately employed or used in connection with each other, accord- ing to the powers conferred by law on the commission, board, or official having in charge the enforcement of the law, and according to the dis- cretion of such official. Publication. — Under the laws of some states, the only means of pro- tecting the people lies in publishing lists of adulterated foods with their brands and manufacturers' names and addresses in periodical bulletins or reports. Sometimes it is considered best to publish for the informa- tion of the pubHc lists of unadulterated brands as well, and, again, it is held that only the offenders should thus be advertised. Such pubhcation, by keeping the trade informed of the blacklisted brands and manufacturers, certainly has a decidedly beneficial effect in reducing adulteration, and involves less trouble and expense than any other method. It is obviously an advantage, however, in addition to this to be able in certain extreme cases to use more stringent methods when necessary. Notification and Prosecution. — The adulteration of food is best held in check in localities where under the law cases may be brought in court and are occasionally so brought. The mere power to prosecute is in itself a safeguard, even though that power is not frequently exercised. Under a conservative enforcement of the law, actual prosecution should be made as a last resort. Neither the number of court cases brought by a food commission nor the large ratio of court cases to samples found adulterated are criteria of its good work. Except in extreme cases, it is frequently found far more effective to notify a violator of the law, especially if it is a first offense, giving warning that subsequent infraction will be followed by prosecution. Such a notification frequently serves to stop all further trouble at once and with the minimum of expense. Instances are frequent in Massachusetts where, by such simple notifica- tion, widely distributed brands of adulterated foods have been immediately withdrawn from sale. Massachusetts was the first of all the states to enact pure-food legisla- tion, and since the year 1883 has had a well-established system of inspection, prosecuting cases under its laws through the Food and Drug Department of the State Board of Health. Cases are brought in court with practically no expense for legal services. Complaints are entered by FOOD ANALYSIS AND OFFICIAL CONTROL. 11 the collector, or, as he is termed, inspector, who makes complaint not in his official capacity, but as a citizen who under the law has been sold a food found to be adulterated, and who is entitled to conduct his own case, which he does with the aid of the analyst and such other witnesses as he may see fit to employ. Experience is readily acquired by the inspector in conducting such cases in the lower police or municipal courts, where they are first tried, and years ago the services of legal counsel in Massa- chusetts were dispensed with as superfluous. Where such a practice is in vogue an intelligent inspector must of course be chosen with reference to his ability to do this court work. The food laws are few and simple, as are also the court decisions rendered under them, so that it is no great task for the inspector to become much more familiar with them than the average general lawyer whom he meets in court and who not infrequently consults the inspector for information regarding these laws. Statistics in the annual reports of the Massachusetts Board show with what uniform success these trials have been conducted. While more often settled in the lower courts, occasional appeal cases are car- ried to the superior courts, where the services of the regular district attor- ney are of course availed of in prosecuting the case. Such a system as the above, while admirable for a state or city after long experience in the enforcement of food laws in the courts, is obviously impracticable with newly established systems of state food inspection. CHAPTER II. . THE LABORATORY AND ITS EQUIPMENT. Location.— The selection of a location for a food laboratory cannot always be made solely with reference to its needs and its convenience, but it is more often subject to economic conditions beyond the analyst's control. Under very best conditions, such a laboratory should be situated in a building designed from the start exclusively for chemical or biological and chemical work. Almost any well-Hghted rooms in such a building can be readily adapted for the purpose. When, however, as is frequently the case, rooms for such a laboratory are provided in municipal, govern- ment, or office buildings, in which for the most part clerical work is done, the problem of adequately utilizing such rooms so that they may not at the same time prove offensive to or interfere with the comfort of other occupants of the building is sometimes difficult. It is obvious that base- ment rooms in such a building, as far as ventilation is concerned, are less readily adapted for the requirements in hand than are those of the top floor, though, if the light is good and there are abundant and well-arranged ventilating-shafts, such rooms may be made to serve every purpose. In the basement one may most easily obtain water, gas, and steam, and dispose of wastes without annoyance to one's neighbors. When, how- ever, it is possible to do so, rooms on the top floor of an office building should be utilized for a food laboratory, for in such rooms the problems of Hghting, heating and ventilating are comparatively simple and may usually be solved without regard to other occupants. In such a case ample provision must be made, preferably through shafts which are readily accessible for water-, gas-, steam-, and soil-pipes passing down below. The actual equipment of the food laboratory depends of course largely on its particular purpose; and while it is manifestly impossible to do other- wise than leave the details to the individual taste and needs of the analyst. 12 THE LABORATORY AND ITS EQUIPMENT. 13 modified by the means at his disposal, a few general suggestions regarding important essentials may prove helpful. These imply a fairly liberal though not extravagant outlay, with a view to saving both time and energy by convenient surroundings well adapted to the work in hand. Floor.— The best material for the floor of the working laboratory is asphalt. Such a floor is firm but elastic, is readily washed by direct application of running water, if necessary, and resists well the action of ordinary reagents. An occasional thin coating of shellac with lampblack applied with a brush gives the asphalt floor a smooth, hard surface and may be applied locally to cover spots and blemishes. Lighting. — The ideal arrangement is with benches for analytical work running north and south, the principal light being from south win- dows, and with benches for microscopes, balances, colorimeters, and standard solutions along the north wall where the north windows admit a soft light and never direct sunshine. FIXTURES. Ventilation by forced draft is a great convenience. For this purpose an exhaust fan driven by an electric motor and controlled in speed by a fractional rheostat is admirable. Such a fan would best be located in a small closed compartment or closet near the centre of the series of rooms designed to be ventilated by it, and this closet should have directly over the fan an outlet-shaft passing through the roof of the building. With such a system, a series of branching air-ducts should radiate from the fan closet, conveniently arranged either above or along the ceiling and communicating with the various hoods, closets, and rooms near the top. Benches. — The working benches should have wooden or glazed tile tops. White glazed tile, if properly laid, furnish a very clean, sanitary, and resistant surface, besides being often convenient for color tests. If laid on a plank surface, cement should not be applied directly, as it swells the wood before drying out and results in a loose and often uneven surface. Cement may be avoided altogether and the tiles after first soaking in oil may be laid in putty directly on the wood. Tiles may be laid in cement by first covering the plank surface with cheap tin plate, overlapping the edges and securing by tacks. This prevents swelling of the wood. The tin may be covered to advantage with cheap paint. The tiles may then be embedded in a layer of cement spread over the tin surface. Soft encaustic glazed tiles commonly used for wall finish are not as 14 FOOD INSPECTION AND ANALYSIS. effective as hard floor tiles specially glazed, since the former crackle and lose color when subjected to heat. A suitable material for the top of the titration bench is opal plate glass with a polished surface. Jet-black plate glass with a honed surface is admirably suited for the microscope table. When wooden bench tops are used they may be treated to advantage by staining with the following solutions: Solution I. loo grams of anilin hydrochloride, 40 grams of ammonium chloride, 650 grams of water. Solution 2. 100 grams of copper sulphate, 50 grams of potassium chlorate, 615 grams of water. Apply solution i thoroughly to the bare wood and allow it to dry; then apply 2 and dry. Repeat these applications several times. Wash with plenty of hot soap solution, let dry and rub well with vaseline. It is claimed that wood so treated is rendered fire-proof and is not acted on by acids and alkalies. When the finish begins to wear, an application of hot soap solu- tion or vaseline will bring back the deep black color. Gas and water outlets, sinks and waste pipes should be conveniently arranged, while the space beneath the benches should be utilized for drawers and cupboards. A clear bench width of 24 inches is ample for most work; if wider there is a temptation tc allow apparatus to accumulate at the back. At the back of the bench and within easy reach, a raised narrow shelf should be provided to be used exclusively for common desk reagents. This again should not be so wide as to allow the accumulation of useless bottles. A narrow raised guard or beading at the edge of the reagent shelf prevents the bottles from accidently slipping off. Hoods. — Closed hoods with sliding sash fronts are almost indispensable. These hoods should be directly connected with the ventilating shafts or pipes, or with the air-ducts that radiate from the exhaust-fan closet, when such a system is provided. Gas outlets inside the hoods are neces- sary. When there is a good draft, either natural or forced, a hooded top over the working bench, such as that shown in Fig. 3, is quite as efficient as a closed hood for most purposes. This is best made of galvanized iron, painted on the outside and treated on the inside with a preparation of graphite ground in oil. Here are best carried out all the processes involving the giving off of fumes and gases, which, if the ventilation is efficient, should pa^s directly up the flues and not come out in the room. THE LABORATORY AND ITS EQUIPMENT. 15 Sinks and Drains. — The sinks should preferably be o f iron or porce- lain. If iron, they should at frequent intervals be treated with a coat of Fig. 3. — Hooded Top of Galvanized Iron over Working-bench, Connected with \'entilating Air-ducts. asphalt varnish. A great convenience is a hooded sink (Fig. 4) in which foul- smelling bottles, or vessel? giving off noxious or offensive fumes 16 FOOD INSPECTION AND ANALYSIS. or gases, may be rinsed under the tap while completely closed in. Open- work rubber mats at the bottom of the sinks help to insure against break- age. Open plumbing of simplest design should be used, and a multi- plicity of traps should be avoided. Sinks may be variously located for Fig. 4. — A Hooded Sink. An injector-like arrangement of steam and cold-water pipes furnishes water of any desired temperature. convenience without regard to situation of soil-pipes, if the floor is thick enough to allow an open drain with sufficient pitch to flow readily. Such open drains are much more readily cleaned than closed pipes, and are best constructed by splitting a lead pipe and laying it in an iron box which is sunk into the floor. The edges of the lead pipe arc rounded over those of the box as in Fig. 5, filling the joints with hydraulic cement, and the top of the drain is covered by a series of readily removable iron plates THE LABORATORY AND ITS EQUIPMENT. 17 flush with the top of the floor. Waste-pipes from sinks, still-condensers, refrigerators, and various forms of apparatus involving flowing water may be led into this drain, holes being drilled in the iron cover for their insertion. Gas, Electricity, and Steam. — While formerly gas, made either in public or private plants, was the sole dependence for laboratory work, to-day gas, electricity, and steam are often on tap in the same laboratory, for some processes one and for others another giving the best results. If only one can be had, gas is usually the cheapest and most satisfactory, but in many office buildings only electricity is available as it may be im- practicable to pipe in gas from the city mains and against insurance regu- lations to make it on the premises from gasoline. Laboratories and Fig. 5. — Section of Open Drain-pipe in Floor, works remote from centers often have an abundance of home-generated electricity and steam, but no gas. Fortunately electrical heaters for almost every kind of laboratory apparatus, such as furnaces, drying ovens, evaporators, thermostats, Kjeldahl digestors, and stills, are obtainable, although somewhat expensive. An electric current is also of great value in carrying out electrolytic methods and in running motors for driving centrifuges, shaking apparatus, ven- tilating fans, air pumps, etc. Whenever in an electrically equipped lab- oratory a free flame is indispensable, which is rarely the case, alcohol or blue flame kerosene oil burners are fairly satisfactory. Steam, when available, may be used to advantage for boiling ether or benzine in con- nection with continuous fat-extraction apparatus, for furnishing the motive power for driving the Babcock centrifuge, for heating water-baths and hot closets, and, in connection with cold water, to furnish a supply 18 FOOD INSPECTION AND ANALYSIS. of hot water when wanted at the sink. The latter application is illus- trated in Fig. 4. Suction and Blast. — If the water-pressure is ample, both air-pressure and exhaust for blast-lamps, vacuum filtration, and other purposes are readily available through the agency of the various devices used in con- nection with the flow of water, as, for instance, the Richards pump. When however, the water pressure is insufficient, other means must be employed for furnishing these much-needed requisites. Fig. 6 illustrates a simple Fig. 6. — Portable Pressure- and Exhaust-pump Run by Electric Motor, Useful for blast-lamps, vacuum filtration, etc. and almost noiseless pressure and exhaust pump run by a i-H.P. electric motor, which with the pressure-equalizing tank and the appropriate connections are mounted on a light wheel truck, and readily movable to any part of the laboratory. By simply screwing the plug into an electric-light outlet, either suction or blast may be had at will, depending on the position of a knife-edge switch which determines the direction of the current. By means of a fractional rheostat the speed may be varied and the pressure thus controlled. APPARATUS. The laboratory is of course to be supplied with the usual assortment of test-tubes, flasks, beakers, evaporating and other dishes of porcelain, platinum and glass, funnels, casseroles, crucibles, mortars, burettes, THE LABORATORY AND ITS EQUIPMENT. 19 pipettes, graduates, rubber and glass tubing, lamps, ring-stands and ' various supports, clamps and holders, the nature, number, and sizes cf which are determined by individual requirements. Special forms cf apparatus peculiar to certain processes of analysis or to the examination of special foods will be described in their appropriate connection. The following apparatus of a general nature may be regarded as indispensable for the proper fitting out of the food laboratory : Balances. — These should include (i) an open pan balance for coarse weighing, having a capacity up to i kilogram and sensitive to o.i gram, with a set of weights; and (2) an analytical balance, enclosed in a case, sensitive to .0001 gram under a load of 100 grams, with an accurate set of non-corrosive weights. The short-beam analytical balance is prefer- able for quick work, and as constructed by the best modern makers leaves nothing to be desired. Water-baths. — These are such an important accessory to food analysis that they should, if possible, be specially designed to meet the requirements, though the ordinary copper baths, supported on legs and designed to be heated by gas-burners, as kept in regular stock by the dealers, will sometimes serve the purpose. For nearly all moisture determinations the platinum dishes described on page 119 and the somewhat larger wine-shells of 100 cc. capacity are most used, and for this purpose the top of the bath should have plenty of openings of the right size for these. A very economical construction of bath admirably adapted for the food analyst's use is shown in Fig. 7, being the form employed by the writer. The size and number of openings are determined by the number of samples to be simultaneously analyzed. A steam coil within the body of the bath serves to boil the water. Fig. 7 also shows the hood for carrying off the steam and fumes, the sliding front of which is furnished with a hasp and a padlock, so that it may always be kept locked by the analyst whenever he is temporarily absent from the laboratory. This is a useful precaution, when the residues left thereon are from samples which are to form subjects for possible prosecution in court later. Steam, if available at all seasons of the year, or electric immersion coils furnish a ready means of heating the bath. In the absence of both steam and electricity, the bath must be boiled by gas burners. Drying-oven. — Water ovens heated by gas and steam ovens are com- monly used, although the drying cell seldom reaches a temperature above 98° C. The electric oven shown in Fig. 8 obviates this difficulty, the regulator permitting of adjustment so that full 100°, as well as any de- 20 FOOD INSPECTION AND ANALYSIS. sired temperature can be attained. Fig. 9 shows an asbestos-covered, jacketed air-oven, heated by a gas burner, with an efficient form of gas- pressure regulator. Water-still. — An efficient still should be provided, capable of supply- FlG. 7. — Water-bath, Enclosed in Hood, with Sliding-sash Front. ing the laboratory with an ample quantity of pure water for analytical purposes. Fig. 10 illustrates a compact form of still, which is particu- larly economical in view of the fact that a single stream of inflowing cold water first serves to cool the condenser, and, rising, becomes vaporized in the boiler directly connected with the condenser at the top. This apparatus is capable of distilling six gallons of water in twelve hours. Universal Centrifuge. — This convenient apparatus merits a separate brief description, being useful for a wide variety of purposes, such as THE LABORATORY AND ITS EQUIPMENT. 21 breaking up ether and other emulsions, quickly settling out precipitates, and roughly estimating chlorides, sulphates, phosphates, etc., by the volume of the precipitate in graduated tubes. Fig. 8. — Freas Electrically Heated Drying Oven with Accurate Temperature Control. n Fig. 9. — Asbestos-covered Air-oven, with Gas-pressure Regulator. The centrifuge (Fig. 11) is inclosed within a cast-iron case and is driven by an electric motor concealed at the base. The vertical spindle 22 FOOD INSPECTION AND ANALYSIS. f;; provided with interchangeable heads carrying various forms of swinging holder? for tubes, bottles, beakers, and separatory funnels. Holders are obtainable for tubes ranging from 2 cc. to 200 cc. capacity, for Squibb's form of separatory funnel of 150 cc. capacity, and for graduated bottles such as are used in determining fat by the Babcock method and in meas- FiG. 10. — A Convenient Laboratory Water-still with Earthenware Receptacle, Provided with Faucet and Glass Gauge. uring precipitates, as for example, in Hortvet's method of estimating the amount of lead precipitate formed in solutions of maple sugar or syrup. The electrical machinery is entirely enclosed, thus obviating the danger of exploding mixtures of vaporized ether and air by sparking — a danger which always must be carefully guarded against in the food laboratory. The various types of centrifuges designed for the Babcock test (page 124) may also be used for general work especially if fitted with inter- changeable heads carrying different forms of holders. THE LABORATORY AND ITS EQUIPMENT. 23 Other special Apparatus. — The following list includes pieces which are more or less indispensable : Continuous Extraction Apparatus (Figs. 20, 21, and 22). Apparatus for Nitrogen Determination (Figs. 26, 27^, and 276). Apparatus for Distilling Various Food Products . Fig. II. — A Universal Electric Centrifuge. A Bahcock or other Milk-fat Centrifuge (Figs. 11 and 45). A Butyro Refractometer (Fig. 38). An Immersion Refractometer (Fig. 42). A Microscope and its Appurtenances (Chapter V). A Polariscope and its Accessories (Figs. 102, 103, and 104). Specific Gravity Apparatus (Figs. 14, 15, 16, and 17). Carbon Dioxide Apparatus (Fig. 71). Melting-point Apparatus (Fig. 93). Freezing-point Apparatus. Electrical Conductivity and Hydrogen Ion Concentration Apparatus (Chapter XXII). Marsh Arsenic Apparatus (Fig. 28). Electrolytic Apparatus (Fig. no). Separatory Funnels and Stand (Figs. 24 and 25). A Spectroscope, either of the direct-vision variety for the pocket, or the Kirschoff & Bunsen style on a stand. Spectroscope Cells, parallel-sided, for observation of absorption spectra. 24 FOOD INSPECTION AND ANALYSIS. A Photomicro graphic Camera and Appurtenances * (pp. 80. to 85). A Muffle Furnace, gas (Fig. 3), or, preferably, electric (Fig. 19). An Ehullioscope (Fig. 113). An Assay Balance, for weighing arsenic mirrors to o.oi mg. An Abbe Refractometer (Fig. 39). A Schreiner Colorimeter (Fig. 30). A Lovibond Tintometer (p. 67). REAGENTS. Under the appropriate methods are described the reagents for carrying out the processes treated of in this volume, together with their strength, mode of preparation when necessary, and other data. Reagents, especially those constantly employed, should be assigned to regular places on the shelves, and should invariably be kept in place when not in use. Among the standard solutions for volumetric work, none is more frequently of service in the food labora- tory than a tenth-normal solution of sodium hydrox- ide, and a large supply of this reagent, carefully standardized, should be at all times conveniently at hand. Besides being useful for standardizing tenth- normal solutions, it is constantly needed for deter- mining various acids in food products, such as milk, vinegar, butter, lime juice, cream of tartar, liquors, and many others. Time is well spent in carefully ad- justing this solution to its exact tenth-normal value, thus simplifying the calculation of results. A large stock bottle (say of two gallons capacity) containing the standard tenth-normal sodium hydroxide, is con- veniently mounted with a side-tube burette in con- nection, in some such manner as shown in Fig. 12. A small connecting side bottle contains a strong solution of sodium hydroxide through which the air that enters the large bottle is passed, thus depriving it of CO 2- In this manner the standard solution may readily be kept of unvarying strength for a year or more. Fig. 12. — Stock Bot- tle of Tenth-normal Alkali. * A photographic dark room is also necessary if photomicrographic work is to be done. THE LABORATORY AND ITS EQUIPMENT. 25 EQUIVALENTS OF STANDARD SOLUTIONS. Decinormal Sulphuric Acid. One cc. is equivalent to Ammonia gas NHj 0.C017 granx Ammonia NH,OH 0.0035 Ammonium carbonate (NHJ2CO3 0.0046 (NHj^COg^zO 0.0057 Calcium carbonate CaCOg o . 0050 Calcium hydroxide Ca(OH)2 0.0037 ' ' oxide CaO o . 0028 Lead acetate Pb(C2H30 2)2,31120 0.0189 Magnesia MgO o . 0020 Magnesium carbonate MgCOj 0.0042 Nitrogen N 0.0014 Potassium acetate * KCgHgO, o . 0098 bicarbonate KHCO3 o.oioo bitartrate * KHC^H^e 0.0188 carbonate K2CO3 0.0069 citrate* KgCjHjOjjHgO 0.0106 hydroxide KOH; 0.0056 and sodium tartrate . KNaC^H^08,4H20 0.0141 Sodium acetate NaC2H302,3H20 0.0136 " benzoate * NaCyHjO, 0.0144 " bicarbonate NaHC03 0.0084 " borate Na2B^07,ioH20 0.0191 " carbonate Na2C03 0.0053 Na2C03,ioH20 0.0143 " hydroxide NaOH 0.0040 ' ' salicylate * NaC7H503 o . 01 60 Decinormal Sodium Hydroxide Solution. One cc is equivalent to Acid, acetic H,C2H302 0.0060 gram. " boric H3BO3 0.0062 " citric H3CgH:,07,H20 0.0070 " hydrobromic HBBr 0.0081 " hydrochloric HCl 0.00365 " hydriodic HI ■ 0.0128 ** lactic HC3H5O3 0.0090 " malic C^HeOj 0.0067 *' nitric HNO3 0.0063 " oxalic H2C20^,2H20 0.0063 „ , , . zT-or^ '^ ^° ^°^™ K.HPO.with I " phosphoric H..PO. -j , , : , , . r 0.0049 ^ ^ J 4 ( phenolphthalein ) ^^ ,, ^^ ( to form KH,PO,with ) ' phosphoric H,PO. i , , ~ * r 0.0098 ^ ^ •= M methyl orange ) ^ " sulphuric H2SO^ 0.0049 " tartaric H2C^H^08 0.0075 Potassium bitartrate KHC^H^Oj 0.0188 Sodium borate i.... Na^B^Oj, loHjO o. 00955 * To be ignited. 26 FOOD INSPECTION AND ANALYSIS. Decinormal Iodine Solution. One cc. is equivalent to Arsenious oxide ASjOg 0.00495 gram, Potassium sulphite K2S03,2H20 0.0097 Sodium bisulphite NaHSOj 0.0052 " sulphite, Na2S03,7H20 0.0126 " thiosulphate NajSjOjjSHjO 0.0248 Sulphur dioxide SOj 0.0032 Sulphurous acid HjSO-j 0.0041 Decinormal Sodium Thiosulphate Solution. One cc. is equivalent to Bromine Br o . 0080 gram. Chlorine CI 0.00355 " Iodine I 0.01266 " Iron (in ferric salts) Fe 0.0056 " Decinormal Silver Nitrate Solution.* One cc. is equivalent to Ammonium bromide NH^Br o . 0098 gram. " chloride NH^Cl 0.00535 " Chlorine CI 0.00355 " Cyanogen (CN)2 0.0052 " Hydrocyanic acid HCN with indicator 0.0027 " < , TT-^xT { to formation of precip- [ " " HCN . ^ ^ f 0.0054 " ( itate ' ^^ Hydrobromic acid HBr 0.0080 " Potassium bromide KBr 0.0119 " chloride KCl 0.00745 " " cyanide KCN with indicator 0.0065 " " KCN r°^°™^''''''°^P''"P'' 0.0130 " j itate i ■^ Sodium bromide NaBr 0.0103 " " chloride NaCl 0.00585 " Decinormal Potassium Bichromate Solution.! One cc. is equivalent to Ferrous carbonate FeCOj 0.0116 gram. Ferric oxide FcjOj 0.0080 '* Ferrous oxide FeO 0.0071 " " sulphate FeSO^ 0.0152 " " FeSO,,7H20 0.0278 " Iron (ferrous) Fe 0.0056 " Decinormal Potassium Permanganate Solution. One cc. is equivalent to Oxalic acid H2C20^,2H20 0.0063 gram, and to same weights for iron salts as given under N/io K2Cr20,. * Use potassium chromate solution as an indicator, or add till precipitate appears. + Use a freshly prepared solution of potassium ferricyanide as an mdicator, applying a drop of titrated solu- tion to a drop of indicator on a white surface. THE LABORATORY AND ITS EQUIPMENT. 27 The following table from Talbot * shows the reactions of the com- mon indicators used in acidimetry: Indicator. Reaction with Acids. Reaction U^\^''> • . \ Carbonic Alkalies. Acid in Cold solution. Use with Carbonic Acid in Hot Solution. Use with Ammonium Salts. Use with Organic Acid. Litmus Red Pink Colorless Purple-red Purple -red Yellow Yellow Blue Yellow Pink Blue Blue Pink Red Unreliable Reliable Unreliable Unreliable Reliable Unreliable Unreliable Reliable Unreliable Reliable Reliable Reliable Reliable Reliable Reliable Reliable Unreliable Reliable Reliable Unreliable Reliable Relia"oi3 Unreliable Reliable Unreliable ( ?) Unreliable Unreliable^ Reliable Methyl orange. . . Phenolphthalein. . Lacmoid Cochineal Rosolic acid Alizarine * Talbot, Quantitative Analysis, page 75. t Reliable wiih oxa'ic acid. CHAPTER III. FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS, AND NUTRITIVE VALUE. Nature and General Composition. — Food is that which, when eaten, serves by digestion and absorption to support the functions and powers of the body, by building up the material necessary for its growth and by supplying its wastes. The raw materials that constitute our food- supply are not all available for nourishment, but often contain a propor- tion of inedible or refuse matter, which it is customary to remove before eating, such as the bones of fish and meat, the shells of clams and oysters, eggshells, the bran of cereals, and the skins, stones, and seeds of fruits and vegetables. The proximate components which make up the edible portion of food include in general water, fat, various nitrogenous bodies consisting chiefly of proteins, carbohydrates, organic acids, and mineral matter. Of these water is hardly to be considered as a nutrient, though it plays an important part in nearly all foods as a diluent and solvent. The fats, proteins, and carbohydrates all contribute in varying degree to the supply of fuel for the production of heat and energy. Besides this universal function, the fats and the carbohydrates serve especially to fur- nish fatty tissue in the body, while the proteins are the chief source of muscular tissue. Liebig's classification of foods into nitrogenous, or flesh formers, and non-nitrogeneons, or heat generators, is now no longer accepted as strictly logical, in view of the well-known fact that the nitrogenous materials, besides building up the body, aid in supplying the wastes and yielding energy, and may even be converted into fats or carbohydrates, while the non-nitrogenous aid in furnishing tissue growth in addition to serving as fuel. The Fat of Food.— Fats and oils consist essentially of the glycer- ides of the fatty acids, the characteristics of the various edible fats and 28 FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS, ETC. 29 oils being treated under their appropriate headings elsewhere. Fat in human food is suppHed by milk and its products, by the adipose tissue of meat, and in slight extent by the oil of cereals and by the edible table oils. The term "ether extract" is sometimes used in stating the results of the analysis of foods and this includes other substances than fat which when present are extracted by ether, such as chlorophyl and other color- ing matters, lecithin, alkaloids, etc. The glycerides occurring in foods are of acids belonging in four series as follows, the value for 11 being in parentheses : A. Acetic Series (C„H2„02).— Butyric (4), caproic (6), caprylic (8), capric (10), lauric (12), myristic (14), palmitic (16), stearic (18), arachidic (20), behenic (22), and lignoceric (24). B. Oleic Series (C„H2„-202).— Hypogoeic (16), oleic (18), isooleic (18), rapic (18), and erucic (22). C. LmoLic Series (CnH2n-402).— LinoHc (18). D. LiNOLENic Series (C„H2„-602).— Linolenic (18). E. Clupanodonic Series (C„H2„-802).— Clupanodonic (18). Fats contain not only simple glycerides, consisting of glycerol com- bined with three equivalents of the same fatty acid, but mixed glycerides with two or three acids in the same molecule. Other substances present are free fatty acids, lecithin, cholesterol, phytosterol, sitosterol, coloring matter, and other matters in minute amount. Nitrogenous Compounds and their Classification — These substances may for convenience be grouped as follows : A. Proteins, B. Amino-acids, Amides, Amines, etc., C. Alkaloids, D. Nitrates, E. Ammonia, F. Lecithin, and G. Cyan Compounds. ^ A. Proteins. — Occurrence. — Under the term proteins are included numerous bodies consisting, according to our present knowledge, essen- tially of combinations of a-amino-acids and their derivatives. Proteins in one form or another exist in nearly all natural foods both animal and vegetable, but are supplied chiefly by the flesh of meat and fish, by milk, cheese, and eggs, and in the vegetable kingdom by grain, seeds, nuts, and vegetables, especially the legumes. The proportion of crude protein, often designated merely as " protein," is commonly estimated by mul- tiplying by 6.25 the percentage of nitrogen found in the material anal- yzed. This is done on the assumption that all of the nitrogen present in the substance belongs to protein and that the protein contained 16 per cent of nitrogen, neither of which assumptions is usually true, al- though for most purposes the results are sufficiently accurate. In certain 30 FOOD INSPECTION AND ANALYSIS. cases, as for example, wheat flour and milk, special factors (5.70 and 6.38 in the :ases :ited) are used. Methods depending on the separation of the proteins as such are used in special investigations, but these, with few exceptions, are not adapted for practical purposes. There is no marked distinction in chemical constitution between animal and vegetable proteins, although some of the types have as yet been found only in one or the other kingdom. The terms " proteids " or " albu- minoids " were formerly used generically as synonymous with " protein " to include all nitrogenous bodies of this group, but in 1908 a joint com- mittee on protein nomenclature of the American Physiological Society and the American Society of Biological Chemists recommended that the word " proteid " be abandoned; that " protein " be used to designate the entire group; and that the word "albuminoids" be restricted to a sub-group of proteins. A committee of the Physiological Society of England also made the same recommendation as to the use of the term protein. The classification and most of the definitions here given are those adopted by the American committee.* The examples in most cases were kindly furnished by Dr. T. B. Osborne. For further details the reader is referred to the works of Mathews,! Osborne,t Plimmer,§ and Jones, 1 1 also journal articles by Emil Fischer, Kossell> and their students. I. The Simple Proteins. — Protein substances which yield only a- amino acids or their derivatives on hydrolysis. Although no means are at present available whereby the chemical individuality of any protein can be established, a number of simple pro- teins have been isolated from animal and vegetable tissues which have been so well characterized by constancy of ultimate composition and uniformity of physical properties that they may be treated as chemical individuals until further knowledge makes it possible to characterize them more definitely. (a) Albumins. — Simple proteins soluble in pure water and coagulable by heat. Examples. — Seralbumin of blood and other animal fluids; lactalbumin of milk; leucosin of the seeds of wheat, rye, and barley; legumelin of legu- minous seeds. * Amer. Jour. Phys., 21, 1908, xxvii. t Physiological Chemistry, New York, 1916. X The Vegetable Proteins, London, 191 2. § The Chemical Constitution of the Proteins, London, 1917. II Nucleic Acids, London, 1914. FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS, ETC. 31 Coagulation. — Animal albumins usually coagulate at about 75°; vegetable albumins at about 65°. Miscellaneous Reactions. — Very dilute acids precipitate albumins with the aid of heat. Nitrate of mercury (in dilute nitric acid) precipitates albumins from their solutions; also Mayer's solution acidified with acetic acid. They are precipitated by saturation with ammonium sulphate. These reactions are not, however, characteristic of the group. (b) Globulins. — Simple proteins insoluble in pure water, but soluble in neutral solutions of salts of strong bases with strong acids. Examples. — Myosin of muscle substance; legumin of leguminous seeds; amandin of almonds. Qualitative Tests. — Globulins are precipitated from their solution by dialysis or dilution. Albumins are not thus precipitated. (c) Glutelins. — Simple proteins insoluble in all neutral solvents, but readily soluble in very dilute acids and alkalies. Examples. — Glutenin of wheat is the only well defined protein of this group. (d) Prolamins. — Simple proteins soluble in relatively strong alcohol (70-80 per cent), but insoluble in water, absolute alcohol, and other neutral solvents. Examples. — Gliadin of wheat; zein of maize; hordein of barley. Found as yet only in the seeds of cereals. The use of appropriate prefixes will suffice to indicate the origin of compounds of sub-classes a, b, c, and d, as for example: ovoglobulin, myalbumin, etc. (e) Albuminoids. — Simple proteins which possess essentially the same chemical structure as the other proteins, but are characterized by great insolubility in all neutral solvents. Examples. — Keratins of hair, nails, hoofs, horn, feathers, etc.; elastin of connective tissues; collagen of connective tissues and cartilage; fibroin and sericin of raw silk. No albuminoids have yet been discovered in plants. Gelatin is usually regarded as an albuminoid but does not come strictly within the requirements of the above definition. It is an artificial deriva- tive of collagen and is formed from it by boiling with water or subjecting to steam under pressure. It is prepared from bones and other animal parts, and is insoluble in cold, but soluble in hot water. When the hot water solution containing one per cent or more of gelatin cools, it forms a jelly. By prolonged boiling the gelatinizing power is lost. Aqueous solutions are strongly laevo-rotary. 32 FOOD INSPECTION AND ANALYSIS. Gelatin in common with most proteins is precipitated from its solution by mercuric chloride, picric acid, and tannic acid. It is readily distin- guished from soluble proteins, in that it is not precipitated from its solution by lead acetate, nor by most of the metallic salts that throw down proteins. (f) Histones. — Soluble in water and insoluble in very dilute ammonia, and, in the absence of ammonium salts, insoluble even in an excess of ammonia; yield precipitates with solutions of other porteins, and acoagu- lum on heating, which is easily soluble in very dilute acids. On hydrolysis they yield a large number of amino-acids, among which the basic ones predominate. Examples. — Thymus histone. Not found in plants. (g) Protamins. — Simpler polypeptides than the proteins included in the preceding groups. They are soluble in water, uncoagulable by heat, have the property of precipitating aqueous solutions of other proteins, possess strong basic properties, and form stable salts with strong mineral acids. They yield comparatively few amino-acids, among which the basic amino-acids greatly predominate. Examples. — Salmin, clupein, and other protamins of fish spermatozoa. Not found in plants. II. Conjugated proteins. — Substances which contain the protein molecule united to some other molecule or molecules otherwise than as a salt. (a) Nucleoproteins. — Compounds of one or more protein molecules with nucleic acid. Examples.— ThQ nucleins salmin nucleate and clupein nucleate. (b) Glycoproteins.— Compounds of the protein molecule with a sub- stance or substances containing a carbohydrate group other than a nucleic acid. Examples. — Mucins; ovomucoid; ovalbumin; ichthulin. (c) Phosphoproteins. — Compounds of the protein moiCcule with some yet undefined phosphorus-containing substance other than a nucleic acid or lecithins. Examples .—Casein of milk; vitellin of egg yolk. (d) Haemoglobins. — Compounds of the protein molecule with haematin or some similar substance. Example. — Oxyhaemoglobin of red blood corpuscles. (e) Lecithoproteins. — Compounds of theprotein molecule with lecithins, (lecithans, phosphatides). Examples. — Lecithalbumin ; lecithin-nucleovitellin. J FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS, ETC. 33 III. Derived Proteins. 1. Primary Protein Derivatives. — Derivatives of the protein mole- cule, apparently formed through hydrolytic changes which involve only slight altterations of the molecule. (a) Proteans. — Insoluble products which apparently result from the incipient action of water, very dilute acids or enzymes. Examples. — Edestan; blood fibrin; insoluble myosin. (b) Metaproteins. — Products of the further action of acids or alkalies, whereby the molecule is so far altered as to form products soluble in very weak acids and alkalies, but insoluble in neutral fluids. Examples. — Acid albumin; alkali albumin. This group will thus include the familiar "acid proteins" and "alkali proteins," not the salts of proteins with acids. (c) Coagulated Proteins. — Insoluble products which result from (i) the action of heat on their solutions, or (2) the action of alcohol on the protein. Examples. — Albumin coagulated by heat or alcohol. 2. Secondary Protein Derivatives. Products of the further hydro- lytic cleavage of the protein molecule. (a) Proteoses. — Soluble in water, uncoagulated by heat, and precipi- tated by saturating their solutions with ammonium or zinc sulphate. As thus defined this term does not strictly cover all the protein deriva- tives commonly called proteoses, e.g. heteroproteose and dysproteose. Subdivision of the Proteoses. — According to the proteins from which they are derived the proteoses may be designated albumose, from albumin, globulose, from globulin, vitellose, from vitellin, caseose, from casein, etc. Proteoses are subdivided into proto-proteose , soluble in water (both cold and hot) or in dilute salt solutions, but precipitated by saturation with salt; hetero- proteose, insoluble in water, and deutero- proteose, soluble in water, but not precipitated by saturation with salt. Vegetable proteoses are sometimes called phyt-albumoses. Qualitative Tests. — Besides responding to the biuret reaction (p. 34) proteoses are precipitated by nitric acid, the precipitate being soluble on heating, but reappearing on coohng. Proto-proteose is precipitated from its solution by mercuric chloride and copper sulphate; hetero-proteose is precipitated by mercuric chloride, but not by copper sulphate. (b) Peptones. — Soluble in water, uncoagulated by heat, and not pre- cipitated by saturating their solutions with ammonium sulphate. 34 FOOD INSPECTION AND ANALYSIS. Qualitative Tests. — Besides giving the biuret reaction, peptones are precipitated from their solution by tannic acid, picric acid, phosphomolybdic acid, and by sodium phosphotungstate acidified by acetic, phosphoric, or sulphuric acid. Peptones are the only soluble proteins not precipitated by saturation with ammonium sulphate. (c) Peptides. — Definitely characterized combinations of two or more amino-acids, the carboxyl group of one being united with the amino group of the other, with the elimination of a molecule of water. The peptones are undoubtedly peptides or mixtures of peptides, the latter term being at present used to designate those of definite structure. Qualitative Tests for Proteins. — Xanthoproteic Reaction. — Concen- trated nitric acid containing nitrous acid formed during standing added to a solution of a protein may or may not form a precipitate. It, however, produces a yellow coloration on boiling. Addition of ammonia in excess turns the precipitate or liquid yellow or orange; proteins in suspension also react. Milton's Reaction. — Millon's reagent is prepared by dissolving metallic mercury in twice its weight of concentrated nitric acid, diluting with an equal volume of water, and allowing to settle. When added to a protein solution it produces a white precipitate, which becomes jDrick-red on heating. Solid proteins give the red color by direct treatment. Sodium chloride prevents the reaction. Various organic substances are precipi- tated by Millon's reagent, but these precipitates do not turn red on heating. Biuret Reaction. — If a solution of a protein in dilute sulphuric acid be made alkaline with potassium or sodium hydroxide and very dilute copper sulphate be added, a reddish to violet coloration is produced, similar to that formed if biuret be treated in the same way, hence the name. An excess of copper sulphate should be avoided lest its color obscure that of the reaction. In solutions which are strongly colored this reaction is of little use unless modified as follows: A considerable quantity of the dilute copper sulphate solution is added to the solution made alkaline with a large excess of potassium hydroxide, and then solid potassium hydroxide is dissolved to almost complete saturation in the solution. The mixture is then shaken with about one half its volume of strong alcohol. On standing the alcohol separates as a clear layer or a violet or crimson color if proteins are present. B. Amino-acids, Amides, Amines, and Allied Products.— Under this head are included products derived from acids or bases, the radicles FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS, ETC. 35 of which replace one or more hydrogen atoms in ammonia. The most common bodies of this class occurring in foods follow : I. AminO-ACIDS — The following are obtained by the hydrolysis of the different proteins: i. glycocoll; 2. alanine; 3. valine; 4. leueine; 5. glyco-leucine, 6. iso-leucine, 7. serine, 8. cysteine, 9. aspartic acid, 10. glutamic acid, 11. arginine, 12. lycine, 13. cystine, 14. tyrosine, 15. phenyl- alanine, 16. proline, 17. oxy-proline, 18. histidine, 19, tryptophane. Of these, I to 13 inclusive belong to the aliphatic series, 14 and 15 to the carbocyclic series, and 16 to 19 inclusive to the heterocyclic series. II. Amides. — Asparagin occurs in the young shoots of asparagus, lettuce and other green vegetables, and marshmallow root. Glutamine occurs in seeds during sprouting. III. Amines. — Choline is found in meat, egg yolk, and certain fungi. Betaine is a constituent of beets, hops, and certain mollusks. Carnitine occurs in meat extract. IV. Creatine and Creatinine.— These are constituents of meat extracts. V. Purine Bases. — In the vegetable kingdom these are represented by the caffeine of tea, coffee, and cocoa , and the theobromine of cocoa, in the animal kingdom by xanthine, hypoxanthine, guanine, and adenine of meat and meat extracts. They are also classified with the alkaloids. C. Alkaloids. — This group is characteristic of certain drugs; in foods they are of infrequent occurrence. Aside from the purine bases caffeine and theobromine, the piperine and piperidine of pepper are the only common examples. D. Nitrates. — These occur mostly in growing parts of the plant and only in traces. E. Ammonia. — This occurs in ripened cheese of certain varieties and meat that is undergoing decomposition. F. Lecithin. — This is a phosphorized fat occurring in egg yolk and other animal and vegetable substances. G. Cyan Compounds. — The bitter cassava contains hydrocyanic acid. Cyanides and sulphocyanides (thiocyanates) are found in small amounts, in various foods. Common examples of sulphocyanides are the pungent principles of mustard and horse radish. Amygdalin of bitter almonds is a glucoside containing the cyan group. Carbohydrates and their Classification.— Of the total number of carbohydrates which have been described only a limited number occur in food products and of these a considerable number do not exist in the 36 P^OOD INSPECTION AND ANALYSIS. original vegetable or animal substance, but are formed during manu- facture. A classification of the common food carbohydrates is given below. Descriptions of the more important individuals appear in chapters X and XIV. Other details will be found in the works of Armstrong,* and Browne,! as well as in special papers by Emil Fischer, Tollens, and their, students. I. Monosaccharides. — These, also known as simple carbohydrates, are either aldehyde alcohols (aldoses) or ketone alcohols (ketoses) with usually one carbonyl and one or more alcohol groups. One of the hydro- gens of the end group CHjOH may be replaced by an alkyl group, usu- ally methyl. The formulae of the ^forms are mirror images of the d- forms. (a) Dioses. — No representative of this group occurs in foods, but an example is here given to illustrate the simplest form of monosaccharide. Example. — Glycolose (CHjOH-CHO), prepared synthetically. (b) Methyl Dioses. — Example. — Dimethylglycolose (CH3.CHOH.COCH3), occurs in vinegar and other fermented products. (c) Trioses. — Example. — Dioxyacetone (CHsOH-CO-CHgOH), a ketose, is formed in various fermentation processes. (d) Tetroses. — No example in food products. (e) Methyl Tetroses. — Example. — Apiose (CH20HHOC(CH20H)CHOHCHO), a constituent of the glucoside apiin of parsley. (f) Pentoses (C5H10O5). — These sugars occur seldom and in only small amounts in foods, but are prepared from the corresponding pento- sans by hydrolysis. Aldoses. — Examples. — J-Arabinose (CH2OH • (HOCH) 2 • HCOH • CHO) ; /-arabinose (CH20H(HCOH)2-HOCH-CHO), a constituent of certain glucosides; /-xylose (CH^OH-HOCH-HCOH -HOCH -CHO); (/-ribose (CH20H-(HOCH)3-CHO), a constituent of various nucleic acids. Ketoses. — Little studied. * Simple Carbohydrates, London, 191 2. t Handbook of Sugar Analysis, New York, 191 2. FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS. ETC. 37 (g) Methyl Pentoses. — Examples. — Rhamnose (CH3 • CHOH HCOH • (HOCH) 2 CHO), occurs in various glucosides; fucose (CH3CHOH(HOCH)2.HCOHCHO), derived by hydrolysis of fucosan. (h) Hexoses (CoHioOe). "" Aldoses. — Examples. — (^-glucose or dextrose (CH.OH(HOCH),HCOHHOCHCHO), abundant in nature, forming with J-fructose invert sugar, occurs in nu- merous glucosides, formed by hydrolysis of starch, and is one of the chief constituents of commercial glucose; (/-mannose (CH2OH • (HOCH) 2 . (HCOH) 2 • CHO), found in plant juices, germinating seeds, and molasses; ^-galactose (CH30H-HOCH-(HCOH)2-HOCHCHO), a constituent of certain glucosides, occurs free in whey and germinating seeds; /-galactose (CH2OH HCOH (HOCH) 2 HCOH CHO); d, /-galactose or racemic galactose, identified in certain oriental food products. Ketoses. — Examples. — c?-Fructose or levulose (CH20H(HOCH)2HCOHCOCH20H), occurs v/ith (/-glucose in invert sugar; J-sorbose (CH.OHHCOHHOCHHCOHCO-CH^OH), formed by fermentation of the juice of the sorb apple; glutose, found in molasses. n. DiSACCHARIDES. — These yield on hydrolysis two monosaccharides. Their constitutional formulae have not been fully decided on. Examples. — Sucrose or common sugar (C12H22O11); maltose (C12H22O11) formed by the action of diastase on starch; lactose or milk sugar (Ci2H220ii-H20); trehalose or mushroom sugar (Cj 2H 2 20ii-2H20) melibiose (Ci2H220ii-2H20), formed by action of yeast on raffinose. Of these maltose, lactose, and melibiose are copper reducing. III. TRISACCHARIDES.— These yield on partial hydrolysis a monosac- charide and a disaccharide. Example. — Raffinose (Ci8H320i6-5H20), occurs in sugar beets, cotton seed, etc. IV. Tetrasaccharides.— These yield on partial hydrolysis a mono- saccharide and a trisaccharide. Kraw/'/e.— Stachyose (C24H4202r4H20), found in various roots and in ash manna. 38 FOOD INSPECTION AND ANALYSIS. V. Polysaccharides.— This group includes the pentosans ((C5H,s04)„-H20) and the hexosans ((C6Hio05)n-H20). The value of n is so large that the water may for practical purposes be ignored. For descriptions of the individual pentosans and hexosans see Chapter X. (a) Pentosans. — Examples. — Araban; metaraban; xylan. (b) Hexosans. — Examples. — Mannan; galactan; inulin; dextrin; starch; cellulose. Closely allied to the carbohydrates, if not actually belonging to them, are inosite (CjHijOe), occurring in muscular tissue, and peclose, found in green fruits and vegetables. The Organic Acids. — These acids are minor though important constituents of foods. From their conversion into carbonates within the body, they are useful in furnishing the proper degree of alkalinity to the blood and to the various other fluids, besides being of particular value as appetizers. They exist in foods both in the free state and as salts. Acetic acid is supplied by vinegar; lactic acid by milk, fresh meat, and beer; citric, malic, and tartaric acids by the fruits. Mineral or Inorganic Materials. — These substances occur in food in the form of chlorides, phosphates, and sulphates of sodium, potas- sium, calcium, magnesium, and iron, and are furnished by common salt, as well as by nearly all animal and vegetable foods. The inorganic salts are necessary to supply material for the teeth and bones, besides having an important place in the blood and in the cellular structure of the entire body. Fuel Value of Food. — In order to express the capacity of foods for yielding heat or energy to the body, the term fuel value is commonly used. By the fuel value of a food material is meant the amount of heat expressed in calories equivalent to the energy which we assume the body could obtain from a given weight of that food material, if all of its nutritents were thoroughly digested, a calorie being the amount of heat required to raise a kilogram of water i° C. This definition apphes to what is known as the large calorie, which is one thousand times as large as the small calorie. Large calories are meant wherever the term occurs in this volume. The fuel value, or, as it is sometimes called, ''heat of combustion," may be determined experimentally with a calorimeter, or may be calculated by means of factors based on the result of many experiments showing the mean values for protein, fats, and carbohydrates. The Bomb Calorimeter.'^ — This apparatus in its most approved form, * U. S. Dept. of Agric, Off. of Exp. Sta., Bui. 21, pp. 120-126. FOOD, ITS FUNCTIONS, PROXIMATE COMPONENTS, ETC. 39 Fig. 13, consists of a water-tight, cylindrical, platinum lined, Stcel bomb, adapted to hold in a capsule the substance whose heat is to be determined, y,nd containing also oxygen under pressure. This bomb is immersed in water contained in a metal cyHnder, which is in turn placed inside of concentric cylinders containing alternately air and water. The heat for igniting the substance is supphed by the electric current passing through wires to the interior of the bomb and acting upon a cleverly devised mechanism therein. The heat developed by the ignition is measured by Fig. 13. — Bomb Calorimeter of Hempel and Atwater the rise in temperature of the water surrounding the bomb, as indicated by a very delicate thermometer graduated to hundredths of a degree, certain corrections being made, as, for instance, for the heat absorbed by the metal of the apparatus. A mechanical stirrer serves to equalize the temperature of the water surrounding the bomb. The Respiration Calorimeter is a combustion apparatus on a large scale, of which a living human being or animal confined in a tight chamber, is a part. The food is carefully weighed and analyzed and the oxygen is supplied in known amount from a cylinder to replace that consumed by oxidation in the lungs. The water and carbon dioxide exhaled are 40 FOOD INSPECTION AND ANALYSIS. absorbed in calcium chloride tubes and potash bulbs or their equivalents on a large scale while the excreta is collected, weighed, and analyzed. The heat produced is measured by delicate appliances. In the United States human calorimeters are maintained at the Carnegie Nutrition Laboratory, Boston, under the direction of F. G. Benedict and at The Department of Agriculture, Washington, under the direction of Langworthy. A calorimeter for farm animals is in operation at State College, Pennsyl- vania, by Armsby. Calculation of Fuel Value. — The bomb calorimeter is beyond the reach of many laboratories while the respiration calorimeter can be main- tained only in specially equipped institutions, hence the expression of fuel values by calculation is the most common method employed. For this the factors of Rubner are generally used, in accordance" with which the amount of energy in one gram of each of the three principal classes of nutrients are, for carbohydrates 4.1, for protein 4,1, and for fats 9.3. Expressed in pounds, each pound of carbohydrate or protein has a fuel value of i860 calories, while each pound of fat has a fuel value of 4220 calories. For further details on the caloric value of foods and the science of nutrition the works of Jordan,* Lusk,t Sherman, J and Snyder § may be consulted. * The Principles of Human Nutrition, New York, 1914. t The Science of Nutrition, Philadelphia, 191 7. I Chemistry of Food and Nutrition, New York, 1918. § Human Food, New York, 1916. .CHAPTER IV. GENERAL ANALYTICAL METHODS. Bxtent of a Proximate Chemical Analysis. — For purposes of studying the proximate composition of food for its dietetic value, it is nearly always necessary to make determinations of moisture, ash, fat, total nitrogen, and carbohydrates (when present), as well as of the fuel value. In some cases it may be desirable to proceed further, to make an analysis of the ash, for instance, to separate, at least into classes, the various nitrogenous bodies, especially in flesh foods, and perhaps to subdivide the starch, sugar, gums, and cellulose or crude fiber that make up the carbohydrates in the case of cereals, A.n analysis is considered complete whenever the purpose for which the examination has been made has been accomplished, and on that pur- pose depends solely the extent to which the various compounds present shall be subdivided and determined. Such a subdivision may be extended almost indefinitely. For example, a milk analysis may consist simply in the determination of the total solids and (by difference) the water. Again, it may be desirable to divide the milk solids into fat and solids not fat, and in some cases to carry the subdivision still farther and separate the solids not fat into casein, albumin, milk sugar, and ash. Determinations of one or more of the proximate components natural to food are frequently of great service in proving their purity or freedom from adulteration. For the latter purpose, especially in such foods as milk, vinegar, oils, and fats, the determination of specific gravity is also an important factor. Special methods of a peculiar nature are often neces- sary in the examination of particular foods, and such methods will be treated subsequently under the appropriate headings. In the present chapter only such general methods as are applicable to a large variety of cases will be discussed. Expression of Results of a Proximate Analysis. — However complete the division of the various proximate compounds or classes of compounds 41 42 FOOD INSPECTION AND ANALYSIS. which the analyst sees fit to make, the results of his various determina- tions in a proximate analysis are expected to aggregate about 100%. If every determination be directly made, the result will rarely be exactly 100, but the precision of the work is apt to be judged by its approach to 100. It is often the custom to determine certain compounds or classes of compounds by difference. Thus in cereals moisture, proteins, fat, crude fiber and ash may be determined by the regular analytical methods, and by subtracting their sum from .100 the difference may be expressed as " nitrogen- free extract" or carbohydrates. It has long been customary in food analysis to calculate the protein by multiplying the total nitrogen by the factor 6.25, and on this basis analyses of thousands of animal and vegetable foods have been made. WTiile the figure thus obtained is an arbitrary one, being at best but a rough approximation of the amount of protein present, yet for many reasons there is much to commend this practice of reporting results. In the first place, in most cases it actually does approach the truth. Again, the nitiogenous ingredients of many foods are so numerous and varied, that for the every-day study of dietaries and food values it would be well-nigh impossible with our present knowledge to subdivide these compounds with any degree of accuracy, and especially with uniformity between different chemists, to say nothing of the time involved. From the fact that so many valuable analyses have 'already been expressed on the basis of NX 6.25 for protein, the advantage of comparison with the results thus recorded would seem to be in itself a good reason for continuing the practice, especially until a factor that gives better average results can be adopted. By recording the actual nitrogen found as well as the "protein," old results may at any time be recalculated under new conditions, if found desirable. In flesh foods, when carbohydrates are known to be absent, the total protein may conveniently be determined by difference. Rather more progress has been made in the separation of the nitrogenous compounds of meats than of the vegetables and cereals, though the methods are by no means accurate or uniform. Most of the recorded analyses of vegetable foods express the carbohy- drates as a whole without attempting to subdivide them, at least furthei than possibly to express the crude fiber or cellulose separately. A much more intelligible idea of the dietetic value of these foods would be gained by a further separation into starch and sugars. d GENERAL ANALYTICAL METHODS. 43 Preparation of the Sample.— It is at the outset of the utmost importance in all cases that a strictly representative portion of the food to be examined should be submitted to analysis. All refuse matter, such as bones, shells, bran, skins, etc., are removed as completely as possible from the edible portion and discarded. If the composition of the entire mass cannot be made homogeneous throughout, it may be best to select from various portions in making up the sample for analysis, in order to represent as fair an average of the whole as possible. Finally the sample, if solid or semi-solid, should be divided as finely as possible, by chopping, shredding, pulping, grinding, or pulverizing according to its nature and consistency. For disintegrating such substances as vegetables and meats for analysis, the common household rotary chopping-machine is admirably adapted. For pulverizing cereals, tea, coffee, whole spices, and the like, the mortar and pestle may be used, or a rotary disk mill or spice-grinder. Specific Gravity or Density of Liquids.— Where formerly it was cus- tomary to compare the density of liquids with that of water at 4° C. (its maximum density) it is now more common to refer to water at 15.5° C. or 20° C, making the determination at that temperature. A common form, of expressing the temperature of the determination and the tempera- ture of the standard volume of water with which that of the substance is to be compared, is the employment of a fraction, the numerator of which expresses the temperature of the determination and the denominator that of the standard volume of water, as — ^o , ^ ^ s* ^ C* 4 15-5 15-5 4° When extreme accuracy in the determination of density is required, the pycnometer or Sprengel tube should be employed. The Hydrometer. — This instrument furnishes the most convenient and ready means of determining the density of liquids where extreme nicety is not required. If well made and carefully adjusted, the hydrometer may be depended on to three decimal places, but before relying on its accuracy, it should be tested by comparison with a standard instrument, or with the pycnometer. The liquid whose density is to be determined is contained in a jar whose inner diameter should be at least f '' larger than that of the spindle- * LTnless otherOTse stated, all specific gravities in this volume are assumed to be expressed I? <:° on the basis of ^'-^ 15-5° 44 FOOD INSPECTION AND ANALYSIS. bulb, and the temperature of the hquid should be exactly 15.5° when the reading is taken. For best results for use with liquids of varying densities, the laboratory should be furnished with a set of finely graduated hydrometers, each limited to a restricted part of the scale, together with a universal hydrom- eter coarsely graduated, covering the entire range, to show by preliminary test which of the special instruments should be used. A convenient set of seven such hydrometers are graduated as follows: 0.700-0.850, 0.850-1.000, 1. 000-1.200, 1. 200-1. 400, 1. 400-1. 600, 1.600- 1.800, 1.800-2.000, while the universal hydrometer has a scale extending from 0.700 to 2.000. Another less delicate set of three only has one for liquids lighter than water and two for heavier liquids. Some instruments have thermometers in the stem. Others require a separate thermometer. The Westphal Balance (Fig. 14). — This instrument consists of a scale-beam fulcrumed upon a bracket, which in turn is upheld by a sup- porting pillar. The scale-beam is graduated into ten equal divisions. From a hook on the outer end of the beam hangs a glass plummet pro- vided with a delicate thermometer, the beam being so adjusted that when the dry plummet hangs in the air, the beam is in exact equilibrium, i.e., perfectly horizontal as shown by the indicator on its inner end. If the large rider be placed on the same hook as the plummet and the latter immersed in distilled water of the standard temperature at which the determinations are to be made (say 15.5° C), the scale-beam should again be in equihbrium if the instrument is accurately adjustedo As commonly made, the weight of the plummet including the platinum wire to which it is attached amounts to 15 grams, and the displacement of its volume to 5 grams of distilled water at 15.5° C, the normal temperature on which the determinations are based. Thus the unit (or largest) rider should weigh 5 grams, while the others weigh 0.5, 0.05, and 0.005 gram respectively. If, instead of distilled water, the plummet be immersed in the liquid whose density is to be determined, the position of the riders on the scale- beam, when so placed as to bring the same into equihbrium, and when read in the order of their relative size (beginning at the largest), indicates directly the specific gravity to the fourth decimal place. If the hquid is lighter than water, the large rider is first placed in the notch where it comes closest to restoring the equilibrium of the beam, but with the plummet still underbalanced. The rider next in size is then applied in a similar manner, and, unless equilibrium is exactly re- GENERAL ANALYTICAL METHODS. 45 Stored, the third and the fourth riders successively. If it happens that two riders should occupy the same position on the beam, the smaller is suspended from the larger. If the liquid is heavier than water, the method employed is the same except that one of the largest or unit riders is in this case always hung from the hook which supports the plummet, while the others cross the L J 1 Fig. 14. — The Westphal Balance. beam at the proper points. If carefully made and adjusted, the Westphal balance is capable of considerable accuracy. A delicate analytical balance can be used in place of the less carefully adjusted Westphal instrument, by hanging the Westphal plummet from one of the scale-hooks of the same, and employing a fixed support for the glass jar that holds the liquid in which the plummet is to be immersed. The support is so arranged that the scale-pan below it can move freely *vithout coming in contact with it. This arrangement is shown in Fig. 15. The Pycnometer, or Specific- gravity Bottle. — Fig. 16 shows the two 46 FOOD INSPECTION AND ANALYSIS. forms of pycnometer commonly made. The plain form has a ground- glass stopper with a capillary passage through it, the other has a fine ther- mometer connected with the stopper and a capillary side tube provided with a ground hollow cap. Both are made in different sizes to hold respectively lo, 25, 50, and 100 grams of distilled water at the standard •jSMiijr' O ^ o Fig. 15. — ^The Analytical Balance Arranged for Determining Specific Gravity witli the Westphal Plummet. temperature. It is convenient to have a counterweight for each pycnom- eter as fitted with its stopper, thus avoiding much trouble in calculation. The calculation of results is simplified also if the pycnometers are accurately constructed to contain exactly the weight of distilled water which they purport to contain at the standard temperature, but it is rather difficult to procure such instruments, especially of the form furnished with the ther- mometer. Most instruments hold approximately the amount specified, the exact net weight of distilled water which they hold at standard tem- perature being found by careful test and kept on record. In determining the density of a liquid, the pycnometer is carefully filled with it at a tem- perature below the standard, the stopper carefully inserted, and the bottle wiped dry. Care should be taken that the liquid completely fills the bottle and is free from air-bubbles. The net weight of the liquid is then taken I GENERAL ANALYTICAL METHODS. 47 on the balance, when the temperature has reached the standard (say 15.5° C), being careful to wipe off the excess of hquid that exudes from the capil- lary due to expansion. The net weight of the hquid is divided by that of the same volume of distilled water, previously ascertained under the same conditions at the same temperature, the result being the density of the liquid. The pycnometer with thermometer attachment is obviously susceptible of a greater degree of accuracy than the other form, since the temperature of the hquid, even though 15.5° C. at the start, soon rises. Fig. 16. — ^Types of Pycnometer. The writer prefers to use the pycnometer provided with the ther- mometer, but without the hollow cap that covers the capillary side tube, unless hquids hke strong acids are to be operated on, that might other- wise injure the balance. By keeping the liquid to be tested for some time in a refrigerator, it acquires a temperature of from 10 to 12° C. It is then transferred in the regular manner to the pycnometer and the ther- mometer-stopper inserted (but not the hollow cap) and the bottle wiped dry. There is ample time to adjust the balance- weights with extreme care while the temperature of the liquid is rising, leisurely wiping off 48 FOOD INSPECTION AND ANALYSIS. at intervals with a soft towel the excess that exudes from the capillary tube, the final weight of the dry bottle and contents being made at the exact temperature of 15.5° C. In taking the tare or adjusting the counterweight of a specific-gravity bottle, the latter should be perfectly clean and dry. It had best be rinsed first with water, then with alcohol, and finally with ether^ all traces of the latter being removed by a current of dry air, or otherwise, before weighing. In making successive determinations of density of a number of different liquids with the same pycnometer, it is sufficient to rinse the bottle once with a little of the liquid to be tested before making each determination, when the various liquids are miscible. When the liquids are immiscible, the bottle should be carefully cleaned in the manner described in the previous paragraph before making each test. The Sprengel Tube. — The Sprengcl tube is a variety of pycnometer useful when only a small quantity of the liquid to be tested is available. It is susceptible of great accuracy. It consists of a U-shaped tube (Fig. 17), each branch of which termi- nates in a horizontal capillary tube bent outward. One of the capillaries, b, has a mark m thereon and has an inner diameter of about 0.5 mm. The diameter of the other capillary, a, should not exceed 0.25 mm. The liquid at room temperature is as- pirated into the tube so as to fill it completely, the end b being dipped in the liquid while suction is applied at the end a. The tube is then placed in a beaker of water kept at the standard temperature, the beaker being of such size that the capillary ends rest on the edge. The temperature of the liquid in the tube may be assumed to be constant *tG. 17.— Sprengel Tube when there is no further movement due to contrac- for Determining Spe- tion in the larger capillary end, b. The meniscus of cific Gravity. ^-^^ liquid, when cooled, should not be inside the mark m, and is brought exactly to the mark by applying a piece of bibulous paper to the other end, a. If a drop or two of hquid has to be added, this may be done by applying to the end a sl glass rod dipped in the liquid. When exactly adjusted, the whole is wiped dry and quickly weighed, hung from the arm of the analytical balance. To avoid evaporation by contact with the air, the ends of the capillaries are sometimes ground to receive hollow glass caps not shown in the figure. ^ GENERAL ANALYTICAL METHODS. 49 Determination of Freezing Point—The Beckmann Apparatus^ consists of a cooling jar provided with a stirrer, an ordinary thermometer register- ing temperatures below zero, and a siphon for emptying, an air jacket, a freezing tube with a stirrer, and a Beckmann thermometer graduated too.oi°C. The reservoir in the top of the Beckmann thermometer is for a reserve supply of mercury. If the capillary tube contains so much mercury that the top of the column when cooled to the freezing point is not within the scale, by gently tapping a portion may be made to drop into the reser- voir; if it contains too little a portion may be added in the same manner after inverting the thermometer. Process.— Fla.ce an amount of the sample in the freezing tube sufficient to cover the thermometer bulb and cool in the cooling jar, containing a mixture of crushed ice and salt sufficient to produce a temperature several degrees below zero, until the mercury column ceases to fall and begins to rise. Then quickly transfer the freezing tube to the ah- jacket and continue the cooling, with gentle stirring, until the mercury column remains constant. Read the temperature with the aid of a lens. Determine the reading for distilled water in the same manner. The difference between the two readings is the freezing point of the sample. Keister f in the examination of milk recommends as a check removing the freezing tube, after taking each reading, warming with the hands or in water at 40° until the contents melt, and repeating the cooling. He also emphasizes the necessity of controlling the supercooling within narrow limits— from 1° to 1.2° for the apparatus used by him. Determination of Moisture.— This is usually calculated from the loss in weight at the temperature of boiling water. Platinum dishes (Fig. 51) are well adapted for the drying as the residue can be ignited for the determination of ash. If only the moisture is desired, dishes of other metals or glass weighing bottles may be used. Caps for wide- mouthed bottles made of tinned lead are convenient and can be thrown away after using. Viscous substances are best spread over asbestos or sand to hasten the drying. Some materials must be heated above 100° C, while certain saccharine products are dried at 70° C. in vacuo to avoid decomposition. If alcohol, acetic acid, essential oils, or other volatile substances are present the loss includes these as we ll as moisture. As the water or steam oven seldom * Zeits. physik. Chem., 2, p. 638. t Jour. Ind. Eng. Chem., 9, 191 7, p. 862. 60 FOOD INSPECTION AND ANALYSIS. attains a temperature above 98°, the loss sustained in these is, strictly speaking, at the " temperature of boiling water." Figs. 8 and 9 show electric and gas ovens for heating at full 100°. Benedict has shown that certain materials can best be dried at room-temperature over sulphuric acid in vacuo. Trowbridge * has shortened this process in the case of meat, by gently agitating the desiccator during the drying. Fig. 18. — Apparatus for Drying in Hydrogen. Drying in Hydrogen. — Fig. 18 shows the apparatus devised by Win ton f for drying cereal products, legumes, cattle foods, etc.. The material is weighed out on a watch glass and transferred to the drying tube (G), wisps of cotton, too small to contain an appreciable amount of moisture, being used at both ends to prevent mechanical loss. The hydrogen is purified by passing through sodium hydroxide solution {A) and dried by sulphuric acid in the jar (B). The acid drops over the glass beads into the chamber at the bottom of the jar where the gas bubbles through it before passing out over the beads. A siphon automatically removes the * U. S. Dept. of Agric, Bur. of Chem., Bui. 122, p. 219. t Conn. Agric. Exp. Sta., Rep. 1889, p. 187. GENERAL ANALYTICAL METHODS. 51 excess of acid. The drying tubes pass through the copper tubes of the water oven and are fitted at the posterior ends with capillary exit tubes of 0.5 mm, bore, thus creating a slight pressure and insuring even dis- tribution of current. When the drying is begun the exit tubes should be within the copper tubes to avoid stoppage of the current by condensed moisture, but later they should be pushed out, as m the cut, and each tested by lighting. Determination of Ash.— The residue from the determination of moisture or else a new portion, is burned at a very faint red heat until white or gray, cooled in a desiccator and weighed. A flat-bottomed platinum dish is most convenient for the pur- pose. Platinum, however, is at- tacked by free chlorine, bromine, and iodine, sulphur and phosphorus, sulphates and phosphates with re- ducing agents, all sulphides, sodium or potassium hydroxide, nitrate and cyanide, metals, and metallic com- pounds reduced in fusion, such as lead, tin, zinc, bismuth, mercury, arsenic, and antimony. In such cases porcelain must be used. Fig. 19.— Hoskins Electric Furnace. The degree of heat employed in ashing should be the lowest possible to insure complete oxidation of the carbon, so as to avoid driving off certain volatile salts that are sometimes present and that would be lost if the heat were too high. At a bright red heat potassium and sodium chloride are slowly volatilized, and calcium carbonate is converted into oxide; further- more alkali phosphates fuse about particles of carbon, protecting them from oxidation. To avoid overheating it is recommended not to allow the flame to impinge directly against the dish, but to carry out the burn- ing on a piece of asbestos paper supported on a triangle. The asbestos also serves to distribute the heat and to protect the dish from the injurious action of the direct flame on long heating. In order to burn off the last traces of carbon, a second piece of asbestos paper may be placed over the top of the dish, or the incineration may be completed in a gas or electric muffle furnace (Figs. 3 and 19). Heating should be continued till the carbon is all oxidized, which is in most cases indicated by a white 52 FOOD INSPECTION AND ANALYSIS. ash. It is, however, sometimes impossible to obtain a perfectly white ash, but the appearance of the ash usually indicates when all the carbon has been burnt off. It is sometimes necessary to stir the contents of the dish with a stiff platinum wire from time to time during the ignition. Methods for the detection and determination of the various ash ingre- dients are described in detail in Chapter X. Such cases as are peculiar to certain foods, like the metallic impurities that occur in canned, bottled, and preserved foods under certain conditions, will be considered in their appropriate place. Extraction with Volatile Solvents. — Whenever it is necessary to exhaust a substance of its ether-soluble or alcohol-soluble ingredients, some form of continuous extraction apparatus is emplo}?ed with ad- vantage. Preliminary Drying. — In the case of cereal, legume, and oil-seed products, meats, etc., the portion of the material dried in hydrogen, in vacuo, or in contact with air in an ordinary oven, for the determina- tion of moisture, may be used for extraction. If volatile oil is present, as in spices, the drying must be performed at room temperature in a desiccator. Milk and other liquids are absorbed in a roll of bibulous paper, in asbestos, or in sand, previous to drying (Chapter VII). The evaporation may be carried on in shells of thin glass (Hoffmeister Schalchen) which are finally broken previous to extraction, or in tinned lead bottle caps which may be crumpled up and inserted in the extractor. The Soxhlet Extractor. — This apparatus is shown in Fig. 20. The substance to be extracted is subjected to successive treatment with freshly distilled portions of the solvent in the tube 5. Dry powders are con- tained in extraction thimbles of filter paper or in filters folded over the end of a flat-bottomed cylinder so as to form a cartridge; liquids, such as milk, previously dried in a paper coil or in a wad of asbestos, are extracted without a filter. The vapor from the solvent, boiling in the flask F, passes up through the side tube a' into the condenser C, where it is lique- fied and falls drop by drop on the substance. When the level of the solvent in the tube 6* reaches the top of the siphon the liquid drains off into the tared flask F, carrying with it what- ever it dissolves. The operation is automatically repeated, the sub- stance being successively extracted with freshly distilled portions of the solvent, which leaves behind in the flask F the material in solution. The heater employed should be a hot plate heated by steam, or, as GENERAL ANALYTICAL METHODS. 53 shown in Fig. 20, an electric stove, which may be provided with a frac- tional rheostat for varying the amount of heat. If neither of these is available the extraction flask may be rested on a piece of asbestos paper Fig. 20. — The Soxhlet Extractor with Electric Heater. -Johnson Extraction Tubes. supported by a lamp stand, the heat being supplied by an ordinary Bunsen burner. The degree of ebullition is so regulated as to allow the solvent to saturate the sample and siphon over into the flask F from six to twelve times an hour, the extraction being continued from two to six hours, or until all the ether-soluble material has been removed. Care should be taken also that 54 FOOD INSPECTION AND ANALYSIS. the rate oi "boiling and the rate of condensation are so regulated that no appreciable loss of reagent occurs during the extraction. A strong smell of ether perceptible at the top of the condenser indicates a loss. The solvent is recovered at the end of the extraction by disconnecting the weighing flask at a time when nearly all of the solvent is in the part 5 and before it is ready to siphon over. The weighing-flask is then freed from all traces of the solvent by drying first on the water-bath and then in the oven, after which it is cooled in the desiccator and weighed, the difference between this and the first weighing representing the weight of the fat or ether extract. The Johnson Extractor. — This form of apparatus (Figs. 21 and 22) has the advantage of the Soxhlet extractor in that it is simpler and employs a much smaller amount of ether. The substance is contained in the inner tube of the extractor (Fig. 21), which is closed at the lower end by one thickness each of filter paper and cheese cloth, held tightly in place by means of a linen thread wrapped several times about the tube in the con- striction and tied in a fast knot. This inner tube properly prepared can be used over and over for extractions. The outer tube, also shown in Fig. 21, is of such a size that the inner tube fits loosely within it. A slight bulge on one side prevents trapping by means of the condensed solvent. The extraction flask is preferably of only 30 to 35 cc. capacity. It is attached to the extractor, as is also the extractor to the condenser tube, by means of a carefully bored cork stopper. For ordinary deter- minations of ether extract the outer tube should have an inside diameter of 26 mm. and the inner tube an outside diameter of 22 mm., only 8 to 10 cc. of the solvent being required. If, however, large amounts of material (25 to 50 grams) are to be extracted, the diameters may be made 32 mm. and 28 mm. respectively and a larger amount of solvent employed. Where only a few extractions are made, the heating can be performed over (but not on) a metal plate heated by a Bunsen burner, and the conden- sation effected by an ordinary Liebig condenser. If, however, a considerable number of extractions are carried out, the set apparatus shown in Fig. 22 will be found convenient and also economical of space. It may be attached to the wall or placed at the back of a working desk. The heating, as shown in the cut, is effected by means of two steam pipes, but some form of elec- tric heater answers equally well. The case with glazed door prevents the radiation of heat. At the top is shown the multiple condenser consisting of a copper tank with block tin tubes. Water is introduced at the left and carried off at the right. I GENERAL ANALYTICAL METHODS. 55 The solvent is best poured through the material, thus obviating in large degree the crawling of the extract. The door should be opened several times during the extraction and kept open for a few minutes for the pur- pose of rinsing down the sides of the tubes by means of the condensed vapors. Preparation of Solvents. — In taking the so-called ether extract, some- times reckoned as fat, the solvent employed is either ethyl ether or the cheaper petroleum ether. Whichever reagent is employed, certain pre- cautions are necessary for the purity of the reagent. If ethyl ether is Fig. 22. — Johnson Multiple Extraction Apparatus with Heating Closet and Condenser. used, it should be entirely freed from moisture and alcohol by first shaking with water to remove the larger portion of the alcohol, allowing it to stand for some time over dry calcium chloride, and then distilling over metallic sodium. The ether thus prepared should be kept till used with sodium in the container, the latter being somewhat loosely corked, to allow escape of the hydrogen formed. Petroleum ether is variously termed benzine, naphtha, or gasoline. It should be low-boiling, preferably between 35° and 50°, and it is always best to redistil it before using, in order to be sure it is free from residue. As to the choice of the two reagents for use in fat extraction, it may be said that ethyl ether is the solvent most used, but if a large number of determinations are to be made, the lower cost of petroleum ether is to 56 FOOD INSPECTION AND ANALYSIS. Fig. 23. — Fractionating-still, Arranged for Petroleum Ether. Fig. 24. — A Convenient Form of Separatory Funnel. GENERAL ANALYTICAL METHODS. 57 be considered. A convenient still for fractionating such substances as petroleum ether is shown in Fig. 23. Extraction with Immissible Solvents. — It is frequently necessary to dissolve out a substance from a liquid by shaking it with an immiscible solvent, as, for example, in the extraction of certain preservatives from aqueous or acid solutions with ether, petroleum ether, or chloroform. This can be done by shaking in ordinary flasks, but is attended by some difficulty and loss on decantation. A separatory funnel of the type shown in Fig. 24 is almost indispensible for this kind of extraction. The liquid Fig. 25. — Separatory Funnel Support. and solvent are transferred to the funnel, which is then stoppered and shaken. If the solvent is heavier than water, as in the case of chloroform, it is drawn off from beneath through the outlet-tube of the funnel, or, if the solvent is the lighter, as in the case of ether, the aqueous liquid lying beneath is first drawn off and finally the solvent is poured out through the top. If troublesome emulsions form when shaken, they may frequently be broken up by adding an excess of the solvent and again very gently shaking, or by careful manipulation with a stirring rod, or by centrifug- ing. If the solvent is ether, and an obstinate emulsion forms, it may frequently be broken by the addition of chloroform. Such a mixture of ether and chloroform sinks to the bottom and may be drawn -off as in the case of chloroform alone. 58 FOOD INSPECTION AND ANALYSIS. A separatory funnel support, devised by Win ton, is shown in Fig. 25. It serves for holding the separatory funnels while drawing from one into another, and also as a support for ordinary funnels. The two shelves are adjustable by means of thumbscrews. The holes in these shelves are somewhat wider than the slots, so that the separatory funnels after being introduced through the latter drop into position and are held firmly while manipulating the stop-cock. Winton attaches all stop-cocks and stoppers to the funnel by means of small brass chains, thus preventing breaking and interchange of these parts during washing. ' Determination of Nitrogen by Moist Combustion. — In thus determin- ing nitrogen, the organic matter is first decomposed by digestion with sulphuric acid and an oxidizer, the carbon and hydrogen being driven off as carbon dioxide and water respectively, while the nitrogen is converted into an ammonium salt, from which free ammonia (NH3) is later liberated by making alkaline. The ammonia is then distilled into an acid solution of known value and calculated by titrating the excess of acid. In the Kjeldahl process the oxidation is effected by means of a mercury compound, in the Gunning method, by potassium sulphate which forms the bisulphate with the acid. Neither method in its simplest form is applicable in the presence of nitrates; if these are present, a modification must be used. The Gunning- Arnold method (page 446) is employed for the determination of nitrogen in pepper, as the piperin is not completely decomposed by the usual processes. The Gunning Method. — Reagents: Standard alkah solution, N/io NaOH or NH4OH.* Pulverized potassium sulphate. Sulphuric acid, concentrated, free from nitrogen. Sodium hydroxide, saturated solution. Standard acid solution, N/io H2SO4 or HCl.* An indicator, cochineal solution (page 28). Granulated zinc, passing a i-mm. mesh. * Winton employs standard acid of such a strength that i cc. is equivalent to i% of nitrogen, working on a gram of material, and titrates back with standard alkali two cind one-half times weaker than the acid. In order to insure accurate readings, burettes of narrow bore (i cc.= 2.6cm.) are employed. The alkali burette is so graduated that a reading of i corresponds to 2.5 cc, thus allowing for the greater dilution. The advantage of this system is that the per cent of nitrogen is obtained by simply subtracting the alkali reading from the number of cc. of acid employed. GENERAL ANALYTICAL METHODS. 59 The digestion and distillation are preferably carried out in the same flask, which should be pear-shaped with flat or round bottom and made of moderately thick Jena glass. A convenient size has the following dimen- sions: length 29 cm., maximum diameter 10 cm., tapering gradually to a long neck, which near the end is 28 mm. in diameter with a flaring edge. Its capacity is about 550 cc. If desired, the digestion may be conducted in a smaller hard-glass flask of about 250 cc. capacity and of the same shape as the above, and the distillation in an ordinary round-bottomed flask cf 500 cc. capacity. Introduce from 0.5 to 3.5 grams of the sample into the digestion-flask with 10 grams of potassium sulphate and from 15 to 25 cc. of concentrated sulphuric acid. The flask is inclined over the flame and heated gently for a few minutes "below the boiling-point of the acid till the frothing has ceased, after whic"h the heat is gradually increased till the acid boils, and the boiling is continued till the contents have become practically colorless or at least of a pale straw color. Wire gauze may be interposed between the flask and flame, but a triangle or a similiar support is to be preferred. The contents of the flask are then cooled, and, if the digestion has been conducted in the larger flask suitable also for distilling, is above recommended, 300 cc. of water are added and sufficient strong sodium hydroxide to make the contents strongly alkaline, using phenolphthalein as an indicator. If a separate flask is used for the distillation, the contents of the digestion-flask are transferred thereto with the water and the alkah added. A few pieces of granulated zinc should also be introduced, which by the evolution of gas prevents bumping and the sucking back of the distillate. The flask is then without delay connected with the con- denser, the bottom of which is provided with an adapter, dipping below the surface of the standard hydrochloric or sulphuric acid, a measured quantity of which is contained in the receiving- flask. The distillation is then continued till all the ammonia has passed over into the acid, this part of the operation requiring from forty-five minutes to an hour and a half. As a rule the first 250 cc. of the distillate will contain all the ammonia. The excess of acid in the receiving-flask is then titrated with standard alkali, and the amount of nitrogen absorbed as ammonia is calculated. The reagents, unless known to be absolutely pure and free from nitrates and ^ 60 FOOD INSPECTION AND ANALYSIS. ammonium salts, should be tested by conducting a blank experiment with sugar, by means of which any nitrates present are reduced. Any nitrogen due to impurities should be corrected for. In purchasing sulpliuric acid for nitrogen determination it is important to specify that it be "nitrogen-free" as the so-called chemically pure acid often contains a considerable amount of nitrogen. Modification of Gunning Method to include Nitrogen of Nitrates. — In addition to the reagents used in the simpler Gunning method, sodium thiosulphate and salicyhc acid are required. A mixture of salicylic and sulphuric acids is made in the proportion of 30 cc. of concentrated sulphuric to i gram of sahcyhc. From 30 to 35 cc. of Fig. 26.— Bank of Stills for Nitrogen Determination by Gunning Process. the mixture are added to the 0.5 to 3.5 grams of the substance in the di- gestion-flask, the flask is well shaken and allowed to stand a few minutes, GENERAL ANALYTICAL METHODS. 61 occasionally shaking. Then 5 grams of sodium thiosulphate are added, and 10 grams of potassium sulphate, after which the heat is applied, at first very gently and afterwards increasing slowly till the frothing has ceased. The heating is then continued till the contents have been boiicd practically colorless. From this point on, proceed as in the Gunning method. The Kjeldahl Method. — One gram of the air dry substance, or a propor- tionately larger amount of a moist or liquid substance, and 0.7 gram of mercuric oxide (or an equivalent amount of metallic mercury) are placed Fig. 27a. — Johnson Digestion Stand for Nitrogen Determination with Lead Pipe for Carrying off Fumes. in a 550-cc. Jena flask and 20 cc. of sulphuric acid added. The flask is placed in an inclined position over a Bunsen burner, and the mixture heated below boiling for 5 to 1 5 minutes or until the frothing ceases, after which the heat is raised until the mixture boils briskly. The boiling is continued until the liquid has become nearly colorless and for a half hour in addition. The lamp is then turned out, the flask placed in an upright position, and potassium permanganate slowly added with shaking until the solution takes on a permanent green or purple color. After cooling, 250 cc. of water are added, then 25 cc. of potassium sulphide solution (40 grams of the commercial salt in i liter of water), sufficient saturated sodium hydroxide solution to render the solution alkaline, and finally a few grains of granulated zinc, shaking the flask after each addition. Without delay connect with the distillation appa- ratus, and proceed as in the Gunning method. 62 FOOD INSPECTION AND ANALYSIS. Apparatus for Nitrogen Determination. — A bank of stills used by the author in nitrogen determination and in other processes is shown in Fig, 26. The digestion apparatus shown in Fig. 27a is that devised by Johnson, Winton, and Boltwood. The stand is of cast iron, with holes provided with three projections that support the flask. The lead pipe with holes for receiving the ends of the flasks serves to carry off the acid fumes. Sy has devised apparatus for sucking the fumes from the flask into water by means of a filter pump, thus dispensing with a hood. Fig. 2 7 J. — Johnson Distilling Apparatus for Nitrogen Determination. The Johnson distilling apparatus, with accessories by Winton, is hown in Fig. 27^. The distillation tubes, except for the glass traps and bulb receiver tubes, are of block tin, and are cooled in a copper tank filled with water. The receivers for the distillate are ordinary pint milk bottles. At the left are two bottles with suspended tubes for measuring the potassium sulphide and sodium hydroxide solutions. Determination of Ammonia. — A weighed quantity of the finely divided sample, treated with ammonia-free water and made alkaline with magnesium oxide free from carbonate, is distilled into a measured quan- tity of standard acid (tenth-normal hydrochloric or sulphuric acid) and the amount of ammonia determined by titration. GENERAL AJMALYTICAL METHODS. 63 Determination of Protein Nitrogen. — Stutzer Method.^ — Boil 0.5-2.0 grams of the sample, ground to pass a i-mm. mesh, with 100 cc. of 1% acetic acid in 95% alcohol, cool, filter, and wash by decantation with warm alcohol. Heat the insoluble matter in the beaker with 100 cc. of water for 10 minutes on a boiling water-bath with stirring, cool, and add copper hydroxide suspension (2% copper sulphate solution 'containing 0.05% of glycerol, precipitated with an excess of sodium hydroxide, washed by decanta- tion with water containing 0.5% of glycerol, and finally suspended in 10% glycerol) sufficient to contain 0.3-0.4 gram of copper hydroxide as deter- mined by evaporation and ignition. Allow to settle, collect on a paper, wash with water, and determine nitrogen in filter and contents. In the absence of alkaloids heat directly with water and precipitate with the copper reagent. Determination of Nitrogen in Amino Acids. — Van Slyke Method.-\ — This method has proved valuable in physiological investigations and is useful in food examination in special cases. The manipulation is quite simple, but the apparatus is somewhat expensive. For further details reference should be made to Van Slyke's original articles or Mathews' Physiological Chemistry. Determination of the Various Carbohydrates. — Under title of "Cereals" in Chapter X are given in detail methods for separation and determination of sugar, starch, dextrin, crude fiber, etc. Detection of Poisons. — Metallic impurities present in foods incidental to their preparation, or as adulterants, are considered under title of foods liable to such adulteration. The detection of highly toxic substances, such as arsenic, corrosive sublimate, and alkaloids, added with criminal intent, comes within the province of the medico-legal chemist or toxicologist and is beyond the scope of this work. The methods involved are fully described in the treatises of Autenrieth | and Blyth,§ only those for arsenic, which occurs also as an accidental impurity, being here considered. Detection and Determination of Arsenic. — Methods of Solution. — • Syrups, baking powders and other materials soluble in water or acid do not need preliminary treatment. Beer is treated as described in Chapter XV. Other methods of solution are as follows: I. Johnson-Chittenden-Gautier Method.\\ — This method is suitable for meat, vegetables, and the like, the proportion of acids used being * Jour. Landw., 29, 1881, p. 473. t D. D. Van Slyke, Jour. Biol. Chem., 12, 1912, p. 275; 16, 1913, p. 121; 23, 1915, p. 408. X Detection of Poisons and Strong Drugs, trans, by Warren, Phila., 1905. § Poisons, their Efifects and Detection, London, 1906. II Amer. Chem. Jour., 2, 1880-81, p. 250. 64 FOOD INSPECTION AND ANALYSIS. varied to suit conditions. Heat at i5o°-i6o° C, in a porcelain dish, loo grams of the finely divided material with 23 cc. of pure concentrated nitric acid, stirring occasionally. When the mixture assumes a deep orange color, remove from the heat, add 3 cc. of pure concentrated sul- phuric acid, and stir while nitrous fumes are given off. Heat to 180° and add while hot, drop by drop, with stirring, 8 cc. of nitric acid, then heat at 200° till sulphuric fumes come off and a dry charred mass remains. Pulverize the mass, exhaust with hot water, filter, evaporate to small volume, take up in cold 20% sulphuric acid and treat by the modified Marsh or Gutzeit method. 2. Sanger Method.'^ — Digest at room-temperature for some hours 5 to 20 grams of the material in a casserole with about an equal bulk of \=- Fig. 28. — Marsh Apparatus for Arsenic. concentrated nitric acid, add 20 cc. of concentrated sulphuric acid and digest further at a gentle heat until the mixture begins to char. Add about 2 cc. of nitric acid and heat until sulphuric fumes appear, repeating the addition of acid and heating until oxidation appears to be practically complete. Remove all nitric acid by dilution and evaporation to the fuming stage, then dilute with 4 volumes of water. At this point about twice the bulk of saturated sulphurous acid solution may be added and the evaporation repeated, thus reducing to the arsenious condition, but this is not usually necessary. Methods of Determination. — i. Marsh Test. — The apparatus (Fig. 28) consists of a generating flask with funnel tube, a U-tube containing cotton * Proc. Am. Acad. Arts, Sci., 26, 1891, p. 24. GENERAL ANALYTICAL METHODS. 65 moistened with io% lead acetate solution (to remove hydrogen sulphide), a calcium chloride drying tube, and a hard glass tube of 6 mm. bore, drawn down near the end to a uniform constriction about 4 cm, long and i mm. inside diameter and also at the very end to a narrow exit tube. The tube is sup- ported over a three-burner furnace the part in contact with the flame being wrapped with wire gauze. Introduce into the generating flask from 20 to 30 grams of arsenic-free stick zinc and a perforated platinum disk to form an electric couple. Stopper and add through the funnel tube 20% sulphuric acid sufficient to start the reaction and drive out all air. When danger of explosion is over heat the tube to bright redness. After running the current long enough to prove the absence of arsenic in the reagents add slowly from the funnel tube the solu- tion of the material in 20% sulphuric acid or the solu- tion obtained by one of the foregoing methods containing about 20% of that acid, keeping a steady evolution of gas. When the flow slackens add 30% sulphuric acid and later 40% acid until all arsenic has been expelled, which usually requires 2 to 3 hours. If no arsenic mirror forms in the constriction of the tube in one hour, further test may be abandoned. If more than o.i mg. of arsenic appears to be present cut off the constriction from the tube and weigh it on an assay balance; then dissolve the arsenic in a solution of sodium hypochlorite, (antimony being insoluble), wash with water and then with alcohol, dry, cool, and weigh. The loss is arsenic. If the amount of arsenic is very small Sanger com- pares the mirror with a series of standard mirrors pre- pared in the same apparatus using quantities of a stand- ard solution containing from 0.005 to 0.05 mg. of AS2O3. To prepare the standard solution i gram of pure AS2O3 is dis- solved in arsenic-free sodium hydroxide, acidified with sulphuric acid, made up to one liter and 10 cc. of this stock solution further diluted to I liter; i cc. = o.oi mg. AS2O3. 2. Sanger -Black-GiUzeit Method.'^ — The apparatus (Fig. 29), devised by Bishop, consists of a 30 cc. salt-mouth bottle provided with three upright * Jour. Soc. Chem. Ind., 26, 1907, p. 1115. Fig. 29. — Bishop Apparatus for Arsenic. 66 FOOD INSPECTION AND ANALYSIS, tubes one above the other. The lower tube is 7 cm. long, i cm. in bore, and contains strips of filter-paper previously soaked in 5% lead acetate solution and dried. The middle tube is of the same size as the lower but shorter. It is loosely filled with cotton moistened with 1% lead acetate solution. The upper tube has a uniform bore of 2.5 mm. and is bent twice so that the upper end is vertical. In this tube is placed a strip of cold-pressed drawing paper 2 mm. wide which has been soaked in 5% alcoholic mur- curic chloride (or bromide) and dried. Place in the evolution bottle 10 grams of stick zinc, a few crystals of stannous chloride, a perforated platinum disk and from 2 to 5 grams of the material or else the extract of the charred or digested material pre- pared as described in the foregoing sections, containing about 20% of sulphuric acid. Add enough 20% (1:4) sulphuric acid to nearly fill the bottle, attach the three tubes and allow to react for 45 minutes. Com- pare the color on the sensitized strip with that of standard strips obtained with from 0.005 to 0.05 mg. of AS2O3 in the same apparatus, using measured quantities of the standard solution described under the Marsh test. Colorometric Analysis. — Certain analytical processes depend on the formation of a compound of the substance to be determined having a definite color, and the calculation of the quantity present from the inten- sity of the color of the solution, compared with that of a solution contain- ing a known amount. The comparisons may be made in a special form of cylinder or in a colorimeter. The latter has the advantage that a single solution of known strength serves within reasonable limits for matching any shade in the unknown solution, and for any number of determina- tions, the desired depth of the color being secured by varying the length of the column. Schreiner's Colorimeter.* — This apparatus, shown in Fig. 30, consists of two graduated tubes {B), containing the standard and unknown colori- metric solutions, the height of the column of liquid in both tubes being changed by two immersion tubes {A), which remain stationary while the graduated tubes arc raised or lowered in the clamps (C). The mirror D reflects the light through the tubes, and the mirror E reflects it again to the eye of the operator at F. In making the comparisons, the tube containing the solution of either known or unknown strength is set at a definite point, and the other tube is raised or lowered until the colors match. If R is the reading of the standard solution of the strength 5, and r the reading of the colorometric solution of unknown strength s, then s = —S. r * Tour. Am. Chem. Soc. 27, 1905, p. 1192. GENERAL ANALYTICAL METHODS. 67 If desired, standard slides of colored glass, such as accompany the Lovibond tintometer, may be used at G for matching the solution of un- known strength, the value of these slides being determined by comparison with a standard solution. The Lovibond Tintometer may be used for colorometric chemical analysis, but is not so well suited for this purpose as the Schreiner colorimeter, it is especially designed for deter- mining the color value of liquid and solid technical products, such as beer, wine, oil, flour, paper, etc. The instrument itself is of simple construc- tion, consisting of an elongated box with an eyepiece at one end and two rectangular openings at the other, one for the solution or substance to be examined, the other for the standard glass slides used for matching the color. Light is reflected through the openings by means of a square piece of opal glass mounted on a jointed standard. Liquids are examined in rectangular cells with glass sides by transmitted hght, while powders are pressed into a form and examined by reflected light. The standard slides used in general work are red, yellow, and blue in even graduation from .006 to 20 tint units which can be combined so as to produce any desired tint or shade of any color. The results are expressed in terms of standard dominant colors (red, yellow, and blue), subordinate colors (orange, green, and violet) obtained by combining equal values of two dominant colors, and neutral tint (black) obtained by combining equal values of the three dominant colors. Thus o.6i? + 5.6F = o.60+5.oF o.oSi? + 1.5 F+o.2j5=o.o8iV+o. 12^ + 1.37 i.2R + i.oB = i.oV +0.2R in which i? = red, F = yellow, -S = blue, 0= orange, G = green, F = violet, AT" = neutral tint or black. Special slides may be obtained for the examination of any desired product. For example, slides of brown shades are furnished for beer, of yellow shades for oils, and so on. Fig. 30. — Schreiner's Colori- meter with a Tube showing Graduation. 1 CHAPTER V. THE MICROSCOPE IN FOOD ANALYSIS. Microscopical vs. Chemical Analysis. — A very important means of identification of adulterants in many classes of food products is furnished by the microscope, which in many cases affords more actual information as to the purity of food than can be obtained by a chemical analysis. This is especially true of coffee, cocoa, and the spices, wherein the micro- scope serves to reveal not only the nature of the adulterants, but also not infrequently the approximate amount of foreign matter present. In the case of the cereal and leguminous products so commonly employed as adulterants, a microscopical examination is of paramount importance. The chemical constants of many of the adulterants of coffee and the spices do not always differ sufficiently from those of the pure foods in which they appear to be distinguished therefrom with accuracy and confidence by a chemical analysis alone. On the other hand, one who is familiar with the appearance under the microscope of the pure foods and of the starches and various ground substances used as adulterants, can, with certainty, identify very minute quantities of these materials, when present, with the same ease that one can recognize megascopically the most famihar objects about him, A chemical test may, for example, indicate the presence of starch, but it cannot reveal the particular kind of starch. The microscope will at once show whether the starch present is wheat or corn or potato or arrowroot, since these starches differ almost as much in microscopical appearance as do the physical characteristics of the grains or tubers from which they are obtained. Again, by a chemical analysis an abnormal amount of crude fiber may show the presence of a woody adulterant, but only the microscope will enable one to decide whether the impurity consists of sawdust, chaff, or ground nut shells. Not only in such in- stances as these is the microscopical examination of greater importance than a chemical analysis, but it is a much quicker guide. The Technique of Food Microscopy. — The recognition of adulterants by the microscope requires some experience but no more than may be acquired by a chemist who will give the subject serious attention. In 68 THE MICROSCOPE IN FOOD ANALYSIS. 69 the examination of flour, commercial starch, cocoa, coffee, tea, and the spices for adulteration, a careful study of the powdered substance in tem- porary water mounting will in most cases prove sufficient to familiarize the food analyst with their characteristics under the microscope. In extended studies standard works on the microscopy of foods should be consulted. It is not necessary for him to familiarize himself with the details of section cutting, dissecting, or permanent mounting unless he so desires. Such details are given by Behrens,* Chamberlain, f Gage, J and Zimmer- man. § Microchemical methods of ana'ysis, a subject quite distinct from food histology, is fully treated by Chamot.lj Standards of Comparison. — For standards the analyst should provide himself with as complete a set as possible of the various materials to be examined, taking care that their absolute purity is established. Where- ever possible, he should grind the sample himself from carefully selected whole goods. These, together with samples of the starches and other adulterants, all of known purity, should be contained in small vials care- fully stoppered and plainly labeled, arranged alphabetically or in some equally convenient manner in the desk or table on which the microscope is commonly used. The adulterants included in this set of standards should be not only those which experience has shown most liable to be employed, but any which, by reason of their character, might in the analyst's opinion be used under certain conditions. APPARATUS. The Microscope-stand. — An expensive or complicated stand is un- necessary. The prime requisites for good work in a microscope-stand are firmness or rigidity, and accuracy in centering. An inexpensive stand possessing these features can be used for the best work, providing the optical parts are satisfactory. It is well, if economy must be practiced, to purchase a simple stand provided with the society screw, and let the larger portion of the allowance go for a high grade of lenses, since many of the attach- ments inherent in a high-priced stand, though often of convenience, may well be dispensed with. * Guide to the Microscope in Botany. t Methods in Plant Histology. X The Microscope and Microscopical Methods. § Botanical Microtechnique. II Elementary Chemical Microscopy, New York, 1915. 70 FOOD INSPECTION AND ANALYSIS. A stand of the so-called continental type (having the horseshoe base) Is preferable. A square stage is rather more convenient than the circular form, and the jointed pillar possesses advantages over the rigid variety in ease of manipulation that are certainly worth considering. The smooth working of both the coarse and fine adjustments should not be lost sight of. If the microscope is to be used exclusively for food work, a substage condenser is unnecessary, hence the construction of the Fig. 31. — Continental Type of Microscope. substage may be very simple, unless bacteriological work is to be done as well. A nose-piece, while not indispensable, is a great convenience for the quick transfer of objectives. A double nose-piece carrying two objectives is ample for routine food work. The Optical Parts are by far the most important, and should be of superior quality, though not necessarily of the most expensive makers. The food analyst should have at least two objectives, one for high- and one for low power work, and preferably two oculars. For the routine examination of powdered food substances the writer prefers a ^-inch objective, used with a medium ocular, the combination giving a magnificatiDn of from 240 to 330 diameters, according to the jcular employed. For a low-power objective the |-inch is a conven- THE MICROSCOPE IN FOOD ANALYSIS. 71 lent size. It is useful as a finder preliminary to examination with the higher power, and, in connection with a low-power eyepiece, is well adapted for the examination of butter and lard, anc^for use with the polariscope. An eyepiece micrometer mounted in an one inch ocular is indispen- sable for measuring starch grains and other elements. It is calibrated by means of a stage micrometer. The Micro-polariscope. — This accessory is useful in the identification of starches and other ingredients, and for ascertaining whether or not fats have been crystallized. The polarizer is held below the stage, while the analyzer is applied above the objective, either in the tube or above the ocular. Fig. 32. — Polarizer and Analyzer for the Microscope. A common form of construction is one in which the substage is adapted to carry interchangeably the diaphragm tube and the polarizer. If the polariscope is much used, it becomes desirable to provide means for quickly changing the polarizer and diaphragm tube below the stage, and for moving the analyzer in and out of place above the objective. Winton* has devised a microscope-stand with this in view, especially adapted to the needs of the food analyst. If the polariscope is to be used often, it is convenient to have within easy access two stands, one with the polariscope mounted in place in v-^onnection with low-power glasses ready for use, and the other stand )rovided with the ordinary high- and low-power objectives only. Microscope Accessories include of necessity a large number of slides ind cover glasses. The latter should be No. 2 thickness, | inch, either round or square. One or more dissecting-needles in holders and a sniall hand magni- fying-glass should also be provided. * Journal App. Microscopy, 2, p. 550. 72 FOOD INSPECTION AND ANALYSIS. Other useful accessories are. a mechanical stage, a pair of fine tweezers, knives, scissors, and, if sections are to be cut, a plano-concave razor. MICROTECHNIQUE. Preparation of Vegetable Food Products for Microscopical Examina- tion. — The ground spices and cocoas of commerce are usually of the requisite fineness for direct examination without further treatment. Coffee, chocolate, starches, and similar products should be ground in a mortar fine enough to pass througii a sieve with from 60 to 80 meshes to the inch. A small portion of the powdered sample is taken up on the tip of a clean, dry knife-blade, and placed on the microscope-slide. By means of a medicine-dropper a drop of distilled water is applied, and the wetted Fig. 33. — Mechanical Stage for Microscope. powder is then rubbed out under the cover-glass between the thumb and finger to the proper fineness. The water-mounted slide thus prepared, while useful only for tem- porary purposes, has proved to be best adapted to the analyst's require- ments for routine microscopical examination of powdered food products for adulteration, partly because water is the best medium in most cases for showing up the structural characteristics of these substances and their adulterants, and partly because it serves best for the "rubbing out" process between thumb and finger under the cover-glass, whereby the sample is brought to the requisite degree of fineness. Experience will soon show how far this rubbing out should be carried for the best effects. Gentle pressure should be applied, care being taken not to break the cover-glass, especially if the sample contain anything of a grittv nature. The rubbing should be continued till the coarser par- THE MICROSCOPE IN FOOD ANALYSIS. 73 tides and overlying masses are separated and distributed uniformly, but if too long persisted in, the forms of the tissues, starch grains, and other characteristic portions will be partially destroyed and of too fragmentary a nature to be readily recognizable. Canada Balsam in Xylol is a useful mountant for the examination of starches with polarized light. In this medium, under ordinary illumina- tion, the starches are not plainly visible, since the refractive index of the two are nearly identical, but with crossed nicols the starch grains stand out clearly and distinctly in a dark background. If the material is not perfectly dry it should be soaked in absolute alcohol and then in chloroform or xylol until dehydrated. Glycerin. — A mixture of equal parts of glycerin and water is perhaps the best medium for permanent mounts, but considerable skill is required to finish the preparation with cement on the edge of the cover- glass. Glycerin jelly is more readily handled by the beginner since no cement is required. Glycerin Jelly * is prepared as follows : i part by weight of the finest French gelatin is soaked two hours in 6 parts of distilled water, after which 7 parts by weight of C. P. glycerin are added, and to each lOo parts of the mixture add i part of concentrated carbolic acid. Heat the mixture while stirring till flocculency disappears and filter through asbestos while warm, the asbestos being previously washed and put into the funnel while wet. The jelly is solid at ordinary temperatures, and must be warmed to melt. A small bit of this jelly is removed from the mass by a knife-blade and placed on the clean-slide, which is held over a gas flame till the jelly is melted. The powdered specimen being then shaken into the molten drop, the cover-glass is gently placed upon it (being brought down obliquely to avoid formation of air-bubbles) and pressed down in place. Microscopical Diagnosis. — It is never safe to pass judgment on a spice or other food by the microscopical examination of a single portion. Several slides should be prepared with bits of the powder taken from different parts of the mass, before the character and extent of the adultera- tion can be safely determined. Care should be taken that the shde, the knife-blade, the water, and the medicine-dropper be perfectly clean and free from contamination with previous specimens. It should be borne in mind that at best a composite powdered sample * Botan. Centralbl., Bd. i, p. 25. 1 74 FOOD INSPECTION AND ANALYSIS. is but a mechanical mixture of various tissues, and that no two portions will show exactly the same composition. Characteristic Features of Vegetable Foods under the Microscope.— The structural features of a powdered spice, examined microscopically, will be found to differ considerably in appearance from those of a thin, carefully mounted section of the same spice. Instead of the beautiful arrangement of cells and cell contents with the perfect order of various parts as seen in the mounted section, one finds in the powdered sample under the microscope what often appears to be a most confusing mass of fragments of various tissues. For this reason the most striking charac- teristics seem to vary with different observers, and it is a well-known fact that microscopists differ widely as to conceptions of size, shape, and ordinary appearance, even in the case of certain of the well-known starch grains. It is on this account that, irrespective of the description of others, the analyst should familiarize himself with the microscopical appearance of the foods with which he is dealing, as well as of their adulterants, form- ing his own standards as to what constitute the recognizable features, from specimens prepared by himself. In the large variety of ground berries, buds, tubers, barks, etc., from which the spices and condiments are prepared, as well as in the grains, legumes, shells, fruit stones, and other materials forming the most familial adulterants, the kinds of plant tissues and cell contents which, under the microscope, serve as distinguishing marks or guides for identification are comparatively few in number. The most common of these varieties of cell tissue and of cell contents to be met with by the food microscopist in his work are briefly the follow- ing: Parenchyma. — This is most abundant and widely distributed, forming as it does the thin-walled, cellular tissue of nearly all vegetable food sub- stances. The walls of parenchyma cells are, as a rule, colorless and transparent. The forms of the cells are varied and are often sufficiently characteristic in themselves to identify the substance under examination. Sclerenchyma, or stone cells, are the thick-walled woody cells forming the hard part of nut shells, fruit stones, and seed coverings, occurring also in some fruits and barks. These cells are more often colored and of various shapes but almost always irregular, sometimes elongated, as in cocoanut shells and olive stones, occasionally nearly rectangular, as in pepper shells, and sometimes polygonal or nearly circular. In appearance the sclerenchyma cell commonly has a more or less THE MICROSCOPE IN FOOD ANALYSIS. 75 deep, central or axial cavity, from which small fissures extend through the thick walls. See Fig. 35. Variously shaped sclerenchyma cells are found in allspice, cassia, 9.^ ? Fig. 34.— Typical Forms of Various Cell Tissues. Longitudinal section through a clove, showing: Fp, two forms of parenchyma; J5, bast fibers; g, vascular and sieve tissue; KK', cells with calcium oxalate crystals. (After Vogl.) pepper, clove stems, nut shells, etc. Stone cells are optically active to polarized light, and between crossed nicols are very conspicuous by their bright appearance. St — Fig. 35. — Sclerenchyma, or Stone-cell Tissue. A cross-section through the stone-cell layer of the fruit shell of black pepper. (After Vogl.) Fibro-vascular Bundles are composed of three parts: the bast fibers, or mechanical elements, the phloem, and the xylem. 76 FOOD INSPECTION AND ANALYSIS. Bast Fibers are elongated, pointed sclerenchyma cells, of which flax fibers are examples. Sieve Tubes, the characteristic elements of the phloem, are thin- walled tubes with perforated partitions known as sieve plates. Vessels or Ducts occur in the xylem. They are designated as spiral, annular, reticulated, or pitted, according to the nature of the walls. Corky Tissue, or Suberin, constitutes the thin-walled, spongy cells forming the protective, outer dead layers of the bark. This is found in cassia, and in the barks used as adulterants. Suberin is tested for by potassium hydroxide (p. 80). jf^ Starch wherever it occurs furnishes the most charac- teristic feature of the cell contents, and, as a rule, will at once indicate under the microscope, by the shape and grouping of its granules, the particular substance of which it forms a part. It is very abundantly distributed through- out the vegetable kingdom and occurs in a wide variety of forms. It is particularly conspicuous when viewed by polarized light. Between crossed nicols such starches as corn, potato, and arrowroot show out brightly from a dark background with dark crosses, the bars of which ^^°' •^^• , , ., . , , ,,„ , . ted Ducts of Chic- intersect at the hilum of each granule. When a selemte ory. (After Vogl.) plate is introduced above the polarizer, a beautiful play of colors is seen with various starches, a phenomenon which Blyth apphes as a means of identification and classification, but which more modern micro- scopists regard as of minor importance to distinguishing the various starches morphologically. Starch is found naturally in the cereals, legumes, and many vegetables, in cassia, allspice, nutmeg, pepper, ginger, cocoa, and turmeric. The cereal and leguminous starches from their inertness and cheapness constitute the most common adulterants of the spices and of powdered foods in general. Starch grains are found in the cells of the parenchyma and in other cellular tissues. Iodine is the special reagent (p. 78). Gums and Resins occur in characteristic forms among the cell contents of some of the spices. As an example, the portwine-colored lumps of gum in allspice furnish one of the most ready means of recognizing that spice microscopically. Resin is tested for microchemically with alkanna tincture (P- 79)- -Reticula- THE MICROSCOPE IN FOOD ANALYSIS. 77 Aleurone or Protein Grains are found in many seeds, but are not especially characteristic. They somewhat resemble small starch grains. Most varieties of protein grains are soluble in water, but some are insoluble. The soluble varieties, which are not apparent in water- mounted specimens, must be examined in absolute alcohol, glycerin, or oil. In leguminous seeds aleurone occurs closely intermingled with starch in the same cells, while in the cereals it occupies the whole cell. Protein grains are tested for under the microscope by iodine in potas- sium iodide, which turns them brown or yellowish brown, and by Millon's reagent, which colors them brick red. Plant Crystals are not uncommon in the class of substances which the food analyst examines. Among the common forms are the piperin crystals found in pepper. Calcium oxalate occurs in many vegetable products as prismatic crystals, crystal aggregates, or needle-shaped crystals (raphides). Crystals of calcium carbonate are sometimes met with also, as, for example, in hops. Calcium oxalate crystals are insoluble in acetic acid, while being readily soluble in dilute hydrochloric. Calcium carbonate crystals are soluble with effervescence in both acids. The acid reagents are directly applied to the sample in water-mount under the cover-glass, and the reaction observed through the microscope. Fat Globules are of common occurrence in many foods and appear of various sizes, sometimes large and conspicuous, and again almost lost sight of because of their minuteness. They are sometimes colorless, as in mace, and sometimes deeply tinted, as in cayenne. Alkanna tincture is used as a reagent for fat (p. 79). Other Cell Contents of less importance, but which may be identified by the microscope with reagents, are tannic acid (tested for by chloriodide ot zinc and ferric acetate (pp. 78 and 79), and various essential oils, for the detection of which alkanna tincture is employed. REAGENTS IN FOOD MICROSCOPY. Unless a more extended microscopical investigation of vegetable food substances is contemplated than is involved in the mere identification of adulterants, the analyst will have little need for reagents other than iodine in potassium iodide, chloral hydrate solution, and potassium hydroxide solution, the last two for clearing, but will depend almost entirely on the form and appearance of the various tissues or tissue fragments, as well as on the abundance, shape, and distribution of such distinctive cell con- tents as the starches, fat globules, or crystals. 78 FOOD INSPECTION AND ANALYSIS. Analytical reagents are applied to the water-mounted sample by means of a glass rod or pipette, with which a drop of the reagent is deposited on the sample upon the slide, having previously lemoved the cover, which is afterwards replaced. Or, without removing the cover-glass, a drop of the reagent is placed in contact with one side of it on the slide. Along the opposite side of the cover is then placed a piece of filter-paper. The latter withdraws by capillary attraction a portion of the water from under the cover-glass, and this is replaced by the reagent, which thus intermingles with the particles of the substance. The following reagents include those needed in routine work as well as some others suited for studies of the general nature of tissues and cell contents. A. Analytical Reagents. — Iodine in Potassium Iodide. — Two grams. of crystallized potassium iodide are first dissolved in loo cc. of distilled water and the solution is saturated with iodine. This reagent is indispensable for the identification of starch, especially when the latter is present in minute quantities. Starch granules when moistened with water are turned blue by iodine, the reaction being exceed- ingly delicate under the microscope, even when the starch granules are very minute and insignificant without the reagent. Iodine in connection with sulphuric acid is also useful in distinguishing pure cellulose from its various modifications, such as lignin and suberin. For this purpose the water-mounted sample is first permeated with the iodine reagent, after which concentrated sulphuric acid is applied, with the result that all pure cellulose is turned a deep-blue color, while the modified forms of cellulose are colored yellow or brown. The cellulose is first converted by the sulphuric acid into a carbohydrate isomeric with starch, known as amyloid. Protein grains are colored brown or yellow brown by the action of iodine. Chloriodide 0} Zinc. — Pure zinc is dissolved in concentrated hydro- chloric acid to saturation, and an excess of zinc added. The solution is then evaporated to about the consistency of concentrated sulphuric acid, after which it is first saturated with potasshim iodide, and finally with iodine. This reagent may be used instead of sulphuric acid and iodine for the detection of cellulose, since the zinc chloride converts the cellulose into amyloid, which the reagent colors blue. Chloriodide of zinc is useful for detecting tannic acid in cell contents. For this purpose the above reagent is much diluted by the addition of THE MICROSCOPE IN FOOD ANALYSIS. 79 a 20% solution of potass'mm iodide. In this diluted form, when applied to the sample, a reddish or violet coloration is imparted to cell contents having tannin. Phenol-hydrochloric Acid is prepared by saturating concentrated hydrochloric acid with the purest crystallized carbolic acid. Wood fiber, or lignin, when treated with a drop of this reagent under the cover-glass, and exposed for half a minute to the direct sunlight, will be colored an intense green, which quickly fades. Indol. — Several crystals of indol are freshly dissolved in warm water. Lignified cell walls assume a deep-red color, when the specimen to be examined is treated first with a drop of the indol reagent, and afterwards washed with dilute sulphuric acid, i : 4. Millon's Reagent. — This is prepared by dissolving metallic mercury in its weight of concentrated nitric acid, and diluting with an equal volume of water. This reagent, which should be freshly prepared, is of use in testing for protein compounds, which turn brick red when treated with it, especially on gently warming the slide. Tincture 0} Alkanna. — A 70 or 80% alcoholic extract of alkanna root, when kept in contact with resins, fixed oils, fats, or essential oils for a short time, stains these cell contents a lively red. The staining is hastened by the aid of heat. Essential oils and resins are soluble in strong alcohol, while iixed oils and fats are insoluble, hence the distinction between these classes of cell contents may be made by the application of alcohol to the alkanna-stained specimen. Ferric Chloride, Ferric Acetate, or Ferric Sulphate, used in dilute aqueous solution, are all applicable as reagents for tannic acid, which, when present in appreciable amount, will be colored green or blue by either of these reagents. B. Clarifying Reagents. — ]\Iany of the harder cellular tissues are too opaque for careful examination, and may be rendered transparent by clarify- ing or bleaching. The simplest and for many purposes the most satis- factory method for clearing the tissues is by boiling a water mount, replacing the water lost by evaporation. Proceeding in this manner, there is ordi- narily no danger of the slide or cover-glass breaking; if the boiling is carried out without a cover-glass, the slide is alm.ost sure to break. A portion of the powdered sample is cither boiled with a drop. of the reagent under the cover-glass or is allowed to soak for hours or even days in the reagent, using a drop of the same reagent as a medium for examination on the object-glass, instead of water. The clarifying reagents mxost com- monly used are the following: 80 FOOD INSPECTION AND ANALYSIS. Chloral Hydrate. — A 60% solution. Ammonia. — Concentrated, or 28% ammonia is commonly used. Potassium Hydroxide, used in various degrees of concentration, often in dilute solution, say 5%. This reagent, added to a water mount, causes swelling of the cell wall, and dissolves intercellular substances and protein. It bleaches most of the coloring matters, destroys the starch, and forms soluble soaps with the fats. Potassium hydroxide is also used in testing for subcrin, which is extracted from corky tissue on boiling with the reagent, and appears as yellow drops. Schnitzels Macerating Reag'^nt (concentrated nitric acid and chlorate of potassium) is best used by placing the powder or bit of tissue to be treated in a test-tube with an equal volume of potassium chlorate crystals, adding about 2 cc. of concentrated nitric acid, and warming the tube till bubbles are evolved freely, or until the necessary separation of cells is effected. The sample is then removed and washed with water. By this treatment, bast and wood fibers as well as stone cells are readily separated from other tissues. Cuprammonia (Schweitzer's Reagent). — This is prepared by adding slowly a solution of copper sulphate to an aqueous solution of sodium hydroxide, forming a precipitate of cupric hydroxide, which is separated by filtration, washed, and dissolved in concentrated ammonia. It should be freshly prepared, and is never fit for use unless it is capable of immediately dissolving cotton. Indeed its chief use is as a test for cellulose, which it readily dissolves. In observing this reaction under the microscope, the powdered specimen under the cover-glass should be only slightly damp before a drop of the fresh reagent is applied. The cell walls are seen to swell up and gradually become more and more indistinct, till they finally disappear. Cuprammonia is also used as a test for pectose, which occurs in many cell walls, often intermixed with cellulose. When treated with this reagent, cellular tissue containing pectose is acted upon in such a manner that a delicate framework of cupric pectate is sometimes left behind, after the dissolution of the cellulose with which it is mingled.* PHOTOMICROGRAPHY. The photomicrograph serves as a simple means of keeping perma- nent records of unusual forms of adulteration encountered in the course of routine examination. Besides this, the photomicrograph has at times proved its usefulness as a means of evidence in court, showing as it does with faithfulness the pres ence of a contested adulterant. It is true * Poulsen, Botanical Micro-chemistry, p. 15. THE MICROSCOPE IN FOOD ANALYSIS. 81 that from an artistic and didactic standpoint the photomicrograph of a powdered sample is often disappointing, due to the fact that ordinarily much of the field is out of focus, unless a very simple homogeneous sub- ject is photographed, as, for instance, starch. As compared with the care- fully prepared drawing of a section, which shows minute details of struc- ture, the photomicrograph portrays what happens to be in focus. SUMMARY OF MICROCHEMICAL REACTIONS FOR IDENTIFYING CELLULAR TISSUE AND CELL CONTENTS. BASED ON BEHRENS'.* Iodine in Potassium Iodide. Chlor- iodide of Zinc. Iodine and Sul- phuric Acid. Cupram- monia. Potassium Hydroxide. Concen- trated Sulphuric Acid. Schultze' s Mixture. Cellulose, cell substance. Lignin, wood substance. Middle lamella, inter- Yellow to brownish Yellow Yellow Yellow or brownish Blue Brown yellow Violet Yellow Yellow Yellow or brown Blue Yellow to brownish Yellow Brown Dissolves Insoluble Insoluble Insoluble Swells up Dissolves Dissolves Dissolves Dissolves Dissolves easily Suberin, cork substance. Starch Insoluble in cold. By boiling it comes out in drops Dissolves Dissolves Insoluble easily Gives eerie acid reac- tiont Fat Saponifies Reddish to violet Phenol- hydro- chloric Acid. Indol. Ferric Acetate or Sul- phate. Alkanna Tincture. Hydro- chloric Acid. Acetic Acid. Millon's Reagent. Cellulose, cell substance. Lignin, wood substance. Middle lamella, inter- Uncolored Green Green Uncolored Uncolored Cherry red Cherry red Uncolored Brick red Bright red Bright red Bright red Fat Blue or green Calcium oxalate crystals Calcium carbonate ' ' Soluble without ef- fervescence Soluble with effer- vescence Insoluble Soluble with effer- vescence * Microscopical Investigation of Vegetable Substances, page 356. t When treated with the reagent, suberin forms masses of eerie acid, soluble in ether, alcohol, or chloroform. While the analyst examines microscopically the ordinary powdered spice, for example, he constantly moves with his hand the fine adjustment- screw, bringing into focus different parts of the field successively. This 82 FOOD INSPECTION AND ANALYSIS. he does unconsciously, so that he does not realize how far from flat the field actually is till he undertakes to photograph it, when, as a rule, only a small portion is in good focus. It is therefore impossible in one photo- graph to show successfully many varied forms of tissue or cell contents in the powder, but separate photographs should be made as far as possible with only a little in each. Thus, for example, with a composite subject like powdered cassia bark, it would be very difficult to show starch, stone cells, and bast fibers in one field, all in equally good focus, and, for the best results only, one, or at most two, such varied groups of elements should be shown in one picture. Appurtenances and Methods of Procedure. — The temporary method of water-mounting employed by the analyst in routine examination pre- sents many difficulties from a photographic point of view. The vibrating motion of the particles is very annoying, and some skill is required in using just the right amount of water, in avoiding air-bubbles, in waiting the requisite amount of time before exposing the plate for the vibratory motion to cease, and, on the other hand, avoiding too long delay, which would result in the evaporation of the water, and the consequent breaking up of the field. In the writer's experience, however, in spite of these difficulties, the water-mounting gives decidedly the clearest results, and, with patience on the part of the operator, it is in many ways the most desirable method of mounting for photographic purposes. It is in fact the method employed in making most of the photomicrographs of powdered specimens that appear in the plates at the end of this volume, though a few were mounted in glycerin jelly, and the starches for the polarized-light pictures in Canada balsam. The sections of tissues shown in the plates were mounted some in glycerin and others in glycerin jelly. Experience has shown that two degrees of magnification well cal- culated to bring out the chief characteristics of the spices and their adul- terants in a photomicrograph are 125 and 250 diameters. The starches, which are the most common of any one class of adulterants, vary very widely in the size of their granules. With these the larger magnification of 250 has been found satisfactory, while the general appearance of the composite ground-spice itself under the microscope, as well as that of such adulterants as ground bark, sawdust, chicory, pea hulls, and the like, is best shown with the lower power of 125.* * The degrees of magnification adopted in the originals of most of the photomicrographs illustrated in the accompanying plates are accordingly 125 and 250, but in the process of lithographing, the photographs were slightly reduced, so that the actual scales in the repro duction are 110 and 220 respectively. THE MICROSCOPE IN FOOD ANALYSIS. 83 1 he object, mounted in the manner above described, is best examined when held in a mechanical stage, furnished with micrometer adjust- ments, in such a manner that a typical field may be selected and held in place long enough to photograph. The Camera. — This need not of necessity be complicated, but may consist simply of a horizontal wooden base on which the microscope Fig 37a. — A Convenient Photomicrographic Camera, rests, and an upright board firmly secured to the base, carrying a frame for an interchangeable ground glass and plate-holder, with a rubber gauze skirt hanging from the frame, adapted to be gathered and tied about the top of the microscope-tube. Means are further provided, as by a slotted guide and screw, for adjusting the frame at any desired height on the upright board.* A more convenient form of apparatus now employed by the writer is that shown in Figs. 37a and 376. * Such a contrivance as this was employed in making some of the accompanying photo- micrographs. 84 FOOD INSPECTION AND ANALYSIS. The base is a solid iron plate upon which the microscope rests (any microscope may be used with this camera), and above which the camera bellows is supported on two solid steel rods. The bellows is supported at either end on wooden frames. The ground glass is provided with a central transparent area, formed by cementing a cover-glass upon the ground glass, and permits the accurate focusing of the most delicate detail by means of a hand magnifying-glass. The vertical rods supporting the bellows are attached to metal arms, immovably fixed to a horizontal axis, thus permitting the camera to be tilted Fig z^b. — Photomicrographic Camera in Horizontal Position to any angle from vertical to horizontal. It is fixed at the desired angle by means of heavy hand-clamps. In use the camera is placed in a vertical position and the microscope adjusted on the base so that its tube will coincide with the opening in the front of the camera. The connection between microscope and camera is made light-tight by means of a double chamber, which permits consider- able vertical motion of the tube of the microscope without readjustment. A jointed telescoping rod is attached to the upper end of the camera to act as a support, giving perfect steadiness when in a horizontal position, and folding down parallel with the bellows so as to be out of the way when in any other position. Amplification. — The vertical rods are graduated in inches for deter- mining the amount of amplification, and to show when the ground glass is at right angles to the optical axis. The following simple rule for deter- mining the amount of amplification will give sufficiently accurate results. When photographing without the eyepiece, divide the distance of the ground glass from the stage of the microscope in inches, by the focal length in inches of the objective used. When photographing with the eye- piece, proceed as above and multiply the result by the quotient obtained by dividing lo by the focus in inches of the eyepiece used. THE MICROSCOPE IN FOOD ANALYSIS. 85 Adjustment and Manipulation. — The microscope can be placed in any position desired, and the camera adjusted to it. The bellows can then be raised and the microscope used as though no camera were present. When an object is to be photographed, the bellows may be slid into posi- tion without in any way disturbing the arrangement of light or object, the final focusing on the ground glass being effected quickly by means of the fine adjustment-screw of the microscope. The exposure having been made, observation through the microscope may be continued with- out interruption by simply raising the bellows again. When a water-mounted specimen is to be photographed, the camera and microscope tube should be vertical instead of inclined as shown in the cut. The camera is best kept in a dark room where the exposures are to be made, the source of light being a i6- or 32-candle-power electric lamp, preferably provided with a ground-glass bulb. The light from this lamp is first carefully centered by moving the reflector of the microscope. In making pictures, for instance, of the magnification of 250 diameters, the objective, having an equivalent focus of ^ inch, may be used in combination with the one-inch ocular, with the ordinary tube length of microscope. For a lower power, such as 125 diameters, the same objec- tive is employed, but the eyepiece is left out, it being found necessary in this case to remove the upper tube of the microscope, which ordinarily carries the eyepiece, as otherwise the size of the field to be photographed would be restricted. In each case a diaphragm is used in the microscope stage, having an opening of about the same size as that of the front lens of the objective. By means of a stage micrometer scale, the proper posi- tion of the camera back is previously determined to give the required magnification. CHAPTER VI. THE REFRACTOMETER. The refractive index ranks in importance with the specific gravity as a means of determining the identity and purity of various food products, as well as of estimating the percentage of valuable constituents. Various forms of refractometer are used in food analysis. The Abbe refractometer is of general application in determining the refractive index of fats, fatty oils, waxes, and essential oils, in esti- mating the solids in saccharine substances, and in other analytical opera- tions. It employs but a few drops of the material, and reads the refractive index directly, using ordinary white light. The immersion refractometer, an instrument of recent introduction, is suited for the examination of milk serum to detect added water therein, the detection and determination of methyl alcohol in ethyl alcohol, and the standardization of a wide variety of solutions. The instrument is immersed directly in the liquid to be examined, the degree of refraction being indicated on an arbitrary scale. The Pulfrich is used with the sodium light, and requires a larger amount of material than the Abbe, the liquid being held in a cylinder above the prism. The scale reading is in angular degrees, from which the index of refraction is calculated by a formula or from a table. The instrument is provided with a temperature-controlling apparatus. In the Amagat and Jean or oleo-refractometer, an outer and an inner cylinder are respectively filled with an oil of known value or purity, and with the oil to be examined. By the comparative displacement to the right or left of a beam of white light passing through both cylinders, the displacement being read in degrees on an arbitrary scale, the refraction of an oil may be measured. Two oils may thus be readily compared under the same conditions, one of known purity, for example, with a doubtful sample of the same kind. The butyro-refractometer and the Wollny milk fat refractometer (p. 126) are, as their names imply, instruments primarily intended for more restricted fields of work than the foregoing. They involve the same principle as the Abbd, but are simpler in construction and have arbitrary scales. Unless such widely varying substances as the waxes and the essential oils are to be studied, the Zeiss butyro-refractometer, though primarily 86 THE REFRACTOMETER. 87 intended for the examination of butter and lard, answers most of the purposes of the Abbe instrument with the advantage of greater sim- phcity, being equally well adapted for examining all the common edible oils and fats, as well as other materials. THE ZEISS BUTYRO-REFRACTOMETER. This instrument (shown in Fig. 38) is so constructed that the degree of refraction of a beam of light, which passes obliquely through a thin Fig. 38. — The Zeiss Butyro-refractometer. film of the fat, is read on an arbitrary scale of sufficient extent to cover the widest limits of deviation possible for butter fat and oleomargarine under ordinary temperatures. The graduation is in divisions from i to 100, covering a variation in refractive indices of from 1.4220 to 1.4895. A and B are the two hinged hollow portions of the prism casing of the instrument, so arranged that when closed together the melted fat is held in a film of sufficient thickness between the two opposed transparent prism surfaces, the beam of light, either diffused daylight or lamplight, being reflected through it by means of the mirror /. The transparent scale is within the telescope tube at the height indicated by G. 88 FOOD INSPECTION AND ANALYSIS. The refractometer is connected to any kind of heating arrangement, which admits of warm water being transmitted through the prism casing, in at D and out at E. A simple arrangement, which suffices for all ordinary cases, may expeditiously be improvised in the following manner: Fill a vessel of say 2 gallons capacity with water of 40° to 50° C. Into this vessel dip the free end of an india-rubber tube slipped over the nozzle D and let the vessel be placed at a height of about one-half or one yard above the refactometer. Then it will be seen that suction at a tube attached to E will cause the warm water to flow through the prism casing by the action of the siphon arrangement. By means of a pinch clip the velocity of the water may be regulated at will. The waste water may be allowed to flow into a second vessel and, provided its tem- perature does not fall below 30°, it may be used for replenishing the upper vessel. When working with solid fats, a temperature must be maintained by the heated water well above the melting-point of the fat. With liquid oils no heater is necessary, as determinations may be made at room temperature, but it is advisable in all cases to have a constant stream of water passing through the water jacket, which may be done by directly connecting it with the water faucet in the case of oils, since, without such precautions to insure even temperature, disturbing variations are liable to occur, due to the warming of the prisms by the manipulation of clean- ing, etc. Refractometer Heater. — ^A regular heater, shown in Fig. 39, is furnished by the manufacturers, capable of supplying a current of water of approx- imately constant temperature, and will be found of great convenience when the instrument is to be used constantly, especially with .the solid fats. A supply reservoir A is secured to the wall and is connected by means of a rubber inlet tube G to the water faucet C The reservoir is provided with a waste overflow pipe and with an outlet tube D, the flow through the latter being regulated by the cock H. The tube D leads to the spiral heater HS, which is heated by a Bunsen burner. From the heater the tube E conducts the warm water through the refractometer, from which it flows through the tube F, either directly into the sink, or into the inter- mediate vessel B. The temperature of the water is regulated by adjust- ing the cock iJ, and the height of the flame of the Bunsen burner. Manipulation of the Butyro-refractometer. — The prism casing is first opened by giving about half a turn to the right to the pin F, Fig. 38, until it meets with a stop. Then simply turn the half B of the prism THE REFRACTOMETER. 89 casing aside. Pillar H holds B in the position shown in Fig. 38. The prism and metallic surfaces must now be cleaned with the greatest care, the best means for this purpose being soft linen, moistened with a little alcohol or benzine. If the sample to be examined is a solid fat, maintain the temperature above the melting-point, and apply by a glass rod a drop or two of the clear melted fat (filtered if turbid) to the surface of the prism contained in the casing B. For this purpose the apparatus should be raised with Fig. 39.— The Zeiss Heating Apparatus for all Forms of Refractometer. Shown in the cut in connection with the PulMch refractometer. the left hand so as to place the prism surface in a horizontal position. A liquid oil is directly applied in the same manner without preliminary precautions as to heating. Now press B against A, and place F by turning it in the opposite direction, in its original position; thereby B is prevented from falling back,, and both prism surfaces are kept in close contact. Place the instrument again upon its sole plate. While looking into the telescope, give the mirror / such a position as to render the critical line, which separates the bright left part of the field from the dark right part, distinctly visible. It may also be necessary to move or turn the instrument about a little. First it will be necessary to ascertain whether the space between the prism surfaces be uniformly filled with oil or fat, failing which the critical line will not be distinct. For this purpose examine the rectangular image of the prism surface formed about i cm. above the ocular with a hand magnifier or with the 90 FOOD INSPECTION AND ANALYSIS. naked eye, placing the latter at its proper distance from the ocular. Finally adjust the movable front part of the ocular so that the scale becomes clearly visible. By allowing a current of wsLter of constant temperature to flow through the apparatus some time previous to the taking of the reading, the at first somewhat hazy critical line approaches in a short time, generally after a minute, a fixed position, and quickly attains its greatest distinctness. When this point has been reached, note the appearance of the critical fine (i.e., whether colorless or colored, and in the latter case of what color); also note the position of the critical line on the centesimal scale, which admits of the tenth divisions being conveniently estimated; at the same time read the position of the thermometer. Testing the Adjustment of the Ocular Scale. — It is imperative that the adjustment of the instrument be tested periodically, and in particular when it is being used for the first time. This may be done by means of the standard fluid supphed with the instrument, the critical line of which is approximately colorless, and must occupy the following positions in the scale. Temper- Scale Temper- Scale Temper- Scale Temper- Scale ature. Division. ature. Division. ature. Division. ature. Division. 30= 68.1 25° 71.2 20° 74-3 15° 77-3 29° 68.7 24° 71.8 19° 74-9 14° 77-9 28° 69-3 23° 72.4 18° 75 -S 13° 78.6 27° 70.0 22° 73-0 17° 76.1 12° 79-2 26° 70.6 21° 73-6 16° 76-7 11° 79-8 25 = 71.2 20° 74-3 15° 77-3 10° 80.4 The fractional parts of a degree can accordingly easily be brought into calculation (0.1=0.06 scale div.). Deviations of i to 2 decimals of the scale divisions are of no consequence, and are in most cases due to inexact determinations of temperature. Should, however, careful tests result in the discovery of greater deviations, readjustment of the scale will be necessary, which may be effected by means of a watch-key supplied with the instrument, in accordance with the values given in the above table. The watch-key is inserted at G in Fig. 38, and by its means the position of the objective, and therefore that of the critical line with respect to the scale may be altered. Trans] ormation 0} Scale Divisions into Indices of Refraction. — The following table, adapted from that of Pulfrich, enables one to convert scale readings on the butyro-refractometer into indices of refraction, «^, and vice versa: THE REFRACTOMETER. 91 EQUIVALENTS OF INDICES OF REFRACTION AND BUTYRO-REFRAC- TOMETER READINGS. Refrac- tive Fourth Deci nal of M^_ Index. j 1 "A 1 2 3 4 5 6 7 8 9 SCALE READINGS 1.422 0.0 0.1 0.2 0.4 0-5 0.6 0.7 0.9 I.O I.I 1.423 1.2 1-4 1-5 1.6 1-7 1-9 2.0 2.1 2.2 2.4 1.424 2-5 2.6 2-7 2.8 3-0 3-1 3-2 3-3 3-5 3-6 1-425 3-7 3-8 4.0 4-1 4-2 4-3 4-5 4.6 4-7 4.8 1.426 5-0 5-1 5-2 5-4 5-5 5-6 5-7 5-9 6.0 6.1 1.427 6.2 6.4 6-5 6.6 6.8 6.9 7.0 7-1 7.2 7-4 1.428 7-5 7-6 7-7 7-9 8.0 8.1 8.2 8.4 8.5 8.6 1.429 8-7 8.9 9.0 9-1 9-2 9-4 9-5 9.6 9.8 9-9 1.430 10. 10. 1 10.3 10.4 10-5 10.6 10.7 10.9 II. II. I I-431 11-3 II. 4 11-5 11.6 II. 8 II. 9 12.0 12.2 12.3 12.4 1-432 12.5 12.7 12.8 12.9 13.0 13.2 13-3 13-5 13.6 13-7 1-433 13-8 14.0 14-1 14-2 14.4 14-5 14-6 14-7 14.9 15.0 1.434 iS-i 15-3 15-4 15-5 15.6 15.8 15-9 16.0 16.2 16.3 1-435 16.4 16.6 16.7 16.8 17.0 17. 1 17.2 17-4 17-5 17.6 1.436 17-8 17.9 18.0 18.2 18.3 18.4 18.5 18.7 18.8 18.9 1-437 19.1 19.2 19-3 19-S 19.6 19.7 19.8 20.0 20.1 20.3 1.438 20.4 20.5 20.6 20.8 20.9 21. 1 21.2 21.3 21.4 21.6 1-439 21.7 21.8 22.0 22.1 22.2 22.4 22.5 22.6 22.7 22.9 I -44c 23.0 23.2 23-3 23-4 23-5 23-7 23.8 23-9 24.1 24.2 I-44t 24-3 24-S 24.6 24.7 24.8 25.0 2S-I 25-2 25-4 "1-5 1.442 25.6 25.8 25-9 26.1 26.2 26.3 26.5 26.6 26.7 26.9 1.443 27.0 27.1 27-3 27-4 27-5 27-7 27.8 27-9 28.1 28.2 1.444 28.3 28.5 28.6 28.7 28.9 29.0 29.2 29-3 29-4 29.6 1-445 29.7 29.9 30.0 30.1 30-3 30-4 30.6 30-7 30.8 30-9 1.446 31-1 31.2 31-4 31-S 31.6 31.8 31-9 32.1 32.2 32.3 1.447 32-5 32.6 32.8 32-9 33-0 33-2 33-3 33-5 33-6 33-7 1.448 33-9 34-0 34-2 34-3 34-4 34.6 34-7 34-9 35-0 35-1 1.449 35-3 35-4 35-6 35-7 35-8 36-0 36-1 36-3 36-4 36-S 1.450 36-7 36-8 37-0 37-1 37-2 37-4 37-5 37-7 37-8 37-9 1. 45 1 38.1 38-2 38-3 38-5 38-6 38-7 38-9 39-0 39-2 39-3 1.452 39-5 39-6 39-7 39-9 40.0 40.1 40-3 40.4 40.6 40.7 1-453 40.9 41.0 41. 1 41-3 41.4 41-5 41.7 41.8 42.0 42.1 1-454 42.3 42-4 42-5 42.7 42.8 43-0 43-1 43-3 43-4 43-6 I-45S 43-7 43-9 44.0 44-2 44-3 44.4 44-6 44-7 44.9 45 -o 1.456 45-2 45-3 45-5 45-6 45-7 45-9 46.0 46.2 46.3 46-4 1-457 46.6 46.7 46.9 47.0 47-2 47-3 47-5 47-6 47-7 47-9 1.458 48.0 48.2 48.3 48.5 48.6 48.8 48.9 49-1 49-2 49 4 1-459 49-5 49-7 49-8 50.0 50.1 50.2 50-4 50-5 50-7 50.8 1.460 51.0 51-1 S^-^ 51-4 51-6 51-7 51.9 52.0 52.2 52-3 1. 461 52-5 52-7 52-8 53-0 53-1 53-3 53-4 53-6 53-7 53-9 1.462 54-0 54-2 54-3 54-5 54-6 54.8 55-0 55-1 55-3 55-4 1.463 55-6 55-7 55-9 56-0 56.2 56.3 56-5 S6.6 S6.8 56-9 1.464 57-1 57-3 57-4 57-^' 57-7 57-9 58.0 58-2 58-3 58-5 1.465 58.6 58.8 58-9 59-1 59-2 59-4 59-5 59-7 59-8 60.0 1.466 60.2 60.3 60.5 60.6 60.8 60.9 61. 1 61.2 61.4 61.5 1.467 61.7 61.8 62.0 62.2 62.3 62.5 62.6 62.8 62.9 63.1 1.468 63.2 63-4 63 5 63-7 63.8 64.0 64.2 64-3 64-5 64-7 1.469 64.8 65.0 65.1 65-3 65-4 65-6 65-7 65-9 66.1 66.2 92 FOOD INSPECTION AND ANALYSIS. EQUIVALENTS OF INDICES OF REFRACTION AND BUTYRO-REFRAC TOMETER READINGS— (Continued). Refrac- Fourth Decimal of «£), tive Index, »D. 1 2 3 4 5 6 7 8 9 SCALE READINGS 1.470 66.4 66.5 re. 7 66.8 67.0 67.2 67-3 67-5 67-7 67.8 1. 471 68.0 68.1 68 3 68.4 68 6 68 7 68 9 69 I 69 2 69.4 1.472 69-s 69.7 69 9 70.0 70 2 70 3 70 5 70 7 70 8 71.0 1-473 71. 1 71-3 71 4 71.6 71 8 71 9 72 I 72 2 72 4 72.5 1-474 72.7 72-9 73 73-2 73 3 73 5 73 7 73 8 74 74-1 1-475 74-3 74-5 74 6 74-8 75 75 I 75 3 75 5 75 6 75-8 1.476 76.0 76.1 76 3 76.5 76 7 76 8 77 77 2 77 3 77-5 1-477 77-7 77-9 78 I 78.2 78 4 78 6 78 7 78 9 79 I 79-2 1.478 79-4 79-6 79 8 80.0 80 I 80 3 80 5 80 6 80 8 81.0 1.479 81.2 81.3 81 5 81.7 81 9 82 82 2 82 4 82 5 82.7 1.480 82.9 83-1 83 2 83-4 83 6 83 8 83 9 84 I 84 3 84-5 1. 481 84-6 84.8 85 85.2 85 3 85 5 85 7 85 9 86 86.2 1.482 86.4 86.6 86 7 86.9 87 I 87 3 87 5 87 6 87 8 88.0 1.483 88.2 88.3 88 5 88.7 88 9 89 I 89 2 ■89 4 89 6 89.8 1.484 90.0 90.2 90 3 90-5 90 7 90 9 91 I 91 2 91 4 91.6 1=485 91.8 92.0 92 I 92-3 92 5 92 7 92 9 93 93 2 93-4 1.486 93-6 93-8 94 94-1 94 3 94 5 94 7 94 8 95 95-2 1-487 95-4 95-6 95 8 96.0 96 I 96 3 96 6 96 7 96 9 97.0 1.488 97-2 97-4 97 6 97-8 98 98 I 98 3 98 5 98 7 98.9 1.489 99-1 99.2 99.4 99-6 99-8 100. The Critical Line. — It should be remembered that the instrument is primarily intended for use with butter, and that the prisms are so con- structed that the critical line of pure butter is colorless, while various other fats and oils, notably oleomargarine, which have greater dispersive powers than natural butter, show a colored critical line. When too great dis- persion is apparent to render possible an accurate reading, or when the critical Hne presents very broad fringes, as with linseed oU, poppyseed oil, turpentine, etc., use a sodium light, obtained by the apphcation of table salt to the Bunsen gas flame, or the diffused daylight may be re- flected in the mirror through a flat bottle filled with a dilute solution of potassium bichromate, to give a yellow Hght. The advantages of the refractometer for examination of fats and oils consist in the convenience with which very accurate determinations of the refractive index may be made at any temperature between 10° and 50° C, inclusive of thermal variations of refractive powers, and also in the possibihty which it affords of distinguishing substances by their different dispersive powers, rendered visible by the different coloring of the critical line, a red-colored critical line being indicative of a relatively low dispersive power, a blue line of relatively high dispersion. S-J THE REFRACTOMETER. 93 ■^- O _|_| [-§ s si— S SM- -^^-3 li. f. E — cx^ §-l Variation of Reading with the Temperature. — No definite temperature has been adopted as a standard for readings of this instrument, but it is easy to reduce readings at any temperature to terms of any other temperature for purposes of comparison. While the change in index of re- fraction for 1° C. is the same whatever the temperature, as Tolman and Munson have pointed out,* the change in scale reading per i° C. de- creases as the temperature increases, and varies slightly with different oils. For correcting read- ing R' at a temperature T' to a reading R at temperature T, their formula is R = R' — X{T — T'), X being the change in scale reading due to change of i° C. in temperature. For butter, oleomargarine, beef tallow, lard, and other fats reading from 40° to 50° or there- abouts on the scale, X = o.55. For oils reading between 60° and 70°, like olive, mustard, rapeseed, cottonseed, peanut, etc., X = 0.58, and for oils read- ing between 70° and 80°, like corn oil, X = o.62. The slide rule f shown in Fig. 40, for use with the refractometer, has been jointly devised by H- C. Lythgoe and the writer, to render unnecessary' the use of tables or formulas. The extreme upper and lower scale divisions indicate indices of re- fraction, and adjacent to these are the scale divisions indicating readings on the butyro- refractometer. By comparison, therefore, the values of either the Abbe or the butyro scale may be readily ascertained in terms of the other. The sliding scale, expressing temperature readings in degrees centigrade, is intended to be used in connection with the adjacent scale of butyro-refractometer readings, to readily express the butyro-scale reading of any fat or oil taken at a given temperature, in terms of that at any other temperature. This is frequently convenient Fig. 40. — Comparative fractometer Scale. .lai-tuiiicuc. o.cx. * Jour. Am. Chem. Soc, XXIV, p. 755. t Mtnufaclure'd by Messrs. Bairdand Tatlock, Ltd., 14 Cross Street, Hatton Garden, London. 94 FOOD INSPECriOxNT AND ANALYSIS. in comparing the work of various observers, where different temperatures have been employed. The correction for change in w^ on the scale is 0.000365 for 1° C, being based on the experimental work of Tolman, Long, Proctor, Lythgoe, and the author. THE ABBE REFRACTOMETER. This instrument, Fig. 41, has a much wider range in reading than either the butyro or the Wollny instruments already described, read- FiG. 41. — The Abbe Refractometer with Temperature-controlled Prisms. ing as it does to the fourth decimal between the limits of 1.3 and 1.7 in indices of refraction. The equivalent readings of the Wollny milk fat refractometer, in indices of refraction, range from 1.3332 to 1.4220, while those of the butyro instrument run from 1.4220 to 1.4895. The Abbe instrument is thus necessary for use with the high-refracting essential THE REFRACTOMETER. 95 oils. Its construction is such that the prisms can withstand a higher heat than in the case of the butyro-refractometer, and it is hence better adapted for the examination of samples having a high melting-point, such as beeswax and paraffin. An advantage of the Abbe over the butyro instrument lies in the fact that the wide dispersion, inevitable when read- ing many substances on the butyro, may be entirely compensated for with the Abbe, and a clear sharp line be obtained. The construction of the prisms in relation to the heating jacket is similar in both instruments, and a film of the substance to be examined is held in the same manner between the surfaces of the prisms. Construction and Manipulation. — The Abbe refractometer is mainly composed of the following parts (see Fig. 41) : 1. The double Abbe prism AB, which contains the fluid and can be rotated on a horizontal axis by means of an alidade. 2. A telescope OF for observing the border-line of the total reflec- tion which is formed in the prism. 3. A sector .5, rigidly connected with the telescope, on which divisions representing refractive indices are engraved. The double prism (AB, Fig. 41) consists of two similar prisms of flint-glass, each cemented into a metal mount and having a refractive index ^£,= 1.75. The former of the two prisms, that farthest from the telescope, which can be folded up or removed, serves solely for the purpose of illumination, while the border-line is formed in the second flint prism. A few drops of the fluid to be investigated is deposited between the two adjoining inner faces of the prisms in the form of a thin stratum, about 0.15 mm. thick. The double prism is opened and closed by means of a screw-head V, which acts in the manner of a bayonet catch. In order to apply a small quantity of fluid to the prisms without opening the casing, the screw V is slackened and a few drops of fluid poured into the funnel- shaped aperture of a narrow passage, not seen in the figure. On again tightening the screw, the fluid is distributed by capillary action over the entire space between the two prisms. This arrangement facili- tates the investigation of rapidly evaporating fluids, such as ether solu- tions. In the case of viscous fluids (resins, etc.) , a drop of moderate size is apphed with a glass rod to the dull prism surface, the double prism being opened for the purpose. The prisms are then closed again, and before the measurement is proceeded with, the refractometer is left standing for a few minutes in order to compensate for any cooling or heating of the prisms which might occur while they were separated. 96 FOOD INSPECTION AND ANALYSIS. The arrangement for controlling the temperature of the prisms of the Abbe refractometer is essentially after Dr. R. Wollny's plan of enclos- ing the prisms in a metal casing with double walls, through which water of a given temperature is circulated. The border-line is brought within the field of the telescope OF by rotating the double prism by means of the alidade in the following manner: Holding the sector, the alidade is moved from the initial position at which the index points to ^£,= 1.3, in the ascending scale of the refractive indices until the originally entirely illuminated field of view is encroached upon from the direction of its lower half by a dark portion; the line dividing the bright and the dark half of the field then is the "border-line." When daylight or lamplight is being employed, the border-line, owing to the total reflection and the refraction caused by the second prism, assumes at first the appearance of a band of color, which is quite unsuitable for any exact process of adjustment. The conversion of this band of color into a colorless line sharply dividing the bright and dark portions of the field is the work of the compen- sator, which consists of two similar Amici prisms of direct vision for the D-WxiQ, and rotated simultaneously, though in opposite directions, round the axis of the telescope by means of the screw-head M. The dispersion of the border-line, which appears in the telescope as a band of color, can thus be counteracted by rotating the screw-head M till the equal but opposite dispersions are neutralized, making the line color- less and sharp. The border-line is now adjusted upon the point of intersection of the crossed lines by slightly inclining the double prism to the telescope by means of the alidade. The position of the pointer on the graduation of the sector is then read by the aid of the magnifier attached to the alidade. The reading supplies the refractive index w^, of the substance under investigation without any computation, and with a degree of exactness approaching to within about two units of the fourth decimal. Simultaneously, the reading of the scale on the drum of the compensator {T in Fig. 41) enables the mean dispersion to be arrived at by means of a special table and a short process of computation. Influence of Temperature. — As the refractive index of fluids varies with their temperature, it is of importance to know the temperature of the fluid contained in the double prism during the process of measure- ment. If, therefore, it is desired to measure a fluid with the highest degree of accuracy attainable with the Abb^ refractometer (to within one or THE REFRACTOMETER. 97 two units of the fourth decimal of w^),it is absolutely necessary to bring the fluid, or rather the double prism containing it, to a definite known temperature, and to be able to control this temperature so as to keep it constant to within some tenths of a degree for a period of several hours; hence a refractometer principally required for the investiga- tion of fluids must be provided with beatable prisms. The type of heater shown in Fig. 39. and described in connection with the butyro-refractometer on page 88, is equally adapted for con- trolling the temperature of the prisms in the Abbe instrument, the flow of water entering at D and passing out at E, Fig. 41. THE IMMERSION REFRACTOMETER. This form of refractometer is of more recent introduction than the others made by Zeiss, and has many features that especially commend it to the use of the food analyst. The construction of the immersion refrac- tometer is such that, as its name implies, it may be immersed directly in an almost endless variety of solutions, the strength of which, within Hmits, may be determined by the degree of refraction read upon an arbitrary scale. Thus, for example, the strengths of various acids and of a variety of salt solutions used as reagents in the laboratory, as well as of formaldehyde, of sugars in solution, and of alcohol, are all capable of determination by the use of the immersion refractometer. Figure 42 shows the form used by the writer. P is a glass prism fixed in the lower end of the tube of the instrument, while at the top of the tube is the ocular Oc, and just below this on a level with the vernier screw Z is the scale on which is read the degree of refraction of the liquid in which the prism P is immersed. The tube may be held in the hand and directly dipped in the liquid to be tested, this liquid being contained in a vessel with a translucent bottom, through which the light is reflected. The preferable method of use is, however, that shown in the cut. A is a metal bath with inlet and outlet tubes, arranged whereby water is kept at a constant level. The water is maintained at a constant tem- perature by means of a controller of the same type as the refractometer heater shown in Fig. 39. In the bath A are immersed a number of beakers, containing the solutions to be tested. T is a frame on which is hung the refractometer by means of the hook H, at just the right height to permit of the immersion of the prism P in the liquid in any of the beakers in the row beneath. Under this row of beakers the bottom of the tank is composed of a strip of ground glass, through which light is reflected by an adjustable pivoted mirror. 98 FOOD INSPECTION AND ANALYSIS. The temperature of the bath is noted by a delicate thermometei immersed therein, capable of reading to tenths of a degree. Returning to the main refractometer-tube, i? is a graduated ring or collar which is connected by a sleeve within the tube with a compound prism near the bottom, the construction being such that by turning the collar R one way or the other the chromatic aberration or dispersion of any liquid may be compensated for, and a clear-cut shadow or critical line projected across the scale. By the graduation on the collar R, the degree of Fig. 42. — The Zeiss Immersion Refractoraeter. dispersion may be read. Tenths of a degree on the main scale of the in- strument may be read with great accuracy by means of the vernier screw Z, graduated along its circumference, the screw being turned in each case till the critical line on the scale coincides with the nearest whole number. The scale of the instrument reads from — 5 to 105, corresponding to indices of refraction of from 1.32539 to 1.36640. It should be noted th?- ing. ing. ing. ing. ing. 50.0 I . 346500 55-0 T. 348360 60.0 I. 350210 65.0 1-352050 70.0 1-353880 50.1 1-346537 55-1 1-348397 60.1 1.350247 65.1 1.352087 70.1 1-353917 2 574 2 434 2 284 2 124 2 954 3 611 3 471 3 321 3 161 3 991 4 648 4 508 4 358 4 198 4 1.354028 5 685 5 545 5 395 5 235 5 065 6 722 6 582 6 432 6 272 6 102 7 759 7 6x9 7 469 7 309 7 139 8 796 8 656 8 506 8 346 8 176 9 833 9 693 9 543 9 383 9 213 Si-o 870 56.0 730 61.0 580 66.0 420 71.0 250 Si-i 1-346907 56.1 r. 348767 61. 1 I. 35061 7 66.1 1-352457 71. 1 1.354286 2 944 2 804 2 654 2 494 2 322 3 981 3 ' 841 3 691 3 531 3 358 4 I. 347018 4 878 4 728 4 568 4 394 5 055 5 915 5 765 5 605 5 430 6 092 6 952 6 802 6 642 6 466 7 129 7 989 7 839 7 679 7 502 8 166 8 1.349026 8 876 8 716 8 538 9 203 9 063 9 913 9 753 9 574 52.0 240 57-0 100 62.0 950 67.0 790 72.0 610 52.1 1.347277 57-1 1-349137 62.1 1-350987 67.1 1.352827 72.1 1.354646 2 314 2 174 2 I. 351024 2 864 2 682 3 351 3 211 3 061 3 901 3 718 4 388 4 248 4 098 4 938 4 754 5 425 5 285 5 135 5 975 5 790 6 462 6 312 6 172 6 I -353012 6 826 7 499 7 359 7 209 7 049 7 862 8 536 8 396 8 246 8 086 8 898 9 573 9 433 9 283 9 123 9 934 53-0 610 58.0 470 63.0 320 68.0 160 73-0 970 53-1 r. 347647 58.1 1-349507 63.1 1-351357 68.1 1-353196 73-1 1-355006 2 684 2 544 2 394 2 232 2 042 3 721 3 581 3 431 3 268 3 078 4 758 4 618 4 468 4 304 4 114 5 795 5 655 5 505 5 340 5 150 6 832 6 692 6 542 6 376 6 186 7 869 7 729 7 579 7 412 7 222 8 906 8 766 8 616 8 448 8 258 9 943 9 803 9 653 9 484 9 294 54-0 980 59-0 840 64.0 690 69.0 520 74-0 330 541 I. 348018 59-1 1-349877 64.1 I. 351726 69.1 1-353556 74-1 1-355366 2 056 2 914 2 762 2 592 2 402 3 C94 3 951 3 798 3 628 3 438 4 132 4 988 4 834 4 664 4 474 5 170 5 1-350025 5 870 5 700 5 510 6 208 6 062 6 906 6 736 6 546 7 246 7 099 7 942 7 772 7 582 8 284 8 136 8 978 8 808 8 618 9 322 9 173 9 I. 352014 9 844 9 659 S5-0 360 60.0 210 65.0 C50 70.0 880 7S-0 690 THE REFRACTOMETER. 105 TABLE OF INDICES OF REFRACTION, n^—(Contmiied). Scale Scale Scale Scale Scale Read- »»£)• Read- »«£>- Read- «£,. Read- «/)- Read n,j. ing. ing. ing. ing. 90.0 ing. 75-0 1-355690 .*^o.o 1-357500 85.0 I - 359300 1 .361090 95 • 1 . 362870 75-1 I 355727 80.1 1-357536 85.1 1-359336 90. I I . 361126 95-1 I .362Q06 2 764 2 572 2 372 2 162 2 042 3 801 3 608 3 408 3 198 3 978 A 838 4 644 4 444 4 234 4 I -363014 5 875 5 680 5 480 5 270 5 050 6 912 6 716 6 516 6 306 6 086 7 949 7 752 '7 552 1 342 7 122 8 986 8 788 8 588 8 378 8 158 9 1.356023 9 824 9 624 9 414 9 194 76.0 060 81.0 860 86.0 660 91 .0 450 96.0 230 76.1 1.356096 81. 1 1-357896 86.1 1 . 359696 91.1 I. 361486 96.1 1-363256 2 132 2 932 2 732 2 522 2 292 3 168 3 968 3 768 3 558 3 328 4 204 4 I . 358004 4 804 4 594 4 364 5 240 5 040 5 840 5 630 5 400 6 276 6 076 6 876 6 666 6 436 7 312 7 112 7 912 7 702 7 472 8 348 8 148 8 948 8 738 8 518 9 384 9 184 9 984 9 774 9 554 77.0 420 82.0 220 87.0 I . 360020 92.0 810 97-0 590 77.1 1.356456 82.1 1.358256 87.1 1.360056 92.1 I 361846 97-1 I . 363625 2 492 2 292 2 092 2 882 2 660 3 528 3 328 3 128 3 918 3 695 4 564 4 364 4 164 4 954 4 730 s 600 5 400 5 200 5 990 5 765 6 636 6 436 6 236 6 I .362026 6 800 7 672 7 472 7 272 7 062 7 835 8 708 8 508 8 308 8 098 8 870 9 744 9 544 9 344 9 134 9 905 78.0 780 83.0 580 88.0 380 93-0 170 98.0 940 78.1 I. 356816 83.1 1-358616 88.1 I. 36041 6 93-1 1.362205 98.1 1-363975 2 852 2 652 2 452 2 240 2 I. 364010 3 888 3 688 3 488 3 275 3 045 4 924 4 724 4 524 4 310 4 080 5 960 5 760 5 560 5 345 5 IIS 6 996 6 796 6 ■596 6 380 6 160 7 1-357032 7 832 • 7 632 7 415 7 19s 8 068 8 868 8 668 8 450 8 230 9 104 9 904 9 704 9 485 9 265 79.0 140 84.0 940 89.0 740 94.0 520 99.0 290 79.1 1-357176 84.1 1.358976 89.1 1-360775 94-1 I 362555 99.1 1-364325 2 212 2 1.359012 2 810 2 590 2 360 3 248 3 048 3 845 3 625 3 395 4 284 4 084 4 880 4 660 4 430 5 320 5 120 5 915 5 695 5 465 6 356 6 156 6 950 6 730 6 500 7 392 7 192 7 985 7 765 7 535 8 428 8 228 8 I. 361020 8 800 8 570 9 464 9 264 9 055 9 835 9 605 80.0 500 85.0 300 90.0 090 95 870 100. 640 106 FOOD INSPECTION AND ANALYSIS. degradation of the sharpness of the border-line. On the other hand, with a sufficient quantity of solution, the border-line is surprisingly sharp. The refractometer is now suspended on the frame, and the measure- ment proceeded with as before described. After measurement, the cover is first removed, and the prism allowed to fall into the hollow of the hand, then the beaker is removed to enable the refractometer to be conveniently cleaned. Strengths of Various Solutions. — The most extensive work on the quantitative determination of the strength of a large number of common aqueous solutions with the immersion refractometer has been done by Wagner, who has published a large number of tables. These tables show the percentage strength (grams per loo cc. at 17.5° C.) of a large number of salt solutions and of acids, corresponding to the range of scale readings of the instrument, as well as of cane sugar, dextrose, formalde- SCALE READINGS ON IMMERSION REFRACTOMETER OF VARIOUS STAND- ARD REAGENTS USED IN VOLUMETRIC ANALYSIS.* Temperature C. 16°. 17°. 17.5°- i8°- 19°. 20°. 21". aa' Hydrochloric acid: Normal Tenth-normal Sulphuric acid: Normal Fifth-normal Tenth-normal Oxalic acid: Half-normal. « Tenth-normal Potassium bitartrate: Tenth-normal Potassium hydroxide: Normal Tenth-normal Sodium hydroxide: Tenth-normal Sodium thiosulphate ; Tenth-normal Potassium bichromate: Tenth-normal Silver nitrate: Tenth-normal Sodium chloride: Tenth-normal Ammonium sulphocyanate : Tenth-normal 37-45 17.80 30.60 18.75 17-15 22.45 17-15 17-75 43-90 18.45 18.50 24.20 17-75 20.20 18.20 20.60 37.20 17.60 30.40 18.60 16.95 22.30 16.95 17-55 43-65 18.30 18.35 24.05 17-55 20.05 18.00 20.45 36.85 17-30 30. 10 18.30 16.65 22.00 16.65 17-25 43-25 18.00 18.05 23-75 17-25 19-75 17.70 20.15 36.70 17.20 29-95 18.20 16.55 21.90 16.55 17-15 43.10 17.90 17-95 23-65 17-15 19.65 17.60 20.05 36-45 17.00 29-75 18.00 16.35 21 .70 16.35 16.95 42.80 17.70 17-75 23-45 16.95 19-45 17.40 19.85 35-70 16.30 29.00 17-30 15-65 21.00 15-65 16.25 41-95 17.00 17-05 22.70 16.25 18.75 16.70 19-15 * According to Wagner, all these solutions were made up at 17.5° C. Readings at different t«m> peratures are given for convenience. THE REFRACTOMETER. 107 hyde, alcohol, etc. All these observations have been based on the Mohr liter, at a temperature of 17.5°. More convenient for the American analyst would be tables based on the use of a higher temperature, say 20°, and the analyst is recommended to work out his own standards for com- parison, at the temperature best suited to his special locality and conven- ience. The instrument is especially useful in preparing normal and tenth- normal solutions. The table on page 106, from Wagner, shows the strength of various common laboratory reagents. SCALE READINGS AT TEMPERATURES FROM 10-30° C. Corrected to 17.5°, According to Wagner. No. X. 2. 3- 4- 5- 6. 7- 8. 9. 10. It. 12 & 13. No. fed Scale Reading at 17.5° C. id IS. 30. 25- 30. 35. 40. 4S. 50. 60. 70. 80. 90 = —8c (Hoppe- Seyler) . Laclalhumin is the soluble albumin of milk, existing therein to the extent of about 0.6% and forming about 15% or more of the milk proteins. It much resembles the albumin of eggs, being coagulated at 72° to 84° C. It is readily soluble in water. Its specific rotation is [a]z)= - 37. Lactoglohulin has been discovered by Emmerling as a constituent in milk, but exists in traces only. According to Babcock, it may be separated from milk whey by carefully neutralizing with sodium hydroxide, and afterwards saturating with magnesium sulphate. It much resembles the globulin of blood serum, being coagulated at 67° to 76° C. Fibrin. — Babcock has discovered in milk very minute traces of a substance analogous to the fibrin of blood. This substance, it is claimed, forms a part of the slime found in the separator-bowl of a centrifugal skimmer. Other Nitrogenous Substances. — Besides the above normal constituents of milk, certain bodies may be formed by proteolytic action during fer- mentation, such, for example, as caseoses and peptones, formed for the most part by the decomposition of a part of the casein. Galactin is a gelatin-like body of the nature of peptone, occurring in traces in milk. Besides these, minute traces of amino-bodies, such as creatin, urea, and allantoin, are sometimes present, and also ammonia. Citric Acid has been found to exist in milk, probably in combina- tion with certain of the mineral constituents, being present to the extent of about 0.1%. Other Organic Constituents reported in milk are lecithin, cephalin, cholesterol, acetone, and thiocyanates. The Enzymes of Milk have been subjects of extensive investigation. The presence or amount of four of these, namely, peroxidase, reductase, aldehyde reductase, and catalase, are of considerable importance in sani- tary milk examination. Peroxidase originates in the mammary glands. Since it is destroyed at about 80° C, it is the basis of various tests for distinguishing raw from heated milk. Peroxidase acts in the presence of hydrogen peroxide, from which it splits off an atom of active oxygen, the latter combining with various chromogens (page 173). Reductase is indicated by the decolorizing power of milk for certain dyes. Since reductase is believed to be a product of bacteria, the tests MILK AND ITS PRODUCTS. Ill W O S rs TJ T) rt rt fi) 0) ^ 1-1 >, " C '-' >. 3 i3 O .S 5 S O C c t^ :S ^ 2 O Ph C/J S m m C . .-5 ■3 ">, .S ^ I-, u cx cx &, U U U 10 M 4 d mO O t^Mj-^o O f-.t-~.^M o N ^-O mOmooOwm 00006606 cS 3 Si £ y -^ a -"^ -^ s § ° .2 c S O .2 -S o P 3 ^ J3 m O -CI < o 112 FOOD INSPECTION AND ANALYSIS. are used for detecting pollution as an adjunct to bacteriological examina- tion. Aldehyde Reductase is a term applied to the enzyme which decolorizes methylene blue in the presence of formaldehyde, the latter inhibiting, it is believed, the action of bacteria so that the decolorizing action is due largely to the enzyme. The test furnishes information as to whether or not milk has been properly pasteurized at 63° C. (page 174). Catalase splits up two molecules of hydrogen peroxide into two mole- cules of water and one of oxygen. The latter may be measured or other- wise determined. The enzyme has been shown to be derived from leu- cocytes and the test is therefore useful in detecting milk from diseased udders (mastitis, etc.). Average Composition of Milk. — On page 11 1 is given in schematic form the average percentages of the principal constituents as arranged by Babcock. The following table shows the forms in which, according to Van Slyke and Bosworth,* the constituents are probably combined: Fat 3-90 Lactose 4-9° Proteins combined with calcium 3 . 20 Dicalcium phosphate (CaHP04) o - ^75 Calcium chloride (CaCb) o. 1 19 Monomagnesium phosphate (MgH4P208) o . 103 Sodium citrate (NasCeHsOT) c . 222 Potassium citrate (K3C6H5O7) 0.052 Dipotassium phosphate (K2HPO4) o . 230 Total solids 12.901 Composition of the Ash of Milk.— The ash of milk does not truly represent the mineral content, since, in the process of incineration, the character of some of the constituents is altered by oxidation and otherwise. The composition of the ash of the typical milk sample, the full analysis of which is given on page iii, would be about as follows: * N. Y. State Agric. Exp. Sta., Tech. Bui. 39, 1914. MILK AND ITS PRODUCTS. 113 Potassium oxide 25 .02 Sodium oxide 10.01 Calcium oxide 20.01 Magnesium oxide 2 .42 Iron oxide 0.13 Sulphur trioxide 3 . 84 Phosphoric pentoxide 24. 29 Chlorine 14. 28 100.00 Composition of Milk of Different Animals. — A summary of analyses of human, goat's, ewe's, mare's, and ass's milk, as well as of cow's milk for comparison, is given in the following table, the figures for human milk being compiled by Richmond,* those for the milk of other animals by Konio;: No. of Anal- yses. Specific Gravity. Water. Fat. Lactose Total Pro- tein. Casein. Albu- min. Ash. Fuel Value per Lb., Calories Cow's milk .... 800 Maximum . . . 1.0370 90-32 6.47 6. 12 6.40 6.29 1.44 I. 21 Minimum . . . 1.0264 80.32 1.67 2. II 2.07 1.79 0.25 0-35 Average IO31S 87.27 3-64 4.88 3-55 3.02 0.53 0.71 310 Human milk. . . 94 Maximum. . . 1.0426 9-oS 8.89 5-56 0.50 IMinimum. . . 1.0240 0.47 4. 22 0.85 0.09 Average IO313 88.20 3-30 6.80 1-50 0.20 295 Goat's milk. . . . 200 Maximum. . . 1.0360 90. 16 7-55 5-77 3-94 2.01 1.06 Minimum. . . 1.0280 82.02 3-10 3.26 2-44 0.78 0-39 Average I 0305 85.71 4-78 4.46 4.29 3.20 1.09 0.76 364 Ewe's milk .... 32 Maximum. . . I 0385 87.02 9.80 7-95 5-69 1-77 1.72 Minimum. . . 1.0298 74-47 2.81 2.76 3-59 0.83 0.13 Average I. 0341 80.82 6.86 4.91 6.52 4-97 1-55 0.89 502 Mare's milk . . . 47 Average I 0347 90.78 I. 21 5.67 1-99 .1.24 0.75 0.35 194 Ass's milk 5 Average 1.0364 89.64 1.64 5-99 2, 22 0.67 1-55 0-51 222 Fore Milk and Strippings. —Unless a portion drawn from the well- mixed or whole complete milking of an animal is taken for analysis, one Dairy Chemistry, London, 1914, p. 394. 114 FOOD INSPECTION AND ANALYSIS. does not get a fair representative sample of the milk, for it is a well-known fact that the first portion of milk drawn from the udder, termed the " fore milk," is very low in fat, while the last portions or " strippings " con- tain a very high fat content, sometimes exceeding io% fat. The following analyses show the difference between fore milk and strippings in two cases : Per Cent Water. Per Cent Solids. Per Cent Fat. (i) Fore milk. Strippings (2) Fore milk. Strippings 88.17 80.82 88.73 80.37 11.83 19.18 11.27 19.63 1.32 963 1 .07 10.36 The percentages of protein, lactose, and ash are nearly the same in both fore milk and strippings. Colostrum.— The milk given by cows and other mammals for two or three days after the birth of young is termed colostrum, and diiTers ma- terially in composition from normal milk. It is yellow in color, of an oily consistency, and has a pungent taste. It acts as. a purge upon the young. Under the microscope may be seen fat globules, which are larger than at subsequent stages of lactation, and circular cells (0.005 ""0-025 mm.) related to, if not identical with, the leucocytes or white corpuscles of the blood. It is very high in albumin, which seems to be similar to blood albumin. The following analyses were made by Engling, showing the composition of colostrum from a cow eight years old : Time after Calving. Specific Gravity. Fat. Casein. Albumin. Lactose. Ash. Total Solids. Immediately 1.068 1.046 I 043 1.042 1 .035 3-54 4.66 4-75 4.21 4.08 2.65 4.28 450 3-25 3-33 16.56 932 6.25 2.31 1.03 3.00 1.42 2.8s 3 46 4.10 1. 18 1-55 1.02 0.96 0.82 26.93 21.23 19-37 14.19 13 36 After 10 hours " 24 " " 48 " " 72 " The average of twenty-two analyses of colostrum from different cows by Engling showed total solids 28.31, fat 3.37, casein 4.83, albumin 15.85, lactose 2.48, ash 1.78. Changes in Composition During Lactation. — Crowther and Ruston * in Scotland, and Eckles and Shaw f in the United States have found * Trans High. Agric. Soc. Scotland, v. 23, 191 1, p. 93. t U. S. Dept. of Agric, Bur. of Anim. Ind., Bui. 155, 191J MILK AND ITS PRODUCTS. 115 tRat fat, protein, and total solids are highest in the earliest and latest stages of lactation, while ash remains practically constant throughout the period. LactosQ according to Crowther and Ruston decreases steadily after the first month or so, while according to Eckles and Shaw the only change attributable to the stage of lactation is a slight decline toward the end. The last named authors note that the fat globules decrease sharply in size during the first 6 weeks, remain practically constant 5 to 6 months, then decrease more rapidly to the end of the period. Milk of Young and Old Cows.— Less data are available on this point than on the other common factors influencing composition. La Cour* found that the milk from young cows was generally higher in fat content than that of old cows. Milk of Different Breeds. — The following table and the table on page 152 give analyses showing the general characteristics of the milk of single cows o"^ several well-known breeds. The following results by Eckles and Shaw f are the averages of determinations made throughout the whole period of lactation. AVERAGE COMPOSITION OF MILK OF INDIVIDUAL COWS REPRESENTING FOUR BREEDS (ECKLES AND SHAW). Breed. Age of Cow. Total Solids. Fat. Total Pro- tein. Casein Lac- tose. Relative Vol. of Fat Glo- bules. Total Milk Yield. Holstein . . Holstein . . Holstein. . Average Ayrshire . . Ayrshire. . Average Jersey Jersey. . . Jersey Average Shorthorn Shorthorn Shorthorn , Average Yrs. Mos. 5 3 5 o 3 8 4 8 3 8 4 8 4 2 6 10 8 I 4 8 9 4 4 4 II 6 o 5 I II 12. 12 10.73 11-35 11.38 12.08 12. 71 12.41 14.09 13-34 15.02 14.09 13.08 13.01 12.17 12.69 23 3 93 2 10 3 .09 2 SI 3 85 3 68 3 87 3 64 3 36 3 95 3 89 3 13 3 37 3 73 3- .00 ,70 21 •93 . II ■33 25 70 27 -97 .64 .40 -49 ,28 -38 2-49 2. II 2-49 2.36 2.62 2.81 2. 70 2-93 2.65 3-13 2-93 2.74 2.87 2.62 2-74 127 164 134 142 141 160 150 309 336 338 328 3" 353 211 282 lbs. 8994 8814 8831 6275 6382 6329 5429 6115 5733 5 759 5172 4449 6539 5387 * Tidskr. Landokon, 13, 1894, p. 303. t U. S. Dept. of Agric, Bur. of Anim. Ind., Bui. 156, 1913. 116 FOOD INSPECTION AND ANALYSIS. Influence of Feed on Composition. — A great amount of work has been done on this subject, but the results are conflicting and not such as can be readily summarized. In general it may be stated that the influence exerted by the feed, except under abnormal conditions or in the case of a few special feeds, is slight compared with that of breed. This point is worthy of consideration in view of the common practice of attributing to feed abnormalities really due to adulteration. Intervals Between Milking. — Several observers have shown that the longer the intervals between milkings the lower the percentage of fat. When the milking night and morning is at the same hour there is little difference. Frozen Milk. — Since it is the water that freezes, it follows that in partially frozen milk the unfrozen portion becomes concentrated. This is borne out by the following figures of Richmond : * Frozen Portion. Unfrozen Portion. Specific gravity i .0090 i .0345 Water 96-23 85 . 62 Fat 1.23 4.73 Lactose 1.42 4.95 Protein 91 3.90 Ash .21 .80 The freezing point of milk is considered on page 153. Fermentations of Milk.— These are due to the action of bacteria of various kinds, the most common being the lactic bacilli. The Souring of Milk is caused by the action of a large number of species of acid-forming bacteria, chief among which is the Bacillus acidi lactici, which multiplies faster than other bacteria in raw milk under favorable conditions of temperature. Part of the milk sugar is acted on and transformed, first into dextrose and galactose, the latter sugar subsequently forming lactic acid, as follows : (1) Ci2H220il,H20 = C6Hi,>06 + C6Hi206 Lactose Dextrose J Galactose (2) C6Hi206=2C3H603 Galactose Lactic acid In experiments by Van Slyke and Bosworth,f 22% of the lactose was decomposed, of which amount 88.5% went into lactic acid. The citric * Analyst, 18, 1893, P* 53- t N. Y. State Agric. Exp. Sta., Tech. Bui. 18, 1916. MILK AND ITS PRODUCTS. 117 acid was entirely decomposed into acetic acid and carbon dioxide. Al- bumin was so changed as to pass completely through a porcelain filter. Calcium caseinate reacted with the lactic acid, forming the free protein, which precipitated, and calcium lactate, which remained in solution. Abnormal Fermentation. — Through the agency of micro-organisms that may develop under certain conditions, various changes are produced in milk that to some extent alter its character. Thus bitter milk is some- times produced as the result of some organism as yet but little understood. Occasionally milk is found possessing a peculiarly thick and slimy consistency, whereby it may be drawn out in threads, by dipping a spoon into the milk and withdrawing it therefrom. This is termed ropy milk, and is more often met with in warm weather. It is undoubtedly produced as a result of bacterial action. Enzyme-forming Bacteria are not uncommonly developed in milk, causing various proteolytic changes, whereby the casein is partially trans- formed into peptones, caseoses, etc. Chromogenic Bacteria are the agencies that produce peculiar pigments in milk. Thus red milk is due to Bacillus erythrogenes; yellow milk to Bacillus xynxanthus; blue milk to Bacillus cyanagenes. The latter is quite common, appearing ordinarily in patches in the milk. CHEMICAL ANALYSIS OF MILK. Ordinarily, in ascertaining the nutritive value of milk, one determines its specific gravity, total solids, fat, protein, lactose, and ash. Occa- sionally it is thought desirable to make a distinction in the case of protein between the casein and the albumin. Rarely is it necessary to further subdivide the nitrogenous bodies in milk, unless in connection with a special study of the proteolytic changes which it undergoes. The total solids, fat, and ash are usually all determined directly, and, in the case of the lactose and the protein, a determination of either one may be directly made (whichever is most convenient), the other being calculated by difference. When foreign ingredients or adulterants are present in milk, special methods are employed to detect them. Preparation of the Sample. — In procuring a sample for analysis, the greatest care is necessary to insure a homogeneous sample. By far the best method in every case, where possible, is to pour the milk back and forth from one vessel to another (i.e., pour from the original container 118 FOOD INSPECTION AND ANALYSIS. mbm / into an empty vessel and back at least once). Where this is impossible from the size of the container or for any other reason, the milk should be thoroughly mixed with a dipper. A " sampler," of which the Scovell sampling- tube (Fig. 43, A) is a, convenient form, also aids in securing a representative sample, and is invalu- able when it is desirable to secure a definite fraction of the whole for a composite sample. This instrument consists of a brass or copper tube made in two parts which telescope accurately together as shown in Fig. 43, A, the lower part being closed at the bottom, but provided with three or more lateral slits. The sampler, drawn out to its full length, is carefully inserted in the tank containing the milk and lowered to the bottom, after which the upper part is pressed down over the lower so as to close the slits, and the tube is then lifted out of the tank, containing a fairly representative sample of the milk. Samples may be preserved in condition suitable for determination of fat and solids for several days by add- ing to each quart i gram of potassium bichromate, 0.2 gram of mercuric chloride mixed with a coal-tar color to show its poisonous nature, or i cc. of 40 % formalde- hyde. If other determinations are to be made, the analyst should make certain that the results on the rgm m, prescrvcd samples are the same as those on the fresh III ^a material. In all operations to which a milk sample is submitted during the process of analysis, it should invariably be poured into a clean empty vessel and back, or shaken, whenever it has been at rest for an appreciable time, in order to insure a homogeneous mixture. Determination of Specific Gravity. — This is most readily obtained with the aid of a hydrometer, accurately graduated within the limits of the widest possible variation in the specific gravity of milk. Hydrometers for special use with milk are known as lactometers, and are graduated variously. One of the most convenient forms of this instrument is the Quevenne lactometer, graduated from 15° to 40°, corresponding to specific gravity 1.015 to 1.040. This instrument, shown in Fig. 43, B, has a thermometer combined with it, the stem con- A B Fig. 43. A, Scovell Milk- Sampling Tube. B, Quevenne Lac tometer. MILK AND ITS PRODUCTS. 119 taining a double scale, on the lower part of which the specific gravity is read, while the temperature is read from the upper part. Another form of instrument is termed the New York Board of Health lactometer, which is not graduated to read the specific gravity directly, but has an arbitrary scale divided into 120 equal parts, the zero being equal to the specific gravity of water, while 100 corresponds to a specific gravity of 1.029. Deghuee * has devised a special form requiring only 4 ounces of milk. To convert readings on the New York Board of Health scale to Quevenne degrees they must be multiplied by .29. QUEVENNE LACTOMETER DEGREES CORRESPONDING TO NEW YORK BOARD OF HEALTH LACTOMETER DEGREES. Board of Quevenne Scale. Board of Quevenne Scale. Board of Quevenne Scale. Health Degrees. Health Degrees. Health Degrees. 60 17.4 81 23-5 lOI 29-3 61 17-7 82 23.8 102 29 6 62 18.0 83 24.1 103 29 9 63- 18.3 84 24.4 104 30 2 64 18.6 85 24.6 105 30 S 65 18.8 86 24.9 106 30 7 66 19. 1 87 25.2 107 31 67 19.4 88 25-5 108 31 3 68 19.7 89 25.8 109 31 6 69 20.0 90 26.1 no 31 9 70 20.3 91 26.4 III 32 2 71 20.6 92 26.7 112 32 5 72 20.9 93 27.0 113 32 8 73 21.2 94 27-3 114 33 I 74 21-5 95 27.6 "5 33 4 75 21.7 96 27.8 116 33 6 76 22.0 97 28.1 117 33 9 77 22.3 . 98 28.4 iiS 34 2 78 22.6 99 28.7 119 34 5 79 * 22.9 100 29.0 120 34 8 80 23.2 . If extreme accuracy is desired, the Westphal balance or the pycnometer should be used for the determination of specific gravity. For ordinary cases, however, the lactometer, if carefully made, is sufficiently accurate. With any other form of lactometer than the Quevenne, a separate thermometer is necessary in order to determine the temperature, the common practice being to standardize all such instruments at 60° F. (15.6° C). Readings at temperatures other than 60° may be corrected to that temperature by the aid of the table on page 133. DETERMINATION OF TOTAL SOLIDS.— Dish Method.— For purposes of milk analysis, platinum dishes are by far the most desirable. These, if made for the purpose, should be of the shape shown in Fig. 51, measur- Jour. Ind. Eng. Chem., 3, 191 1, p. 405- 120 FOOD INSPECTION AND ANALYSIS. FOR CORRECTING THE SPECIFIC GRAVITY OF MILK ACCORDING TO TEMPERATURE (BY DR. PAUL VIETH). Degrees of Degrees of Thermometer (Fahrenheit). Lactom- ster. 45 46 47 4« 49 so SI 52 53 54 55 50 57 5« 59 60 20. 19.0 19.0 19. 1 19. 1 19.2 19.2 19.3 19.4 19.4 19-5 19.6 19.7 19.8 19.9 19.9 — 21. iQ.q 20.0 20.0 20.1 20.2 20.2 20.3 20.3 20.4 20.5 20.6 20.7 20.8 20.9 20.9 — 22. 20.9 21 .0 21.0 21. 1 21.2 21 .2 21 .3 21-3 21.4 21-5 21.6,21.7 21.8 21. 9 21 .9 — 2S- 21.9 22.0 22.0 22.1 22.2 22.2 22.3 22.3 22.4 22.5 22.6'22.7 22.8 22.8 22.9 — 24. 22.9 22.9 23-0 23.1 23-2 23.2 23.3 23-3 23-4 23-5 23-6;23.6 23-7 23.8 23-9 — 2S. 23.8 23-9 24.0 24.0 24.1 24.1 24.2 24-3 24.4 24-5 24.6 24-b 24.7 24.8 24.9 — 2(5. 24.8 24-0 24.9 25.0 25-1 25-1 25.2 25.2 25-3 25-4 25-5 25.6 25-7 25.8 25-9 — 27. 2^.8 2=^.9 2S-Q 26.0 26.1 26.1 26.2 26.2 26.3 26.4 26.5 26.6 26.7 26.8 26.9 — 28. 26.7 26.8 26.8 26.9 27.0 27.0 27.1 27.2 27-3 27.4 27-5 27.6 27-7 27.8 27.9 — 2Q. 27.7 27.8 27.S 27.9 28.0 28.0 28.1 28.2 28.3 28.4 28.5 28.6 28.7 28.8 28.9 — 30. 28.6 28.7 28.7 28.8 28.9 29.0 29.1 29.1 29.2 29-3 29.4 29.6 29-7 29.8 29.9 — 31- 29-5 29.6 29.6 29.7 29.8 29.9 30.0 30.1 30.2 30-3 30-4 30-5 30.6 30.8 30-9 — 32. 30-4 30.5 30-5 30.6 30-7 30-9 31.0 31-1 31.2 31-3 31-4 31-5 31.(3 31-7 31-9 — .IV 31-3 31-4 31-4 31-5 31.6 31.8 31-9 32.0 32.1 32-3 32-4 32-5 32.0 32-7 32-9 — ■ 34- 32-2 32.3 32-3 34-432-5 32-7 32-9 33-0 33-^ 33-2 33-3 33-5 33-6 33-7 33-9 — 35- ... 33-0 33--^ 33-2 33-4 33-5 33-b 33-^ 33-9 34-0 34-2 34-3 34-5 34-6 34-7 34-9 61 62 63 64 6s 66 67 68 69 70 71 72 73 74 75 20. 20.1 20.2 20.2 20.3 20.4 20.5 20.6 20.7 20.9 21.0 21. 1 21.2 21-3 21.5 21.6 21. . . . 21. 1 21.2 21.3 21.4 21-5 21.6 21.7 21.8 22.0 22.1 22.2 22.3 22.4 22.5 22.6 22. 22.1 22.2 22.3 22.4 22.5 22.6 22.7 22.8 23.0 23.1 23.2 23.3 23.4 23-5 23-7 23- 23.1 23.2 23-3 23-4 23-5 23.6 23.7 23.8 24.0 24.1 24.2 24-3 24.4 24.6 24-7 24. 24.1 24.2 24-3 24.4 24-5 24.6 24.7 24.9 25-0 25.1 25.2 25.3 25-5 25-6 25-7 2S- 25-1,25-2 25-3 25-4 25-5 25.6 25.7 25-9 26.0 26.1 26.2 26.4 26.5 26.6 26.8 26. 26.I126.2 26.3 26.5 26.6 26.7 26.8 27.0 27.l'27.2 27.3 27.4 27-5 27-7 27.8 27. . . . 27.1 27-3 27-4 27-5 27.6 27.7 27.8 28.0 28.1 28.2 28.3 28.4 28.6 28.7 28.9 28. 28.1 28.3 28.4 28.5 28.6 28.7 28.8 29.0 29.1 29.2 29.4 29-5 29-7 29.8 29.9 29. 29.1 29-3 29.4 29-5 29.6 29.8 29.9 30.1 30.2 30-3 30-4 30-5 30.7 30-9 31-0 30- 30.1 30-3 30-4 30-5 30-7 30.8 30-9 3I-I 31.2 3^-3 31-5 31.6 31.8 31-9 32.1 31- 31.2 3^-3 31-4 31-5 31-7 31.7 31.8 32.0 32.2 32.4 32.5 32-6 32.8 33-0 33.1 32. 32.2 32.3 32-5 32.6 32.732.9 33.0 33.2 33.333.4 33-6 33-7 33-9 34-0 34.2 33- 33-2 33-3 33-5 33.6 33-833.9 34.0 34.2 34.334.5 34.6 34-7 34-9 35-1 35-2 34- 34-2 34-3 34.5 34.6 34.834.9 35.0 35-2 35.3,35-5 35.6 35 -« 36.0 36.1 36.3 35- ... 35-2 35-3 35-5 35. (^ 35.8|35-9 3^.1 36.2 36.4136.5 36.7 36.8 37-0 37.2 37.3 ing about 2f inches in diameter at the top, and 2^ inches in diameter at the bottom, having carefully rounded rather than square edges, and being ^ inch deep. The bottom is not perfectly flat, but slightly crowned outward. Such a dish will hold about 35 cc. For purposes of economy it is best to have these dishes spun out with a thick bottom, but with thin sides, not so thin, however, as to be too readily bent. If platinum dishes cannot be afforded, dishes of porcelain, glass, aluminum, nickel, or even tin may be used, but in all cases should be as thin as practicable. About 5 cc. of the thoroughly mixed sample of milk are carefully MILK AND ITS PRODUCTS. 121 transferred by means of a pipette to a tared dish on the scale-pan, and its weight accurately determined. The dish with its contents is then trans- ferred to a water-bath, being placed over an opening preferably but little smaller than the diameter of the bottom of the dish, so that as large a surface as possible is in contact with the live steam of the bath. Here it is kept for at least two hours, after which the dish is wiped dry while still hot, transferred to a desiccator, cooled, and weighed.* Babcock Asbestos Method. f — Provide a hollow cylinder of perforated sheet metal, 60 mm. long and 20 mm. in diameter, closed 5 mm. from one end by a disk of the same material. The perforations should be about 0.7 mm. in diameter and about 0.7 mm. apart. Fill loosely with from 1.5 to 2.5 grams of freshly ignited, woolly asbestos, free from fine and brittle material, cool in a desiccator, and weigh. Introduce a weighed quantity of milk (between 3 and 5 grams), and dry in a water- oven to constant weight, which is usually reached after four hours' heating. Determination of Ash. — The platinum dish containing the milk residue, obtained in the determination of total solids by the dish method described above, is next placed upon a suitable support above a Bunsen flame (a platinum triangle or a ring stand is convenient for this), and the residue is ignited at a dull-red heat to a perfectly white ash, after which it is cooled and weighed. Determination of Fat.— Babcock Asbestos Method.— Extract the residue from the determination of water by the Babcock asbestos method with anhydrous ether in a continuous extraction apparatus, until all the fat is removed, which usually requires two hours. Evaporate the ether, dry the fat in the extraction flask at the temperature of boiling water, and weigh. The fat may also be determined by difference, drying the extracted cylinders at the temperature of boiling water. * It is a common practice to transfer the milk residue, after a preliminary drying on the water-bath, to an air-oven, kept at a temperature of from 100° to 105°, where it is dried to a constant weight; but after an experience in analyzing over 30,000 samples of milk, the author is prepared to state that in his opinion the results obtained by the above method of procedure, using the water-bath alone, are more satisfactory. It is impossible to keep a milk residue at a temperature above 100° for any length of time without its undergoing decomposition, especially as to its sugar content, as is shown by the darkening in color. A milk residue should be nearly pure white, a brownish color showing incipient decomposi- tion. Hence, by continued heating, especially at the temperature of 105°, the residue would continue to lose weight almost indefinitely. If it is thought best to give a final drjang in the air-oven, the time should be short and the temperature employed should not in any case exceed 100°. t U. S. Dept. of Agric, Bur. of Chem., Bui. 38, p. 100. 122 FOOD INSPECTION AND ANALYSIS. The Adams Method. — For this method a strip of fat-free filter-paper about 2h inches wide and 22 inches long is rolled into a coil and held in place by a wire as shown in Fig. 44. Schleicher and Schiill furnish fat- free strips especially for this work, but it is very easy to prepare the strips and extract them with the Soxhlet apparatus. About 5 grams of milk are run into a beaker with a pipette, and the weight of the beaker and milk are determined. The coil is then intro- duced into the beaker, holding it by the wire in such a manner that as much as possible of the milk is absorbed by the paper. It is often possible to take up almost the last drop of the milk. By then weighing the beaker, the amount of milk absorbed by the coil is determined by difference, and the paper coil is hung up and dried, first in the air and then in the oven at a temperature not ex- ceeding 100°. Another method of charging the paper coil consists in suspending it by the wire and gradually de- livering upon it 5 cc. of the milk from a pipette, the dens- ity of the milk being known. The coil containing the dried residue is then transferred to the Soxhlet extraction apparatus (see p. 53) and sub- jected to continuous extraction with anhydrous ether for at least two hours, the receiving-flask being first accur- ately weighed. The tared flask with its contents is freed from all remaining ether, first on the water-bath and finally in the air-oven. It is then cooled and weighed, the in- Adams Milk- urease in weight representing the fat in the amount of fat Coil. milk absorbed by the coil. If there is any doubt about all the fat having been extracted at first, the process of extraction may be continued till there is no longer a gain in weight of the flask. Experience soon shows the length of time necessary for the complete extraction, which of course depends on the degree of heat employed, and the frequency with which the extracting-tube overflows. Two hours is ample for most cases, in which the conditions are such that the ether siphons over from the extraction-tube ten times per hour. FAT Methods Based on Centrifugal Separation.— These methods are the most practicable for commercial work and for use by the public analyst, since they are much more rapid, and, if carefully carried out, practically as accurate as the Adams method. They all depend upon the use of a centrifuge usually having hinged pockets in which are carried graduated bottles, into each of which a measured MILK AND ITS PRODUCTS. 123 quantity of milk is introduced. The milk is then subjected to the action of a suitable reagent, which dissolves the casein and liberates the fat in a pure state, after which, by whirling at a high speed, the pockets are thrown out horizontally and the milk fat driven into the neck of each bottle, where the amount is directly read. The Babcock Test, although devised originally for the use of creameries and dairymen, is now extensively employed for fat determination in the laboratory. Leach found that the results by the Babcock test and the Adams method, obtained from time to time during ten years, agreed within narrow limits. The following ifigures show the results of such comparative determinations made in duplicate on three samples of milk, viz., a pure whole milk, (i) and (2) ; a watered milk, (3) and (4), and a milk centrifugally skimmed, (5) and (6). COMPARATIVE FAT DETERMINATION BY ADAMS-SOXHLET AND BY BABCOCK PROCESSES. Per Cent of Fat by the Adams-Soxh- let Process. Per Cent of Fat by the Babcock • Process. A whole milk . . . (i) 4.27 4.28 2.70 2.74 0.16 0.14 4-30 4-35 2.70 2.80 oiS 015 (2) A watered milk (3) (4) A skimmed milk (5) (6) Equally satisfactory results were obtained by Winton, using the Bab- cock asbestos method for comparison. The Centrifuge. — Various styles of centrifuge, carrying from 2 to 40 bottles, are in use for this process. Two forms of hand machine are shown in Fig. 45, one {D), for two bottles, arranged to screw on the edge of a table, the other for twelve bottles inclosed in a cast-iron case. The number of revolutions of the revolving frame for each turn of the crank and the number of turns per minute necessary to secure the requisite number of revolutions of the frame should be determined once for all for each machine and the latter adhered to in making all tests. 124 FOOD INSPECTION AND ANALYSIS. Fig. 45. — Apparatus for Babcock Test. A, Burrell's electric centrifun;e; B, Burrell's steam turbine centrifuge; C and D, Burrell's hand centrifuges; E, milk bottle; F, Wagner's skim-milk bottle; G, Swedish or combined acid bottle. MILK AND ITS PRODUCTS. 125 The steam turbine machines (Fig. 45, B) are simple in construction and the steam serves to keep the bottles warm as well as to furnish power. The steam impinges against a series of paddles on the outer periphery of the revolving frame, driving it like a horizontal water-wheel. A reverse steam jet, steam gauge, and hot-water tank for filling the bottles are also provided. Fig. 45, A shows an electric machine for 24 to 36 bottles. Laboratory centrifuges are also provided with frames for Babcock bottles. Glassware. — The ordinary test bottle for milk is shown in Fig. 45, E. It has graduations corresponding to from o to 10% of fat, using 17.6 cc. of milk. One of various forms of skim milk bottle is also shown (F), The graduated tube has a capacity corresponding to only 0.25% for its entire length, hence the need of a second tube of larger bore for filling. The pipettes are graduated to hold 17.6 cc, which for average milk weighs 18 grams. The lower tube should be of such a size as to enter the nerk of the test bottle. A 17.5 cc. cylinder is provided for measuring the acid, but where considerable numbers of tests are made some special measuring device is desirable. Fig. 45, G shows a combined acid bottle and pipette, the latter being filled by tipping up the bottle. Manipulation. — Pipette 17.6 cc. (corresponding to 18 grams) of the milk into the test bottle and add 17.5 cc. of commercial sulphuric acid. (sp.gr. 1. 82-1. 84), Mix thoroughly by a vigorous rotatory movement holding the neck of the bottle between the fingers and at a slight angle away from the body. The lumps of curd which at first form disappear upon shaking; much heat is developed during the mixing and the color changes to deep brown. Place the test bottles in the pockets of the centrifuge (symmetrically arranged to keep the revolving frame in balance) and whirl at the rate of 800 to 1000 revolutions per minute, according to the diameter of the frame, for 5 minutes. Stop the machine, fill each bottle up to the neck with boiling water and whirl for two minutes longer. Add boiling water up to near the top of the graduation and whirl finally for two minutes. Remove the bottles from the machine and take the readings of the bottom and the very top of the fat column, the difference being the per cent of fat. If desired, the percentage may be obtained directly by means of calipers. To avoid danger of cooling it is well to immerse the bottles nearly to the top of the neck in water at 60° C, removing one at a time for reading. 126 rOOD INSPECTION AND ANALYSIS. The Werner-Schmidt Method.— Ten cc. of milk are introduced by means of a pipette into a large test-tube of 50 cc. capacity, and 10 cc. of concentrated hydrochloric acid are added. The mixture is shaken and heated till the liquid turns a dark brown, either by direct boiling for a minute or two, or by immersing the tube in boihng water for from five to ten minutes. The tube is then cooled by im- mersion in cold water, and 30 cc. of washed ether is added. The tube is closed by a cork provided with tubes similar to a wash-bottle, the larger tube being adapted to slide up and down in the cork, and preferably being turned up slightly at the bottom. The contents of the tube are shaken, the ether layer allowed to separate, and the sliding-tube arranged so that it terminates slightly above the junction of the two layers. The ether is then blown out into a weighed flask. A second and a third portion of ether of 10 cc. each are successively shaken with the acid Hquid and added to the contents of the weighed flask, from which the ether is subse- quently evaporated and the weight of the fat easily obtained. FiG.46.^TheWerncr-Schm;dt . 1 -n • 1 • ^^^ Apparatus. Instead of measurmg the milk mto the testmg- tube, a known weight of milk may be operated on. A sour milk may be readily tested in this way, provided it is previously well mixed. Determination of Fat by the Wollny Milk-fat Refractometer.* — This instrument presents the same appearance as the butyro-refractometer, Fig. 38, with an arbitraiy scale reading from o to 100, the equivalent readings in indices of refraction of the Wollny instrument varying from 1.3332 to 1.4220. Exactly 30 cc. of the milk to be tested are measured into the stoppered flask A, Fig. 47. This may be done by the use of the automatic pipette, which holds exactly 7I cc, removing four pipettes full of the milk. 5 is a numbered tin samphng-tube in which the milk sample is kept for convenience, and into which the automatic pipette readily fits. Having measured 30 cc. of the milk into the flask A, 12 drops of a solution of 70 grams potassium bichromate and 312.5 cc. of stronger ammonia in one liter of water may be added as a preservative. * Milch Zeit., 1900, pp. 50-53. MILK AND ITS PRODUCTS. 127 if the sample is to be kept for some time before finishing the test. Twelve drops of glacial acetic acid are added to curdle the milk. The flask is then corked and shaken for one to two minutes in a mechanical shaker, after which 3 cc. of a standard alkaline solution are added, and the flask corked and shaken for ten minutes in the mechanical shaker, the tempera- ture being kept at i7.5°C. The standard alkaline solution is prepared Fig. 47. — Accessories for Carrying Out the Wo liny Milk-fat Process. by dissolving 800 cc. of potassium hydroxide in a liter of water, adding 600 cc. of glycerin and 200 grams pulverized copper hydrate, the mixture being allowed to stand for several days before using, shaking at intervals. Finally 6 cc. of water-saturated ether are added to the mixture in the flask, using for convenience the automatic pipette fitted in the corked bottle as shown. The flask is again shaken for fifteen minutes in the mechanical shaker, and whirled for three minutes in the centrifuge, after which a few drops of the ether solution are transferred to the refractometer, and the reading taken. The percentage of fat is obtained by means of the following table: 128 FOOD INSPECTION AND ANALYSIS. PERCENTAGES OF FAT CORRESPONDING TO SCALE READINGS ON THE WOLLNY REFRACTOMETER. Scale Per Scale Per Scale Per Scale Per Scale Per Scale Per Read- Cent Read- Cent Read- Cent Read- Cent Read- Cent Read- Cent ing. Fat. ing. Fat. ing. Fat. ing. Fat. ing. Fat. ing. Fat. 20. o 24.5 0.41 29.0 0.87 33-5 1-34 38.0 1-85 42.5 2.41 I 6 0.42 I 0.88 6 I-3S I 1.87 6 2-43 2 7 0.43 2 0.89 7 1.36 2 1.88 7 2-44 3 8 0.44 3 0.90 8 1-37 ' 3 1.89 8 2.46 4 9 0-45 4 0.91 9 1.38 4 1.90 9 2.47 5 25.0 0.46 5 0.92 34-0 1-39 5 1. 91 43-0 2-49 6 0.00 I 0.47 6 0-93 I 1.40 6 1.92 I 2.50 7 O.OI 2 0.48 7 0.94 2 1.42 7 1-93 2 2.51 8 0.02 3 0.49 8 0-95 3 1-43 8 1.94 3 2.52 9 0.03 4 0.50 9 0.96 4 1-44 9 1-95 4 2-54 21.0 0.04 5 0-51 30.0 0.97 5 I-4S 39-0 1.96 5 2-55 I 0.05 6 0.52 I 0.98 6 1.46 I 1.98 6 2.56 2 0.06 7 0-53 2 0.99 7 1-47 2 1-99 7 2.58 3 0.08 8 0.54 3 1. 00 8 1.48 3 2.00 8 2.60 4 0.09 9 0-S5 4 1. 01 9 1-49 4 2.02 9 2.61 5 O.IO 26.0 0-57 5 1.02 35-0 1-50 5 2.03 44.0 2.63 6 O.II I 0.58 6 1.03 I i-Si 6 2.04 I 2.64 7 0.12 2 0-59 7 1.04 2 1-52 7 2.05 2 2.65 8 0.13 3 0.60 8 1.05 3 1-54 8 2.07 3 2.67 9 0.14 4 0.61 9 1.06 4 1-55 9 2.08 4 2.68 32.0 0-15 5 0.62 31.0 1.07 5 1.56 40.0 2.09 5 2.70 I 0.16 6 0.63 I 1.08 6 1-57 I 2.10 6 2.71 2 0.17 7 0.64 2 1.09 7 1-58 2 2.12 7 2.72 3 0.18 8 0.65 3 l.IO 8 1-59 3 2.13 8 2.74 4 0.19 9 0.66 4 I. II 9 1.60 4 2.14 9 2-75 5 0.20 27.0 0.67 5 I. 12 36.0 1-61 5 2-15 45-0 2.77 6 0.21 I 0.68 6 I-I3 I 1.62 6 2.16 I 2.78 7 0.22 2 0.69 7 I. 14 2 1.64 7 2.18 2 2-79 8 0.23 3 0.70 8 i-iS 3 1.65 8 2.20 3 2.80 9 0.24 4 0.71 9 I. 16 4 1.66 9 2.21 4 2.82 33.0 0.25 5 0.72 32.0 I. 17 5 1.67 41.0 2.23 5 2.84 I 0.26 6 0-73 I I. 18 6 1.68 I 2.24 6 2-85 2 0.27 7 0.74 2 I. 19 7 1.69 2 2-25 7 2.87 3 0.28 8 0-7S 3 1.20 8 1.70 3 2.26 8 2.88 4 0.29 9 0.76 4 1.22 9 1. 71 4 2.27 9 2.89 5 0.30 28.0 0.77 5 1-23 37-0 1.72 5 2.28 46.0 2.90 6 0.31 I 0.78 6 1.24 I 1-73 6 2.30 I 2.92 7 0.32 2 0.79 7 1.25 2 1-75 7 2-32 2 2-93 8 0-33 3 0.80 8 1.26 3 1.76 8 2-33 3 2-94 9 0-34 4 0.81 9 1.27 4 1.78 9 2.34 4 2.96 24.0 0.36 5 0.82 33-0 1.28 5 1-79 42.0 2-35 5 2.98 I 0-37 6 0.83 I 1.29 6 1.80 I 2-37 6 3.00 2 0.38 7 0.84 2 1.30 7 1. 81 2 2.38 7 3.01 3 0-39 8 0.85 3 I-3I 8 1.82 3 2-39 8 3.02 4 0.40 9 0.86 4 1.32 9 1.84 4 2.40 9 3-03 5 0.41 29.0 0.87 5 1-34 38.0 1.85 5 2.41 47.0 3-05 MILK AND ITS PRODUCTS 129 PERCENTAGES OF FAT CORRESPONDING TO SCALE READINGS ON THE WOLLNY REFRACTOMETER —{Continued). Scale Per Scale Per Scale Per Scale Per Scale Per Scale Per Read- Cent Read- Cent Read- Cent Read- Cent Read- Cent Read- Cent ing. Fat. ing. Fat. ing. Fat. ing. Fat. ing. Fat. ing. Fat. 47.0 3-05 50-5 3-59 S4-0 4.18 57-5 4-78 61.0 5-44 64-5 6.14 I 3.06 6 3.60 I 4.20 6 4.80 I 5-46 6 6.16 2 3.08 7 3-61 2 4.22 7 4.82 2 5-48 7 6.18 3 3.10 8 3-63 3 4-23 8 4-84 3 5-50 8 6.20 4 3.12 9 3-64 4 4-25 9 4.86 4 5-52 9 6.22 5 3-14 51-0 3.66 5 4.26 58.0 4.88 5 5-54 65.0 6.24 6 3-15 I 3-67 6 4.28 I 4.90 6 5-56 I 6.27 7 3-16 2 3-68 7 4-29 2 4-92 7 5-58 2 6.29 8 3-17 3 3-70 8 4-31 3 4-94 8 5.60 3 6.31 9 3-18 4 3-72 9 4-33 4 4-95 9 5.61 4 6.34 48.0 3.20 5 3-74 55-0 4-35 5 4-97 62.0 5-63 5 6.36 I 3-21 6 3-76 I 4-37 6 4-98 I 5-65 6 6.38 2 3-23 7 3-78 2 4.38 7 5.00 2 5-66 7 6.40 3 3-25 8 3.80 3 4.40 8 5.02 3 5-68 8 6.42 4 3-27 9 3-82 4 4-42 9 5-04 4 5-70 9 6-44 5 3-28 52.0 3-84 5 4-43 59-0 5.06 5 S-72 66.0 6.46 6 3-30 I 3-85 6 4-44 I 5.08 6 5-74 7 3-32 2 3-87 7 4.46 2 5-10 7 5-76 8 3-33 3 3-89 8 4-48 3 5-II 8 5-78 9 3-34 4 3-90 9 4-49 4 5-13 9 5-80 49 3.36 5 3-92 56.0 4-51 5 5-iS , 63.0 j 5-82 I 3.38 6 3-93 I 4-53 6 S-17 j I 5-84 2 3-40 7 3-95 2 4-55 7 5-19 1 2 5-86 3 3-42 8 3-97 3 4-57 8 5.20 3 5-88 4 3-43 9 3-99 4 4-59 9 5-22 4 5-90 5 3-44 53-0 4.01 5 4.60 60.0 5-24 5 5-92 6 3-45 I 4-03 6 4.61 I 5-26 6 5-94 7 3-46 2 4.04 7 4-63 2 5-28 7 5-96 8 3-48 3 4.06 8 4-65 3 5-30 8 5-98 9 3-50 4 4.07 9 4.67 4 5-32 9 6.00 5©.o 3-51 5 4.09 57-0 4.69 5 5-34 64.0 6.02 I 3-53 6 4.10 I 4.71 6 S-36 I 6.04 2 3-55 7 4.12 2 4-73 7 5-38 2 6.07 3 3-56 8 4.14 3 4-75 8 5-40 3 6.09 4 3-57 9 4.16 4 4.76 9 5-42 4 6.12 5 3-59 54-0 4.18 5 4.78 61.0 5-44 5 6.14 The following table is of use for those who wish to employ the Wollny meihod, but have the Abbe refractometer instead of the milk-fa*^ refractometer. 130 FOOD INSPECTION AND ANALYSIS. INDICES OF REFRACTION (np) CORRESPONDING TO SCALE READINGS OP THE WOLLNY MILK-FAT REFRACTOMETER. Refrac- tive Fourth Decimal of tij). Index, "D- 1 2 3 4 5 6 7 8 9 Scale Readings. 1-333 1-334 0.0 0.1 0. 2 0-3 1.2 0.4 1-3 0.5 1-4 0-5 1-5 0.6 0.7 ' ' 0.8 ' 0.9 I.O I.I 1.6 1-335 1-7 1.8 1.9 2.0 2.1 2.1 2.2 2-3 2.4 2-5 1-336 2.8 2-7 2.8 2-9 3-0 3-1 3-2 3-3 3-4 3-5 1-337 3-6 3-7 3-7 3-8 3-9 4-0 4-1 4-2 4-3 4-4 1-338 4-5 4-6 4-7 4-8 4-9 5-0 5-1 5-2 5-3 5-4 1-339 5-5 5-6 5-7 5-8 5-9 6.0 6.1 6.2 6.3 6.4 1.340 6-5 6.6 6-7 6.8 6.9 6.9 7-0 7-1 7-2 7-3 I -341 7-4 7-5 7-6 7-7 7-8 7-9 8.0 8.1 8.2 8.3 1-342 8.4 8.5 8.6 8.7 8.8 8.9 9.0 9.1 9.2 9-3 1-343 9-4 9-5 9.6 9-7 9.8 9-9 10. 10. 1 10.2 10.3 1-344 10.4 10.5 10.6 10.7 10.8 10.9 II. II. I II. 2 11-3 1-345 II. 4 11-5 "-5 II. 6 II. 7 II. 8 II. 9 12.0 12. 1 12.2 1-346 12.3 12.4 12.5 12.6 12.7 12.8 12.9 13.0 13-1 13.2 1-347 13-3 13-4 13-5 13.6 13-7 13-8 13-9 14.0 14. 1 14.2 1.348 14-3 14.4 14-5 14.6 14-7 14.8 14.9 15-0 15-1 15.2 1-349 15-3 15-4 15-5 15-6 15-7 15-8 15-9 16.0 16. 1 16.2 1-35° 16.3 16.4 16.S 16.6 16.7 16.8 16.9 17.0 17. 1 17.2 1-351 17-3 17-4 17-S 17.6 17.7 17.8 17.9 18.0 18. 1 18.2 1-352 18.3 18.4 18.5 18.6 18.7 18.8 18.9 19.0 19. 1 19.2 1-353 19-3 19.4 19-5 19.6 19.7 19.8 19.9 20.0 20.1 20.2 1-354 20.3 20.4 20.5 20.6 20.7 20.8 20.9 21.0 21. 1 21.2 1-355 21-3 21.4 21-5 21.6 21.7 21.8 21.9 22.0 22.1 22.2 1-356 22.3 22.4 22.5 22.6 22.7 22.8 22.9 23.0 23.1 23.2 1-357 23-3 23-4 23-5 23.6 23-7 23-8 23-9 24.0 24.1 24.2 1-358 24-3 24-4 24-5 24.6 24-7 24.8 24.9 25.0 25-1 25.2 1-359 25-3 25-4 25-5 25.6 25-7 25-8 25-9 26.0 26.1 26.2 1.360 26.3 26.4 26.5 26.6 26.7 26.8 26.9 27.0 27.1 27.3 1-361 27-4 27-5 27.6 27.7 27.8 27.9 28.0 28.1 28.2 28.3 1.362 28.4 28.5 28.6 28.7 28.8 28.9 29.0 29.1 29.2 29-3 1-363 29-4 29-5 29.6 29.7 29.8 29.9 30.0 30.1 30.2 30-3 1.364 30-4 30-5 30.6 30-7 30.8 31.0 31-1 31.2 3^-3 31-4 1-365 31-5 31-6 31-7 31-8 31-9 32.0 32.1 32.2 32-3 32-4 1.366 32.5 32.7 32.8 32-9 33-0 33-1 33-- 33-3 33-4 33-5 1-367 33-6 33-7 33-8 33-9 34-0 34-2 34-3 34-4 34-5 34-6 1.368 34-7 34-8 34-9 35-0 35-1 35-2 35-3 35-4 35-5 35-6 1.369 35-7 35-8 36.0 36.1 36.2 36-3 36.4 36-5 36-6 36.7 1-370 36.8 36-9 37-0 37-1 37-2 37-3 37-4 37-6 37-7 37.8 1-371 37-9 38.0 38.1 38-2 38-3 38-4 38.5 38.6 38-7 38.8 1-372 38-9 39-0 39-2 39-3 39-4 39-5 39-6 39-7 39-8 39-9 1-373 40.0 40.1 40.2 40.3- 40.4 40.5 40.7 40.8 40.9 41.0 1-374 41. 1 41.2 41-3 41.4 41-5 41.6 41-8 41.9 42.0 42.1 '•375 42.2 42.3 42.4 42.5 42.6 42.7 42.8 42.9 43-0 43-1 1-376 43-2 43-3 43-4 43-6 43-7 43-8 43-9 44.0 44-1 44-2 1-377 44-3 44-4 44-6 44-7 44-8 44-9 45-0 45-1 45-2 45-3 1-378 45-4 45-6 45-7 45-8 45-9 46.0 46.1 46.2 46.3 46.4 1-379 46.6 46.7 46.8 46.9 47.0 47-1 47-2 47-3 47-4 47.6 MILK AND ITS PRODUCTS. 131 INDICES OF REFRACTION (no) CORRESPONDING TO SCALE READINGS OI THE WOLLNY MILK-FAT REFRACTOMETER— (Continued). Refrac- Fourth Decimal of "r • tive Index, 1 2 3 4 5 6 •7 8 9 1 Scale Readings. 1.380 47-7 47-8 47-9 48.0 48.1 48.2 48.3 48.4 48.6 48.7 I.381 48.8 48.9 49.0 49-1 49-2 49-3 49.4 49-6 49-7 49-8 1.382 49-9 50.0 50-1 50.2 50-3 50.4 50.6 50-7 50.8 50-9 1-383 51.0 51-1 51.2 51-3 51-4 51.6 51-7 51-8 51-9 52.0 1.384 52-1 52.2 52-3 52.4 52.6 52-7 52.8 52-9 53-0 53-1 1-385 53-2 53-3 53-4 53-6 53-7 53-8 53-9 54-0 54-1 54-2 1.386 54-3 54-4 54-6 54-7 54-8 54-9 55-0 55-1 55-2 55-3 1-387 55-4 55-6 55-7 55-8 55-9 56.0 56-1 56.2 56.3 56.5 1.388 56.6 56-7 56.8 56.9 57-1 57-2 57-3 57-4 57-6 57-7 1.389 57-8 57-9 58.0 58.1 58.2 58-3 58-4 58.6 58-7 58.8 1.390 58.9 59-0 59-1 59-2 59-4 59-5 59-6 59-8 59-9 60.0 I-391 60.1 60.2 60.3 60.4 60.6 60.7 60.8 60.9 61.0 61.1 1.392 61.3 61.4 61-5 61.6 61.8 61.9 62.0 62.1 62.2 62.3 1-393 62.4 62.6 62.7 62.8 62.9 63.0 63-2 63-3 63-4 63-5 1-394 63.6 63.8 63-9 64.0 64.1 64.2 64-4 64-5 64.6 64-7 1-395 64.8 65.0 65.1 65-2 65-3 65-4 6c;. 6 65-7 65.8 65-9 1.396 66.0 66.2 66.3 66.4 66.5 66.6 66.8 66.9 67.0 67.1 1-397 67.2 67.4 67-5 67.6 67-7 67.8 67-9 68.1 68.2 68.3 1.398 68.4 68.6 68.7 68.8 68.9- 69.0 69.1 69-3 69-4 69-5 1-399 69.6 69.8 69.9 70.0 70.1 70.2 70.4 70-5 70.6 70.8 1.400 70.9 71.0 71.1 71.2 71.4 71-5 71.6 71.8 71.9 72.0 1. 401 72.1 72.2 72.4 72-5 72.6 72.8 72-9 73-0 73-1 73-2 1.402 73-4 73-5 73-6 73-8 73-9 74.0 74-1 74-2 74-4 74-5 1.403 74-6 74-8 74-9 75-0 75-1 75-2 75-4 75-5 75-6 75-8 1.404 75-9 76.0 76.1 76.2 76.4 76-5 76.6 76.8 76-9 77.0 1-405 77-1 77-2 77-4 77-5 77-7 77-8 77-9 78.1 78.2 78.3 1.406 78.5 78.6 78.7 78.8 79.0 79-1 79-2 79-4 79-5 79-6 1.407 79-8 79-9 80.0 80.1 80.2 80.4 80.5 80.6 80.8 80.9 1.408 81.0 81. 1 81.2 81.4 81. 5 81.6 81.7 81.9 82.0 82.1 1.409 82.3 82.4 82.5 82.6 82.8 82.9 83.0 83.2 83-3 83-4 1. 410 83.6 83-7 83.8 84.0 84.1 84.2 84-4 84-5 84.6 84.8 1. 411 84.9 8s-o 8^.2 85-3 85-4 85-5 85.6 85-7 85-9 86.1 1. 412 86.2 86.3 86.5 86.6 86.7 86.9 87.0 87.1 87-3 87.4 1-413 87-5 87-7 87.8 87-9 88.1 88.2 88.3 88.=; 88.6 88.7 1. 414 88.9 89.0 89.1 89-3 89.4 89.6 89.7 89.9 90.0 90.1 I -415 90.2 90.4 90-5 90.6 90.8 90.9 91.0 91.2 91-3 91-5 1. 416 91.6 91.7 91.9 92.0 92.1 92-3 92-4 92-5 92-7 92.8 1. 417 92-9 93-1 93-2 93-3 93-5 93-6 93-8 93-9 94.0 94-2 1.418 94-3 94-4 94-6 94-7 94-8 95 -0 95-1 95-3 95-4 95-6 1. 419 95-7 95-8 96.0 96.1 96.3 96-4 96.6 96-7 96.8 97.0 1.420 97.1 97-3 97-4 97-6 97-7 97-8 98.0 98.1 98-3 98-4 1.421 98-5 98.7 98.8 99.0 99-1 99-3 99-4 99-5 99-7 99-9 1.422 100. 132 FOOD INSPECTION AND ANALYSIS. Determination of Proteins. — For determination of the total nitro- gen in milk, 5 cc. are measured direct into a Kjeldahl digestion-flask, or a known weight from a weighing-bottle may be used, and the regular Gunning method is employed as described on page 69, proceeding with the digestion at once without evaporation. The total nitrogen, multipHed by 6.38, gives the total proteins. By many the old factor of 6.25 is still employed, but in view of the fact that both casein and albumin have been found to contain 15.7% of nitrogen, there would seem to be the best reasons for employing 6.38 as a factor 100 15-7/ Ritthausen's Method. — ^Ten grams of milk are measured into a beaker and diluted with water to about 100 cc. Five cc. of a solution of copper sulphate (strength of Fehhng's copper solution, 34.64 grams CuSO^ in 500 cc. of water) are added and the mixture stirred. A solution of sodium hydrox- ide (25 grams to the liter) is added cautiously a little at a time, till the liquid is nearly, but not quite neutral, avoiding an excess of alkali, as this would prevent the complete precipitation of the proteins. Allow the precipitate to settle, and pour off the supernatant Hquid through a weighed fiker, previously dried at 130° C. Wash a number of times by decantation, and transfer the precipitate to the filter, being careful to remove the por- tions adhering to the sides of the beaker with a rubber-tipped rod. Wash thoroughly with water, and drain dry, after which the precipitate is washed with strong alcohol, dried, extracted with ether, preferably in a Soxhlet extractor, and then transferred on the filter to the oven, dried at 130° C, and weighed. The filter and precipitate are then burnt to an asii in a porcelain crucible, and the weight of the residue subtracted from the first weight gives that of the proteins. Richmond * recommends modifying this process to the extent of neutralizing the milk, using phenolphthalein as an indicator, before adding the copper sulphate solution, and using only 2.5 cc. of the latter. Determination of Casein.— Faw Slyke Method.-\— Ten grams of the milk sample are placed in a beaker, and made up with water to about 100 cc. at 40° to 42° C. One and one-half cc. of a 10% solution (by weight) of acetic acid are added, the mixture stirred, warmed to the above tem- perature, and allowed to stand for from three to five minutes, till a floc- * Dairy Chemistry, London, 1914, p. 127. t U. S. Dept. of Agric, Div. of Chem., Bui. 43, p. 189; Bui. 51, p. 108. MILK AND ITS PRODUCTS. 133 culent precipitate separates, leaving a clear supernatant liquid. Decant upon a filter, wash with cold water two or three times by decantation, and finally transfer the whole of the precipitate to the filter, and, after filtering, wash two or three times. The filtrate should be clear or nearly so. If not, it can generally be made so by repeated filtrations, and the washing done afterwards. The filter containing the washed precipitate is transferred to the Kjeldahl digestion-flask and the nitrogen obtained by the Gunning process. Nx 6.38 = casein. Determination of Albumin. — Van Siyke Method. — To the filtrate from the direct determination of casein by the acetic acid method as described in the preceding section, exactly neutralized with sodium hydroxide, 0.3 cc. of a 10% solution of acetic acid is added, and the mixture is boiled till the albumin is completely precipitated. The precipitate is collected on a filter and washed, the nitrogen being determined in the precipitate, and the factor 6.38 used in calculating the albumin therefrom. Leffman and Beam Modification of the Sebelien Method.^ — Owing to the tedious processes of washing and filtering incidental to the above method for determining casein, the following is suggested. Mix 10 cc. of the milk with saturated magnesium sulphate solution, and saturate the mixture with the powdered salt. Make up to 100 cc. with the same solu- tion, mix, and allow the precipitate to settle, leaving a clear, supernatant layer. Withdraw as much as possible of the clear portion by a pipette and filter through a dry filter. Precipitate the albumin in an aliquot portion by Almen's reagent (4 grams tannin in 1900 cc. of 50% alcohol mixed with 8 cc. of 25% acetic acid), filter, wash, and determine nitro- gen. Nx 6.38 = albumin. To obtain the casein, subtract the albumin from the total protein. Determination of Nitrogen as Caseoses, Amino-compounds, Peptones, and Ammonia. — Van Slyke f proceeds as follows : The filtrate from the determination of the albumin, as above, is heated to 70° C, i cc. of 50% sulphuric acid is first added, and afterwards chemically pure zinc sulphate to saturation. The mixture is allowed to stand at 70° until the caseoses separate out and settle. Cool, filter, wash with a saturated zinc sulphate solution slightly acidified with sulphuric acid, and determine the nitrogen of the caseoses in the precipitate. For Amino-compounds and Ammonia treat 50 grams of the milk in a * Allen's Commercial Organic Analysis, 4th Ed., Phila., 1914, 8, p. 156. t N. Y. Exp. Sta. Bui. 215, p. 102. 134 FOOD INSPECTION AND ANALYSIS. 250-cc. graduated flask with i gram sodium chloride and a 12% solution of tannin, added drop by drop till no further precipitate is formed. Dilute to the 250-cc. mark, shake, and filter. Determine the nitrogen in 50 cc. of the filtrate, the result being the combined nitrogen of the amino-com- pounds and ammonia. Distil with magnesium oxide 100 cc. of the filtrate from the tannin salt solution, receiving the distillate in a standardized acid, and titrating in the usual way for the ammonia. Calculate the nitrogen of the peptones by subtracting from the total nitrogen that due to all other forms. Van Slyke has furnished the following unpublished analysis of a sample of milk three months old, kept under antiseptic conditions by chloroform. Per Cent Total N. Per Cent Sol. Nitrogen. Per Cent N as Paranuclein, Caseoses, and Peptones. Per Cent N as Amino- compounds. 0.561 0.099 0.074 0.025 DETERMINATION OF MiLK SUGAR. — If a polariscope is available, the sugar of milk can most readily and conveniently be determined by optical methods. In the absence of a polariscope, the reducing power of milk sugar on copper salts may be utilized quite accurately in determining the sugar, using either volumetric or gravimetric methods as desired. Determination by Polarization. — Wiley Method.* — i. Reagents. — Mer- curic Nitrate. — This solution is prepared by dissolving metallic mercury in twice its weight of nitric acid of specific gravity 1.42, and adding to the solution an equal volume of water. One cc. of this reagent will be found sufficient to precipitate the proteins and fat completely from 65 grams of milk, but if more is employed the result of the analysis is not affected. Mercuric Iodide Solution. — 33.2 grams of potassium iodide are mixed with 13.5 grams of mercuric chloride, 20 cc. of acetic acid, and 640 cc. of water. Suhacetate of Lead Solution, U. S. P. See page 610. Notes. — For the Laurent polariscope, in which the normal weight for sucrose is 16.19 grams, the corresponding normal weight for lac- ■ Am. Chem. Jour., 6, 1884, p. 2S MILK AND ITS PRODUCTS. 135 tose is 20.496, while for the Soleil-Ventzke instrument, in which the su- crose normal weight is 26.048 grams, the corresponding lactose normal weight is 32.975.* It is customary to employ three times the normal weight of milk in the case of the Laurent instrument (viz., 61.48 grams) and twice the normal weight in the case of the Soleil-Ventzke (viz., 65.95 grams). As it is more convenient to measure the milk than to weigh it, and as the volume varies with the specific gravity, the following table is use- ful, showing the quantity to be measured in any case, having first deter- mined the specific gravity. specific Gravity. Volume of Milk to be Used. For Polariscopes of which the Sucrose Normal Weight is 16.19 Grams. For Polariscopes of which the Sucrose Normal Weight is 26.048 Grams. 1.024 60.0 cc. 64 . 4 cc. 1.026 1.028 59-9 cc. 59.8 cc. 64.3 cc. 64. 15 cc. 1.030 59-7 cc. 64 . cc. 1.032 59.6 cc. 63.9 cc. 1-034 59-5 cc. 63.8 cc. I -03s 59-35 cc. 63.7 cc. For ordinary work it is sufficiently close to have a pipette gradu- ated to deliver 59.7 cc. if the Laurent instrument is used, and 64 cc. for the Soleil-Ventzke. 2. Process. — Measure as above, the equivalent of 61.48 grams of the milk for the Laurent, or 65.95 grams for the Soleil-Ventzke, instru- ment into a loo-cc. graduated flask, add, in order to clarify, 2 cc. of acid nitrate of mercury solution, or 30 cc. of mercuric iodide solution, or 10 cc. of lead subacetate solution. Shake gently and fill to the mark with water, then add from a pipette 2.5 cc. of water to make up for the volume of the precipitated proteins and fat, insuring 100 cc. of sugar solution. Shake thoroughly, filter through a dry paper, and polarize the filtrate, which must be perfectly clear, in a 2co-mm. tube. Divide the reading by 3 for the Laurent and by 2 for the Soleil-Ventzke instrument. The quotient is the percentage of lactose. 3. Allowance for the Volume of the Precipitate. — This of course varies with the content in proteins, and fat, and while the above allowance gives *[a]D for lactose = 52.53, [a]z) for sucrose = 66.5, hence for the Laurent instrument 52.53 : 66.5:: 16.19 : 20.496, and for the Soleil-Ventzke instrument 52.53 : 66.5 :: 26.048 ; 32.975. 136 FOOD INSPECTION AND ANALYSIS. in most cases sufficiently close results, it is not exact. Leffmann* recom- mends that the amount of water to be added above loo cc. be calculated in each case from the percentage of proteins and fat previously found by analysis, multiplying the actual weight of the fat in grams in the sample taken by 1.075, ^^^ the weight of proteins by 0.8, the sum of the two results being the volume in cubic centimeters occupied by the precipitate. All calculations are avoided by employing the double-dilution method, which is to be recommended when very particular results are required. Wiley and Ewell's Double-dilution Method.f — Two flasks are em- ployed graduated at 100 and 200 cc. respectively, into each of which are introduced 65.95 grams of milk, if the Soleil-Ventzke instrument is used (or 61.48 grams in case the Laurent is used) and 4 cc. of the mer- curic nitrate solution are added, both flasks being filled to the mark and shaken. The contents are filtered and the polarization is made in each case in a 400-mm. tube. The second reading (that of the more dilute solution) is multiplied by 2, and the product subtracted from the first reading; the remainder is then multiplied by 2, and the product subtracted from the first read- ing (that of the stronger or 100 cc. solution). The result is the cor- rected reading, which, divided by 4, gives the exact per cent of milk sugar in the sample. This method depends on the fact that within ordinary limits the polarizations of two solutions of the same substance are inversely proportional to their volumes. Determination of Milk Sugar by Fehling's Solution.— Twenty- five grams of the milk (24.2 cc.) are transferred to a 250-cc. flask, 0.5 cc. of a 30% solution of acetic acid are added and the contents well shaken. After standing for a few minutes, about 100 cc. of boiling water are run in, the contents again shaken, 25 cc. of alumina cream are next added, the flask shaken once more, and set aside for at least ten minutes. The supernatant liquid is then poured upon a previously wetted ribbed filter, and finally the whole contents of the flask are brought thereon, and the filtrate and washings made up to 250 cc. The filtrate must be perfectly clear. The milk sugar in a solution thus precipitated would ordinarily not exceed ^ of i per cent. Scheibe { after precipitating with copper sulphate, adds 2 cc. of saturated sodium fluoride solution to precipitate the lime which otherwise would cause an error of 0.10%. * Milk and Milk Products, p. 38. t Wiley's Agricultural Analysis, p. 278; Analyst, 21, 1896, p. 182. X Zeits. Anal. Chem., 40, 1901, p. i. MILK AND ITS PRODUCTS. 137 Volumetric Fehling Process. — From a burette containing the cleai milk sugar solution above prepared, run a measured volume into the boiling Fehling liquor containing 5 cc. each of copper and alkali solution till sufficient has been introduced to completely reduce the copper, con- ducting the operation in the manner described in detail on page 615. As 0.067 gram of milk sugar will reduce 10 cc. of Fehling solution (see p. 616), it follows that the number of cubic centimeters of sugar containing solution required for making the test (using preferably the average of several determinations) will contain 0.067 gram of milk sugar, from which the percentage is readily computed. Thus if 16 cc. of the milk sugar solution are necessary to reduce the copper, then 16 cc. contain 0.067 gram milk sugar. 250 cc. of solution contain 25 grams milk, ICC. '' " " 0.1 « " i6cc. " " " 1.6 " " and 1.6 grams milk contain 0.067 gram milk sugar. Therefore the , ^ . .067X100 „ sample contams 7 = 4.19%. Gravimetric Fehling Processes.— O'SulUvan-Dejren Method.— Twenty- five cc. of the above milk sugar solution are added to the hot mixture of 15 cc. each of Fehling copper and alkali solutions and 50 cc. water, pre- pared as directed on page 615, and the test carried out in accordance with the details given on page 618. The weight of the cupric oxide, CuO, as formed, may be roughly calculated to anhydrous milk sugar by multiply- ing by 0.6024. For more accurate results, however, the Defren table, page 619, should be used. Soxhlet's Method."^ — Twenty-five cc. of milk are diluted with 400 cc. .of water in a half-liter graduated flask and 10 cc. of Fehling's copper solu- tion are added. Then 8.8 cc. of half-normal sodium hydroxide are run in, or a sufficient quantity to nearly but not quite neutralize, the solutior. being still slightly acid. The flask is filled to the mark, shaken, and the contents filtered, using a dry filter. One hundred cc. of the fiUrate are added to 50 cc. of the mixed Fehhng solution, which is boiled briskly in a beaker (using 25 cc. each of the copper and alkali solution). After boiling for six minutes, fiher rapidly through a Gooch crucible provided with a layer of asbestos as described on page 618, and wash with boiling water till free from alkah. The asbestos * U. S. Dept. of Agric, Bur. of Chem., Bull. 46, p. 41; Bui. 107 (rev.), p. 119. 138 FOOD INSPECTION AND ANALYSIS. film with the adhering cuprous oxide is washed into a beaker by hot dilute nitric acid, and after complete solution of the copper is assured, it is again filtered and washed with hot water till a clean solution containing all the copper is obtained. Add lo cc. of dilute sulphuric acid (containing 200 cc. of sulphuric acid, specific gravity 1.84 per liter) and evaporate on the steam- bath till the copper has largely crystallized, then carefully continue the heating over a hot plate till the nitric acid is driven out, as evidenced by the white fumes of sulphuric. Add 8 or 10 drops nitric acid (specific gravity 1.42) and rinse into a very clean tared platinum dish of about 100 cc. capacity, in which the copper is deposited by electrolysis. See page 634. The weight of milk sugar is determined from that of copper found, from the table on page 139. If the apparatus for the determination of the copper by the elec- trolytic method is not at hand, the cuprous oxide may be weighed directly in the Gooch crucible. In order to facilitate drying, it should be washed successively with 10 cc. of alcohol, and 10 cc. of ether, after which it is dried thirty minutes in a water-oven at 100° C, cooled, and weighed. The weight of copper is obtained from the weight of the cuprous oxide by the use of the factor 0.8883. Mimson and Walker Method. — The milk sugar solution is prepared as in Soxhlet's method. For details as to the copper reduction process see page 622. Relation between Specific Gravity, Fat, and Total Solids of Milk.— The close relationship existing between these factors has long been known, and many formulae have been devised, whereby, if two of them are known, the third may be computed with considerable approach to accuracy. The specific gravity and the fat are very readily determined by any dairyman, by the aid of a lactometer and the Babcock apparatus. The total solids are ascertained with more difficulty, since the use of more involved and costly apparatus is necessary, besides considerable tech- nical skill. It is therefore common for producers to calculate the total solids from the fat and specific gravity, using one of the many tables pre- pared for the purpose, based on some one of the best accepted formulae. The total solids can thus be calculated to within two or three tenths of a per cent. The two most commonly used formulae for this purpose are those of Hehner and Richmond in England, and Babcock in the United States. Hehner and Richmond's formula is r = o.255+ 1.2F+ 0.14, 1 MILK AND ITS PRODUCTS. 139 SOXHLET-WEIN TABLE FOR THE DETERMINATION OF LACTOSE. Milli- ' MiUi- Milli- Milli- Milli- Milli- Milli- Milli- Milli- MUli- grams grams grams grams grams of Cop- grams grams grams grams grams of C!op- of Lac- 1 of Cop- of Lac- of Lac- of Cop- of Lac- of Cop- of Lac- per. tose. per. tose. per. tose. per. tose. per. tose. lOO 71.6 161 117. 1 221 162.7 281 209.1 341 256-5 lOI 72.4 162 117.9 222 163.4 282 209.9 342 257.4 I02 73-1 1 163 118. 6 223 164.2 283 210.7 343 258.2 103 73-8 1 164 119. 4 224 164.9 284 211.5 344 259.0 104 74-6 165 120.2 225 165-7 i 285 212.3 345 259-8 105 75-3 166 120.9 226 166.4 1 286 213.1 346 260.6 106 76.1 167 121. 7 227 167.2 1 287 213.9 347 261.4 107 76.8 168 122.4 228 167.9 , 288 214.7 348 262.3 108 77-6 169 123.2 229 168.6 1 289 215-5 •349 263.1 109 78-3 170 123.9 230 169.4 i 290 216.3 350 263.9 IIO 79.0 171 124.7 231 170.1 1 291 217. 1 351 264.7 III 79-8 172 125-5 232 170.9 1 292 217.9 352 265.5 112 80.5 173 126.2 233 171.6 293 218.7 353 266.3 113 81-3 174 127.0 234 172.4 294 219-5 354 267.2 114 82.0 175 127.8 235 I73-I 295 220.3 355 268.0 "5 82.7 176 128.5 236 173-9 296 221.1 356 268.8 116 83-S 177 129.3 237 174.6 j 297 221 .9 357 269.6 117 84.2 178 130. 1 238 175.4 1 298 222.7 358 270.4 118 85.0 179 130.8 239 176.2 299 223-5 359 271.2 119 85.7 180 131.6 240 176.9 1 300 224 4 360 272.1 120 86.4 181 132-4 241 177-7 301 225.2 361 272.9 121 87.2 182 133-I 242 178-5 302 225.9 362 273-7 122 ll^ 183 133-9 243 179-3 1 303 226.7 363 274-5 123 88.7 184 134-7 244 180.1 304 227-5 364 275-3 124 89-4 185 135-4 1 245 180.8 305 228.3 365 276.2 125 90.1 186 136.2 246 181. 6 306 229.1 366 277.1 126 90.9 187 137-0 247 182.4 307 229.8 367 277-9 127 91.6 188 137-7 248 183.2 308 230.6 368 278.8 128 92-4 189 138.5 249 184.0 309 231.4 369 279.6 129 93-1 190 139-3 250 184.8 310 232.2 370 280.5 130 93-8 191 140.0 251 185-5 311 232.9 371 281.4 131 94-6 192 140.8 ' 252 186.3 312 233.7 372 282.2 132 95-3 193 141. 6 253 187.1 313 234-5 373 283.1 ^33 96.1 194 142.3 254 187.9 314 235.3 374 283.9 134 96-9 195 143-1 255 188.7 315 236.1 375 284.8 135 97-6 196 143-9 256 189.4 316 236.8 376 285.7 136 98.3 197 144.6 257 igo.2 317 237.6 377 286.5 137 99-1 198 145-4 258 191.0 318 238.4 378 287.4 138 99-8 199 146.2 259 191.8 319 239.2 379 288.2 139 100.5 200 146.9 260 192-5 320 240.0 380 289.1 140 101.3 201 147-7 261 193-3 321 240.7 381 289.9 141 102.0 202 148.5 262 194.1 322 241-5 382 290.8 142 102.8 203 149-2 263 194.9 323 242.3 383 291.7 143 103-5 204 150.0 264 195.7 324 243-1 384 292-5 144 104-3 205 150.7 265 196.4 325 243.9 385 293-4 I4S 105. 1 206 151-5 ' 266 197.2 326 244.6 386 294.2 146 105.8 207 152.2 267 198.0 327 245-4 387 295.1 147 106.6 208 153-0 268 198.8 328 246.2 388 296.0 148 107-3 209 153-7 269 199-5 329 247.0 389 296.8 149 108. 1 210 154-5 270 200.3 330 247-7 390 297-7 150 108.8 211 ISS-2 1 271 201.1 33^ 248.5 391 298.5 151 109.6 212 156.0 272 201.9 332 249.2 392 299.4 152 no. 3 213 156.7 273 202.7 333 250.0 393 300.3 153 III. I 214 157-5 274 203 -5 334 250.8 394 301.1 154 III. 9 215 158.2 275 204.3 335 251.6 395 302.0 155 112. 6 216 159.0 1 276 205.1 336 252-5 396 302.8 156 113-4 217 159-7 i 277 205.9 337 253-3 397 303-7 157 114. 1 218 160.4 278 206.7 338 254-1 398 304.6 158 114. 9 219 161.2 279 207.5 339 254-9 399 305-4 159 115.6 220 161. 9 280 208.3 340 255-7 400 306.3 160 116. 4 ! ■ 140 FOOD INSPECTION AND ANALYSIS. wheie T is the per cent of total solids, S the lactometer reading, and F the fat. An ingenious instrument known as Richmond's milk-scale (Fig. 48) is useful in making the calculation, instead of employing either the formula or a table. This is constructed on the principle of the slide rule, and by its use the specific gravity may be corrected to the proper temperature, and the solids calculated from the fat and specific gravity. Babcock's formula for solids not fat is as follows : Solids not fat = looS-FS -i)(ioo-F)2.5, ,100 — 1.0753^5 S being the specific gravity, and F the percentage of fat. On this formula he has prepared a table * by means of which one may calculate solids not fat agreeing quite closely with results obtained by gravimetric analysis.f The table on page 141 has been recomputed and enlarged from that of Babcock, so as to express results in total solids rather than solids not fat. Calculation of Proteins. — Van Slyke's % formula for calculating proteins (P) from the fat {F) is: P=(i^-3)Xo.4 + 2.8. Olsen § has devised the following formula for calcu- lating proteins from total solids {TS): TS P=TS- 1.34 Approximately 0.8 X proteins = casein. The proteins being thus calculated, the sugar may be computed by difference. These calculations, while only approximate, give quite satisfactory results for normal, healthy milk, especially from herds. Determination of Acidity. — While milk is still fresh, i.e., before it has begun to undergo lactic fermentation, it will show an acid reaction,- which is sometimes expressed in terms of lactic acid. In view of the fact that * U. S. Dept.of Agric, Div. of Chem., Bui. 47, p. 123; Bui. 107 (rev.) p. 225. t For approximate work Babcock has suggested the following simpli- ied formula;: Solids not fat = o.25G + o.2i^ and total solids=o.25G-f- 1.2F, G being the lactometer reading and F the fat. I Jour. Am. Chem. Soc. 30, 1908, p 1182. § Jour. Ind. and Eng. Chem., i, 1909, p. 253. KI? a^ = (r - = - _ CD tH = Q. - = '" si E = m - 37<» 1 ~ t^ w = = 36^1 ~ CO z E35„-| z 00 = 'i*.r,-- eo 05 ^ z = - st^ z -M E th CO D CO j§0 - 29 - Z ~. a - p= LO z = < -1- 1- CD - z -27 UJ -^ 2 : I. 1- - E263 :2S l?i :23 T^ -eo- -75- -70- -66- -co? 65- - CO T-1 ■H lO -46- -to- 36- -32 3 .1- E i 322 -tH 1 '1 CD = T-1 MILK AND ITS PRODUCTS. 141 TABLE SHOWING PER CENT OF TOTAL SOLIDS IN MILK CORRESPONDING TO QUEVENNE LACTOMETER READINGS* AND PER CENT OF FAT.f Per Cent Lactometer Reading at i 5.5° c. of Fat. 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 o.o 5- 50 5-75 6.00 6.25 6- so 6-75 7 .00 7.25 7.50 7-75 8-00 8.25 8.50 8-75 9.00 O . I 5 -62 5-87 6.12 6.37 6.62 6.87 7.12 7-37 7 . 62 7-87 8.12 8.37 8.62 8.87 9.1 O. 2 5.74 5-99 6. 24 6.49 6-74 6-99 7.24 7-49 7-74 7-90 8.24 8-49 8.74 8.99 9. 24 0.3 S.86 6. II 6.36 6.61 5.86 7-11 7-36 7.61 7.86 8.11 8.36 8.61 8.86 9. II 9-36 0.4 5-98 6.23 6. 48 6.73 6.98 7-23 7-48 7-73 7.98 8.23 8.48 8.73 8.99 9-23 9-48 0.5 6. TO 6.35 6.60 6.85 7.10 7-35 7.60 7-85 8.10 8.35 8.60 8.85 9. 10 9-35 9.60 0.6 6.22 6.47 6.72 6.97 7.22 7-47 7.72 7-97 8.22 8.47 8.72 8.97 9.22 9-47 9-72 0.7 6.34 6.59 6.84 7.09 7-34 7-59 7.84 8.09 8.34 8.50 8.84 9.09 9-34 9-59 9-84 0.8 6.46 6.71 6.96 7.21 7.46 7-71 7.96 8.21 8.46 8.71 8.96 9.21 9.46 9-71 9.96 0.9 6.58 6.83 7.08 7-33 7-58 7.83 8.08 8.33 8.58 8.83 9.08 9.33 9.58 9-83 10.08 1 .0 6.70 6-95 7. 20 7-45 7-70 7.95 8.20 8.45 8.70 8.95 9. 20 9.45 9.70 9-95 10. 20 I.I 6.82 7-07 7.32 7-57 7.82 8.07 8.32 8-57 8.82 9-07 9-32 9-57 9-82 10.07 10. 32 I . 2 6-94 7.19 7-44 7-69 7-94 8.10 8.44 8.69 8.94 9.19 9-44 9.69 9-94 10. 19 10.44 1.3 7 .06 7-31 7.56 7-81 8.06 8.31 8.56 8.81 9.06 9-31 9- 56 9.81 10 .06 10.31 10. s6 1.4 7.18 7-43 7.68 7.93 8.18 8.43 8.68 8.93 9.18 9-43 9-68 9-93 10.18 10.43 10.68 1.5 7.30 7-55 7.80 8.05 8.30 8.55 8.80 9 -OS 9 30 9-55 9-80 10.05 10.30 10.55 10.80 1.6 7.42 7.67 7-92 8.17 8.42 8.67 8.92 9-17 9.42 9.67 9.82 10.17 10.42 10.67 10.92 1.7 7-54 7.79 8.04 8.29 8.54 8.79 9.04 9.29 9-54 9-79 10 . 04 10.29 10.54 10.79 11 .04 1.8 7.66 7-91 8.16 8.41 8.66 8.91 9. 16 9.41 9.66 9-91 10-16 10.41 10.66110.91 11.17 1.9 7.78 8.03 8.28 8.53 8.78 9-03 9.28 9-53 9.78 10-03 10.28 10.55 10.78 II .04 11 . 39 2.0 7.90 8.15 8.40 8.65 8.90 9-15 9.40 9.65 9.90 10-15 10.40 10.66 10.91 11.16 II .41 2. 1 8.02 8.27 8.52 8.77 9.02 9-27 952 9-77 10.02 10 - 27 10.52 10.78 II .03 II .28 11.53 2. 2 8.14 8.39 8.64 8.89 9.14 9-39 9.64 9-89 10.14 10-39 10.64 10.90 11.15 11 .40 11 .65 2.3 8.26 8-51 8.76 9.01 9. 26 9-51 9.76 10.01 10.26 10.51 10.76 11.02 11.27 11.52 11-77 2-4 8.38 8.63 8.88 9.13 9-38 9-63 9.88 10. 13 10.38 10.63 10.88 II . 14 11.39 11 .64 11.89 2-5 8.50 8.75 9.00 9-25 9-50 9-75 10.00 10. 25 10 . 50 10. 75 11 .00 11.26 II. 51 11.76 12.01 2.6 8.60 8.87 9.12 9-37 9.62 9.87 10.12 10.37 10. 62 10.87 11.12 11.38 11 . 63 11.88 12.13 2.7 8.74 8.9*9 9.24 9-49 9-74 9-99 10. 24 10.40 10.74 10.99 11.24 11 .50 11.75 12.00 12.25 2.8 8.86 9. II 9.36 9-61 9.86 10.11 10.36 10. 61 10.86 11.11 11.37 11.62 11.87 12.12^12.37 2.9 8.98 9-23 9.48 9.73 9-98 10.23 10.48 10.73 10.98 11.23 11.49 11.74 11.99 12. 24 12.49 3-0 9. 10 9-35 9.60 9-85 10- 10 10.35 10.60 10.85 11.10 11.36 II. 61 11.86 12. II 12.36 12. 6l 3-1 9. 22 9-47 9.72 9-97 10.22 10.47 10.72 10.97 11.23 11.48 11.73 11.98 12.23 12.48 12.74 3-2 9-34 9-59 9.84 10 .09 10.34 10.59 10.84 1 1 .09 11.35 11 .60 11.8s 12.10 12.35 12.61 12.86 3-3 9.46 9.71 9-96 10. 21 10.46 10.71 10.96 11.22 11.47 11.72 11.97 12.22 12.48 12.73 12.98 3-4 9-58 9.83 10.08 10.33 10.58 10.83 11 .09 11.34 11-59 11.84 12 .09 12.34 12 . 60 12.85 13-10 3-S 9.70 9-95 10. 20 10.45 10.70 10.95 11.21 1 1 . 46 II. 71 11 .96 12.21 12.46 12.72 12.97 13-23 3-6 9.82 10.07 10.32 10.57 10.82 11.08 11-33 11.58 1 1 . 83 12.08 12.33 12.58 12.84 13.09 13-34 3-7 9.94 10. 29 10.44 10.79 10.94 II . 20 II -45 11.70 11-95 12. 20 12.45 12-70 12 . 96 13-21 13-46 3-8 lo .06 10.31 10.56 10.81 11 .06 11.32 11-57 11.82 12.07 12.32 12.57 12.82 13.08 13-33 13-58 3-9 10.18 10.43 10.68 10.93 II. 18 11.44 1 1 . 69 11.94 12.19 12.44 12.69 12.94 13.20 13-45 13.70 4.0 10.30 10. SS 10.80 11.05 11.30 11.56 11.81 12.06 12.31 12.56 12.81 13-06 13.32 13-57 13.83 4.1 10.42 10.67 10.92 11.17 11 .42 11.68 11-93 12.18 12.43 12.68 12.93 13-18 13.44 13-69 13.9s 4-2 10. 54 10.79 1 1 . 04 1 1 . 29 11-54 11.80 12.05 12.30 12.55 12.80 13-05 13-31 13.56 13-82 14.07 4-3 10. 66 lo. 91 II . 16 II .41 11.66 II .92 12.17 12.42 12.67 12.92 13-18 13-43 13-68 13-94 14.19 4-4 10.78 11.03 II .28 11-53 11.78 I 2 .04 1 2 . 29 12.54 12.79 13.04 13-30 13-55 13-80 14-06 14.31 4-5 10. 90 II. 15 II . 40 11.65 11 .90 12.16 12.41 12.66 12.91 13.16 13-42 13-67 13-92 14.18 14.43 4.6 1 1 .02 11.27 11.52 11.78 12.03 12.28 12.53 12.78 13-03 13.28 13-54 13-79 14.04 14-30 14-55 4-7 1 1 . 14 1 1 .40 1 1 . 65 11.90 12.15 12 .40 12.65 12 .90 13.15 13-40 13-66 13.91 14.16 14-42 14-67 4.8 11.27 11-52 11-77 12.02 12. 27 12.52 12.77 13.02 13-27 13-52 13.78 14-03 14.28 1454 14-79 4-9 11-39 11. 64 11.89 12.14 12.39 12.64 12.89 13.14 13-39 13-64 13-90 14-15 14-40 14-66 14.91 5-0 ii-Si II - 76 12.01 I 2 . 26 12.51 12.76 13.01 13.26 13-51 13-76 1 14.02 14-27 14-52 14-78 15-03 S-i 11-63 11-88 12.13 12.3S 12.63 12.88 13.13 13.38 13-63 13-89 14.14 14.39 14.64 14-90 IS-15 S-2 11.75 I 2 .00 12.25 12. 50 12.75 13-00 13.25 13-50 13-75 14.01 14.26 14.51 14-76 lS-02 iS-27 5-3 11-87 12.12 12-37 12.62 12.87 13-12 13-37 13-62 13-87 14-13 14.38,14.63 14-88 15-14 15-39 5-4 11-99 I 2 . 24 12.49 12.74 12.99 13-24 13-49 13-71 14.00 14-25 14.50 14-76 IS .01 15 . 26 15-51 S-S I 2 . I I 12.36 12.61 12.86 13-11 13-36 13 ■ 61 13-86 14.12 14-37 14.62 14.88 15-13 15-38 15-63 5.6 12.23 12.48 12.73 12.98 13-23 13.48 13-73 13-99 14.24 14.49 14.75 15.00 15-25 15-50 I5-7S 5-7 12.35 12 . 60 12.85 13.10 13-35 13-60 13.85 14- 1 1 14-36 14.61 14.87jlS.12 15.37 15-62 15-87 5.8 12.47 12.72 12.97 13-22 13-47 13-72 13-97 14. 22 14-48 14.74 14.99 15.24 15-49 15-74 15-99 S-9 12.59 12.84 13-09 13-34 13-59 13-84 14.10 14-35 14-60 14.86 15.11 15.36 15.61 15-86 16. 13 6.0 12.71 12 .96 13-21 13.46 13.71 13.96 14. 22 14.47 14-72 14-98 15.23 15.48 15-73 15.98 16. 24 *The lactometer reading is expressed in whole numbers for convenience. The true specific gravity Corresponding to a given lactometer reading is obtained by writing i.o before the lactometer reading. Thus, 1.026 is the specific gravity corresponding to lactometer reading 26, etc. t An. Rep. Mass. State Board of Health, 1901, p. 445. (Analyst's Reprint, p. 25.) 142 FOOD INSPECTION AND ANALYSIS. the acidity of " sweet " milk is due partly to the presence of acid phos- phates and partly to dissolved carbonic acid in the milk, and not to lactic acid, which is probably absent, a better plan is to express the acidity in terms of the number of cubic centimeters of tenth-normal alkali necessary to neutralize a given quantity of the milk, either 25 or 50 cc, using phenol- phthalein as an indicator. See also page 1033. If it is desired to calculate the acidity in terms of lactic acid, multiply the number of cubic centimeters of tenth-normal alkali used by 0.897, and divide by the number of cubic centimeters of milk titrated, the result being the percentage of lactic acid. MODIFIED MILK. A comparison of the composition of cow's milk and human milk, as in the following table by Dr. Em^mett Holt,* shows very marked differ- ences. Woman's Milk, Cow's Milk, Average. Average. Fat 4-00 3.50 Sugar 7.00 4.30 Proteins 1.50 4.00 Ash 0.20 0.70 Water 87.30 87.50 The per cent of fat in the two kinds of milk is nearly the same. There is, however, too little sugar and an excess of proteins and ash in the milk of the cow, assuming human milk as the ideal infant food, so that in basing a diet for infants on the basis of human milk considerable modi- fication is necessary. Moreover, aside from the actual variation in the amount of ingredients, there are certain inherent differences in the char- acter of the same ingredient, as found in the milk of the cow and in human milk. The proteins of cow's milk, are for instance, found to be much more difficult of digestion than those of woman's milk, and the same is probably true of the fat. Aside from the mere statement of a few of these differences, it is obviously beyond the scope of this work to discuss this phase of the subject in detail, reference being made, how- ever, to such books as Dr. T. M. Rotch's " Pediatrics," and " Infancy and Childhood " by Dr. Emmett Holt, for full particulars. So great has been the demand by physicians for "modified milk" for infant feeding, that laboratories for this exclusive purpose have been established * "Infancy and Childhood." MILK AND ITS PRODUCTS. 143 in many of the larger cities, in which not only is milk prepared in accordance with certain fixed formulae supposed to be adapted to average infants of varying age, but milk of any desired composition is prepared, in accordance with special prescriptions of physicians to apply to indi- vidual cases. Methods and Ingredients. — The proteins and the ash in cow's milk are much higher than in human milk, and both are brought to the proper degree of reduction by diluting the milk with water. Milk sugar is increased by the addition of lactose, and the fat is increased or diminished by addition of cream or by skimming. The dilution of cow's milk with a measured amount of water shows the following results on the proteins and ash: Cow's Milk. Diluted Once. Diluted Twice. Diluted Three Times. Diluted Four Times. Proteins. . . ........ Per cent. 4.00 0.70 Per cent. 2.00 0-35 Per cent. 1-33 0.23 Per cent. I.OO 0.18 Per cent. 80 Ash 0.14 The ingredients commonly employed for modifying milk are (i) cream, containing 16% of fat, (2) centrifugally skimmed milk, otherwise known as "separator milk" from which the fat has been removed, (3) milk sugar, or a standard solution of milk sugar of, say, 20% strength, and (4) lime water. Unusual care should be taken in the selection of the milk supply to insure cleanness, purity, and freshness, as well as in the care of utensils, etc., used in the laboratory, which should in all cases be scrupulously clean. Samples prepared in accordance with a given formula or formulae are pasteurized in separate bottles, or, if desired, sterilized, and after stoppering with cotton are kept on ice. FormulcB. — It is obviously impossible to establish formulae univer- sally applicable even to healthy infants, but the following may be regarded as typical formulae, representing the composition of modified milk to suit the needs of an average growing infant during its first year: Period. Fat. Proteins. Sugar. Third to fourteenth day Second to sixth week Per Cent 2 2-5 3 3-5 4 3-5 Per Cent 0.6 0.8 I.O I-S 2 2-5 Per Cent 6 6 6 / 7 3-5 Sixth to eleventh week -Eleventh week to fifth month.. Fifth to ninth month Ninth to twelfth month 144 FOOD INSPECTION AND ANALYSIS. Fig. 49.— The "Materna" Graduate for Modifying Milk. Milk according to the above formuloe can be very simply prepared by the aid of a spe- cially made graduate known as the " Materna " and shown in Fig. 49. Sodium Citrate has long been used in modify- ing milk in cases where the casein forms large lumps which pass through the body undigested. England * attributes the beneficial action to the formation of sodium chloride with the hydro- chloric acid of the stomach which influences the digestion of the protein. Van Slyke and Bos- worth t more recently have observed that sodium citrate reacts with calcium caseinate, forming sodium caseinate or sodium-calcium caseinate. With 0.4 gram per 100 cc. no curdling takes place, with smaller amounts the curd is more or less soft, depending on the amount. ADULTERATION OF MILK. Systems of Milk Inspection. — A typical method of general food inspec- tion has already been outlined (see pp. 6 and 8), which may easily be modified to include the inspection of milk in connection with other foods, or to provide for a system of milk inspection exclusively. In the exam- ination of such a perishable food as milk, it has not been found practicable for the analyst to reserve for the benefit of the defendant a sealed sample, as in the case of other foods, but experience has shown it had best be made the duty of the collector or inspector to give a sealed sample of milk to the dealer, when the latter requests it at the time of taking the sample. For this purpose the collector is provided with small bottles and sealing paraphernalia, in addition to the tagged sample bottles or cans in which he collects the milk. The collector should use the same precautions for obtaining a perfectly fair representative sample as does the chemist in making the analysis, i.e., he should carefully pour the milk from the original container into an empty can or vessel and back again, before taking his sample. Each sample is properly numbered by the collector in presence of the dealer, and the data as to the taking of the sample entered at once under * Jour. Amer. Med. Assn., 47, 1906, p. 1241. t N. Y. State Agr. Exp. Sta. Tech. Bui., 34, 1914. MILK AND ITS PRODUCTS. 145 the proper number in the collector's book. If a sealed sample is given, it should bear the same number as the sample reserved for analysis, and a receipt should invariably be required from the dealer, as evidence that his request for a sealed sample has been complied with. Milk Standards Fixed by Law. — In localities where a systematic form of milk inspection prevails, there is usually in force a statute fixing the legal standard for the total solids, and in many cases for the fat or for the solids exclusive of fat. In some states the statute is so drawn that any deviation from the legal standard constitutes an adulteration in the eye of the law, and hence the offender, who has such milk in his possession with intent to sell, is liable to the same fine as if he actully added water or a foreign substance to the milk. In other states a distinction is made by the statute between milk that is simply below the legal standard of total solids, and milk containing actually added ingredients (water or otherwise), a much lighter fine being imposed for the former than for the latter offense. Where such a dis- tinction prevails, it often becomes incumbent upon the analyst to show to the satisfaction of the court, in case of milk low in solids, whether or not the milk has been fraudulently watered after being drawn from the cow, it being well understood that cows may give milk below the standard. The U. S. standards for some years in force fixed the minimum limits of 8.5% for solids not fat and 3.25% for fat, but more recently it has seemed impracticable to fix minimum limits that will apply to all sections and the state and municipal standards have been deemed suf- ficient. These latter are by no means uniform. The minimum limits for total solids range from 11 to 13% and for fat from 2.5 to 3.7 %. Pure milk that is low in solids may owe its deficiency either to poor feeding, or to an inherent tendency on the part of the cow to give milk always of poor quality. Thus the Holstein cow, more than any other breed, is open to the charge of sometimes giving milk below the standard.* That the Holstein cow is a favorite with the producer is by no means * This statement should not be taken as condemning the Holstein, for it is true that cows of this breed often give milk far above the standard. A large number of samples of milk of known purity from Holsteins analyzed by the writer have been found to be of excellent quality. It is a curious fact that among the samples of known purity analyzed by the Massa- chusetts Board of Health, both the lowest and highest total solids on record came from a Holstein cow; the lowest recorded total solids in a " known purity" milk being 9.96 per cent, (seventh annual report of Massachusetts State Board of Health, Lunacy, and Charity, p. 160), and the highest being 17.06 per cent, (twenty-second annual report of the Massa- chusetts State Board of Health, p. 405). 146 FOOD INSPECTION AND ANALYSIS. Strange, from the fact that no other breed can with moderate feeding be made to give so large a quantity of milk. Wherever there is a statute fixing the standard for milk, it commonly provides also that the addition of any foreign substance whatsoever con- stitutes an adulteration. Forms of Adulteration. — Milk is ordinarily adulterated (i) by watering, (2) by skimming, (3) by both watering and skimming, and (4) by the addition of one or more foreign ingredients. Watering and Skimming. — The fact that milk is found below the standard of total solids, while more often due to an excess of water, may also be due to a deficiency in fat. In one case the milk is commonly termed watered, and in the other skimmed, using the terms broadly and not necessarily meaning actual and fraudulent tampering with the milk. In a third case, and almost invariably fraudulently, both watering and skimming may be found to have been practiced on the same sample. The analyst judges which of these causes have produced a milk low in solids, by a careful study of the relation between the percentages of total solids, fat, and solids not fat. If both the total solids and solids not fat are abnormally low, and the proportion of fat to solids not fat about the same as, or higher than, in a normal milk, it is generally safe to assume that the sample has been watered; if both the total solids and the fat are well below the standard, and the solids not fat nearly normal, then the milk has undoubtedly been skimmed; if, in the third place, the total solids and the solids not fat are proportionally reduced below the standard, w-hile the ratio of fat to solids not fat is abnormally small, it is safe to adjudge the milk to be low by reason of both skimming and watering. Milk of Known Purity. — It is difficult to place the minimum figure for total solids, below which a milk sample may safely be pronounced by the analyst as fraudulently watered after having been drawn from the cow. Nearly nine hundred samples of milk of known purity from various breeds of cow, milked in the presence of an inspector, have been analyzed in the Department of Food and Drug Inspection of the Massa- chusetts State Board of Health, extending over a period of fifteen years, and among these are many samples from Holstein cows. It is extremely rare that any of these known purity samples have been found with total solids as low as 11%, though there are instances where total solids have run as low as 10%. MILK AND ITS PRODUCTS. 147 It is safe to assume that in the few cases on record showing less than 10.75% of total solids, either there was something decidedly abnormal about the health of the cow, or, through some accident, the cow was only partially milked, it being a well-known fact tnat the last fraction of the milking includes the larger percentage of fat. (See page 113.) It is therefore nearly always safe to condemn a milk standing below 10.75 ^s fraudulently watered, if at the same time it has a proportionately high per cent of fat. The average total solids of 800 samples of milk of known purity analyzed by the Massachusetts Board up to and including the year 1890 amounted to about i3i%. It is rare indeed to find a herd of ten or more well-fed cows of mixed breeds in which the average milk of the herd falls below i2j% of solids. The milk of forty-seven Holstein cows, examined in 1885, was found to contain an average of 12.51% of total solids, while the milk of eleven Jerseys examined in the same year averaged 14.02% of solids. Thpse examples represent the two extremes commonly met with. Variation in Standard. — In Massachusetts the law fixes a different standard for total solids in milk during the summer, or pasture-fed season, from that in force during the winter, or stall-fed period. From April to September inclusive the legal standard is 12% of total solids, of which 9% are solids not fat, and from October to March inclusive it is 13%, of which 9.3% are solids not fat. Bearing on the question of difference in normal quality of milk during the two periods, averages were taken of the milks collected by the corps of inspectors of the Massachusetts Board of Health during a month in each period, December and June being selected as most typical, and during these months all the samples were analyzed both for total solids and fat. The samples were taken from stores, milkmen, and producers, and represented as nearly as possible the milk as actually sold to the consumers. In making the averages, all samples of skimmed milk, as well as all ss>,mples standing above 17% of total solids, or under 10.75%, were deducted. The results are summarized as follows: 148 FOOD INSPECTION AND ANALYSIS. QUALITY OF MILK SOLD IN MASSACHUSETTS CITIES AND TOWNS IN WINTER AND SUMMER. December. Number of Samples. Total Solids. Fat. SoKds not Fat. Average Per Cent. Highest Per Cent. Lowest Per Cent. Average Per Cent. Highest Per Cent. Lowest Per Cent. Average Per Cent. Cities Towns Summary .... 403 99 502 16.86 15.48 16.86 10.88 12.02 10.88 13.21 13-44 13-32 8.50 6.65 8.50 2.40 3-5° 2.40 4-37 4-48 4.42 8-74 8.96 8.8s June. Number of Samples. Total Solids. Fat. Solids not Fat. Average Per Cent. Highest Per Cent. Lowest Per Cent. Average Per Cent. Highest Per Cent. Lowest Per Cent. Average Per Cent. Cities Towns Summary .... 3" 76 387 16.90 15-71 16.90 IO-75 10.99 IO-75 12.67 12.63 12.65 8.80 7.10 8.80 2.10 3.00 2.10 4-03 4.09 4.06 8-54 8.54. 8.54 It is interesting to note that the average for total solids of the 88g samples examined for both months stands at just 13%, of which 4.24% is fat and 8.76 is solids not fat. Rapid Approximate Methods of Determining the Quality of Milk. — The Lactometer. — ^A rough idea of the quality of milk can be gained by the use of the lactometer (page 118), but, in view of the fact that a low specific gravity may be the result either of a watered milk or of a milk high in fat, good judgment is necessary in connection with its use. A milk of good standard quality should have a specific gravity between the limits of 1.027 and 1-033. ^ watered milk would run below the former and a skimmed milk above the latter figure, though a milk unusually rich in fat would also run low. It should easily be apparent from the taste and appear- ance of the milk, whether a low specific gravity is due to watering or unusual richness in fat. The fact should also be recognized, that a milk sample may be far below the standard, and still show a specific gravity within the limits of pure milk, by skillfully subjecting the milk to both skimming and watering. The Ladoscope. — Feser's lactoscope (Fig. 50) gives an approximation to the amount of fat in milk, and its use, especially in connection with the lactometer, is of some value. This instrument consists of a graduated glass barrel, a, into the bottom of which i;. accurately fitted the stopper, bearing MILK AND ITS PRODUCTS. 149 a white glass cylinder, having black lines thereon. Four cc. of milk are introduced into the barrel by means of a pipette, c, and water is added with thorough mixing till the translucence of the mixture is sufficient to allow the black lines to be perceptible through it. The height of the level of milk and water in the barrel a is then read off, the number indicating roughly the percentage of fat in the sample. As in the case of the lactometer, the purity of a milk sample cannot be positively established by the lactoscope alone. For instance, a watered milk abnormally high in fat would often be found to read within the limits of pure milk, when as a matter of fact its total solids would be below stand- ard. By a careful comparison of the readings of both the lactoscope and lactometer, however, it is rare that a skimmed or watered sample could escape detection. Thus, if the specific gravity by the lactometer is well within the limits of pure milk, and the fat, as shown by the lactoscope, is above 3^ per cent., the sample may be safely passed as pure, or as conforming to the standard. A normal lactometer reading in connection with an abnormally low lactoscope reading shows both watering and skimming, and with an abnormally high lactoscope reading shows a milk high in fat, or a cream. With the lactoscope reading below three, and a low lactometer reading, watering is indicated. A lactometer reading above thirty-three, and a low lactoscope reading, indicate skimming. Heeren's Pioscope. — This instrument consists of a hard-rubber disk, having in the center a shallow receptacle, the circular rim of which is raised above the level of the disk. Into this receptacle are introduced a few drops of the milk to be tested, and a circular cover-glass containing a number of variously tinted segments is placed over the receptacle, which spreads the milk out into a thin layer, and causes it to assume a tint against the black background that can be matched with one of the colors on the glass, the various tints indicating milks of various grades from the very poorest to rich cream. This test is at best a very rough one. Examination of the Milk Serum. — Detection of Added Water. — This may often be detected by determining the specific gravity or the degree of refraction of the milk serum, since it has been found that under fixed conditions the composition of the milk serum, or clear " whey," is more constant than that of the milk itself. Hence any considerable amount of watering is manifest from the physical constants of the serum. -In using this method the analyst should carefully work out his own 150 FOOD INSPECTION AND ANALYSIS. Standards for comparison, by personal experiment on milk of known composition to which varying amounts of water have been added using the same conditions for obtaining the serum in all cases. f"''v>'^ /•]!! Fig. so. — Feser's Lactoscope. Preparation of the Serum. — In addition to natural souring, the fol- lowing methods of preparing the serum have been described : MILK AND ITS PRODUCTS. 151 1. Acetic Acid Method.^— To loo cc. of the milk at about 20° C, add 2 cc. of 25% acetic acid (sp. gr. 1.035), ^^ weW, and heat on a water- bath at 70° C. for 20 minutes. Cool 10 minutes in ice-water and filter. 2. Calcium Chloride Method. '\ — Mix thoroughly 90 cc. of the milk and 0.75 cc. of calcium chloride solution (sp. gr. 1.1375; refraction diluted I : 10, 26). Heat in a boiling water-bath under a reflux condenser for 15 minutes, cool to 20° C, mix without shaking, and filter. 3. Asaprol Method. % — The reagent consists of 30 grams of asaprol and 55.89 grams of crystallized citric acid in i liter of water, if the refraction is not 36.3 at 20° C, add citric acid or water as required. Mix equal volumes of the milk and the reagent, shake well, and filter. 4. Copper Sulphate Method. I — Dissolve 72.5 grams of crystallized copper sulphate in water and dilute to i liter. The refraction should be adjusted if necessary so as to be 36° at 20° C. To 4 volumes of the milk add i volume of the copper solution, shake well, and filter. Of the above Lythgoe's copper sulphate method has the advantage of simplicity, accuracy, and narrow range of refraction for pure milk. Specific Gravity. — The specific gravity of the clear filtrate, obtained by the method described above, is taken at 15° C, with the Westphal balance. Immersion Refractometer Reading. — The instrument used is the Zeiss immersion or dipping refractometer described on pages 97 to 107. The serum, prepared as directed in a preceding paragraph, is examined in one of the small beakers accompanying the apparatus at a temperature of 20° C. Composition and Serum Constants of Milk of Known Purity. — In the table on page 152 are given Lythgoe's results || on 33 samples from individual cows and 4 samples from herds, all of known purity. He concludes after several years' experience with samples of known purity that the presence of added water is shown by a refraction of less than 36°, furthermore that when the protein exceeds the fat the sample is skimmed milk. Nitrates. — Pure milk, free from contamination with stable filth, con- tains no nitrates; well water, however, often contains a sufficient amount to enable the detection of a 10% admixture in milk. * Woodman, Jour. Amer. Chem. Soc, 21, 1899, p. 503. fAckerman, Zeits. Unters. Nahr. Genussm, 13, 1907, p. 186. X Baier and Neumann, Ibid., p. 369. §Lythgoe, Mass. State Bd. Health Rep., 1908, p. 38. II Ibid., Rep. 1910, p. 44. 152 FOOD INSPECTION AND ANALYSIS. O oo O OO O CO ' NO O 'Tf _ - M rooo tnoo ionO -^sO ^O t^ W -^ Tf CO 00 1^ i^ i-^ t-- r- CO t- t- r^ oo t^ i-^ ooo ooooooooooo t-~oor~cooor^t^oocor^QOr^r^ i>r^t^QO ooooooooooooo oooo 0\ t^ t^00\O 00 ior-00 to»o t^NOO r* r- TfO0 OOOOO Tj-0\iO( Tj- o O O w N f*5 O>oo -^M OO"-" Noo oo^r^ r-co o r^ r^^ i O o H >^ H HH P^ t3 Oh o Ui o CX4 O w < Oo„ ro tJ-oO roO ^OOOOONr^Tj-OOOWM Tt lo roO to ro lO t^ ^00 ^ 0\ "^ ^ "^ N l^ ■*-*'*"*'*'t'*'t'*'*MTO'*^'*'t't ^ Tj-OO M lo ro PO t-t o N rooo M N >o Oi ^ N 00 ■*•*•*■*•>*'* rr 't •'t ■* fO fO •*■* r«3 Tt^Tj-Tt so NO O >00 sO O O too O to too O too too O to to to too OtOtOtOtOtOtOlO OtotOtO Oi-iMOOiiONwMMt^OiOi'^woOMOi'twO 'too OifOH'-'l-'POOO "tO O N " 0> 00 i^i^t^o t^ooooo r^t^totot^i^o t^o t^t^oo totor^r^oo tototototo "^ <:i^ to t^^OfOl^oc M r-OO rotO" O too t~ toOO t^O to O O rj- M too r<3oo 1 1 TJ +J 4J — O c! .9. t^fe OOtoMOOOOO too N *-* tOOO 00 O ■^00 'd-Oa>t^«^0000Ot^ONO00t-lto OOOPOPO lOOPOOOOOOOO)ONOtOt^r^l^OOOOOO^OOOfOlOO>ONI-IOOOOOto 0\0*00000 O\O00 000 O\000000000O00 O\O\3000O0000000O00O00 t^oo t^t^ N 000 OlOOOOOO 000000000000000000000000000000000 r* t^ t^ t^ o o d o POro<^POrOrOfONrOr*^fOfOfONN(NfOrororo'0(«5ror<5r<5NN n w 00 t^ ^ ^ fO ro ':3 "> (5o' 2 c ■" «o O O t^O 0\0 W I 100 to ro rO N M ' ^ 000 O O 00 ro fO rffOrOfOPOi^fOr^rorOfOM N N M W N N 1 no o 00 o >o « o too O " t~co o o 00 00 too oooooooootooooooo ■IM04*HIHMMMM»HMOIMMIHCNM-W«*-,■> 33 ;>,oo :o333 : :o>,ooo c cCd c * -1— M-X" E'EEe SSS2 MILK AND ITS PRODUCTS. 153 The diphenylamin test, first employed by Soxhlet to detect nitrates in milk, has since been variously modified.* Place in a small porcelain crucible one cc. of a solution of o.i gram of diphenylamin in loco cc. of concentrated sulphuric acid and allow a few drops of the milk serum to flow over the surface. A blue color appearing within lo minutes indicates the presence of nitrates. On longer standing, a brown color forms, whether or not nitrates are present. According to Willeke, Schellbach, and Jilke f milk to which hydrogen peroxide has been added also gives the blue color. The delicacy of the test is increased by adding to the reagent a small amount of powdered sodium chloride shortly before using. Determination of Freezing Point.— Beckmann,t who proposed this means of detecting added water, reached the conclusion that the freezing point of pure milk ranged from -0.58° to -0.54° C, and that water influences the result in proportion to the amount added. While most of the later investigators find that -0.58° is none too high for the mini- mum limit, Gr liner § reports a maximum for single cows of —0.535°, Pins II of -0.529°, Stutterheim 1; of -0.52° and Konig ** of -0.515°. Mixed herd milk appears seldom to fall outside of the limits -0.57° and -0.53°. Most authors agree that the per cent of fat, as well as the age, breed, period of lactation, and feed of the cow have little or no influence. Stutterheim, however, found that poor feeding gave freezing points in the case of eight cows from -0.52° to -0.536°. Souring and the addition of certain preservatives without question lower ihe freezing point (Bon- nema,tt Keister ||). Gooren ** finds that homogenizing, pasteurizing, and sterilizing also lower it. While the freezing point is undoubtedly a valuable constant and will detect with reasonable certainty as high as 10% of water, whether it serves for finer distinctions and is as reliable a means of diagnosis as either the ♦Moslinger, Ber. 7 Versain. bayer. chem. Berlin, 1889; Richmond, Analyst, 18, 1893, p. 272; Hefelmann, Zeits. offentl. Chem., 7, 1901, p. 200; Reisz, Pharm. Ztg., 49, 1904, p. 608; see also Tillmans, Zeits. Unters. Nahr. Genussm., 20, 1910, p. 676. tZeitz. Unters. Nahr. Genussm., 24, 1912, p. 227, t Milch Ztg., 23, 1894, p. 702. § Ann. 1st. Agric, 6, 1901-1903, p. 27. 11 Inaug. Dis., Leipzig, 1910. H Pharm. Weekbl., 54, 1917, p. 458. ** Gooren, Centbl. Bakt., 35, II, 191 2, p. 625. tt Pharm. Weekbl., 43, 1906, No. 18. tt Jour. Ind. Eng. Chem., 9, 1917, p. 862. 154 FOOD INSPECTION AND ANALYSIS. solids-not-fat or the refraction, can be settled only by numerous determina- tions on authentic samples produced under a variety of conditions. The apparatus, although not so expensive as the immersion refractometer, requires more skill in manipulation. The possible presence of considerable lactic acid, preservatives, and common salt, the latter added to offset the effects of watering, should always be taken into account. The apparatus and general process of determination are described on page 4.9. Otlier Milk Constants. — The Viscosity of milk has been determined by various chemists. Kooper * claims to be able to detect 5% of added water b}'' this constant. The Specific Heat of milk and milk products has been determined by Hammer and Johnson f because of its practical value in pasteurizing and refrigerating, also in the manufacture of butter and ice cream. The Electrical Conductivity is stated by Favilli | to be unsatisfactory for determining added water in milk. Capillary and Adsorption Phenomena have been studied by Kreidl and Lenk. § Cow's milk on bibulous paper forms three concentric zones — casein, fat, and water. On dilution to a certain point no casein zone is formed. Oxidation Index. — This constant, proposed by Comanducci,|| repre- sents the number of cubic centimeters of N/io potassium permanganate required in the presence of sulphuric acid to oxidize i cc. of milk. It is designed to distinguish cow's from goat's and sheep's milk. Systematic Examination of Milk for Adulteration.— If a large number of samples of milk have to be examined daily for adul- teration, it may be an advantage to submit all to a preliminary test with the lactoscope and lactometer, excluding from further analysis, as above the standard, such samples as pass certain prescribed limits which experi- ence has proved these tests to be capable of showing to an experienced observer, and submitting the remainder to a chemical analysis. In using such an instrument as the lactoscope for this purpose, the individual element is a most important consideration, and the use of this instrument * Milchw. Zentbl., 43, 1914, p. 169. t Iowa Agric. Exp. Sta., Res. Bui. 14, 1913, p. 451. % Riv. sci. latte, i, 191 1, p. ZZ- § Pfliiger's Arch. Ges. Physiol., 141, 191 1, p. 541. 11 Gaz. chim. Ital, 36 II, 1906, p. 813. MILK AND ITS PRODUCTS. 155 in the milk laboratory should be limited only to a skillful operator, accustomed to interpret its results. The method used by the Mass. Board of Health has been to submit all samples to the regular test for solids, and such samples as fall below the legal standard for solids, are further examined for fat. Total Solids, Ash, and Fat.— It is presupposed that the analyst is equipped with a sufficient number of platinum dishes for the number of milk samples daily analyzed. It is a convenience to have these dishes numbered, and instead of weighing each dish_, to have a system of num- bered counterweights (Fig. 51, A) corresponding to the dishes. The counterweights recommended by Leach for this purpose are easily made from half inch lead pipe, cut to the appropriate length and flattened. Each weight is then carefully adjusted to its appropriate dish, by trim- ming off the weight with a knife, or by adding bits of lead scraps, if necessary, by simply prying open in the center, inserting the required amount of scrap, and then closing by a blow of the hammer, the weight being plainly numbered before final adjustment. A rack is provided by the side of the balance-case (Fig. 51) with slits for holding the weights in their appropriate places. Such a set of counterweights is not difificult to make, requires very little care to keep in adjustment, and is an immense labor-saving device. Details of Manipulation. — The method of examining large numbers of milk samples, long in use in the laboratory of the Massachusetts State Board of Health, has proved to be rapid, easy, and accurate. It is here given in some detail. From 12 to 20 samples of milk are conveniently weighed out at a sitting, the unopened sample cans or bottles being contained in a tray at the left of the operator on a low stand, another low stand and tray being at this right hand for the cans, after removing the weighed portions, and a third tray on the table at the right of the balance for the platinum dishes with the weighed samples. The analyst enters the number of the platinum dish in his note-book, or on a card,* in line with the number of the milk sample, verifies the correctness of the counterweight, and weighs out exactly 5 grams of the milk with the aid of a pipette, after first having throughly mixed the sample. This operation is repeated with all the samples, the platinum dishes containing the weighed amounts * Specially ruled library cards, as shown on page 157, are useful for this purpose. 156 FOOD INSPECTION AND ANALYSIS. of each being placed in succession on the tray, which is finally carried to the water-bath and the dishes transferred thereto. The time required for weighing out 1 2 samples of milk in this manner is about fifteen minutes. The water-bath is inclosed in a hood, and the shding front is so arranged that it can be shut down and locked, so that if the analyst has to leave Fig. 51. — Set of Counterweights for Numbered Platinum Dishes, in a Convenient Rack. A. One of the Counterweights. B. Platinum Dishes. the laboratory during the three hours required for the evaporation, he can swear in court that the samples could not be tampered with during his absence (see page 20). WTien ready to make the second weighings for the total soHds, each dish is taken from contact with the steam, and, while still hot, is wiped dry with a soft towel, till twelve of the dishes are placed on the tray, which is then taken to the balance. Experience has shown that with ordinary rapidity in weighing, twelve of the residues may be thus dealt with at a time without the need of a desiccator, the gathering of moisture during that time being inappreciable, excepting in very damp weather, when a less number of dishes should be removed at a time from the bath. In making the second weighing, and employing the counterweight as MILK AND ITS PRODUCTS. 157 ( Vaie.. < ^£Vf/\M(ch r^. /fO^. Inspector's Number. No. of DiJh 5' 6ra»t1X. Total Solids. No. of Botlle Fat. So\i.ds not Htn\a.rhS . Z66-3 J3.0(. 1^V6 ,? .^011 )X.OZ Ib^? V S-^86 yy.96 3 3 Z6' ;? 7/ 26 6t) ,r 72.6? I^S3 Zbt'l. 6 .>^/7V fi.^S "t Z.SO S^s 2.6d^^ 7 .(.^2 3 n.GS 266-6 ,f .6301 )X.(oO I.(y6-S 9 .^9Z^ i^.^y li>(>0 /o f^fSS ll.Xl X.hi>l If j.s-?i- 979 S 0.1 S 9.0*1 Xbb^ /^ ^^^3 9.39 (> iLS6' 6.^^ X6U /3 .66-30 I3.0L XUS J^r IJ^fZ Zii.90 akio /y ^2Cf3 IJ..S9 Q,i>7X /!> 7393 1^19 JVvtA. Xi.7^ 11 .7IDX li^.70 2C.7G /^ .(.010 )X.OX XQ7S 1^ .^.<-oi 9.00 7 I.ZO 1 .80 Ib^O zo . ^^-3/ J3.0G Soecimen Card for Analyst's Records of Milk Analyses. To be filed in a cabinet. 158 FOOD INSPECTION AND ANALYSIS. before, the exact net weight of the residue is at once ascertained and entered in the appropriate column in the note-book. MultipHed by 20 it gives at once the percentage of total soHds. It is a great saving of time to weigh out exactly 5 grams as above described. The knack of quickly measuring out the exact amount is easily acquired with practice, the 5 -gram weight is the only one required for the operation with the counterweight of the dish, and the laborious figuring of percentage due to using a fraction above or below the 5 grams of milk is avoided. Such samples as are found to' stand below the standard of total solids are further examined for fat by the Babcock process (p. 123), entering the number of the fat bottle in the note-book in the appropriate column, and subsequently the percentage of fat. Ordinarily the specific gravity is not determined, excepting in some cases of badly watered milk, when, for purposes of a check, it is customary to take the specific gravity, and calculate the solids from the gravity and the fat by Babcock's formula (p. 140), or the Richmond sliding scale, and compare the result with the figure directly determined. The ash is rarely weighed except in special cases. The dishes containing the dry residues are easily cleaned by first burning to an ash and cooling, after which they are treated successively with strong nitric acid, which is poured from one to another, the dishes being rinsed thoroughly with water and finally heated to redness. A convenient device for ashing a large number of residues for purposes of cleaning the platinum dishes and for final heating is the incinerator shown in Fig. 52, made of Russia iron. The digestion stand for the Kjeldahl method (Fig. 27a) may also be used. Fig. 52. A Sheet-metal Incinerator, Specially Used for Ashing Milk Residue. ADDED FOREIGN INGREDIENTS. — Passing over such mythical adulterants as chalk and such rarely used substances as calves' brains, starch, glycerin, sugar, etc., often discussed in manuals on milk, but MILK AND ITS PR0r3UCTS. 159 with few authentic instances of their actual occurrence, the commonly found adulterants may be divided into two classes: coloring matters and preservatives. The coloring matters almost exclusively used are annatto, azo-colors, and caramel. The preservatives commonly met with are formaldehyde, boric acid, borax, and sodium bicarbonate. Rarely salicylic and benzoic acids are found. Coloring Matters. — While it is more often true that an artificially colored milk is also found to be watered, the coloring being added to cover up evidence of the watering, it is not uncommon to find added coloring matter in milk above the standard.* About 95% of the milks found colored in Massachusetts showed on analysis the fraudulent addition of water. Statistics of the Massachusetts State Board of Health show that out of 48,000 samples of milk collected throughout the state and analyzed during nine years (from 1894 to 1902 inclusive) 342 samples or 0.7% were found to contain foreign coloring matter. Of these samples, about 67% contained annatto, approximately 30% were found with an azo- dye, and about 3% with caramel. Until comparatively recently annatto was employed almost exclu- sively for this purpose. Caramel is least desirable of all the above colors from the point of view of the milk-dealer, in that it is difficult to imitate with it the natural color of milk, by reason of the fact that the caramel color has too much of the brown and too little of the yellow in its com- position. Annatto, on the other hand, when judiciously used and with the right dilution*, gives a very rich, creamy appearance to the milk, even when watered, which accounts for its popularity as a milk adulterant. Of late, however, the use of one or more of the azo-dyes has been on the increase, and so far as a close imitation of the cream color is con- cerned, these colors are quite as efficient as annatto. Appearance of Artificially Colored Milk. — The natural yellow color of milk confines itself largely to the cream. An artificial color, on the contrary, is dissipated through the whole body of the milk, so that when the cream has risen in a milk thus colored, the underlying layers, instead of showing the familiar bluish tint of skimmed milk, are still distinctly tinged below the layer of the fat, especially if any considerable quantity of the color has been used. This distinctive appearance is in itself often * In one instance an azo-dye was found by the writer in a milk that contained over 17% of total solids. 160 FOOD INSPECTION AND ANALYSIS. sufficient to direct the attention of the analyst to an artificially colored milk, in the course of handling a large number of samples. Nature of Annatto. — Annatto, amatto, or annotto is a reddish-yellow coloring matter, derived from the pulp inclosing the seeds of the Bixa orellana, a shrub indigenous to South America and the West Indies. A solution of the coloring matter in weak alkali is the form usually employed in milk. Nature of "Anilin Orange." — Of the coal-tar colors employed for coloring milk, the azo-dyes are best adapted for this purpose and are most used. A few samples of these commercial "milk improvers" have fallen into the hands of the Department of Food and Drug Inspection of the Massachusetts Board of Health, and have proved, on examination, to be mixtures of two or more members of the diazo-compounds of anilin. A mixture of what is known to the trade as "Orange G" and "Fast Yel- low" gives a color which is practically identical with one of these prep- arations, secured from a milk-dealer and formerly used by him. For purposes of prosecution or otherwise, it is obviously best in our present knowledge of the subject to adopt a generic name such as "a coal-tar dye" or "anilin orange"* to designate this class of coloring matters in milk, rather than to particularize. Systematic Examination of Milk for Color. — The general scheme employed by the writer for the examination of milk samples suspected of being colored is as follows:! About 150 cc. of the milk are curdled by the aid of heat and acetic acid, preferably in a porcelain casserole over a Bunsen flame. By the aid of a stirring-rod, the curd can nearly always be gathered into one mass, which is much the easiest method of separa- tion, the whey being simply poured off. If, however, the curd is too finely divided in the whey, the separation is effected by straining through a sieve or colander. All of the annatto, or of the coal-tar dye present in the milk treated would be found in the curd, and part of the caramel. The curd, pressed free from adhering liquid, is picked apart, if necessary, and shaken with ether in a corked flask, in which it is allowed to soak for several hours, or until the fat has been extracted, and with it the annatto. If the milk is uncolored, or has been colored with annatto, on pouring off the ether the curd should be left perfectly white. If, on * The term "anilin orange" has been so commonly applied during Leach's experience to any color or mixture of colors of this class in complaints in the Massachusetts courts, aa to have acquired a special meaning perfectly well understood. t Jour. Am. Chem. Soc, 22, 1900, p. 207. MILK AND ITS PRODUCTS. 161 the other hand, anilin orange or caramel has been used, after pouring off the ether the curd will be colored more or less deeply, depending on the amount of color employed. In other words, of the three colors, annatto, caramel, and anilin orange, the annatto only is extracted by ether. If caramel has been used, the curd will have a brown color at this stage; if anilin orange, the color of the curd will be a more or less bright orange. Tests for Annatto. — ^The ether extract, containing the fat and the annatto, if present, is evaporated on the water-bath, the residue is made alkaline with sodium hydroxide, and poured upon a small, wet filter, which will hold back the fat, and, as the filtrate passes through, will allow the annatto, if present, to permeate the pores of the fiher. On washing off the fat gently under the water-tap, all the annatto of the milk used for the test will be found to have been concentrated on the filter, giving it an orange color, tolerably permanent and varying in depth with the amount of annatto present. As a confirmatory test for annatto, stan- nous chloride may afterward be applied to the colored filter, producing the characteristic pink color. Tests for Caramel. — The fat-freed curd, if colored after the ether has been poured off, is examined further for caramel or anihn orange, by placing a portion of the curd in a test-tube, and shaking vigorously with concentrated hydrochloric acid. If the color is caramel, the acid solution of the colored curd will gradually turn a deep blue on shaking, as would also the white fat-free curd of an uncolored milk, the blue colora- tion being formed in a very few minutes, if the fat has been thoroughly extracted from the curd; indeed, it seems to be absolutely essential for the prompt formation of the blue color in the acid solution that the curd be free from fat. Gentle heat will hasten the reaction. It should be noted that it is only when the blue coloration of the acid occurs in connection with a colored curd that caramel is to be suspected, and if much caramel be present, the coloration of the acid solution will be a brownish blue. If the above treatment indicates caramel, it would be well to confirm its presence, by testing a separate portion of the milk in the following manner.* About a gill of the milk is curdled by adding to it as much strong alcohol. The whey is filtered off, and a small quantity of subacetate of lead is added to it.. The precipitate thus produced is collected ui>on a small filter, which is then dried in a place free from hydrogen sulphide. A pure milk thus treated yields upon the filter-paper a residue which is * See Nineteenth Annual Report of the Mass. State Board of Health (1887), p. 183. 162 FOOD INSPECTION AND ANALYSIS. either wholly white, or at most of a pale straw color, while in the presence of caramel, the residue is a more or less dark-brown color, according to the amount of caramel used. Tests for Coal-tar Dye. — If the milk has been colored with an azo-dye, the colored curd, on applying the strong hydrochloric acid in the test-tube, will immediately turn pink. If a large amount of the anihn dye has been used in the milk, the curd will sometimes show the pink coloration when hydrochloric acid is applied directly to it, before treatment with ether, but the color reaction with the fat-free curd is very dehcate and unmistak- able.* Lythgoe^ has shown that the amount of anihn orange ordinarily present in a milk for the purposes of coloring can be detected by adding directly to say lo cc. of the sample an equal quantity of strong hydro- chloric acid and mixing, whereupon the pink coloration is produced, if the dye is present in more than minute traces. The test is more deli- cate if carried out in a white porcelain dish. It had best be used as a prehminary test only, and confirmed by a subsequent test on the fat-free curd as above. SUMMARY OF SCHEME FOR COLOR ANALYSIS. Curdle 150 cc. milk in casserole with heat and acetic acid. Gather curd in one mass. Pour off whey, or strain, if curd is finely divided. Macerate curd with ether in corked flask. Pour off ether. Ether Extract. Evaporate off ether, treat residue with NaOH and pour on wetted filter. After the solution has passed through, wash off fat and dry filter, which if colored orange, indicates presence of annatto. (Confirm by SnClj.) Extracted Curd. (i) // Colorless. — Indicates presence of no foreign color other than in ether extract. (2) // Orange or Brownish. — Indicates presence of anilin orange or caramel. Shake curd in test-tube with concentrated hydrochloric acid. If solution gradu- ally turns blue, in- dicative of caramel. (Confirm by testing for caramel in whey of original milk.) If orange curd im- mediately turns pink, indicative of anilin orange. PRESERVATIVES. — In most states and municipahties where pure food laws are in force preservatives in milk are regarded as adulterants * Occasional samples of milk colored with a coal-tar dye of a different class from those already described have recently been found in Massachusetts. In these cases the color of the separated fat-free curd does not change when treated with hydrochloric acid. The color of the curd is, however, very marked, being deep orange, bordering on the pink. t Jour. Am. Chem. Soc, 22, 1900, p. 813. MILK AND ITS PRODUCTS. 163 Their use, however, seems to be on the decrease. Of 6,i86 samples of milk examined by the Massachusetts State Board of Heahh during one year (1899) 71 samples, or 1.2%, were found to contain a preservative. Of these 55 were found with formaldehyde, 13 containing boric acid, borax,' or a mixture of the two, and 3 contained carbonate of soda. Comparative tests were made of the keeping equalities of these com- mon preservatives, the milk being kept during the experiment at the temperature of the room, which at that season of the year (February) was about 20° C* The preservatives were added about five hours after milking. The samples were titrated for acidity each morning, the acidity being expressed by the number of cubic centimeters of decinormal sodium hydroxide necessary to neutralize 5 cc. of the milk. The proportions of preservatives used in this experiment, as shown in the table on page 164, were intended to cover a wide range, from the weakest that could aid in preserving the milk up to a strength limited only by being perceptible to the taste. The results obtained appear in the table. Formaldehyde, the most commonly used preservative for milk, is sold to the trade under various names, such as "Preservaline," "Freezine," "Ice- line," etc., all being dilute aqueous solutions of formaldehyde, containing from 2 to 6 per cent of the gas, being nearly always diluted from the 40% solution known as formahn. These preparations are usually accompanied by directions, which specify the amount to be used, varying from a table- spoonful of the solution in 5 to 10 gallons of the milk. It is commonly used in the strength of i part of the gas in 20,000, and rarely less than I part in 50,000. The antiseptic power of formaldehyde increases in a marked degree as the strength of the preservative is increased. Milk treated with i part in 10,000, for instance, according to the table was found to keep sweet 5I days. In the strength of i part to 5000, the milk did not curdle for loj days, while i part of formaldehyde to 2500 parts of milk kept the milk from curdling for 55 days, the acidity up to that time being nearly normal. Formaldehyde is thus shown to be decidedly the most cflEiclent of all milk preservatives, besides being inexpensive and convenient to use. Whether the growth of other bacteria than those that produce lactic fermentation is inhibited by formaldehyde in milk is not definitely settled. The claim has been made that pathogenic varieties are destroyed by its use. * Thirty-first Annual Report Mass. State Board of Health, 1899, p. 611. 164 FOOD INSPECTION AND ANALYSIS. G V CO >> 1 El 1 III II U 1 1 1^ 1-Sl II .S^ 1 III II II 1 II 1 Mi:si >> ■* •* •* - a o Q •o 1 Ml lll| lllj 1 3 V. XI c > ig 1 III III! Mil IIIJ E >> o in-o a jS 1 III MM II 1 1 111'^ 1 III 1 1 1 00 1 1 1 "^ 1 « O>00 III MM II II III- •S 1 III 11 1 ■ ■ ... '5 *2 t Tf O «: < p t3 1 til 1 (4 c4 1 III II 1 1 MM Mil I III l-o-cl •o: -a 1 •O 11 1 w P N to N ro .0 >. 1 d h 15 b tj b« H '•3 1 III MM 11 II III" t c O 1 111 1 3. V 3. . lu 3 a).. ■y 0-J3 o5 1 III I 0- ^ w en c8--| •c^l" <5 M 1 •o >. g^ 1 4} III 1 Ml II II Mil w 13 1— 1 >> 00 "00 00 M in M NvO M 1^ n) cj.ti 1^ Is 1 Ml !:•• M tN « tN. 4 ■^■■'i-M 0> !^ COO to « O P •a o < ■•3 1 III 11 11 11 II 1 1 l<^ ffj ?S q] nl ^111 till 1 1 1 1 < W ^3 T3 -O-O-O "O II 1 II II MM > HH u i d "li < > •H n! P XI x: §•2 1 "••5 III II 1 1 1 II 1 II II 3 3- - 3 S. . 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P^ g c« ol rt B <^ »i rt 3 - 1 ■c o PQ r c 3 - 1 w •c o o M * I MILK AND ITS PRODUCTS. 165 Notwithstanding the claims of manufacturers as to the harmlessness of formaldehyde, its use can not be too strongly condemned.* Detection of Formaldehyde. — Leach Test.-f — Hydrochloric acid (spe- cific gravity 1.2) containing 2 cc. of 10% ferric chloride per liter is used as a reagent. Add 10 cc. of the acid reagent to an equal volume of milk in a porcelain casserole, and heat slowly over the free flame nearly to boiling, holding the casserole by the handle, and giving it a rotary motion while heating to break up the curd. The presence of formaldehyde is indicated by a violet coloration, varying in depth with the amount present. In the absence of formaldehyde, the solution slowly turns brown. By this test I part of formaldehyde in 250,000 parts of milk is readily de- tected before the milk sours. After souring, the limit of delicacy proves to be about i part in 50,000. Various aldehydes, when introduced into milk, give color reactions under the above treatment, but formaldehyde alone gives the violet colora- tion, which is perfectly distinguishable and unmistakable. Heh?ier Test.X — To 5 to 10 cc. of milk in a wide test-tube add about half the volume of concentrated commercial sulphuric acid,§ pouring the acid carefully down the side of the tube, so that it forms a layer at the bottom without mixing with the milk. A violet zone at the junction of the two liquids indicates formaldehyde. This test may be combined with the Babcock test for fat, noting whether a violet color forms on addition of the commercial sulphuric acid to the milk in the test bottle. Tests with Distilled Milk. — To confirm the above test, distil ico cc. of the milk sample acidified with citric or sulphuric acid, and test the first 20 cc. of the distillate as described in Chapter XVIII. The Determination of Formaldehyde in Milk is unsatisfactory since it gradually disappears, as shown by Williams and Sherman, || owing * Milk-dealers are led to believe, by artful dealers in preservative preparations, that the chemist cannot detect them. The manufacturer of a widely used preservative, a weak solu- tion of formaldehyde, issued an attractive pamphlet in which he made the following remark- able claims: "It is not an adulterant. It immediately evaporates, so that no trace of it can be found as soon as it has rendered all the bacteria inert. No chemical analysis can prove its pres- ence in milk, quantitatively or otherwise." t Annual Report Mass. State Board of Health, 1897, p. 558; also 1899, P- 699. t Analyst, 20, 1895, p. 155. § The coloration produced seems to depend on the presence of iron salts in the acid, hence the use of commercial acid is recommended. If only pure acid is available, a little ferric chloride should be added. II Jour. Am. Chem. Soc, 27, 1905, p. 497. 166 FOOD INSPECTION AND ANALYSIS. to the formation of condensation products with the proteins. According to Smith,* the first 20 cc. of the distillate contain nearly one-third of the total formaldehyde then present. In some cases it may be useful to de- termine the amount present in this distillate by the potassium cyanide method (p. 883). Boric Acid, either in the form of the free acid or of the sodium salt borax, has been much used in milk. While its addition to butter is legalized in England, food authorities in all countries are generally agreed that its use in milk is highly objectionable. Detection of Boric Acid. — This is best accomplished by the turmeric- paper test applied either directly to the milk or to the ash (p. 885). In the former case 10 cc. of milk are thoroughly mixed with 6 drops of con- centrated hydrochloric acid, after which the turmeric paper, previously marked for identification with a lead pencil, is moistened with the mix- ture and dried. Bertrand and Agulhon j find by their spectroscopic method 0.5-1. 11 mg. of boron as hydroxide per liter of milk to which nothing has been added. This amount is not evident by ordinary tests. Determination of Boric Acid.— The Gooch method (p. 887) or the Thompson method (p. 886) may be used. Richardson and Walton J propose the following rapid method, which is stated to be more accurate than the Thompson method, since it obvi- ates the loss of boric acid by volatilization with the fat. While other authors, including the author and reviser, have not found this loss con- siderable if the ignition is properly conducted, the proposed inethod rec- ommends itself because of its simplicity. To 50 cc. of milk, or 10 grams of cream diluted with 40 cc. of water, add 5 cc. of 5% copper sulphate solution, stir, heat to boiling for a few seconds, filter, and wash the pre- cipitate containing the proteins and fat. Cool the filtrate and determine the boric acid by tritration, using 2 cc. of 1% neutral phenolphthalein solution as indicator. Carbonate and Bicarbonate of Soda. — These substances are occa- sionally used in milk, though, as the table on p. 164 shows, they possess little or no value as milk preservatives. They do, however, serve to neutralize the acidity of slightly soured milk and to postpone the time of actual curdling. * Jour. Am. Chem. Soc, 25, 1903, pp. 1032, 1037. t Compt. rend., 156, 1913, p. 2027. t Analyst, 38, 1913, p. 40. MILK AND ITS PRODUCTS. 167 Detection of Carbonate and Bicarbonate of Soda. — The addition of carbonates is manifest by the effervescence caused by treating the milk-ash with acid. Effervescence in the milk-ash is quite perceptible, when as much as 0.05% of sodium carbonate is present. Schmidt's method of detecting sodium carbonate or bicarbonate, when present to the extent of 0.1% or more, is as follows: Ten cc. of milk are mixed with an equal volume of alcohol, and a few drops of a 1% solution of rosolic acid are added. If carbonate is present, a rose- red color will be produced, while pure milk shows a brownish-yellow coloration. The suspected sample thus treated should be compared with a similarly treated sample of pure milk at the same time. Salicylic and Benzoic Acids, in view of the much more efficient anti- septics at hand, are now rarely used as milk preservatives, though the analyst should be on the outlook for them. SaHcylic acid is a poor milk preservative, in view of the fact that it affects the taste of the milk, when present in sufficient quantity, to be of service. Detection of Salicylic Acid.— (i) To 50 cc. of the milk add i cc. of acid nitrate of mercury reagent (p. 134), shake and filter. The filtrate, which should be perfectly clear, is then shaken with ether in a separatory funnel, the ether extract evaporated to dryness, and a drop of ferric chloride reagent applied. If salicylic acid be present, a violet color will be pro- duced. In carrying out the test it should be noted that a small portion only of the salicylic acid is in the filtered whey, the larger part being left in the curd. The color test is, however, so delicate as to show its pres- ence, when an appreciable amount is used. (2) Proceed exactly as directed for benzoic acid (below). On apply- ing the ferric chloride to the final solution, after evaporation of the am- monia, a violet color shows the presence of salicylic acid. Detection of Benzoic Acid. — Shake 5 cc. of hydrochloric acid with 50 cc. of the milk in a flask. Then add 150 cc. of ether, cork the flask and shake well. Break up the emulsion which forms by the aid of a centrifuge, or, in the absence of a centrifuge, extract the curdled milk by gently shaking with successive portions of ether, avoiding the forma- tion of an emulsion. A volume of ether largely in excess over that of the curdled milk has been found to be less apt to emulsionize. Transfer the ether extract to a separatory funnel, and separate the benzoic acid from the fat by shaking out with dilute ammonia, which takes out the former as ammonium benzoate. Evaporate the ammonia solution in 168 FOOD INSPECTION AND ANALYSIS. a dish over the water-bath until aeutral to test paper and add a few drops of neutral ferric chloride reagent (page 891). Revis Me//w(/.*— Dilute 100 cc. of milk or 50 cc. of cream to 200 cc, add 5 cc. of 10% sodium carbonate solution, place on a boiling water bath, and after 2 to 3 minutes add 10 cc. of 2J% calcium chloride solution and continue the heating until the casein is coagulated. Cool, filter, add hydro- chloric acid to the filtrate until neutral to litmus, then 10 cc. of Fehling copper sulphate solution and 10 cc. of potassium hydroxide solution (31.81 grams per liter). Filter, acidify the filtrate with hydrochloric acid, extract with 50 cc. of ether, and wash the ether three times with water. Without removing from the separatory funnel add to the ether 10 cc. of water, I drop of phenol phthalein solution, and titrate with saturated barium hydroxide solution until a pink color persists after vigorously shaking. Remove the aqueous layer, filter, and evaporate to about 5 cc. Filter again, add 1% acetic acid until colorless, then 2 drops additional and test with I drop of freshly prepared 10% neutral ferric chloride solution as described on page 891. Rohin Method.-\ — Add 50 cc. of milk slowly with stirring to a mixture of 10 cc. of 5% sulphuric acid and 20 cc. of 95% alcohol, filter after 4 to 5 minutes, extract with ether, and proceed as described on page 891. Determination of Benzoic Acid in Milk. — See pages 893 to 896. Liverseege and Evers Method.X—T>\'=,i\\ a mixture of 100 cc. of milk and ID cc. of concentrated sulphuric acid in a current of steam until 600 cc. have condensed. Acidulate the distillate with 5 cc. of concentrated hydrochloric acid, extract with 100 cc. and two portions of 35 cc. of ether, allow the extract to evaporate at room temperature in a tared dish, dry, weigh, deduct 5 milligrams (or a quantity found by blank experiment) from the total weight, and calculate the percentage of benzoic acid by a factor which should be determined by each analyst for the apparatus employed. In the apparatus used by the originators of the method about 45% of the total amount was recovered. Hydrogen Peroxide is used in " perhydrase " or " Buddized " milk. Detection of Hydrogen Peroxide. — Arnold and Mentzel Vanadic Acid Method.% — To 10 cc. of the milk add 10 drops of a solution of i gram of vanadic acid in 100 grams of dilute sulphuric acid. The presence of hydro- * Analyst, 37, 191 2, p. 346. t Ann. chim. anal, appl., 14, 1909, pp. 2, 53. t Jour. Soc. Chem. Ind., 32, 1913, p. 319. § Chem. Ztg., 26, 1902, p. 589. MILK AND ITS PRODUCTS. 169 gen peroxide is shown by the appearance of a red color. Utz * states that the reaction is obtained whether or not the milk has been heated previous to adding the peroxide. Peroxidase Methods. — Several of the methods for detecting peroxidase (pp. 173 and 174), notably the paraphenylenediamine (Dupouy), the benzidine (Wilkinson and Peters), and the iodide-starch (Roi and Kohler) methods, can be reversed for the detection of hydrogen peroxide. The tests are conducted as described except that the hydrogen peroxide is omitted and, since the peroxidase may have been destroyed by hydrogen peroxide or by heating, it is usually necessary to add raw mJlk of known purity. La Wallf in performing the Wilkinson and Peters test first coagulates a mixture of 10 cc. of raw milk and 2 cc. of 4% alcoholic ben- zidine with 2 to 3 drops of glacial acetic acid, then adds a few cubic centi- meters of the suspected sample. A blue zone is formed when from 1.5 to 30 parts of hydrogen peroxide per 10,000 are present. Hehner-Feder Formaldehyde Method. % — This is the Hehner method for formaldehyde reversed and slightly modified. Mix 5 cc. of the milk with 5 cc. of concentrated hydrochloric acid and a drop of dilute formalde- hyde solution, then heat at 60° C. for 3 to 4 minutes and shake once. If a violet color develops hydrogen peroxide is indicated. Wilkinson and Peters § have shown that the reaction is most decisive when about 0.005% of hydrogen peroxide and 0.004 to 0.013% of formaldehyde are present; with other proportions it may fail. Ferric salts, nitrites, and possibly nitrates also give a \'iolct color. Routine Inspection of Milk for Preservatives. — It was Leach's custom in Massachusetts to examine all the samples of milk collected during the months of June, July, August, and September for the commonly used preservatives, in addition to the regular analysis for total solids and fat. The number of samples thus examined amounted to upwards of 500 per month, varying from 10 to 60 per day. The results of such an examina- tion during four years are shown on p. 170. || Such a system by no means involves a large amount of time or labor, and is really essential before passing judgment upon the purity of the milk, since, unlike added color, there is nothing in the physical appear- * Milchw. Zentbl., i, 1905, p. 175. t Am. Jour. Pharm., 82, 1908, p. 57. t Zeitz. Unters. Nahr. Genussm., 15, 1908, p. 234. %Ihid., 16, 1908, p. 515. II Mass. State Bd. Health, Rep., 1902, p. 474. 170 FOOD INSPECTION AND ANALYSIS. ance of the milk to suggest the presence of preservatives, nor are they rendered apparent by the taste, if skillfully used. PRESERVATIVES IN MILK. Year. Samples Examined. Number Containmg Form- aldehyde. Per Cent Containing Form- aldehyde. Number Containing Boric Acid. Per Cent Containing Boric Acid. Number Containing Carbonate. Total Containing Preserva- 1899 1900 1901 1902 Totals 1046 2105 2018 2154 1934 26 55 61 42 29 2-5 2.6 30 1.9 1-5 II 13 6 12 14 1 .0 0.6 03 0.5 0.7 9257 213 2-3 56 0.6 41 71 67 54 43 376 The methods employed are carried out as follows: * (i) Formaldehyde. — After ha\ing been examined for total solids and fat, the milk samples are arranged in order in their original con- tainers, and about 10 cc. of each sample are poured into a casserole and tested in succession by means of the hydrochloric acid and ferric chloride test (p. 165). A large stock bottle, which may be fitted with a siphon if desired, is kept on hand containing the hydrochloric acid reagent. Less than one minute is required in making the formaldehyde test for each sample. (2) Carbonate and Boric Acid. — These tests have been so simplified as to be, as it were, a side issue in the process of cleaning the platinum dishes used for the determination of total solids. The various residues from the total solids are burnt to an ash in the original numbered dishes in succession, these dishes, after incineration, being arranged side by side on a flat tray. By means of a pipette, one or two drops of dilute hydro- chloric acid are introduced into each dish in succession, noting at the time any effervescence that may ensue, which is in itself an indication 01 sodium carbonate. After every milk ash has been acidulated, a few cubic centimeters of water are added to each dish by means of a wash- bottle, the dissolving of the ash being hastened by giving a rotary motion to the tray containing the dishes. A strip of turmeric-paper is then allowed to soak for a minute or so in each dish, after which it is withdrawn from Mass. State Bd. Health, Rep., 1901, p. 447. MILK AND ITS PRODUCTS. 171 contact with the solution and allowed to adhere to the side of the dish above the liquid, where it remains until dry. If the paper when dry is of a deep cherry-red color, turning a dark olive when treated with dilute alkali, the presence of boric acid is assured. These methods are, of course, preliminary tests for quickly singling out the preserved samples. Such confirmatory tests as are desired may in all cases be employed. Various Adulterants.— Cane Sugar is said to be used to increase the total solids of milk, but if present to any marked degree, it could hardly fail of detection by reason of the sweet taste imparted to the milk. Cane sugar in milk may be detected * by boiling 5 to 10 cc. of the sample with about o.i gram of resorcin and a few drops of hydrochloric acid for a few minutes. In the presence of cane sugar, a rose-red color is pro- duced. According to Richmond, cane sugar may be estimated by first ascer- taining the total polarization of the sample as in the estimation of milk sugar (p. 134). The milk sugar is then determined by Fehling's solution (pp. 136 to 138) either volumetrically or gravimetrically. The difference between the anhydrous milk sugar found by the latter, or Fehling method, and that calculated by dividing the polarization by 1.217 will give the percentage of cane sugar present. Cotton's method f of detecting cane sugar, when present to the extent of 0.1% consists in mixing in a test-tube 10 cc. of the suspected milk with 0.5 gram of powdered ammonium molybdate, and adding to the mixture 10 cc. of dilute hydrochloric acid (i to 10). Ten cc. of milk of known purity, or 10 cc. of a 6% solution of milk sugar are similarly treated by way of comparison. Both tubes are placed in a water-bath and the temperature gradually raised to 80° C. If cane sugar is present, an intense blue coloration is produced, while the genuine milk or the solution of milk sugar remains unchanged at the temperature of 80°. If the temperature is raised to the boiling-point, however, the pure milk or milk sugar solution may alsc turn blue. Detection of Starch in Milk.— A small quantity of milk is heated in a test-tube to boiling, cooled, and a drop of iodine in potassium iodide added. A blue coloration indicates starch. Condensed Skimmed Milk as an Adulterant. — The use of condensed unsweetened skimmed milk to raise the solids of a skimmed or watered * Woodman and Norton, Air, Water, and Food, New York, 1914, p. 151. t Abs. Analyst, 23, 1898, p. 37, - 172 FOOD INSPECTION AND ANALYSIS. milk above the standard has been noted in Massachusetts. This sophis- tication is rendered apparent by the abnormally high solids not fat of the sample, which in some instances have exceeded ii%. A solid not fat in excess of io% is suspicious of this form of adulteration. By fixing a legal standard for both fat and solids not fat, such tampering with milk may readily be checked. Analysis of Sour Milk. — It occasionally becomes necessary for the analyst to deal with samples of sour milk, especially in the summer-time, when the milk has been brought from a long distance. While the process of lactic fermentation results in the formation of traces of volatile acids, unless the sample has become so badly curdled as to render an even homo- geneous mixture of the various parts impossible, a fair determination of the solids and fat can readily be made. Experience has proved that, excepting in instances of milk so badly soured as to have become actually putrid, the analysis of sour milk, if carefully made, should not differ materially from that of the same milk before souring. Care must be taken to secure an even emulsion of the curd and whey. This may sometimes be accomphshed by repeatedly pouring the sample back and forth from one container to another. Again, it is sometimes necessary to use an egg-beater of the spiral wire pattern, which preferably should easily fit the can or milk-container. Unless a fine, even emulsion can be secured, it is impossible to make a satisfactory analysis of sour milk. With such an emulsion restdts can be relied on. In measuring portions of the thoroughly mixed sample of sour milk for analysis, a pipette should be used having a large opening. HOMOGENIZED MILK. This product is prepared from ordinary milk by heating and then passing through the " homogenizer " whereby the fat globules are broken up into smaller globules and the creaming power reduced practically to nil. In the homogenizer the milk is forced, under a pressure varying up to 4000 pounds or more per square inch, into fine jets or sheets which impinge either against each other or against an agate surface thus disrupting the globules. These in normal milk often exceed lo/x and are mostly 5 to 6/i while in well-homogenized milk they are mostly only i to 2/x.* The machine is also used to emulsify olco, cottonseed, and other oils and low melting-point fats with skim milk thus furnishing a wholesome food * Baldwin, Am. Jour. Pub. Health, 6, 1916, p. 862. MILK AND ITS PRODUCTS. 173 for calves, hogs, and even human beings, although the temptation to market the products dishonestly has not always been resisted. Homogenized mixtures have also been used in cream, condensed milk, and ice cream. Analysis of Homogenized Milk. — It has been demonstrated by Rich- mond * that the Adams paper coil method gives low percentages of fat with homogenized milk while the Rose-Gottlieb, Werner-Schmidt, and Gerber methods are satisfactory. Other constituents are determined as in ordinary milk. Distinctions from untreated milk are based on the size of the fat globules as above noted, also on physical constants, particularly the viscosity. PASTEURIZED MILK. The analyst may be called on to determine whether or not milk has been pasteurized to conform with municipal or state regulations. Detection of Peroxidase. — The following tests show whether the milk has been pasteurized at £0° C., or higher but, as found by Lythgoe,t are of no value when 63°, which is now deemed sufficient, is employed. Dupouy Paraphenylenediamin Method.X — Shake 5 cc. of the milk in a test tube with i drop of 0.2% hydrogen peroxide solution (containing I cc. of concentrated sulphuric acid per liter) and 2 drops of 2% paraphenyl- enediamin. If the milk becomes blue immediately it has not been heated to 78° C.; if it becomes gray-blue immediately or within half a minute it probably has been heated to 79-80°; while if it remains white or be- comes a faint violet-red it has been heated above 80°. Wilkinson and Peters Benzidine Method.^ — To 10 cc. of the milk add 2 cc. of a 4% alcoholic solution of benzidine and 2-3 drops of glacial acetic acid, or an amount just sufficient to coagulate the milk, and shake. Add cautiously to the mixture 2 cc. of 3% hydrogen peroxide solution, allowing the reagent to run down the sides of the test tube. With raw milk or milk heated below 78° C. an intense blue color appears at once; with milk heated at 80° or higher no color appears. Other Tests are the original Arnold guaiac test || and its modifications and the Roi and Kohler iodide-starch test.^ * Analyst, 31, 1906, p. 218. t Jour. Ind. Eng. Chem., 5, 1913, p. 922. X Dupouy, Rep. pharm. Ill, 9, 1897, p. 206; Storch, Copenhagen Exp. Sta. Rep., 1898. § Jour. Dep. Agric, Victoria, 6, 1908, p. 251. I Jahr. Konig. Tierarz. Hochsch., 1880-1882, p. 161. \ Milch. Ztg., 31, 1902, pp. 17, 113. 174 FOOD INSPECTION AND ANALYSIS. Detection of Aldehyde Reducta.se.Schardinger Method.* — To 20 cc. of the milk add i cc. of a reagent consisting of 5 cc. of a saturated al- coholic solution of methylene blue, 5 cc. of 40% formaldehyde, and 190 cc. of water. Place in a water-bath kept at 45-50° C, and note the time required for decolorization. Lythgoe found that decolorization with raw milk took place in 5 minutes, while with milk pasteurized at 63° for 35 minutes, kept not longer than 2 days, it did not take place in 20 minutes. FERMENTED MILK. Yogurt is a Bulgarian product, prepared with a starter known as Maya, which, because of the longevity of the natives who subsist to a large degree on it, has come to be regarded as a kind of elixir of life. The souring of the milk is caused by Bacillus Bulgaricus which, like domestic yeast and butter starters, is perpetuated by primitive methods, although other bacteria take part in the changes. Cultures of the bacillus in tablet and liquid form are now on the American market with which the beverage commonly known as buttermilk is prepared either by the dairyman or the housewife from milk or skim milk. The characteristic constituent is lactic acid, both the dextro and levorotary forms, produced at the expense of a portion of the lactose. Other acid products, similar to yogurt, are Leben of Egypt, Gioddu of Sicily (Cieddu of Sardinia), Dadhi of India, and Tatte of Scandinavia. Kumiss is indigenous to Central Asia and the Steppes region of Russia where it is prepared from mare's, camel's, and ass's milk. The alcoholic fermentation is caused by a peculiar yeast that acts directly on the lactose, although bacteria also play a part. With us kumiss is a preparation of cow's milk used chiefly as a therapeutic food, the alcohol being commonly gen- erated by ordinary yeast acting on added glucose or sucrose. In addition to alcohol some lactic acid is also formed from the lactose, the proteins are more or less peptonized or otherwise acted on, butyric acid is liberated, and esters are formed. Dr. L. L. Van Slyke has kindly communicated the following as an average analysis of kumiss made from cow's milk : Total Solids. Lactose. Alcohol. Acidity. Total Nitrogen. Casein Nitrogen. 11.00 5.00 1. 00 0.30 0.65 O.S5 Alcoholic beverages similar to kumiss are Kefir prepared in the Cau- casus from cow's, sheep's, or goat's milk, using so-called " Kefir grains " * Zeits. Unters. Nahr. Genussm., 5, 1902, p. 1113. MILK AND ITS PRODUCTS. 175 which bear much the same relation to the product as yeast cakes do to bread, and Mazun made in Armenia from sheep's, goat's, or buffalo's milk. Ginzberg * has studied the chemical changes which take place in the preparation of both kumiss and kefir, as well as their imitations. Analysis of Fermented Milks. — The sampling requires special care owing to the more or less curdled or granular condition. Lumps of curd may be rubbed through a sieve while lumps of fat, such as occur in butter- milk, may be strained out, weighed, and separately analyzed. In special cases the whole sample may be neutralized with ammonia, taking account of volumes. Total Solids, Total Protein, Casein, Albumin, Other Nitrogenous Con- stituents, Lactose, and Ash are determined by the methods described under milk with such minor modifications as the nature of the substance may require. For example the casein, already partially or completely pre- cipitated, requires only a small addition of acetic acid, if any. Again since lactose is present in only small amount, a correspondingly larger quantity of this milk may be polarized. Fat is best extracted by the Rose-Gottlieb method after neutralizing the free acid. Obviously ether extraction of the acid material whether or not evaporated to dryness would yield fat contaminated with lactic acid. Centrifugal methods should be employed only when checked against the standard method. Total Acids are titrated directly using phenolphthalein as indicator. Volatile Acids and Alcohol are distilled together and the former titrated; the slightly alkaline liquid is then redistilled and the alcohol determined. CONDENSED MILK. Canned condensed milk has become a very important article of food, its use having increased greatly during recent years. The universally accepted meaning of the term " condensed milk " in the United States is milk both condensed and preserved with cane sugar, being what is commonly known in England as " preserved milk." The unsweet- ened variety is termed " evaporated milk " and sold as such. Condensed Milk, or more properly sweetened condensed milk, is prepared by adding cane sugar to whole milk, usually with previous pas- teurization, and evaporating in a special form of vacuum pan to a thick consistency. A considerable quantity is sold to large consumers in bulk, * Biochem. Zeits., 30, 1910, pp. i, 25. 176 FOOD INSPECTION AND ANALYSIS. in which form it keeps indefinitely by reason of the large percentage of sugar, but for domestic use it is commonly packed in hermetically sealed cans. Composition. — Various standards committees agree in placing 28% of milk solids and 8% of fat as the minimum limits. As Hunziker has noted manufacturers are not likely to allow their products to drop below 28% of milk solids as that percentage is essential for holding the sugar in sus- pension without which the product would not be readily marketable. Not infrequently, however, the percentage of fat falls below 8% indicating that skim milk or an abnormally poor product was used. As at no time during the process the heating is carried on at a high temperature, the evapora- tion may be continued until the percentage of milk solids is raised to con- siderably over 30% without danger of curdling. Upward of 350 samples, representing 110 brands, were analyzed in full by the Massachusetts State Board of Health in the course of eight years. As some of the samples were obviously prepared from partially or wholly skimmed milk, maximum, minimum, and average figures have no significance in judging the composition of the genuine product, but the selected analyses of a few typical brands given in the following table are instructive : COMPOSITION OF SWEETENED CONDENSED MILK. Points to be Noted. High in fat, much added sugar High fat, low milk sugar. . . Low fat, high milk sugar, low proteins Normal constituents throughout Condensed from skimmed milk .. ■ ■ ■ Condensed from centrifu- gally skimmed milk Total Solids, Per Cent. 79.17 68.70 69.30 74-29 69.30 69.06 Water Per Cent. 20.83 32.30 30.70 25 71 30.70 30.94 Milk Solids, Per Cent. Cane Sugar, Per Cent. 47.85 38.43 37.47 41.92 40.15 43.18 Lac- tose, Per Cent. 9.57 6.38 16.75 11.97 Pro- teins, Per Cent. 7.95 10.70 6.34 8.46 12. IS 11.78 Fat, Per Cent. 12.00 11.46 7.20 10.65 3 06 0.09 Ash, Per Cent. 1.73 1.54 1 .29 2.05 2.46 Fat in Origi- nal Milk, Per Cent. 4.60 5.63 2.77 456 I . II Trace Evaporated Milk, or unsweetened condensed milk, formerly erroneously branded evaporated cream, differs from the sweetened variety in that it does not contain added sugar and therefore must be marketed in sterilized form if not required for immediate use. Formerly 28% of milk solids containing at least 27.5% of fat was requu-ed but careful investigations by Patrick, Hunziker, and others showed that it was impracticable to comply with this standard in all regions and at all seasons, without the milk curdling. At present 25.5% of solids and MILK AND ITS PRODUCTS. 177 7.8% of fat (the latter percentage being of the evaporated milk and not of the milk solids) are recognized as the minimum limits regardless of con- ditions. Mohan * states that swells, flat sours, and sweet curdling are due to understerilization, while other forms of curdling are due to the action of heat on milk with high solids and acidity, and the hard granules sometimes found at the bottom of cans, chiefly to calcium phosphate precipitated by over evaporation. Composition. — The following typical analyses made at the Massachu- setts State Board of Health are selected from about 30 representing 8 brands: COMPOSITION OF UNSWEETENED CONDENSED MILK. Points to be Noted. Total Solids, Per Cent. Water, Per Cent. Lac- tose, Per Cent. Pro- teins, Per Cent. Fat, Per Cent. Ash, Per Cent. Fat in Original Milk, Per Cent. No. of Times Con- densed. High in fat Low in proteins Normal constituents throughout. Condensed from skimmed milk. . 36.00 3125 28.16 35. 17 64.00 86.75 69. 24 64-83 10.65 13.40 9.8s 13-90 11.63 7 .02 8.66 15-37 12.00 9.60 1.72 1-23 I 55 1.70 4.61 4.18 3-68 A summary of analyses of 12 brands found on sale in the State of Maine during the year 19 16 follow :f Water. Fat. Lactose. Protein. Ash. Maximum Minimum Average 75-93 72.02 73-35 8.84 7.62 8.13 11-45 9-13 10.31 7.17 5-71 6.69 1. 65 1-34 1-52 McGill { gives in the table on page 178 the averages of results obtained during the years 19 10 and 19 15 on 16 brands collected in Canada: Adulteration. — Aside from such foreign substances as may be present in the original milk without the knowledge of the manufacturer, such as preservatives and colors, the only common form of adulteration is the use of skim milk, although homogenized foreign fats are sometimes used to make up for the deficiency. Watering, as it entails greater labor in evaporation, would not be practiced by the manufacturer. If the milk furnished him is watered the defect is corrected by evaporation. * Jour. See. Chem. Ind., 34, 1915, p. 109. t Maine Agr. E.xp. Sta., Off. Ins., p. 76. % Lab. Inl. Rev. Dept. Canada, Buls. 208 and 305. 178 FOOD INSPECTION AND ANALYSIS. I910. ' 1915. Number of . Samples. Solids. Fat. Number of Samples. Solids. Fat. 3 8 2 I I 25.29 29.02 23.86 30.20 22.04 5-92 7-52 6.74 8.12 5-64 6 30 3 I 2 12 31 2 6 2 I 60 19 3 22.63 26.52 25-72 22.35 25-53 27.14 26. II 25-39 26.08 27.25 21.92 26.54 25-55 23-47 6.74 7-51 7.19 6.48 6.62 II I 6 27.47 24.64 26.97 7.27 6.00 6.70 7.67 7.21 6-39 7.00 7-45 6.21 12 26.64 6.94 7-44 6.87 0. 26 ANALYSIS OF CONDENSED MILK. Preparation of the Sample. — Mix the sample thoroughly, best by transferring the entire contents of the can to a large evaporating dish and working it thoroughly with a pestle till homogeneous throughout. Weigh 40 grams of the mixed sample, preferably in a tared weighing-tray for sugar analysis, transfer by washing to a graduated loo-cc. sugar flask, and make up to the mark with water. Another method * is to weigh the can and contents together, remove the contents to a liter flask with tepid water, dry the can, and subtract its weight from that previously obtained. As the weight of the contents varies this method involves more calculation. Determination of Total Solids. — Gravimetric Method. — Dilute an aliquot part of the mixed solution further with an equal amount of water and pipette 5 cc. of the diluted mixture, corresponding to i gram of the sample, into a tared platinum dish, such as is used for ordinary milk, and rinse the pipette into the dish by means of a wash-bottle. Evaporate, dry at the temperature of boiling water and weigh as in the case of milk (p. 119). The character of the residue should be noted. It should not, excepting in the case of a skimmed milk, be caked down hard and glossy on the Conn. Agric. Exp. Sta. Rep. 1904, p. 133. MILK AND ITS PRODUCTS. 179 bottom of the dish, but, if the operation is properly carried out, should have a well-separated fat layer at the top, and the residue should resemble in appearance that from ordinary milk. This result is accomplished by the extreme dilution of the sample. Calculation Methods for Evaporated Milk. — Hunziker's formula * is as follows : T= ( — ^^^^^ ) X 1 ,000 - 1 ,000 X i -t- 1 . 2 X/, in which B is the Baume reading at 60° F. and/ the per cent of fat. The hydrometer reading is calculated to 60° F. by adding 0.0313 for every degree over that temperature. Evenson's modification f of the Babcock formula follows: r=^i:^+i.2x/, 4 in which T is the total solids, L the Quevenne reading at 15.5° C. after holding the sample at 37-40° C. 45 minutes, and/ the per cent of fat. Determination of Fat in Sweetened Condensed Milk. — It has long been known that fat can not be accurately determined in sweetened condensed milk either by extraction after evaporation, as in the asbestos or paper coil methods, or by the ordinary centrifugal methods. In the former case the sugar encloses particles of fat and prevents their contact with the ether while in the latter case it chars with the acid and gives a black fat column. In exact work the Rose-Gottlieb Method (p. 193) should be used but for many purposes the two following modifications of the Babcock method are sufficiently accurate. Leach Method.^ — In a Babcock milk bottle with a mark on the bulb showing a volume of 17.6 cc, place 25 cc. of the diluted sample, add 4 cc. of copper sulphate solution of the strength used for Fehling solution, and allow to stand some minutes without shaking. Add water nearly to the neck, shake thoroughly, and whirl without heating in a centrifuge until the precipitated proteins, carrying with them the fat, have entirely settled. Remove the clear liquid, add water nearly to the neck, break up the lumps *Ind. Agr. Exp. Sta. Rept., 1913, p. 43. t Jour. Ind. Eng. Chem., 9, 191 7, p. 499. t Mass. State Bd. Health Rept., 1896, p. 630; Jour. Amer. Chem. See, 22, 1900, p. 580. SHght changes in the manipulation which Winton has found desirable are given in the above description. 180 FOOD INSPECTION AND ANALYSIS. with a wire, shake, and again whirl. After removing the clear liquid repeat once again the addition of water, shaking, whirling, and decanta- tion. Finally add water up to 17.6 cc, mix thoroughly, and proceed as in the usual Babcock method. To obtain the percentage of fat, multiply the reading by 18 and divide by the grams of condensed milk in the aliquot taken. Farringion Method.^ — Weigh 40 to 60 grams of the sample into a 2cc-cc. flask, dissolve in 100 cc. of water, make up to the mark, and shake. Pipette 17.6 cc. into a milk test-bottle, add 3 cc. of sulphuric acid of the strength used for the test, and shake thoroughly. Whirl for 6 minutes at 1000 revolutions per minute in a steam-driven turbine centrifuge in which the chamber reaches a temperature of about 93° C, pour off cautiously the clear solution, add 10 cc. of water, shake, then add 3 cc. of acid, whirl, and decant a second time. Shake the curd with 10 cc. of water and proceed as in the ordinary Babcock test, calculating to the weight of sample taken. Determination of Fat in Evaporated Milk. — The finely curdled particles of casein formed during sterilization enclose fat which is removed with difficulty by ether extraction. Hunziker and Spitzer f found that, after removing the greater part of the casein from the Adams coils by dilute acetic acid, extraction for 8 hours gave the full amount of fat. The asbes- tos and sand methods are preferable to the Adams method and thorough distribution by dilution facilitates the extraction. Extensive investigations by Patrick and others indicate that the Rose- Gottlieb method gives the best results. The curd flocks are dissolved with difficulty in the Babcock acid, hence clear readings and the full amount of fat are not always obtained by the usual process. The Hunziker and Spitzer Method, by the use of a quarter quantity of the sample and hot i : i acid in filling the test- bottles, largely obviates these defects. Utt % finds additional heating essential and Bigelow and Fitzgerald, § in their modification, use 9 grams of the sample, read to the bottom of the meniscus, and add 15% to the result. As such factors as temperature, thoroughness of mixing, period of action, and method of reading influence the results, the analyst should test his procedure against a standard method or with standard samples derived from milk of known composition evaporated to a definite concentration. * Amer. Chem. Jour., 24, 1900, p. 267. find. Agric. Exp. Sta. Bui. 134, 1909, p. 591. t Jour. Ind. Eng. Chem., 5, 1913, p. 168. § Reb. Lab. Nat. Canners' Assn. Bui. 5, 1915, p. 8. MILK AND ITS PRODUCTS. 181 Determination of Protein. — Proceed with an aliquot of the diluted sample as described under milk (p. 132), calculating the protein from the total nitrogen or determining it directly by the Ritthausen method. Determination of Lactose. — Volumetric Method. — Pipette 25 cc. of the 40% solution into a 500 cc. flask and proceed as directed under milk ^P- 137)- In calculating the percentage of lactose use the following formula : L = 100X0.067 5Xo.o2 in which L is the per cent of lactose and S the number of cubic centimeters of 40% solution required to reduce 10 cc. of Fehling solution. Calculation may be avoided by the use of the following table: PER CENT MILK SUGAR CORRESPONDING TO NUMBER OF CUBIC CENTIMETERS USED. Strength of solution 2 grams in 100 cc. Cu. Cm. Per Cent. Cu. Cm. Per Cent. Cu. Cm. Per Cent. Cu. Cm. Per Cent. 18.0 18.61 25.0 13-40 32.0 10.47 39-0 8.59 18.S 18 10 2SS 13 14 32 5 10 31 39-5 8 49 19.0 17 63 26.0 12.89 33 10 15 40.0 8 37 195 17 18 26. 5 12.64 33 5 10 00 40-5 8 27 20.0 16 75 27.0 12.41 34 9 85 41.0 8 17 20. s 16 34 27-5 12.18 34 5 9 71 41-5 8 07 21.0 IS 95 28.0 11.97 35 9 57 42.0 7 98 21-5 15 58 28. s 11-75 35 5 9 43 42-5 7 88 22.0 IS 22 29.0 ii-SS 36 9 30 43-0 7 78 22-5 14 89 295 11-35 36 5 9 17 43-5 7 70 23.0 14 S6 30.0 II. 16 37 9 05 44.0 7 61 23s 14 25 30-5 10.89 37 5 8 93 44-5 7 53 24.0 13 95 31.0 10.80 38 8 81 24-5 13 67 31-5 10.63 38 5 8 70 Gravimetric Methods. — Lactose may be determined in the 40% solu- tion of the condensed milk by the O'Sullivan-Defren method (p. 137), the Soxhlet method (p. 137), or the Munson and Walker method (p. 138), the solution being treated exactly as if it were milk. It has long been known that the percentages of lactose by copper reduction in sweetened condensed milk are somewhat high owing to the presence of sucrose. This appears to be due to the sucrose itself rather than to reducing sugars present in it as impurities. Winton found, in an 182 FOOD INSPECTION AND ANALYSIS. attempt to determine the corrections for different proportions of sucrose, that while agreeing results could be obtained on solutions of pure lactose, when a definite amount of sucrose was added the figures were not merely higher but were discordant even when the heating and other conditions were apparently the same. The experience of Knight and Formanek would seem to indicate that greater accuracy can be secured by directly determining the sucrose and obtaining the lactose by difference. Cane Sugar.— This is ordinarily obtained by difference, deducting the milk solids (the sum of the milk sugar, proteins, fat, and ash) from the total solids first obtained. When only the sucrose is desired this may be determined by polariza- tion. The Knight and Formanek method depends on double dilution (see Wiley method, p. 136) to correct for the bulk of the precipitate and on a modified Clerget formula to eliminate the rotatory influence of the lactose. Rakshit * destroys the lactose entirely by means of a measured quantity of Fehling solution calculated from a volumetric determination. Knight and Formanek Method. -\ — Make the entire contents of the usual 12 to 15-ounce can up to 500 cc. Place 50 and loo-cc. aliquots in 200-cc. flasks and clarify with 1.7 cc. of 5% phosphotungstic acid solution and 2.1 cc. of 25% normal lead acetate solution for each 10 grams of the sample in the aliquot, shaking well after adding each reagent. Make up to the mark, shake again and filter. To the filtrates, measuring about 100 cc, add potassium oxalate crystals in o.i-gram portions with constant shaking until a curdy precipitate forms which quickly settles leaving a clear liquor. Usually 0.5 gram is sufiicient; a large excess should be avoided. Filter again using hardened filters with 3 to 5 grams of fuller's earth in the apex and test the first 10 cc. with potassium oxalate. Polarize at exactly 20° C. preferably in a Bates instrument set for maximum senti- tiveness and using a bichromate cell. Multiply the reading of the dilute solution by 4 and subtract from the product the reading of the stronger solution. The difference is the direct polarization corrected for the volume of the precipitate. Pipette 50-cc. portions of the filtrates into loo-cc. flasks and invert with 5 cc. of concentrated hydrochloric acid by standing over night at 20 to 25° C. Add a few drops of phenolphthalein solution and strong sodium hydroxide solution until a pink color appears, then a few drops of N/io hydrochloric acid until the color disappears. Make up to the * Jour. Ind. Eng. Chem., 6, 1914, p. 307. t IL>> Undetermined Inosmic acid Uric acid -' Urea o . 01 to o. 03 0.05 to 3.5 Lactic acid o . 05 to 0.07 Butyric acid "j A^^t^^^"d Undetermined Formic acid Inosite ■^ Glycogen 0.3 to o. s Salts 0.8 to 1 . 8 Composed of: Potash 0.40 to o. 50 Soda 0.02 to o 08 Lime o.oi to o 07 Magnesia 0.02 to 0.05 Oxide of iron o . 003 to o. 01 Phosphoric acid o. 40 to o. 50 Sulphuric acid o . 003 to o . 04 Chlorine o.oi to p. 07 Nitrogenized compounds. Fat. Other nitrogen-free compounds . FLESH FOODS. 207 Proximate Composition of the Commoner Meats. — The chief char- acteristics of the flesh of various animals are in the main very similar, whatever the nature of the animal. So true is this, indeed, that it is usually impossible from a chemical analysis to distinguish a particular kind of flesh when mixed with that of other animals in finely divided meat preparations, such as sausages, potted and deviled meats, and the like. The average composition of the commoner cuts of beef, veal, mutton, lamb, and pork, as well as of fowl and game, is shown in the following tables, compiled from the work of Atwater and Bryant *, the accompanying diagrams serving to locate, in the case of ordinary meats, the portion of the animal from which the meat is taken. Constants of Fat. — These as found by Bigelow are given in the table on page 212. Characteristics of Sound Meat. — The reaction of meat should be acid. If neutral or alkaline, decomposition is indicated, except that alkalinity may be due to the use of alkaline salts as preservatives. Letheby t gives the following characteristics of sound, fresh meat. In color it is neither pale pink nor deep purple, the former indicating that the animal was affected with some disease, and the latter that it died a natural death, and was not slaughtered. In appearance it is marbled, due to the presence of small veins of fat distributed among the muscles. In consistency it is firm and elastic to the touch, and should hardly moisten the finger; a wet, sodden, or flabby consistency with a jelly-like fat is indicative of bad meat. As to odor, it is practically free; whatever odor there is should not be disagreeable ; a sickly or cadaverous smell is indica- tive of diseased meat. After standing for a day or so, it should not become wet, but on the contrary should grow drier. When dried at 100° C. it should not lose more than 70 to 74 per cent in weight; unsound meat frequently loses 80% or more. It should shrink very little in cooling. Inspection of Meat. — While carefully drawn laws exist almost every- where relating to the sale of meat, and government inspectors are ap- pointed to carry out the requirements of the laws, yet in this country there is undoubtedly some meat unfit for food on the market, owing to the small number of inspectors, and the consequent comparative safety with which unscrupulous dealers may sell meats forbidden by law and escape detection. The inspection of meats and fish under municipal ordinances is not always carried out as thoroughly as might be desired. * U. S. Dept. of Agric, Off. of Exp. Stations, Bui. 28 (Revised Ed.). t Lectures on Food, p. 210. 208 FOOD INSPECTION AND ANALYSIS. 1. Neck 2. Chack 3. Ribs i. Shoulder clod 6. Fore shank 6. Brisket 7. Cross ribs 8. Plate 9. Navel 10. Loin 11. Flank 12. Rump 13. Round 14. Second cut round 10. Hind shank Fig. 56.— Diagram Showing Cuts of Beef. COMPOSITION OF BEEF. Cut. Num- ber of Anal- yses. Refuse Water. Protein. N < 6.25. By Differ- Fat. Ash. Fuel Value per Pound. Cals. Ribs: Chuck: Lean — Medium- Fat— Lean — Medium- Fat— Loin: Lean — Medium- Fat— Rump: Lean — Medium- Fat— Round: Lean — Medium- Fat— edible portion. as purchased, -edible portion. as purchased. . edible portion. as purchased. . edible portion. as purchased. . -edible portion. as purchased. . edible portion. as purchased. . edible portion. as purchased. . -edible portion. as purchased. . edible portion. as purchased. . edible portion. as purchased. . -edible portion. as purchased. . edible portion. as purchased. . edible portion. as purchased. . -edible portion. as purchased . . edible portion. as purchased . . 19-5 4 4 4 3 6 6 15 15 9 32 32 6 6 4 3 15.2 14.7 22.6 20.8 13 -I 13-3 14.0 20.7 2.^.0 i.I 7-2 12.0 8.2 6.6 II. 9 10. 1 18.8 15-9 9.8 9-3 26.6 21 .2 35-6 30 20.2 17-.5 27.6 24.8 13-7 11. •25-5 20.2 35-7 27.6 7-9 7-3 13.6 12.8 19-S 16. 1 0.8 0.9 0.8 0.9 0.7 0.8 0.7 0.9 0.7 0.7 0.6 i.o 0.9 i.o 0.9 0.9 0.8 I.o 0.9 0.9 0.7 0.8 0.6 0.8 720 580 865 735 "35 965 790 675 1450 "55 1780 1525 900 785 1 190 1040 1490 1305 965 820 1400 mo 1820 1405 730 670 950 895 1 185 1005 FLESH FOODS. 209 '^^i^^fjiM^mi^ l.Neck 2. Chuck 3. Shoulder 4. Fore shank 5. Breast ^^.//.. ^|^£(lfeyii'/'^ 6. Ribs 7 . Loin 8. Flank 9. Leg 10. Hind shank Fig. 57. — ^Diagram Showing Cuts of Veal. COMPOSITION OF VEAL. Num- ber of Anal- yses. Refuse. Protein. Fat. Ash. Fuel Value per Pound Cals. Cut. Water. NX 6.25. By Differ- ence. Chuck: Lean — edible portion. . as purchased Medium — edible portion . . as purchased.. . Ribs: Medium — edible portion. . as purchased — Fat — edible portion. . as purchased Loin: Lean — edible portion. . as purchased.. . Medium — edible portion.. as purchased.. . Fat — edible portion . . as purchased Leg: Lean — edible portion. . as purchased Medium — edible portion., as purchased I I 6 6 9 9 3 3 5 5 6 6 2 2 9 9 10 9 19.0 18.9 25-3 24-3 22.0 "ih'.y 9.1 14.2 76. 2 20.6 16.7 19.2 15-6 20.1 15-0 18.8 14.2 19.9 15.6 19.2 16.0 18. 5 15-1 21.2 19-3 19.8 16.9 1.9 1.6 6.5 5-2 6.1 4.6 19-3 14-S 5-6 4.4 10.8 9.0 18.9 15-4 4-1 3-7 9.0 7-9 1.2 0.9 I.O 0.8 I.I 0.8 1.0 0.8 1.2 0.9 I 0.9 1.0 0.8 1.2 I.I 1.2 0.9 465 380 640 515 640 480 1 1 60 87s 61S 480 82s 690 1 145 935 570 520 755 620 61 73 59 72 54 60 46 73 57 69 57 61 50 73 66 70 60 8 3 5 7 3 9 2 3 I 6 6 4 5 8 I 19 16 20 15 18 14 20 15 19 16 18 15 21 19 20 15 7 7 5 7 2 4 9 9 6 7 3 3 4 2 5 210 FOOD INSPECTION AND ANALYSIS. 1 . Neck 2. Chuck 3. Shoulder i. Flank 5 ■ Loin 6. Leg Fig. 58. — Diagram Showing Cuts of Mutton. COMPOSITION OF MUTTON AND LAMB, Num- ber of Anal- yses. Refuse. Water. Protein. Fat. Ash. Fuel Value per Pound, Cals, Cut. NX 6.25. By Differ- ence: Mutton. Chuck: Lean — edible portion . . as purchased. . . Medium — edible portion . . as purchased. . . Fat — edible portion. . as purchased Loin: Medium — edible portion. . as purchased Fat — edible portion. . as purchased — Flank: Medium — edible portion. . as purchased Leg: Lean — edible portion. . as purchased Medium — edible portion . . as purchased Lamb. Chuck: edible portion . . as purchased Leg: Medium — edible portion . . as purchased Fat — edible portion . . as purchased Loin: edible portion. . as purchased... I I 6 6 2 2 13 12 3 3 8 2 3 3 II II I I 2 2 I I 4 4 19-5 21.3 "ih'.'s' 16.0 II. 7 9-9 18.4 19. 1 17.4 13-4 "2;:8' 64.7 52-1 50-9 39-9 40.6 33-8 50.2 42.0 43-3 38-3 46.2 39-0 67.4 56-1 62.8 51-2 56.2 45-5 63-9 52-9 54-6 47-3 53-1 45-3 17.8 14-3 151 II. 9 13-9 II. 6 16.0 13-5 14-7 13-0 15.2 13-8 19.8 16.5 18.S 15-1 19. 1 iS-4 19.2 15-9 18.3 15.8 18.7 16.0 18 14 14 11 13 II 15 13 14 12 14 13 19 15 18 14 19 15 18 15 17 14 17- IS- .1 •5 .6 ■5 ■7 •5 •9 2 5 8 6 I 9 2 9 2 5 5 2 I 8 6 16.3 13-I 33-6 26.7 44-9 37-5 33-'^ 28.3 41.7 36.8 38.3 36-9 12.4 10.3 18.0 14.7 23.6 19. 1 16-S 13-6 27.4 23-7 28.3 24-1 0.9 0.8 0.9 0.6 0.8 0.7 0.8 0.7 0.8 °-l 0.7 0.6 I.I 0.9 I.O 0.8 1.0 0.8 I.I 0.9 0.9 0-8 1.0 0.8 1020 820 1700 1350 2155 1800 1695 1445 203s 1795 1900 1815 890 740 1 105 900 1350 1090 loss 870 1 495 1295 1540 131S FLESH FOODS. 211 ""'^"^^MWl'n'i ''III ^i'^r^,i''Ti'''iiiil'iiiiO 1. Head. 2 Shoulder. 3. Back. 4. Middle cut. 5. BeUy. 6. Ham. Y. Ribs. 8. Loin. Fig. 59- — Diagram Showing Cuts of Pork. COMPOSITION OF PORK, POULTRY, AND GAME. Num- ber of Anal- yses. Refuse. Water. Protein. Fuel Cut. NX 6.25. By Differ- ence. Fat. Ash. Value per Pound Cals. Pork. Shoulder: edible portion. . as purchased Loin: Lean — edible portion. . as purchased Fat — edible portion . . as purchased. . . Ham: Lean — edible portion. . as purchased.. . Fat — edible portion . . as purchased POXJLTEY AND GaME. Chicken: edible portion . . as purchased Fowl: edible portion . . as purchased... Goose: edible portion . . as purchased... Turkey: edible portion . . as purchased Quail: as purchased 19 19 I I 4 4 2 2 5 5 3 3 26 26 I I 3 3 1 12.4 23-5 0.-9 13.2 41.6 25-9 17.6 22.7 51.2 44-9 60.3 46.1 41.8 34-8 60.0 59-4 38-7 33-6 74-8 43-7 63-7 47-1 46.7 38-5 55-5 42.4 66.9 13-3 12.0 20.3 15-5 14-S II. 9 25.0 24.8 12.4 10.7 21-5 12.8 19-3 13-7 16.3 13-4 21. 1 16. 1 21.8 13-8 12.2 19.7 15-I 13-I 10.9 24-3 24.2 10.6 9.2 21.6 12.6 19.0 14.0 16.3 13-4 20.6 15-7 34.2 29.8 19.0 14-5 44-4 37-2 14.4 14.2 50.0 43-5 2-5 1.4 16.3 12.3 36.2 29.8 22.9 18.4 8.0 0.8 0.7 I.O 0.8 0.7 0.6 1-3 1-3 0.1 o-S I.I 0.7 1.0 0.7 0.8 0.7 1.0 0.8 1-7 1690 1480 1 180 900 2145 1790 1075 1060 2345 2035 505 29s 1045 775 1830 1505 1360 1075 775 212 FOOD INSPECTION AND ANALYSIS. 00 O vO M O in NO t^ vo On m N On NO NO ■* moo H CO On 00 lO Tt rf O On lO 0) CO COO d d d ro ro rO ro fO t-O ■^ LD •* n- M- CO CO Tj- ro Tj- lO CO 'i- Tj- ^ v • t^ •^OO O M M 00 O 00 CO On NO 00 lo ^11 lO W On ro uo lo ro -^ H 00 l^ •* On J^ -i OnnO m aNO ^ lo On M t^ r^ M M M O O n On O O nO r^ r^ W-) 0) t^ mNO CO Tl- lO 01 O O M lONO w Pi •I.s O fONO O r^ t^ On M r^ On ■* ■* fO ro ■* r^ N ro w CNi ro N CO •* P< CO CO 0« oo Tj- 01 Uh s^- H «4-t 00 M On t-~ On On ro w lO VOOO NO 00 r^ CO r^ •* O O O On < i-S M ro O P) T^ O. t^NO « M 'too « r^ r^ CO t-~ On 01 NO LO NO NO w-> vo r^NO NO NO lO NO NO lO NO NO LO VO NO LO W Tf rf ■* Tt ^ ^ ■^ O On O r^ M IT) C r*^ u-> N ■* N O O O N r^ m O NO CO 01 t; >. £ r^ On CO vonO His coo ro Tt- N NO 00 NO OnnO O (N On w On lO Tt" VO 01 00 On O On w 00 00 NO ON r^ Ov w CO Ov 01 I^ < 00 OnOO d o 00 CO 00 d d d On OnOO 6 6 6 00 ONOO 6 6 6 00 OnoO 6 6 6 00 O-OO d d d 00 OnOO d d d > ; ; ; ! ! I \ ', ', I I ! ! I I o : d g" : s s E F ' s S ■ S B ■ § 6 ■^ s : § E u 3 3 fc s s m 3 3 0) =3 b o P p D P 3 J^ S p oOnOsi'->OMM\OOMOOlOMH\OMVO O OQ U^. o 00 "" fOfOP) -^lorO-rt-TtfO lONO •-iNO '+Mr^'troON-i-0 h pi ni^cs m T+rr, <3 r^OO On t^CO TtvO ro Tf ro io\0 vO 0) 00 O 00 P) O 00 po rOOO t^ On O 00 ro lo C) ioOn0 OnI^N q ^qq qq ^ ■'■ " '" """ ~" ""'O rj- r)- to r<^NO t^ 10 ro 10 M u-j t^ (Ono NO •2» iQiOj P- 563. t Arch. Hyg., 51, 1904, p. 165. FLESH FOODS. 225 in a vacuum desiccator over freshly ignited calcium chloride. Determine the usual constants as described in Chapter XIII. In minced prepara- tions these constants furnish a possible clue to the variety of meat used. Determination of Acidity of Fat. — Pennington and Hepburn Method. * Weigh lo grams of the fat, mechanically separated and ground in a meat chopper, directly into a 250 cc. Erlenmeyer flask, add 50 cc. of neutral alcohol, and phenolphthalein as indicator, and bring to a brisk boil. The hot alcohol dissolves the fat. Titrate immediately with tenth normal sodium hydroxide, shaking vigorously, until a pink color appears, which persists for one-quarter of a minute. Calculate the acid value from the amount of sodium hydroxide used, or the free oleic acid by multiplying the acid value by 0.503. Determination of Total Nitrogen. — Proceed according to the Gunning or Kjeldahl method (Chapter IV) employing 2 to 5 grams of the material. If the meat contains nitrates, as is true of corned beef and some other salted products cured with the addition of saltpeter, follow the method modi- fied to include nitric nitrogen. Richardson does not obtain concordant results by the modified method, when a large amount of sodium chloride is present, and recommends preliminary boiling with 10 cc. of saturated ferrous chloride solution and 5 cc. of concentrated hydrochloric acid to remove nitric nitrogen after which the ordinary Kjeldahl or Gunning method may be employed. Calculate protein using the factor 6.25. Although nitrogenous sub- stances other than proteins are present and the factors for the individual proteins vary, this factor gives a fairly close approximation to the total nitrogenous substance present. Determination of Ammoniacal Nitrogen. — Distillation Methods. — Ordi- narily the ammonia, liberated by magnesia (freshly calcined magnesium oxide), is distilled into standard acid and the excess titrated back with standard alkali. This procedure gives results somewhat higher than the truth owing to the decomposition of other nitrogenous compounds. Richardson and Scherubel-\ proceed as follows: Method I, Distil 100 grams of the material, 10 grams of magnesia, and 450 cc. of water until 200 cc. of the distillate have been collected; Method II, Extract 100 grams of the material three times with 150 cc. of 60% (by vol.) alcohol and distil the combined extracts as in Method I. In both methods employ phenol- * Jour. Amer. Chem. Soc, 32, 1910, p. 568. t Ibid., 30, 1908, p. 1527. 226 FOOD INSPECTION AND ANALYSIS. phthalein as indicator. If in method I the water driven off is replaced and the distillation is repeated, additional ammonia is obtained. After ten distillations in this manner the originators of the method obtained a total of 0.088% of ammoniacal nitrogen in a sample of fresh meat and 0.095% in one of frozen meat, whereas after the first distillation they obtained only 0.030 and 0.033% respectively. Method 11 gave results about one-third as high as by Method I and after the first distillation the increase was insignificant. Either method is suitable for comparative purposes as tne increase during spoilage is relatively great. Folin Aeration Method modified by Pennington and Greenlee.^ — The ammonia, set free by sodium carbonate, is evolved at room temperature in a rapid current of air. The ingoing air is purified by passing through sulphuric acid in a flask provided with a safety bulb. It next passes through a liter flask containing 25 grams of the ground meat, i gram sodium car- bonate, 250 cc. of water, and 25 cc. of alcohol, then through an empty flask to intercept spray into a 250 cc. flask containing tenth normal acid and finally through a 100 cc. flask, to catch acid carried over mechanically, to an air pump operated by an electric motor and provided with an anemom- eter. One pump and one air purifier suffices for four series of flasks, the current being divided by means of four- way tubes. A volume of 8000 cu. ft. passed through each series in 3 to 6 hours sufiices to remove all the ammonia liberated. Separation and Determination of Nitrogenous Bodies. — It is rarely necessary to go further than to divide the nitrogenous bodies into several main groups, according to their solubility in water or other solvents, and their behavior toward certain reagents. The nitrogen may be determined separately in each of these groups and by the approximate factor the corresponding substance or class of substances ascertained. A portion of the sample is first exhausted with cold water, which removes the soluble proteins (soluble globulins and albumins, proteoses, and peptones) and meat bases, leaving behind the insoluble globulins, the sarcolemma, the albuminoids of the connective tissue (elastin, etc., also insoluble) and the collagen. By next exhausting with boiling water the collagen is removed in the form of soluble gelatin. The coagulable albumins and globulins are precipitated in the cold water extract by boiling and in the filtrate from these, the proteoses by addition of zinc sulphate. The remainder of the nitrogen obtained by * Jour. Am. Chem. Soc, 32, 1910, p. 561. FLESH FOODS. 227 difference consists in large part of meat bases with a small amount of peptones, the accurate separation of which is impossible with our present knowledge, although the creatine and creatinine either separately or com- bined and the total purine bases may be quite accurately estimated. Determination of Nitrogenous Substances Insoluble in Cold Water. — It is customary to obtain the insoluble nitrogen by difference after determining the nitrogen in an aliquot of the cold water extract. The con- version factor for insoluble protein is 6.25. Trowbridge and Grindley Method.'^ — Digest looo grams for i hour with 1500 cc. of ice water and squeeze through cheese cloth. Divide the residue into equal portions in beakers, wash one after the other with the same portion of water, filtering each time through cheese cloth, and repeat until the last filtrate is colorless, neutral to phenolphthalein, and free from protein as shown by the biuret test. Emmett Method.-\—W&\^ 7 to 25 grams of the material, according to the water content, into a 150-cc. beaker, stir into a homogeneous paste with 5 to 10 cc. of ammonia-free water at 15° C, then add a further portion of 50 cc. Stir frequently for 15 minutes, allow to stand for 2 to 3 minutes, and filter into a 500-cc. graduated flask. Drain off the liquid, using a glass rod to press the meat residue. Wash by decantation with three portions each of 50 cc. and 25 cc. of water, stirring for 5 minutes each time and allowing to settle for 2 to 3 minutes. Transfer the residue to the paper and wash three times with 10 cc. of water. Make up to the mark and determine nitrogen in a 25-cc. ahquot portion. Three aliquot portions of 150 cc. each may be used for the determina- tion of (i) coagulable proteins and, in the filtrate, proteoses, (2) coagulable proteins and in the filtrate total creatinine (creatine and creatinine) and (3) purine bases. If other determinations are desired employ 14 to 50 grams of material and make up to 1000 cc. Emmett rightly observes that by direct treatment with water a solution well adapted for the determination of the various forms of soluble nitrogen is obtained, thus avoiding any changes which might result from preliminary drying and extraction with ether. Pennington Method.X — This method was devised for chicken meat. Shake gently 60 grams of the finely divided meat in a 500-cc. cylindrical bottle with 300 cc. of water for 15 minutes, avoiding sufficient agitation to * Jour. Amer. Chem. Soc, 28, 1906, p. 472. t U. S. Dept. of Agric, Bur. of Chem., Bui. 162, 1913, p. 153. X Ibid., Bui. 115, 1908, p. 64. 228 FOOD INSPECTION AND ANALYSIS. form an emulsion. Centrifuge 20 minutes, decant off the supernatant liquid onto a paper, add 300 cc. of water to the residue, and proceed as before, repeating the treatment until the protein is practically removed as shown by the biuret reaction. Usually a volume of 1500 to 2500 cc. is required. Employ thymol to prevent bacterial decomposition and a low temperature to inhibit the action of natural enzymes. Neutralize the total extract to litmus with N/io sodium hydroxide. Determine nitrogen in a loo-cc. aliquot portion which is evaporated to 10 cc, before adding the acid. Other aliquot portions may be used for determining coagulable and other forms of soluble nitrogen. Considerable difficulty is experienced in complete removal of soluble proteins from the dark meat, especially of cold-storage fowls. The ex- traction should not be continued longer than 26 hours. Cook shakes 200 grams for 3 hours with 250 cc. of water in a shaking machine and washes in linen bags with 2200 to 2500 cc. of water. Weber * finds that higher results are obtained by this method using ice water than with water at room temperature. Determination of Collagen and Gelatin. — The connective tissue of fresh meat consists in large part of collagen which on boiling with water is slowly converted into gelatin. In canned meat or other cooked meat products this conversion has been partly effected. In either case the com- mon methods of determination are based on boiling the cold water insoluble material with water until the conversion into gelatin is as complete as possible. The nitrogen is either determined directly in the filtered extract or in the alcohol insoluble portion of the extract as obtained by Stutzer's method. The factor for both collagen and gelatin is 5.55. Direct Method. — The residue from the cold water extract obtained by Emmett's method may be used for the determination. Boil for several days with water, filter, make up to a definite volume, and determine nitro- gen in an aliquot of about one-fifth the total volume. Stutzer Method.^ — This method was originally designed for meat extracts but has been used by Bigelow for meats. Evaporate another aliquot of one-fifth of the hot-water extract with sand and dry in a water oven. Treat with four portions of 100 cc. of absolute alcohol, decanting each time on a Buchner funnel connected with a suction flask and provided with a layer of long fiber asbestos. Place the beaker in ice water, stir for * U. S. Dept. of Agric, Bur. of Chem., Bui. 122, p. 42. t Zeits. anal. Chem., 34, 1895, p. 568. FLESH FOODS. 229 2 minutes with loo cc. of a mixture of loo grams of alcohol, 300 grams of powdered ice, and 600 grams of ice water, decant onto the filter adding a small piece of ice. Repeat the treatment three times or until the solution is colorless keeping the decanted portions in ice water during filtration, use two or three Buchner funnels if the filtration is slow and take care that the temperature does not rise above +5° C. Finally boil the mixture of sand and residue, together with the asbestos, with several portions of water, filter, wash with hot water, evaporate the filtrate, and determine nitrogen in an aliquot. Determination of Myosin.— Konig * states that myosin may be obtained in the residue after boiling with water by digestion with 15% ammonium chloride solution, filtration and precipitation of the myosin in the filtrate by diluting and boiling or by salting out with sodium chloride or magnesium sulphate. The myosin separated by filtration is dissolved in a definite volume of concentrated sulphuric acid and an aliquot used for nitrogen determination. He considers that the nitrogenous matter remain- ing undissolved after successive treatment with cold water, boiling water, and 15% ammonium chloride solution is sarcolemma or insoluble muscle fiber. The methods for collagen and myosin are not entirely satisfactory especially in view of our imperfect knowledge of the albuminoids and globulins, present in meat.f Determination of Coagulable Protein (A\h\mnn).—Gnndley and Emmett AfeZ/zo J. |— Evaporate 150 cc. of the cold water extract obtained as directed by Emmett to 40 cc. If necessary add carefully very dilute acetic acid or sodium hydroxide solution until faintly acid to litmus paper and boil. Collect the coagulum on a filter, wash with hot water, and determine nitrogen, correcting for any nitrogen that may be present in the paper. Nx6.25 = coagulable protein or albumin. Trowbridge and Grindley § obtain the maximum results in fresh beef by neutralizing one-fourth of the acidity to phenolphthalein before coagu- lation. Some analysts filter before neutralization and determine separately * Chemie der Menschlichen Nahrungs- und Genussmittel, 4 Auf. Ill Bd. 2 Th., 1914, p. 24. t See V. Furth, Arch. Path. Pharm., 37, 1896, p. 389; Ergebnisse der Physiologic Ab. i, I, 1902, p. 110; Ibid., Ab. 2, I, 1903, p. 575. t Jour. Amer. Chem. Soc, 27, 1905, p. 665; U. S. Dept. of Agric, Bur. of Chem., Bui. 1.62, p. 146. § Jour. Am. Chem. Soc, 28, 1906, p. 494. 230 FOOD INSPECTION AND ANALYSIS. any precipitate that forms on boiling after neutralizing. The second precipitate is known as syntonin or acid albumin. The filtrate from one duplicate may be used for determining proteoses, the filtrate from the other for determining total creatinine. Determination of Proteoses, Peptones, Creatine, Creatinine, Purine Bases, and Total Meat Bases. — Follow the methods as described under meat extracts (pp. 253 to 258). No accurate method is available for the determination of total meat bases. The practice of obtaining them from the remainder after sub- tracting the sum of the coagulable and proteose nitrogen from the total water soluble nitrogen, or after subtracting the proteose nitrogen from the total nitrogen in the filtrate from the coagulable nitrogen as followed ty Richardson, does not correct for the peptones or related substances thus determined with the bases. Bigelow and Cook's procedure of calculating the nitrogen in the filtrate from the tannin-salt precipitate, correcting for nitrogen in the reagent and ammonia in the sample, and multiplying by 3.12 to obtain the meat bases is subject to error in that part of the creatine is precipitated by the tannin-salt reagent and that the factor is accurate for only one base, creatine; furthermore, according to Richardson, the method is difficult to handle and obtain concordant results due (in part at least) to nitrogen in the reagent. The estimation of the " peptones " by substracting the sum of the coagulable, proteose, and meat base nitrogen by the tannin-salt method from the total soluble nitrogen and multiplying by 6.25 is likewise unsatisfactory although probably the best procedure now available. Determination of Ash. — Incinerate the residue from the total solids in the original dish at a low red heat. It is usually advantageous, especially in the case of salt meat, to exhaust the charred sample with water, collect the insoluble residue on a filter and ignite. The filtrate is then added, evaporated to dryness, and the whole heated to low redness and weighed. A perfectly white ash is difficult to obtain. Determination of Mineral Constituents. — Determine in the original meat total sulphur and in the ash chlorine, potassium, sodium, phosphoric acid, and other mineral constituents, following the usual methods of analysis. The scheme for ash analysis given on page 310 is applicable to meat ash. Determination of Acidity. — The acidity of meat is due largely to (f-lactic acid with small amounts of succinic, acetic, and other acids. The results by direct titration are usually calculated in terms of lactic acid. FLESH FOODS. 231 Mondschein found that about one- third of the acid is held back in the coaguium and proposes the following method: Mondschein Method.* — Suspend 50 grams of the finely ground sample in 60 to 80 cc. of water; coagulate by boiling, filter by suction, and wash with boiling water three times or until the reaction is no longer acid. Titrate the filtrate with N/io alkali using phenolphthalein as indicator. Calculate as free lactic acid. Remove the matted coaguium from the filter, stir up in a beaker with 50 cc. of water, add 10 cc. of 10% sodium hydroxide solution, and boil, taking care that the liquid does not froth over, thus liquefying the mass except for a few particles. Add 100 cc. of saturated sodium chloride solution, heat to boiling, and saturate at boiling heat with solid sodium chloride. Filter the precipitate thus formed with the aid of suction, wash with a hot saturated sodium chloride solution, and add to the filtrate sul- phuric ftcid to faint acid reaction, thus precipitating proteins. Boil, add 5 cc. of sulphuric acid, make up to 500 cc, and filter through a dry paper. Heat 250 cc. of the filtrate to boiling and add N/10 potassium permanganate solution until the lactic acid is split up into acetaldehyde, carbon dioxide, and water.f Add an equal bulk of potassium bisulphite solution (12 grams per liter), the strength of which has been determined against N/io iodine solution, mix, and after 15 minutes titrate with N/io iodine solution i cc. of which equals 0.005 gram lactic acid.| Mondschein also describes a more complicated method for use in separating J-lactic from /3-hydroxybutyric acid, which however does not appear to have practical application in meat analysis. Determination of Starch.— In the following methods it is assumed that glycogen is not present in sufificient amount to appreciably afTect the results. If microscopic examination shows the presence of starch and horse meat or liver is suspected, follow the Mayrhofer-Polenske method (P- 234). Mayrhofer Method.— The first paragraph of the description of the Mayr- hofer-Polenske method is essentially the Mayrhofer method as originally devised for starch. Mayrhofer- Price Method.^ — Heat on a boiling water bath 10 grams of finely-divided meat with 75 cc. of 8% potassium hydroxide in 95% alcohol * Biochem. Zeits., 42, 1912, pp. 91, 105. fv. Fiirth and Charnass, Biochem. Zeits, 26, 1910, p. 199. t Ripper, Monatsh. Chem., 21, 1900, p. 1079. § U. S. Dept. of Agric. Bur. of Anim. Ind. Circ, 203, 1912. 232 FOOD INSPECTION AND ANALYSIS. until all the meat is dissolved (30 to 40 min.). Add an equal volume of 95% alcohol, cool, and after i hour decant carefully on a Gooch crucible with a thin layer of asbestos. Wash carefully by decantation twice with 4% potassium hydroxide in 50% alcohol and twice with warm 50% alcohol. Add to the residue and crucible with contents 40 cc. of water and then with constant stirring 25 cc. of concentrated sulphuric acid. After 5 minutes add 40 cc. of water and heat just to boiling with constant stirring. Transfer to a 500-cc. graduated l^ask, add 2 cc. of 20% phosphotungstic acid solution, cool, make up to the mark, mix, and filter through starch- free filter paper. Neutralize an aliquot portion of the filtrate and deter- mine dextrose by one of the methods described in Chapter XIV. Price recommends Low's method.* Identification of Horse Flesh. — Although certain authorities have found distinguishing characteristics in color, consistency, odor, etc., between horse flesh on the one hand, and beef and pork on the other, it is extremely difficult, by its physical properties, to detect horse flesh when mixed with other meat, especially when the mixture is chopped. Horse flesh has a much coarser texture and is darker in color than beef. The muscle fibers are, as a rule, shorter in horse flesh. On treating horse flesh with formal- dehyde, Ehrlich f has found that a very characteristic odor is developed within forty-eight hours, suggestive of roasted goose flesh. Certain of the constants of the fat of horse meat differ from those of beef and pork, notably the iodine value and the refractometer readings. These constants are compared as follows: Iodine Value. Butyro- refractom- eter Readings. Temperature 40°. Horse fat 71-86 38-46 50-70 S3 7 49.0 48.6-51.2 Beef fat Hog fat The fact that glycogen usually exists to a much larger extent in horse- flesh than in other meat, and that a considerable amount remains after that of other meat has disappeared, renders it possible in some cases to detect horse flesh, when present in the mixture. The following table prepared by Bujard shows the relative amount of glycogen in various kinds of meat and sausages: . * Jour. Amer. Chem. Soc, 24, 1902, p. 1082. fZeits. Fleisch Milchhyg., 1895, p. 232. FLESH FOODS. 233 Water. Glycogen Direct. Niebel Method. Mayrhofer Method. Glycogen in Dried Substance. Niebel. Mayrhofer. Horse flesh Red sausage (Knackwurst) Pork sausage Veal Pork 0.440 0.600 1-827 0.592 0.445 0.520 1.727 0.610 0.038 0.24 0.086 0.186 1. 721 2.388 7.667 2.466 1. 741 2.069 7.247 2-542 0.124 0.733 0.342 0.744 In beef Bujard found 0.073 ^^^ o-74 P^r cent of glycogen calculated in terms of dried substance, and, in sausages made exclusively from horse meat, amounts of glycogen ranging from 0.05 to 5.34, the sample in the latter case being made from the liver. It was formerly thought possible to detect as small an amount as 5% of horse flesh in mixture, but later investigation showed that after the death of the animal, glycogen, though present at first in considerable quantity, decomposes more or less rapidly, going over into muscle sugar (dextrose). Hence, while the presence of much glycogen is suspicious, its absence is by no means proof that horse flesh was not used. Niebel did not consider the failure of the glycogen test as sufficiently conclusive to establish the absence of horse flesh, on account of the tendency toward decomposition of the glycogen. In the absence of starch, he regards the presence of more than 1% of dextrose in the fat-free meat, after conversion of the carbohydrates, to be proof of the presence of horse- flesh. Detection of Glycogen. — From the well-known reaction produced by iodine on glycogen, horse flesh can often be detected, when present in sausages, unless obscured by the presence of starch or dextrin. Brautigam and Edelmann * proceed as follows : 50 grams of the finely divided meat are boiled with 200 cc. of water for an hour, and, after cool- ing, dilute nitric acid is added to the broth to precipitate the proteins and to decolorize. The broth is then filtered, and a portion of the filtrate is treated in a test-tube with a freshly prepared, saturated, aqueous solution of iodine, or, better, with a mixture of 2 parts iodine to 4 parts potassium iodide and 100 parts water, the reagent being carefully added so as not * Pharm. Central., 1898, p. 557. 234 FOOD INSPECTION AND ANALYSIS. to mix with the broth, but form a layer above it. If glycogen be present in considerable amount, a wine-colored ring is observable at the junction of the two layers. On heating the test-tube, the coloration disappears if due to glycogen, but it reappears on cooling. This reaction was found to occur with horse flesh and not with beef, mutton, veal, or pork.* If the color is not clearly apparent, the chopped meat is heated on the water-bath with a solution of potassium hydroxide (using an amount of potassium hydroxide equivalent to 3% of the weight of the flesh) till the fiber is decomposed, after which the broth is concentrated to half its volume, treated with nitric acid to precipitate the proteins, filtered, and treated with the iodine solution as previously. Determination of Glycogen in the Absence of Starch. — Pfiilger Method.-\ — Heat on a boiling-water bath 100 grams of the material with 100 cc. of 60% potassium hydroxide for 3 hours, cool, transfer to a large beaker, dilute to 400 cc, precipitate with 8co cc. of 95% alcohol, and allow to settle over night. Decant off the liquid as completely as possible onto a filter, fill up the beaker with 66% alcohol containing i cc. of saturated sodium chloride per liter, and stir vigorously for a long time. After the glycogen settles decant off the liquid, repeat twice the washing with the 66% alcohol, and then wash twice with 95% alcohol, once with absolute alcohol, three times with absolute ether, and three times with absolute alcohol. Dissolve the glycogen in a small amount of hot water, make slightly acid with acetic acid, filter, and fill up to a definite volume. Determine the sugar in the solution either by direct polarization, specific rotation of glycogen + 196.5 7°, or by conversion into glucose and copper reduction. In the latter case invert 100 cc. by heating for 3 hours on a water-bath with 5 cc. of hydrochloric acid (sp.gr. 1.19) and proceed according to the AUihn method. Dextrose Xo.927 = glycogen. Separation and Determination of Glycogen and Starch. — Mayrhofer- Polenske Method. % — Dissolve 50 grams of the ground meat, containing as little fat as possible, in a 450 -cc. beaker with 150 cc. of a solution of 80 grams of potassium hydroxide in i liter of 90% (by vol.)' alcohol, by warming on a water-bath with occasional stirring which requires about h hour. - Add 100 cc. of 50% alcohol to the hot liquid, cool, and filter by suction in Witt's or some other suitable filtering device. Wash the residue with * The reaction was found to occur also with the flesh of the human foetus and with the foetus of animals; also with mule meat, but not with the flesh of the dog or cat. t Pfliiger's Arch. Ges. Physiol., 1C3, 1903, p. 169; 114, 1906, p. 231. t Arb. Kaisl. Gsndhtsamt., 24, 1906, p. 576. FLESH FOODS. 235 30 cc. of alcoholic potash at 50°, then with 90% cold alcohol until the filtrate no longer becomes turbid with a few drops of dilute hydrochloric acid. Transfer the insoluble residue to a iio-cc. graduated flask, add 50 cc. of normal aqueous potassium hydroxide and heat J hour on a water bath to dissolve the glycogen and starch. On cooling acidify the solution with concentrated acetic acid, make up to the mark, and filter. To 100 cc. of the filtrate add 150 cc. of absolute alcohol and after the glycogen and starch have settled (12 hours) collect on a tared Gooch crucible or filter paper. Wash with 70% alcohol until the filtrate contains no more solid matter and finally with a little absolute alcohol and ether. Dry first at 40°, then at 100° to constant weight, determine ash in a portion and deduct. Multiply by 2.2 to obtain the percentage of glycogen and starch in the meat. The method up to this point is in all essential details the original Mayr- hofer * method for determination of starch, the amount of glycogen present in aged meat products, such as sausage containing no horse flesh, being too small to appreciably viciate the results in determining a considerable addi- tion of starch. Only when starch has been found by microscopic examina- tion or the iodine test and the presence of meat with high glycogen content, such as horse flesh or liver, is suspected, is it necessary to attempt a sepa- ration by the following procedure: Weigh out 0.3 to 0.5 gram of the precipitate, dissolve in 30 to 40 cc. of water, and add double the volume of saturated ammonium sulphate solution. Allow to stand 2 hour and separate the precipitated starch from the solution of glycogen by filtration. Before washing the precipitate, test the filtrate with a dilute solution of iodine in potassium iodide and if a blue color appears, add saturated ammonium sulphate solution to the filtrate and after the precipitate which forms on standing has settled, filter on the paper containing the former precipitate. If, however, the color obtained with the iodine solution is red-violet by reflected and Bordeaux- red by transmitted light, the second precipitation is unnecessary. Wash the precipitate on the paper three times with half-saturated ammonium sulphate solution, then dissolve with normal sodium hydroxide into a beaker, wash first with normal sodium hydroxide, and finally with water. Neutralize the opalescent filtrate with acetic acid and precipitate with alcohol as above described. Collect on a tared Gooch crucible or filter paper, wash first with 50% alcohol and finally with absolute alcohol, dry at 100°, and weigh. * Forsch. Ber. Lebensm., 3, 1896, pp. 141, 429. 236 FOOD INSPECTION AND ANALYSIS. The glycogen may be obtained by difference, subtracting the weight of starch from that of starch and glycogen previously found, or directly as follows: Dilute the filtrate from the precipitated starch with three to foui volumes of water, add an equal volume of alcohol, allow to settle 12 hours, filter, wash with 50% alcohol, and dissolve in a small quantity of water. Reprecipitate the glycogen in the strongly opalescent solution with alcohol, collect on a tared Gooch crucible or filter paper, wash with alcohol, dry at 100°, and weigh. Identification of Raw Horse Flesh by Biological Tests. — Precipitin Test. — This test depends upon the principle developed by Uhlenhuth and others,* that when a rabbit has been inoculated with the blood of a particu- lar animal, as for instance that of the horse, the serum of the rabbit's blood will react with the blood of the horse and with that of no other animal. Only raw flesh responds to the test, as heating destroys the reacting sub- stance. To prepare the serum (antiserum) reagent, inject into a rabbit, either subcutaneously or intravenously, 5 cc. of defibrinated horse blood and repeat the treatment several times allowing intervals of 2 to 5 days between the treatments and increasing the dose up to 10 cc. or more until the serum of the blood drawn from the rabbit shows the proper activity. When of high potency it should react with horse blood serum diluted with 2o,cco parts of 0.85% (physiological) salt solution but ordinarily a lower potency is sufficient. To obtain the serum from the blood, allow a few cubic centi- meters to coagulate spontaneously. If the blood is replaced by 0.85% salt solution the life of the animal may be preserved. Prepare an extract of 50 grams of the finely ground sample, previously shajcen with chloroform or ether if much fat is present, by soaking for 3 hours at room temperature or over night in an ice box with 100 cc. of 0.85% salt solution. Test the filtered extract to determine if it is of the proper dilution (i part albumin per 300 cc.) by heating i cc. with i drop of nitric acid. If a decided turbidity forms in 5 minutes and settles as a precipi- tate it is of suitable strength. Neutralize with 0.1% sodium hydroxide solution if acid. To i cc. of the extract add carefully without mixing 0.1 cc. of the antiserum. Treat in like manner for comparison i cc. * Uhlenhuth, Deutsch. Med. Wochs., 1901, p. 780; Wassermann and Schiitze, Ibid., igo2, p. 483; Schiitze, Ibid., 1902, p. 804; Miessner and Herbst, Arch. wis. prakt. Tierheilk., 1902, p. 359; Wassermann, Zeits. Hyg., 2, 1903, p. 267; Uhlenhuth, Weidanzand Wedemann, Arb. Kaisl. Gsndhtsamt., 1908, p. 449; Gaujoux, Hyg. viande lait, 4, p. 65, 132; Uhlen- huth and Weidanz, Schweiz. Wochs., 48, p. 724. FLESH FOODS. 237 portions of extracts prepared from horse and other meat. If a cloudiness and finally a decided precipitate forms within 30 minutes the presence of horse meat is indicated. For further particulars the reader is referred to the papers given in the it nnfpc foot notes. The preparation of the antiserum, if not the conducting of the actual test, falls properly within the province of the biologist or serologist who has at his command suitable experimental animals and is experienced in judgmg the tolerance of the rabbit for the injections as well as in carrying out other details of serum work. The Compliment Fixation Test is said to be even more delicate than the foregomg. Details of the process are given by Seiffert.* Determination of Sugars.-The small amount of dextrose naturally present m meat and the sucrose added to ham and other salted meats m cunng are best determined by copper reduction. After removal of mterfermg substance by suitable reagents, W. B. Smith f precipitates with picric acid and phosphotungstic acid thus removing proteins, which have a solvent action on cuprous oxide, and creatinine, which reduces FehlinR solution. ^ Smith Method.-BoW 50 grams of the finely-ground sample, as free as possible from fat, with 15c cc of water for 15 to 20 minutes., cool, add i to 5 grams of solid picric acid and 15 to 20 cc. of 20% phosphotungstic acid solution, and make up to 250 cc. exclusive of the fat. Filter through a dry paper and make up 150 cc. of the filtrate to 160 cc. with 8 cc. of concen- trated hydrochloric acid and 2 cc. of water. Mix, filter through a dry paper and without delay determine reducing sugars (as dextrose) in an ali- quot, after neutralizing, by one of the usual methods. To another por tion of the filtrate add concentrated hydrochloric acid sufficient to bring the total amount present up to one-eleventh of the total volume Neutral ize and determine the dextrose by copper reduction. Deduct the amount obtained by direct inversion and calculate as sucrose. ^ HoaglandX precipitates creatinine and other nitrogenous constituents with phosphotungstic acid alone and removes the excess with potassium chloride thus avoiding the possible inversion of sucrose by free hydro- chloric acid and the necessity of neutralizing. * Zeits. Hyg. Infektionskr., 71, 1912, p. 547; Konig, Chemie der Menschlichen Nahrune*- und Genussmittel, 3, i Th., 1914, p. 340; 2 Th., p. 44. ^aUrung*- t Jour. Ind. Eng. Chem., 8, 1916, p. 1024. t Jour. Biol. Chem., 31, 1917, p. 67. 238 FOOD INSPECTION AND ANALYSIS. Detection and Determination of Sulphurous Acid. — Proceed as directed in Chapter XVIII. Traces should be ignored, as slight reactions for sulphurous acid are obtained with meats that have not been chemically preserved. Winton and Bailey * found that in 50 grams of fresh beef, mutton, veal, and pork not more than o.i mg. of sulphur dioxide and no hydrogen sulphide was present, whereas on decomposition as high as 2.1 mgs. of sulphur dioxide and 3.4 mgs. of hydrogen sulphide were developed. From these figures it is evident that the examination for sulphur dioxide should be made only on the fresh meat. Folck and Farreras f use iodate-starch paper for detecting sodium hydrogen sulphite in meat. They prepare the test paper by mixing a care- fully prepared starch paste (2.5 grams of starch to 95 cc. of water), after cooling, with a solution of i gram of sodium iodate and 2.4 grams of citric acid in 5 cc. of water, saturating filter paper with the mixture, and drying in the dark protected from fumes. In applying the test macerate 5 to 15 grams of the meat for 5 minutes with sufificient water to cover, strain, and test the liquid with the iodate-starch paper which becomes blue in the presence of the sulphite. The method compares favorably with the Rosell method depending on the decolorization of 1% potassium perman- ganate solution by the water extract of the meat. Detection of Boric Acid. — Boil 25 grams of the ground material with 50 cc. of water, cool, and filter on a wet paper to remove fat and meat fibers. Test the acidulated aqueous extract with turmeric paper as directed under milk. A more delicate method of procedure consists in burning to an ash a portion of the meat, after treatment with lime water, and testing with turmeric tincture a solution of the ash slightly acidified with hydrochloric acid. Determination of Boric Acid. — See Chapter XVIII. Detection of Benzoic Acid. — Proceed with a portion of the aqueous solution, prepared as above, according to the instructions given in Chapter XVIII or prepare a special solution as follows: La Wall and Bradshaw Method modified by Fischer and Gr^ienert.X — Agitate 50 grams of the finely ground sample for 30 minutes with ico cc. of 50% alcohol acidified with sulphuric acid. Strain through cloth, add * Jour. Amer. Chem. Soc, 29, 1907, p. 1499. t Boll. chim. farm., 53 1914, p. 106. X Zeits. Unters. Nahr. Genussm., 17, 1909, p. 721. FLESH FOODS. 239 sodium hydroxide solution to alkaline reaction, and evaporate on the water-bath until all the alcohol is removed. Make up to 50 cc, add 5 grams of sodium chloride, acidify with sulphuric acid, heat to boiling, cool, and filter. Shake the filtrate with ether in a separatory funnel, wash the ethereal solution with a little water, and evaporate to dryness at a gentle heat. Test the residue as described in Chapter XVIII for both benzoic and salicylic acids. Determination of Benzoic Acid. — Prepare the solution as described in the foregoing method, except that the meat is extracted with several portions of 50% alcohol, dealcoholize in an alkaline solution and proceed accord- ing to the La Wall and Bradshaw method, page 893. Kriiger Method.'^ — Place 50 grams of the ground sample, containing 70 to 75*^0 of water, in a Kjeldahl flask with 45 cc. of 70^0 sulphuric acid. If less than 70^0 or more than 75% of water is present in the sample use less or more of the material and adjust the strength and amount of acid accordingly. Connect with a steam-distillation apparatus and heat cau- tiously with shaking, using an asbestos pad with a round hole cut in the middle to confine the heat to the portion of the flask in contact with the liquid. When the solution becomes clear distil in a current of steam regulating the heating of the flask so that the volume remains constant and a distillate of 500 cc. is obtained in about 75 minutes. Filter the distillate, which must be cool as it flows from the condenser, wash with a little cold water, add sodium hydroxide solution to faint alkaline reaction, evaporate to small volume and transfer to a porcelain dish of ico-cc, capacity. Heat on a boiling water-bath and add in small portions with stirring sufficient cold saturated potassium permanganate solution to form a red color that persists for five minutes. Destroy the excess of permangan- ate with cold saturated sodium sulphite solution and evaporate to about 10 cc. Transfer to a separatory funnel, acidify with i : 3 sulphuric acid, dissolve the precipitate remaining in the dish with small portions of the sodium sulphite solution and dilute acid using the mixture to rinse the dish. Extract the solution, which should not exceed 20 cc. in bulk three times, with an ec^ual volume of a mixture of ether and petroleum ether. Wash the combined extract three times with 3 cc. portions of water, and remove the last traces of water by shaking with the quantity of powdered gum traga- canth that is held on the end of a small knife blade. Transfer to a weighed glass dish, using a mixture of ether and petroleum-ether for rinsing, allow * Zeits. Unters. Niahr. Genussm., 26, 1913, p. 12. 240 FOOD INSPECTION AND ANALYSIS. to evaporate at room temperature, dry 2 hours over soda lime and weigh. As a check dissolve in neutral alcohol and titrate with N/io sodium hydrox- ide using phenolphthalein as indicator. If the weight of benzoic acid is less than 30 mg. the results may be high in which case the benzoic acid is removed by sublimation and the dish reweighed. Detection of Salicylic Acid. — Test a portion of the ether extract, ob- tained as described for benzoic acid, with ferric chloride solution. A deep- violet coloration indicates salicylic acid. Detection of Starch in Sausages, Meat-balls, etc. — The addition of cracker or bread crumbs is best indicated by the presence of considerable starch, which is readily recognized by the iodine test, applied by boiling up a portion of the sample with water, cooling and adding a drop of iodine reagent to the liquid. The characteristic blue color is produced, if starch be present in notable quantity. Traces of starch may be due to the pepper and spices used in seasoning the sausage. A small admix- ture of starch is rendered apparent if a small portion of the sausage is treated with a drop of iodine reagent and viewed under the microscope. A microscopical examination will sometimes reveal the character of the starch, whether it is from cereals or from pepper, but in some preparations the starch is thoroughly cooked and its structure destroyed. Detection of Coloring Matter. — Red Ocher is indicated by an excessive amount of iron in the ash. Cochineal is most readily tested for by the method of Klinger and Bujard.* The sausage, finely divided, is heated with two volumes of a mixture of equal parts of glycerin and water for several hours on the water-bath, the mixture being slightly acidified. The yellow solution is passed through a wet filter, and the coloring matter, if present, is pre- cipitated as a lake by adding alum and ammonia, the precipitate is filtered off and washed, after which it is dissolved in a small amount of tartaric acid, and the concentrated solution; contained in a test-tube, is examined through the spectroscope for the characteristic absorption-bands of carmine lake, lying between b and D. Spaeth t has shown that both carmine (cochineal) and anilin red, which are the dyes most commonly used for coloring sausages, can be most readily extracted therefrom by warming the finely divided material a short time on the water-bath with a 5% solution of sodium sali- cylate. * Zeits. angew. Chem., 1891, p. 515. t Pharm. Central., 38, 1897, p. 884. FLESH FOODS. 241 Vegetable and Coal-tar Colors. — In addition to the solvents named above various others, such as methylated spirits (Allen), acidified alcohol (A. S. Mitchell), amyl alcohol, ether, ammonia, and those used in the exam- ination of fats and oils (Chapter XIII), are useful in special cases. The solvent, after filtering, is evaporated to small volume, acidified with hydro- chloric acid, and white wool is boiled in it. If the wool is distinctly dyed, a coal-tar color is undoubtedly present, and this can often be identified by methods given in Chapter XVII. According to Marpmann, pure normal flesh containing natural color only is completely decolorized by macerating for two hours in 50% alcohol, while artificially colored meat remains colored after this treatment. Richardson * warns against mis- taking for an artificial color the bright red substance often extracted by ether or alcohol and ether from meats cured with saltpeter. Marpmanri's Microscopical M elhods .'\—Mo\ziexi a thin section of the sausage with 50% alcohol, and examine under the microscope. Some colors are readily apparent without further treatment. If only traces of color are present, clarify the substance by treatment with xylol, which is removed by the use of carbon tetrachloride. The mass rendered trans- parent by this treatment is then immersed in cedar oil and examined, the coloring matters, if present, being especially apparent. If the color used is fuchsin (magenta), carmine, logwood, or orchil, the substance of the cell will appear stained. If acid coal-tar dyes are used, the liquid contents of the cell will show the color. Detection of Frozen Meat.— Maljean J detects frozen meat by the aid of a microscope. A drop of the blood or meat juice is pressed out upon a slide and immediately examined before it solidifies. Fresh meat juice contains many red blood corpuscles, floating in a clear colorless serum, and readily apparent. In blood from frozen meat, the red cor- puscles are nearly always completely dissolved in the serum, due to freez- ing, or, if not dissolved, are much distorted and entirely decolorized, the liquid portion being darker than usual. Megascopically, the fresh meat juice is more abundant than that of frozen meat, and its color is deeper. According to C. A. Mitchell, if a small piece of meat once frozen be shaken in a test-tube with water, color is imparted to the water much more quickly than with fresh meat, and the color is deeper. * Allen's Commercial Organic Analysis, Phila., 1914, 8, p. 364. t Zeits. angew. Mikros, 1895, p. 2. X Jour, pharm. chim., 25, 1892, p. 348. 242 FOOD INSPECTION AND ANALYSIS. MEAT EXTRACTS AND SIMILAR PRODUCTS. Meat Extracts. — Methods of Manufacture. — Numerous preparations sold under the name of meat extracts have been on the market for many years. At the beginning of the nineteenth century the value of such extracts was knov^^n, but Liebig was the first some fifty years later to pro- duce a commercial extract of meat. Liebig's preparation, as originally made, consisted of a cold-water extract of chopped lean meat, strained free from fiber, heated, filtered, and evaporated, thus containing little if any gelatin or proteins. Later, however, Liebig advocated the use of warm and even boiling water for extraction, by which method of prep- aration a greater amount of gelatin is brought into solution. He, how- ever, condemned the use of salt. The best modern meat extracts are prepared from meat freed from bone and superfluous fat by treatment with hot or boiling water, the time and temperature of extraction varying greatly with the different processes. While in Argentina, in former times when cattle were plentiful, meat extract was the main product and the extracted residue was considered of little value, at the present time, at least in the United States, the extract is commonly a by-product obtained by evaporating the liquor in which meat has been cooked for canning. The concentration of the liquor is carried on in vacuum kettles to a water content of about 50% for liquid extracts or 18 to 25% for solid or pasty extracts. As corned beef is the most popular canned meat, the liquor in which it is cooked is the chief source of supply. It contains a considerable amount of salt as well as a little saltpeter and sugar, the salt according to Richardson * being removed in sufficient amount by concentrating and centrifuging to comply with the standards as given on page 252. While in certain cases salt is a willful addition, under conditions now existing in the United States, it is more apt to be an impurity which the manufacturer is concerned in removing. Meat extracts are commonly packed in glass or earthern-ware jars. The use of tin containers has been found objectionable because of the blackening of the cans due, according to Beveridge,t to tin sulphide, iron sulphide, and iron oleate. * Allen's Commercial Organic Analysis, Phila., 1914, 8, p. 396. t Third Rep. Com. Physiol. Effects of Fsod, Training and Clothing on the Soldier, London, 1908, 73. FLESH FOODS. 243 Constituents. — The chief constituents are coagulable proteins belonging to the globulin and albumin groups, proteoses (albumoses), meat bases, phosphates, and chlorides. Small amounts of lactic acid, inosite, and other minor constituents of meat soluble in hot water are also present. True peptones are usually either not present or else the test is obscured by interfering substances. According to Micko * although gelatin in small amounts is present in the liquor from which meat extract is pre- pared, the finished product does not contain gelatin as such, but rather in the form of acid glutin or gelatose which respond to the biuret test like gelatin, but do not form a jelly. This change is due to the action of lactic acid during concentration. Adam f reports formic acid in all the samples of extracts and related products examined. He states it is formed by the action of nitric acid on starch used in the process of manufacture. By far the most important constituents from the physiological stand- point are the meat bases to which the preparations owe their well-known stimulating properties. Indeed, a properly prepared extract has very little actual food value, but is rather to be regarded as a stimulant and condiment serving both purposes in an analogous manner to tea and coffee. Creatine and Creatinine, aside from their value as stimulants, are of importance, as was first pointed out by Micko, in distinguishing true meat extracts from yeast extracts, which formerly, if not at the present time, were used as substitutes. These are usually determined together and the results expressed in terms of creatinine (" total creatinine ") after dehydrolyzing the creatine with acid. Carnosine, Carnitine, and Methyl Guanidine, according to Krimberg, occur in meat extracts as well as in the living muscle. The Purine Bases of meat extracts have been exhaustively studied by Micko. I who found hypoxanthine in the largest amount while xanthine and adenine were present in smaller amounts. He was unable to find either guanine, which according to Kossel is present in meat, or carnine which Weidel § reported in American meat extract. The former Micko considers to have been eliminated in the manufacture of the extract while the latter he believes not to be present in either. Carnine and hypo- * Zeits. Unters. Nahr. Genussm., 14, 1907, p. 284. t Arch. Chem. Mikros., 9, 1916, p. 77. t Zeits. Unters. Nahr. Genussm., 6, 1903, p. 781; 8, 1904, p. 225. § Ann. Chem. Pharm., 158, p. 353. 244 FOOD INSPECTION AND ANALYSIS. xanthine are very similar in their reactions and the latter might easily be mistaken for the former although there could be no question of identity if nitrogen were determined, as carnine contains 28.57% and hypoxanthine 41,18%. In yeast extracts Micko found adenine as the chief purine base; guanine, hypoxanthine, and xanthine were also present, the quantities being in the order named, while carnine was not found. Products of Hydrolysis. — By hydrolyzing meat extracts, according to Fischer's method, Micko* obtained glutaminic acid, alanine, leucine, isoleucine, aspartic acid, and glycocol. In addition other amino acids were obtained but in too small quantities for identification. Hydrolysis of the precipitate obtained by salting out with ammonium sulphate showed that it consisted almost entirely of true proteoses and did not contain gelatin. The filtrate from the proteoses yielded on hydrolysis amino acids of which glutaminic acid and glycocol were the most abundant while alanine, leucine, and aspartic acid occurred in smaller amounts. Proline and phenyl- alanine were not found. Taurine not previously reported was isolated and identified. Chlorine in meat extract is usually calculated in terms of sodium chloride, which Richardson f points out is not scientifically accurate, since the chlorine derived from the meat exists chiefly if not wholly as potas- sium chloride. He considers that after allowing 0.06% of sodium chloride for every unit per cent of dry solid matter present any excess may be fairly considered as added salt. Analyses of both solid and liquid meat extracts by Micko,J Bigelow and Cook, § Street, || and Wright,1[ appear on pages 246 to 249. In a number of instances the results have been recalculated or rearranged to facilitate comparison. Meat Juices. — A true meat juice, as prepared by expressing the liquid portion of meat, is a food product of high nutritive value and differs markedly in this respect from liquid extract and similar preparations on the market, some of which have been sold with misleading claims. WTiile it is impracticable to concentrate a meat juice without precipitation or * Zeits. Unters. Nalir. Genussm., 5, 1902, p. 193. t Allen's Commercial Organic Analysis, Phila., 1914, 8, p. 394. J Zeits. Unters. Nahr. Genussm., 5, 1902, p. 193; 20, 1910, p. 537; 26, 1913, p. 321. § U. S. Dept. of Agric, Bur. of Chem., Bui. 114. 1 1 Conn. Agric. Exp. Sta., Rep. 1907-8, p. 606. 1[ Jour. Soc. Chem. Ind., 31, 1912, p. 176. FLESH FOODS. 245 alteration, the name meat juice is perhaps warranted in the case of some of the preparations now on the market, which unlike hquid extracts give strong tests for hemoglobin and contain considerable amounts of coag- ulable nitrogen. In view, however, of the difficulties of accurate classi- fication, juices and fluid extracts are included under the same head in the tables on pages 246 to 248. Peptones and Meat Seasonings. — Certain meat preparations, known in Germany as " Speisewiirzen," are made by digesting in various ways meat, or meat residues after extracting the soluble constituents, so as to obtain the constituents in a " predigested " condition and develop agree- able flavors. These preparations are generally known as " peptones " in English, although this term is in many, if not all, cases inappropriate in view of their composition. Etienne and Delhaye obtained an English patent in 1890 for preparing a " peptone " from meat by heating the pulp in an autoclave from 150 to 175° C, separating the liquid from the insoluble matter, and digesting the latter with hydrochloric acid until the fibers are destroyed. The hquid obtained by the acid treatment, after neutralizing with sodium carbonate, is added to the concentrated aqueous extract. Micko,* in following this process, obtained by the acid treatment of the extracted meat a product with little odor but a decided meaty flavor which appeared to be due to amino acids. He obtained similarly flavored products by the hydrolysis of casein and silk fibroin. Examination of commercial preparations, made by the hydrolysis of protein matter, showed that they contained no coagulable or insoluble proteins, little if any proteoses or peptones, but often considerable amounts of ammonia. The amount of phosphoric acid present depended on the protein material employed but compared with that present in true meat extract was usually greater. Peptones are commonly used in soup prep- arations, often in conjunction with true meat extract, and various vegetable extracts for flavors. Soy sauce, the characteristic seasoning of chop suey, although a vege- table product rich in carbohydrates, resembles in its other constituents seasonings prepared from meat. Like the peptones, it contains only a trace of purine bases and little or no total creatinine. Suzuki, Aso, and Mitarai f separated from two liters of this sauce the following constituents in the quantities (grams) named: alanine 6.6, leucine 6, proline 3, lysine 2.6, *Zeits. Unters. Nahr. Genussm., 26, 1913, p. 322. t Bui. Col. Agr. Tokyo. Imp. Univ., 7, 1907, p. 477. 246 FOOD INSPECTION AND ANALYSIS. •uusoAiQ •ugSooAjQ puB 'UIJJX3Q 'qoiejg < w SS •sjBSng •pBJixg J3n;a •uiqo[3oui3j^ •Biuoiuiuy •sseg auunj •autu^Baj^ •aui^BajQ •auo^daj •asoa^oj^ •afqE[n3B03 •3iqnjosuj ■p^ox •ppV ouoqdsoqj •9uuom3 oj -Ainba apt -jo[q3 uintpbg •qsv l^^ox •J9;BjV^ aao n fto => r*3 C4 o o d o vO rooo »o O O O O W N 00 f^ o o o o o OOOO OOON 1^ m vO O ro o o o d O M I o o o HMOO OOOOOH OOMOOO o o o o o o moo o o o ^ O O Oi O O O l-» N fO M d d o d fO N M M O " d o H d o o 0\0 -^t^ NrOMfOrO'^ OMvOMwO*^rOO»tHCSfO^ 00 0\ ■^ t^oo t^ Tt Tt lO ^ 00 OvvO \0 O (N r^ -^00 sO O c^ oo 0^M^O^O 0Ot~^«Tl-N\0^r^MN0\io rooOO\C >o O ^ t^ H\Or^»>^0\N OOON 0\0 totHOrO*^rOMOs rONt^-^ o) '^ \n t^so ir> lo ro r~ -^00 t^ t ^5 00 . ui t^ tu 3- ofq jHm;q'3mSm>^ci(.20<;pa 3>mOMMmmOw g- S IS m pq S y ctf D "! " i-gse .t:M^ 6b O (U HS ^3 > *1 sS FLESH FOODS. 247 •p3UItUJ3q.3pUf}^ OoOOi-tOsO t-MMMOOiO vO000»Mi-<00'O t-O O O -^vO I- r^ I- Tti^D 00 to M \0 M O O\00 lO N sO C< ro 0\ t^OO I '^•^V^MOHOOOO lOO O 00 M '-''-' "^ f^ '-' '-' I I M -* w r^'^0\0\ MOOOOO OOOOOOO OOOOmoOOOOOOOmonnm CirON'<:i-t-N M(NNMNWl-t Mt-t(NOO-tOO oooooo OOOOOOO oooooooooooooooooo' H O O ft OiOO D o o :> o o' 2> OO ir, CN 3 o d OO 00 ^J M O r-c0OrO[>00 Ot-t^'^wOiH oOTffOoOiOOOt^iOMOOv^ni^OTfMOO tooONroO"^ r^':ft^r^'^ooO\ l-t^OTl■MM^O'^MloO^O^OMli^\o»Ol-lO HNMMHH OOOOOOO HOcqOONt-t«iNOOMO«0000 inwNt^WvO ^000\"^'^M '^00O0r0iOiOMl>OC^tomr00»O^0 vOOOt^Ooo fOMMO»0'^ro OO 0»^ O m m i> -<^vO tHQ'-'OO'O'^Nio wNNOt-tO OOOOOOO NwwOOrOHMMMHOOOOOOO M o»oo On "^O '^'O ro O r- m 00 roM Ov'Tim mtohh Cn"^!-" w m n o\oo i^ro COMTJ-Nroo O-^Oni-HfOO fOoroooroiorOC^ooOsrO NOO\0\in'^i-- rOTtu^u-jiociM vO "^00 O h sO t^ lO-O mmhitJ-mlomoO TtOiOO\'-'oO \0<^'0'^0'-'(S •i-i\Or^fOC^r*^0'^>'l'rft^QOON -msOih Oi^-ONt^O^ OWO\OOi-iooO •O'^rOO 0\M3 "^Tj-or^OONfO -lOiOO MMTtNoiN Mro(NMNOO •WNOOmOOwOOOOO -OOm '" m M Ot -^00 M O '^ »OsO 00 '^foO .iy^rtwMi>iOO\0 "tTOO tTlO Tf ■ Ov O M fOsO -^MMN NO'^'^fOwM -MrOMO-^Ni-itHOOOOO -OW"^ OOOOOO OOOOOOO 'OOOOOOOiHOOOOO -OOO 0\0»orOC\0\ Nr-i-iOvoOiOO 0O0Q0'^0\00O\r00\NO^f0CJ0i')f0 MTtlOlOOOH fOO\HMrot-P<0 »>^C0 O fO ro "^ -^00 O lOMTtrou^d Mt^t-O'^roO t-t^roOOcir>-ror-0'-«ci ino m co "^ tJ- 00 (^lOOO ro fO 00*0 w r-oO M O OvOO OOOOiOOv'^'^MOOt^t-ioOMfOO M M M l-l M 0» (N M IH \0 rOsO woooO rOHHOMQ^fOiO lOOsn rfoo iriC\0 fOiOtOiO'^MvO i-i t^ro 00'=tC^C^ t~* ^ O ^ro fOr~ t^vO fOO 00 M 0\ O OOO 01 o O lOO O O -^ fO to OOiroroi-iiooooOMOrOOt-Ot^olrfro ^B3j\i J3q;o M N M 01 N N M W M H H O O MHOlOOMOOMOOOMroOOOO •asBg auun^j 00 1~0 ^ M l« 0) ro o O " 't "^ n-o 01 i>- Tt o\oo 01 01 01 H o O O rOO lOUHHO^Mccooro-^ro^OOMOlTf hmOOOOIOmOOOOOmmoOO OOOOOO OOOOOOO ooooooooooooooo o o o •suiuuBaj^ 00 M t^ OOO 0) 00 vO ti^oo OOO to 01 ro Tfoo i« (N OMcoMoioiioo •ot^o^^^-lJ^oo 'tioiOMO'tOM -OmOOOhO . . puB auiiBajQ d w d M d H OOOOOOO OOOOOOOO •OOOOOOO'^'-^ •asEg -O M lO O ro M woo O 01 ^0) O 01 ^ oi roo 00 o a o> oo fo o> 01 roO fO oi >3- 0^ ^ lO O t^oo t^ r- M ro In Oi 0)O\Oitoiw000iMO>«O00MO^^rO iB3H IB^OX CO f*) ro rO fO ^ H H M 0< 01 M O Mt-toloOOlOMMOOOMOOMOOO •(t^Se -d S3S) ,,3U0ld3jJ„ •gsoa^ojjj •ajq'BingBOQ puB aiqn|osuj •i«;ox PPY oi^oBq sy •Ul3 J9Cl -00 'apixojpAfj mnipog oi/jsi ■ppv ouoiidsoq^ oiubSjouj •poy atJoqd -sbq^j 6iub3jo •pioy oijoqd "-soq j p^ox •auiJOjqQ o:j •Ainbg api -jO[q'3 uinip"bg •qsy Ib;ox ■ja^jBAV >P^ o ^ - m C <" .^ ^ ca-o C-, 3j2t; o ^^ c OT3 0) -. rt « CS 2 "J — t; 3r2 .Hex cm 3.„ ■> ° 0) m ■ 4-> ,„,2; Q, », ^"dfL, > o S^v, O 5eqpq2;- Mj^ c-2 (u.s •gEog^^ogge-s 248 FOOD INSPECTION AND ANALYSIS. OOOOOOOOOOO OOOOOOOOOOOOOO OOfOOoO •■Biuouiuiy ddddodooooo i'-O'O 1^00 o>oo f^ trjQoooo d '^vo o ^so oodooooddooooo o o o I o o o o o •sstg Ov N IT) Tj- HI •<:]- r^vO ro M w fO M N On 00 d ^BOJM jsqio OwwwOi-ii-iwOOW OOmOOOwhhoOOmw 0000 •ssBQ auunj 00 N rt f*^QO O 00 O fOOO -^ rnO ■* lO ■"t r- ro ^ -a- rOvO ^0 M t^ 1/5 t^ Tj-sO 10 N 00 vO r^O MrorOOrOMroOHiMMNrOM to 10 r«5 tt Tf 00000 'J OOOOOOOOOOO OOOOOOOOOOOOOO 0000 •guiui^BSjQ \r3\0 w Tj-vOvO Tt N vO »^\0 vO roo 0. Ovoo HWOaONNoo M'*-*HrfNinOOW a. 0^ 1/5 rOOO •* rooo ^ 0.0 r^ ^00 vO r<5 IN H 00 NO asBg ■i'eayi NfONrOW-^NWNMfO OMHHHMMHMMOHWH 0000 W •;dd t^ N 00 O^O 1/5 1^ M Oi O^ M TtOrOO<^Of^NNi-iroiJ^O>o NO t/5 1000 ro -^00 00 0\ -^00 On OnoO -0 •J100 o> -l M 00' ^JBS-UIUUBX rTO00Nt^Oi -MIS^O HMOOHO .HNfOH 00-OvOON^OOrOOOO>/lN mONOOnmmOihOOOOih vO M 00^0 NO 000000 -OOOO OOOOOOOOOOOOOO H 00 10 t^ t^ 0\^0 I-" N Ttoo -^ 'i- 00 •-• o, ( •I^^OX W O -^ t-i ro rf r^ 00 1 000 000 r^c>t^»rii \0 OOOQO ■^000 O ro»0 t^ O O O ro t^ -rj-oo O 0> t^ O r- Tf to 10 ro 00 N o c ^ HH M Oi u ^ 3 •snuiiiq lO'^OOOOO'^t-NOOOO-* 1/51/51/^^ POoo ro ^ »/5 "^ r^ NO MOO w M 000 fOMoo.roNO rot^ M-^rOMfOWfOWNHfOfO'^'^ fO-^OO W fO O O O w « •ulaiBmqd -jouaqj OOO'^fOMt^ONO^^/^tO WHOOONt-MOOOOt^lON ■^wnO O N 000 fOt^^t^O* OnnO «nO\0 fOV^fOl/i^fOrO'i- 1/5NO nO ^ O M 1^ M O w M mnO ►J Z < W td H •qsB^Od NO 00 "^00 10 t^ lOsO NQror^ wio^J^Mrot-iTl-wroHiCNjroio^ OOi •ppv ouoqdsoqj Ov Tt 10 10 1/5 - N ^ ■* ■* O wrt-x iiorOfONiorOMtHwfO N H M O H I i -^O ^•"t d d H H •auiJOiqQ o; •Ainbg apt -joiqQ uinip'og t^vO -^ M w^ ro fOoo C^ w O O 1/^ -rl- r^ w -^00 OnOO I H O M O O •qsy [Biox Onw rft^co r^-^O noo i/> l>^00 u^ to 10 ^ l~- ro 1/5 rf N I PO rf O On ro t^ ( •j3;BjVi. ro O tH i> M N 10 r^oo <:> CO »j:i r^oo 52:3 o_w^ s'e 3 3 O H H 3 S'.S >S-C-C dSo 1 g.2 °^JS g'&'o &£ E o 0.-21^^ w-S rt O 5 c-:^^ 01 K o 6h FLESH FOODS. 249 o N ro lO w lO •IDBJlxg: J3q;a •* ro •o o t^ t^ w O o -A[OJ puE 00 o lO \0 r^ i^ 2 35(Il-3UOld3j; o " " « M M 00 o M N Ol Tl- •asos^oaj -t ro 00 vO 00 00 N N " W Ht M „ O »o t^ r^ r^ •afq-BinSBOQ " o o o o o o o o o o o o 00 00 o o •9iqniosuj ". ^1 •^ " ". ". o o o o o o r^ N r^ M 00 Irt ib;ox 00 ", •* fO 00 o 00 00 CO 00 t^ 00 o o o o o o ■ppv vO l-t N o o\ >o 01 ^oBq SB A^ippv M n n; MO" o o vO N 't N •qsB;oLESH FOODS. - 263 Canned Fish. — Modern methods of canning are particularly valu- able in the fish industry owing to the perishable nature of the product and often the remoteness of the supply. With us salmon, tunny, and lobster are the best known varieties preserved by simple canning, while sardines and herring are the most popular fish treated by salting, smoking, or the addition of oil, spices, and various condiments previous to canning. While the packing of decomposed fish, spoilage due to imperfect sterilization, and the substitution of inferior varieties have not been un- common, the detection of these irregularities or defects, now fortunately infrequent, falls to the bacteriologist or zoologist; the examination for foreign oils and tin, however, is a frequent duty of the chemist. Olive oil is used in packing the best grade of French and Norwegian sardines, but cotton seed oil is commonly substituted in the preparation of the cheaper American product, the nature of the oil being distinctly stated on the label, thus complying with the requirements of food laws. Tin^ in the form of salts dissolved from the can, is still a matter of concern, although packers have made serious effort to reduce the amount by using lacquered cans and paper or veneer linings. In samples of sardines put up in mustard, vinegar, and oil, the Massachusetts Board, has found as high as 0.376 gram of tin in a half-pound can, the corrosion of the can being very marked. Crustaceans, because of their content of free amino compounds, act with special avidity on tin. Bigelow and Bacon * found that monomethylamin in canned shrimps attacks the can as do free amino acids in certain vegetables. The United States Government, pending further investigation, has allowed 0.300 gram of tin per kilo in canned fish, as well as in canned meats, vegetables, and fruits (F. I. D. 126). The unavoidable amount of tin present, however objectionable, is more than offset by the advan- tages of the canning system. For the detection of tin see Chapter XXL Salted and Smoked Fish. — Preservation by drying, salting, or smoking as well as a combination of two or all of these methods, is as ancient as canning is modern. While it is of first importance that the fish is true to name, sound when packed, and kept sound by proper handling, the chemist is chiefly concerned with the examination for colors and preser- atives as noted on page 265. Jour. Ind. Eng. Chem., 3, 191 1, p. 832. 264 FOOD INSPECTION AND ANALYSIS. Floating of Shellfish. — Oysters and other shellfish, either in the shell, or, more commonly, after shucking, are often subjected to " floating " or " drinking " in fresh or brackish water or else shipped in direct con- tact with lumps of ice. Both practices cause the shellfish to greatly increase in size, owing to the absorption of an undue amount of water, and if not labelled " floated " the product is adulterated under the federal law and the laws of certain states. It is, however, not regarded as improper to drink oysters in water of a saline content equal to that in which they will grow to maturity or to wash the shucked oysters in unpolluted, cold or iced water for the mini- mum time required for cleaning and chilling. After washing they should be drained and packed for shipment in tight receptacles surrounded by ice but protected from the absorption of the water resulting from the melting of the ice. Nelson advocates the floating of oysters in clean water with a lower salt content than that of the beds because (i) dirt is eliminated, (2) the volume of flesh is increased, (3) a better color and texture are secured, (4) shrinkage is decreased, and (5) the water content during transporta- tion and storage is retained. Often shellfish is polluted by growing or floating in impure water, handling under insanitary conditions, or packing in unclean receptacles. As oysters cannot reach the consumer in satisfactory condition it shipped in their own liquor, the loss of food constituents on draming comes up for consideration. Baylac * reports in a liter of the liquor about 2 grams of albumin as well as determinable amounts of urea, ammonium salts, and inorganic matter. The amount of organic matter in the liquor from Mediterranean oysters is greater than in that of oysters from the ocean. Scallops. — According to the Maine Experiment Station, f scallops properly handled should contain not less than 20% of dry matter. The following is a summary of analyses of soaked and unsoaked scallops by Sullivan,J the swelling of the meats being sufficient in some cases to make 4^ gallons fill a 7-gallon keg: * Comp. rend. soc. biol., 62, 1907, p. 250. t Offic- Insp., 55, 1913, p. 149. X Amer. Food Jour., 10, 1915, p. 472. FLESH FOODS. 265 Unsoaked (31 Samples). Soaked (12 Samples). Max. Mm. Aver. Max. Min. Aver. Solids Protein Ash 24.17 15.69 1. 81 19. 21 12.62 1-33 22.48 14-38 1.56 19.64 11.80 I. 17 14.18 9.06 0.93 16. 20 10.57 1.02 Clams. — At the Maine Station it was found that the drained meats of clams, which contained when opened 24.990 of sohd matter, took up on soaking over night in salt water sufi&cient liquid to reduce the percentage of dry matter to 15.3. While it is recognized that clams will not keep in their own liquor, it is insisted that they be rinsed not longer than i minute in cold water or else 2 minutes in hot water, followed by 2 minutes in cold water. Preservatives in Fish and Oysters. — Boric acid and borax in mixturfe and sodium benzoate form the most common preservatives of salt dried fish and of oysters. In the case of salt codfish, the preservative is sprinkled on the surface.* Such surface application is allowed under the laws of some states, as for example, Massachusetts, and under the federal law, provided directions for the removal of the preservative are given on the package. In opened oysters sold in casks and kegs, boric mixture has been used commonly in solution in the oyster liquor, but is now infre- quent. Ishida t calls attention to the presence of a trace of formalde- hyde in fresh crab meat and distinct amounts after being preserved 8 months. Artificial Colors of the coal-tar group are used to give smoked fish a rich brown color. The New York City Board of Health has brought to notice the coloring of cheaper fish in imitation of salmon. Methods of Analysis. — These are similar to the methods given for meat. CONCENTRATED FOODS. Under the name of " condensed " or " concentrated foods " or *' emer- gency rations " a number of canned preparations are sold for the use of campers, travelers, armies in the field, etc. These consist usually of mixtures of dried ground meats and vegetables, pressed together in com- pact form, and preserved in tin cans. The claims made for the food value of these preparations are, as a rule, extravagant and erroneous, as shown * Bitting, U. S. Dept. of Agric, Bur. of Chem., Bui. 133, 1911. t Jour. Pharm. Soc. Japan, 422, 1917, p. 300. 266 FOOD INSPECTION AND ANALYSIS. by Woods and Merrill,* who give the following analyses of some of these foods: ' Net Weight Con- tents. Weight of Materials in Package. Water. Pro- teins Fat. Carbo- ] hy- Ash. drates. Total Fuel Value. Ration cartridge, pea, beef, etc Blue ration campaigning food, a... " b.. Red ration campaigning food, a " '' " b.... Ration cartridge, potatoes, beef, etc Emergency ration, a "6 Emergency ration, a " b Nao meat food Army rations Standard emergency ration " " "a " b , Arctic food • Tanty emergency ration F-A Food Company 's stew Grams, 241 i6g 78 122 77 283 120 113 121 127 437 661 418 270 49 423 475 964 Grams. Grams. 34-2 52-9 70-1 37-5 1.0 ^-6 33-8 26.2 1.2 5-0 117.9 62.3 14.2 56.1 1.9 8.2 4-5 71.8 5-7 8-3 231-3 56.9 420.2 101.2 23.6 129.6 17.0 50.6 o-S 3-2 30-7 75-1 313-5 60.2 638.0 149.2 Grams. 42.0 9.0 23.1 18.5 23.0 12.6 29.6 32-7 32.6 15-3 90.1 84-3 90-5 54. « 10. 5 167.3 .6 "4-5 Grams. Grams. 98.0 13-9 37-9 8-5 46.9 1-4 37-8 5-7 46.6 1.2 76.4 13-8 II. 9 7-8 68.0 2.2 6-7 5-4 94-8 2.9 46.2 12.5 47-9 7-4 160.3 14.0 137-0 10.6 34-0 0.8 119. S 30.1 41.9 10.8 52-5 9.8 Gals. 1071 432 436 496 424 772 617 622 776 588 1328 1542 2198 1402 254 2430 1482 2460 * Maine Exp. Sta., Bui. 75, p. 103. CHAPTER DC. EGGS. Nature and Structure. — Though eggs of \'arious birds are used to some extent as food, it is the egg of the hen that is in universal use for this purpose, and therefore the one which is here for the most part dis- cussed, bearing in mind that the structure and composition of all varieties of birds' eggs are closely analogous. Fig. 60 shows the longitudinal section of a hen's egg. J i g I Fig. 60.— Longitudinal Section of a Hen's Egg. a, Shell; b, Double Membrane of Shell; c, Air-chamber; d, Outer, or Fluid Albuminous Layer; e, Thick, Middle Albuminous Layer; /, Inner Albuminous Layer; g, Membrane of the Chalaza; hh, the Chalaza; i, Vitelline Membrane; j, Germ; k, Yolk; I, Latebra. (After Mace.) Weight of Eggs. — The average weights of whole and parts of hens' eggs, as given by Langworthy * and Serono and Palazzi f (the latter for 1000 eggs), are as follows: Langworthy, grams. Serono and Palazzi, grams. Shell 6 18 7 32 19 White Yolk Total 57 S8 * U. S. Dept. Agric, Farmers' Bui. 128, 1901. t Arch. farm, sper., 11, p. 553. 267 268 FOOD INSPECTION AND ANALYSIS. The data given in the following table were obtained by Woods and Merrill:* AVERAGE WEIGHTS OF EGGS AND PARTS AS PREPARED FOR ANALYSIS. Weight as Received. Weight Boiled. Shell (Reiuse). White. Shell (Refuse). White. Yolk. Total. 1 Yolk. Turkey Goose Duck Guinea fowl. . . Grams. 105-5 190.4 70 6 40.2 Grams. II. 7 24.1 7-2 5-6 Grams. 60.1 98-5 36.5 20.9 Grams. 30-9 64.8 24.4 12.5 Grams. 102.7 187.4 68.1 39-0 Per Cent. 11. 4 12. 5 10.6 14.4 Per Cent. 56-5 52.6 53-6 53.6 Per Cent 30-1 34.6 35-8 32.C 'Shrinkage due to loss in preparation and cooking. Proximate Composition. — In the following table appear analyses by Woods and Merrill of the samples described above, also the average of analyses of hens' eggs taken from Atwater and Bryant's Compilation: COMPOSITION OF EGGS. Turkey- Goose — Duck- white yolk entire edible portion.. as purchased white. , yolk entire edible portion.. as purchased white yolk entire edible portion.. as purchased Guinea fowl — white yolk entire edible portion,. as purchased white yolk entire edible portion.. as purchased Hen— ss 13-8 14.2 ^2>-7 iti.g Protein. go .■sx 1-5 7-4 3-4 1.6 1.6 7-3 3-8 i-S I.I 6.8 i-Z 1-5 1.6 6.7 3-5 5 « 12.5 17.6 14.2 12.2 12.9 18.4 15-1 12.9 12.2 16.8 14.0 12. 1 12.6 17-3 14-3 II. 9 13.0 16. 1 14.8 I3-I Trace 32:5> II. 2 9-7 Trace 36.2 14.4 12.3 Trace 36.2 14-S 12.5 Trace 31-8 12.0 9-9 0.2 33-3 10-5 9-3 0.8 1.2 0.9 0.8 0.8 1-3 i.o 0.9 0.8 o.» 1.2 0.9 0.7 0.6 1. 1 1.0 0.9 §9 .2 o > u _ V a) Q, 3 Cal. 325 1875 850 735 330 1975 985 860 315 1980 985 880 325 1800 875 730 250 1705 720 635 * Maine E.xp. Sta., Bui. 75, 1901. EGGS. 269 Ash. — The mineral content of the egg is thus shown by Konig: COMPOSITION OF THE ASH OF EGGS. Ash of the Dry Sub- stance. Potash. Soda. Lime. Mag- nesia. Iron Oxide. Phos- phoric Acid. Sul- phuric Acid. Silica. Chlo- rine. Hen's egg: entire, white . yolk . . 3-48 4.61 2.91 17-37 31-41 9-29 22.87 31-57 5-87 10.91 2.78 13-04 I. 14 2.79 2.13 0-39 0.57 i-6s 37.62 4.41 65.46 0.32 2.12 0.31 1.06 0.86 8.98 28.82 1-95 Egg Shell, according to Konig, has the following composition: Calcium carbonate 89 .0-97% Magnesium carbonate o .0- 2% Calcium and magnesium phosphate o • 5~ 5% Organic substances 2 .0- 5% Egg Membrane, the skin covering the white, consists chiefly of a protein of the keratin group. White of Egg is an albuminous fluid without cellular structure. It has a specific gravity of 1.038-1.045, contains 12-18% of solids, and is always alkaline in reaction. When fresh the alkalinity is slight, but during ageing increases markedly, owing to the formation of ammonia. Determinations of ammonia are accordingly valuable in detecting deteri- oration. A blue color forms in the portion of the white adjacent to the yolk on boiling; this is due to iron sulphide formed by the action of hydro- gen sulphide, liberated from the white, on iron of the yolk. The well- known blackening of silver by eggs is due to silver sulphide formed in a similar manner. The average composition of the white of hens' eggs is as follows: Water 86.2% Fat, lecithin, cholesterol, etc traces Protein 12.7% Dextrose o-5% Ash 0.6% 100 .0% Fats, Lecithin, and Cholesterol are present only in negligible quantities. 270 FOOD INSPECTION AND ANALYSIS. Proteins. — According to Osborne and Campbell * the proteins of the white of egg are four in number: ovalbumin, conalbumin, ovomucin, and ovomucoid. No sharp and distinct separation of these bodies has yet been made. Ovalbumin is a crystallizable protein and forms with conalbumin the largest portion of the protein of the egg white. In a 2.5% solution in water, the ovalbumin starts to coagulate at 60° and yields a dense coagulum at 64°. Stronger solutions require a somewhat higher temperature for coagulation. Conalbumin bears a close resemblance to ovalbumin, but is not crys- talline, coagulates at a lower temperature (below 60°), and the coagulum is more flocculent. Ovomucin is a globulin-like substance, precipitated from egg white by dilution with water. When dried and washed with alcohol it is a light, white powder soluble in strong sodium chloride solution. Some authors consider it as a part of " ovoglobulin " which is precipitated completely by saturation with magnesium sulphate, or half saturation with ammonium sulphate. Ovomucoid is not coagulable by heat and may be separated (imperfectly) from the filtrate from the coagulable proteins. It is precipitated by alco- hol and saturation with ammonium sulphate, but not by half saturation or by any proportion of sodium chloride, sodium sulphate, or magnesium sulphate. Carbohydrates. — Kojo f reports 0.55% and Morner | 0.3-0.5% of dextrose. Diamare § suggests that the sugar is not present as such, at least at the outstart, but is formed by the action of an amylolytic enzyme. Ash is present to the extent of 0.04-0.07% and consists, as shown by the analyses on page 269, chiefly of alkali chlorides. Egg Yolk. — This contains over 50% of solids or about four times that of the white and is also much more complex in composition. In addition to proteins it contains large amounts of fat, lecithin, and other phospho- lipins, also glucolipins, cholesterol, lutein (a lipochrome), hematogen (a nuclein ?), salts, and other constituents. Because of the complex composition of egg yolk which is as yet im- * Jour. Amer. Chem. Soc, 22, iqcxj, p. 422. t Zeits. physiol. Chem , 75, 191 1, p. i. X Ibid., 80, p. 430. § Chem. Zentbl., i, 1910, p. 1732. EGGS. 271 perfectly understood, an accurate statement of composition is impossible. The following is based on the data at present available: Water 49 . 5 % Fat 18.0% Lecithin and other phospholipins 11 .0% Protein (ovovitellin, etc.) 14 -5% Dextrose o-3% Lutein, cholesterol, hematogen, cerasin (?), etc. . . . 5.7% Ash 1.0% 100.0% The Fat of egg yolk, extracted in various v^^ays, has been studied by several investigators, but their results are far from comparable. Pennington * first dried the yolk by extraction for 2 days with abso- lute alcohol, evaporated the extract to dryness, and added the residue to the portion insoluble in the alcohol; she then ground the mass and extracted the fat for 2 days with petroleum ether (b. pt. 60° C). Spaeth f and also Kitt,{ secured the fat by extracting the dried egg yolk with ether, while Palladino and Toso § expressed it from the yolk after boiling. The constants of the fat obtained by the authors named, also Serono and Palazzi,|| follow: Analysts. > . cao • eg- > "> Pi a .s si t-H l| ca 'S . < u C 3 ■Sz; u E 3 !H '0 < Serono and Palazzi. Pennington Spaeth Kitt Paladino and Toso . 9121 o!88i* 0.9144 0.91S6I: 1.4627 1.4713 9° 23° 82.3 62.8 68. 5t 72.1 81.4 198.9 179.9 184.4 190.2 185.8 0V7 0.4 3.82 76^1 95.2 206 195 37° 36° 35° * At 100.° t Of fatty acids 72.6. X At 20°. Lecithin (C42H84NPO9) is a characteristic constituent of egg yolk especially useful in detecting the presence and approximate amount of eggs in alimentary paste. * Jour. Biol. Chem., 7, 1910, p. 109. t Zeits. Nahr. Unters. Hyg., 10, 1896, p. 171. X Chem. Ztg., 21, 1897, p. 303. § Gior. pharm. chim.; abs. Jour, pharm. chim., 6, i{ II Arch. farm, sper., 11, p. 553. ), p. 247. 272 FOOD INSPECTION AND ANALYSIS. Lutein (C40H56O2), the chief coloring matter of egg yolk, has the same empirical formula as xanthophyl and carotin, but has a lower melting point than xanthophyl and is more soluble in alcohol than carotin. Cholesterol (C27H44O) is present, according to Berg and Angerhaucen,* in amounts equivalent to about 1.40% in hens' and duck eggs. Ovovitellin, the characteristic phosphoprotein of eggs, has been studied by Osborne and Campbell, who believe the substance as ordinarily isolated to be a mixture of compounds of true vitellin and lecithin. Hematogen has been isolated by Bunge,t who believes it to be the mother substance of hemaglobin. It is similar to the nucleins and con- tains sulphur, phosphorus, and iron. Sugar. — A small amount of dextrose is present in egg yolk. Grades of Eggs. — Various systems of sorting are in vogue in dif- ferent regions, but the following classification appears to be most common : 1. Extras. — Eggs of good size and uniform color, free from all defects. 2. Firsts. — Same as extras, but not of uniform color. 3. Seconds. — Small, dirty, checked, " weak " (with thin whites), and " leaker " eggs. 4. " 5/>o/5." — showing on candling dark areas due to mold or de- veloping embryo (" blood rings "). 5. " Rots." — Opaque on candling and offensive in odor on opening. In addition the following are distinguished: Green Eggs with a green- ish color in the white. Musty Eggs with a characteristic disagreeable taste, and Sour Eggs, with a sour taste. Preservation of Eggs. — Owing to the porous nature of the shell, the moisture of the contents gradually grows less by evaporation, and the egg loses in weight. Air also passes in through the shell pores, carrying various microbes, which result in ultimate decomposition and spoiling of the egg. Nature has provided the shell with a thin surface coating of mucilaginous matter, which, however, is easily washed off. This coating tends to partially close the pores, and for best results in keeping should not be removed by washing. Eggs are commonly preserved by protecting them as far as possible from the air. This is accomplished in a variety of ways, the most common being to pack the eggs in salt or bran, so that the packing medium fills up the interstices between the eggs. Eggs thus packed will keep con- siderably longer than when exposed to the air. A solution of salt is some- * Zeits. Unters. Nahr. Genussm., 29, 1915, p. 9. t Jour. Chem. Soc, 93-94, p. 1500. EGGS. 273 times employed, and also lime water, the eggs being simply packed in the solution. The use of lime water is, however, open to the serious objec- tion that a disagreeable odor and taste are imparted to the eggs. Eggs are sometimes coated with gelatin, vaseline, wax, or gum, so as to cover them with an impervious layer, either by dipping them in the coat- ing medium, or by varnishing or otherwise applying the substance to the egg shell. By far the most efficacious egg coating has been shown by experiments in the North Dakota Experiment Station,* and also in Ger- many, to be sodium and potassium silicate, or water glass. The fresh eggs, preferably unwashed, are packed in a jar, and a solution of water glass (i part of syrupy water glass to 9 parts of boiled water) is poured over them. According to the North Dakota experiments, at the end of three and a half months, eggs packed in this manner the first of August appeared to be perfectly fresh. One drawback to this method is that eggs so treated break more easily on boiling, but this may be prevented by carefully piercing the shell with a strong needle. Cadet de Vanx has proposed immersing the egg in boiling water for twenty seconds, the result being that a very thin layer of the egg-white next the shell becomes coagulated, thus forming an impervious coating inside the shell. Cold-storage Eggs. — The preservation of eggs by storage at low tem- peratures has become an enormous industry. The temperature employed differs somewhat, but a little below the freezing-point of water ( — 1° to — 2° C.) gives the best results. The length of storage varies usually from one to ten months. Experiments conducted by Wiley,t under authorization from Con- gress, brought out certain points as to the physical and chemical changes found to take place during cold storage. After breaking the shell and keeping atroom temperature one day, the odor of eggs stored for 3.5 months was different from that of fresh eggs, but was not disagreeable. This odor increased on longer storage, and after 12.6 months became very characteristic. After 16.6 months, a musty odor was noticed immediately after opening the egg. Chemical analysis by Cook showed that eggs in storage for one year lost 10% of the total weight, due to evaporation of water from the whites. * Farmer's Bui. 103, U. S. Dept. of Agric, p. 18. t U. S. Dept. of Agric, 'Bur. of Chem., Bui. 115. 274 FOOD INSPECTION AND ANALYSIS. Storage also caused a lowering of the amount of coagulable protein and of lecithin phosphorus, but an increase in lower nitrogen bodies, pro- teoses, and peptones. The acid reaction of yolks diminished during storage. Microscopical examination by Howard and Read brought to light occasional rosette crystals in the yolk of eggs stored for 12 months or longer, but the nature of these crystals and their diagnostic value do not appear to have been established. Spoilage of Eggs. — Pennington * and her co-workers have found an average of 2 and 6 organisms per gram respectively in the white and yolk of strictly iresh eggs when incubated at 37° C, and 7 and 9 organisms per gram when incubated at 20° C. The average percentage of ammo- niacal nitrogen in the whole egg was 0.0013. Resistance to spoilage appears to be greatest in the Spring when the moisture content is least and least in August and September when the moisture content is greatest. On keeping both the bacterial count and the per cent of ammoniacal nitrogen increase, but the latter to a much lesser degree than the former. The authors state that for certain constituents at least the count must approach ioc,coo,ooo per gram before chemical methods for the detection of bacterial activity are of value. Seconds, including medium stale, hatch spots, heavy rollers, dirties, checks, and eggs with yolks partially mixed with the white, opened aseptically, contained less than 1000 organisms per gram, while 26.5% of eggs with adhering yolks, 50% with dead embryos, 75.9% of moldy eggs, 66.7% of white rots, and 100% of black rots contained over loco per gram. With the exception of rots few contained B. coli. Firsts opened commercially in July had low counts and the same was true of most clean-shelled seconds, only 8.3% containing over 1,000,000 organisms per gram, while 16.6% of the dirties, 18.8% of the checks, and 20% of the eggs with yolk partially mixed with the white exceeded that limit. B. coli ranged up to ico,coo per gram being no greater in the last named grades than in clean-shelled seconds. Market seconds in the producing sections during Summer averaged 0.0017-0.0022% of ammo- niacal nitrogen, while other grades better than white rots varied up to 0.0030% or more. Houghton and Weber f obtained the following percentages of am- moniacal nitrogen calculated to the dry substance of the liquid egg: * U. S. Dept. of Agric, Bui. 51, 1914 and 224, 1916. Bur. of Chem. Circ, 98, 1912. t Biochem. Bui. 3, 1914, 447. EGGS. 275 Folin Folin Titration Nesslerization Method. Method. Seconds 0.0114% 0.0124% Spots 0.0141% 0.0200% Light rots 0.0173% 0-0215% Rots o .0262% o .0299% Black rots o . 1696% o . 1486% The authors also found Klein's modification of the Van Slyke method useful in detecting blood rings, spots and light rots, and the acidity of the fat in detecting spots and lower grades, FROZEN EGGS. In the handling of eggs many become cracked or otherwise injured to an extent which renders them unfit for transportation. These are either sold to bakers for immediate use, or else opened and kept from spoiling by freezing, or drying. The portions of " spot eggs " that do not show evidence of damage are also treated by one of these methods, but together with white rots are now legitimately sold only for tanning certain kinds of leather. Pennington and co-workers found that frozen eggs having less than 5,000,000 bacteria and less than 100,000 B. coli per gram, and with less than 0.0024% of ammoniacal nitrogen on the wet basis (0.0087% dry basis) can be made from most of the regular breaking stock. The preservatives formerly much employed in opened eggs are boric acid and formaldehyde. The latter is especially effective as an egg pre- servative. If a small quantity be added and stirred into opened eggs that have become absolutely putrid, the result is astonishing. The product is completely deodorized, and exhibits the outward appearance at least of fresh eggs. Formaldehyde, if present, may readily be detected by heating some of the egg directly with the hydrochloric-acid ferric-chloride reagent used in testing milk for formaldehyde, carrying out the process exactly as in the case of milk. 276 FOOD INSPECTION AND ANALYSIS. DESICCATED EGGS. This product is placed on the market as a coarse orange-yellow powder. It is particularly valuable because of its concentrated form and excellent keeping qualities without storing at freezing temperatures. Preparation of Desiccated Eggs. — Breaking stock suitable for freezing may be preserved by drying, using the same precautions as to cleanliness in opening and handling. Bailey * who is located in one of the principal breaking sections (Kansas) states that the drying is carried out by spreading over cylinders or belts which move in a current of warm air or by heating in a vacuum. In some processes the drying is finished in wire baskets. The temper- ature is kept below 120° F. (49° C.) to prevent coagulation of the albumin. Salt or sugar are sometimes added to aid in preservation. If properly prepared the powder mixes readily with water, assuming much the same form as before drying. Composition.— The following are analyses of two samples one (A) made by the Bureau of Chemistry, the other (B) by the Massachusetts State Board of Health : A. B. Water 6.80 5.95 Protein (NX 6.25) 45-20 48.15 Protein by difference 5 1 - 20 Fat 38.5 40.56 Ash 3.5 5.34 Inspection. — Pennington states that the percentage of ammoniacal nitrogen is not a reliable index of the quality of the stock, owing to the volatilization of more or less of this constituent during desiccation. As in the case of frozen eggs, factory inspection is desirable, particularly as the drying is not carried out at a sterilizing temperature. f ANALYSIS OF EGGS. Physical Examination of Eggs. — Various physical tests, based on the gradual increase in size of the air chamber (Fig. 60), have been pre- scribed for ascertaining the approximate age of an egg. Thus, accord- * Source, Chemistry, and Use of Food Products, Phila., 1914, p. 438. t See Maurer, Kan. Agric. Exp. Sta., Bui. 180, p. 345. EGGS. 277 ing to Delarne, if the egg, when placed in a io% salt solution sinks to the bottom, it may be considered perfectly fresh; if it remains immersed in the liquid, it is to be considered at least three days old; and if it rises to the surface and floats thereon it is more than five days old. This test is a very rough one, and is useful only for eggs that have been kept in the air. Preserved eggs cannot be gauged by this means. The commercial method of examining eggs is by " candling," con- sisting in placing the egg in front of an opening in a screen between a bright light and the eye. If the egg is fresh, it will show a uniform rose-colored tint, without dark spots, the air-chamber being small and occupying about one-twentieth the capacity of the egg. If the egg is not fresh, it will appear more or less cloudy, being darker as the egg grows older, be- coming in extreme cases opaque. At the same time the air-chamber grows larger as the age increases. So-called " spots " show on candling black patches. Greenlee * has proposed the moisture content as an index of age and has devised a " rate formula " for predicting the condition after holding for a definite time at a definite temperature. Preparation of the Sample.!— The egg is first weighed as a whole and afterwards boiled hard, cooled, and again weighed. The shell, white, and yolk are then carefully separated and each weighed. After rejecting the shell, the yolk and white are separately reduced by a chopping-knife to the size of wheat grains. These portions ar^ dried partially at a tem- perature not exceeding 45° C, weighed, and afterwards ground to a fine powder in a mortar. Pennington separates the yolk from the white by draining on a piece of wire gauze, then washes off any adhering white with water and dries by extraction with alcohol as described on page 271. Fat constants are determined on the petroleum ether extract. Determination of Water, Ether Extract, Total Nitrogen, and Ash are made in practically the same manner as with flesh foods. It is well to determine water with the addition of sand, after which the residue may be ground up for extraction with ether, using a continuous flow ex- tractor. Little attention has been paid as yet to the complete separation and determination of the nitrogen compounds in the white and yolk, and it * U. S. Dept. of Agric, Bur. of Chem., Bui. 83, 191 1. t Woods and Merrill, Maine Exp. Sta^^ Bui. Ti. p. 92. 278 FOOD INSPECTION AND ANALYSIS. is customary to calculate the protein by the use of the factor 6,25 or by difference. Determination of Lecithin. — The Juckenack Method (page 366), de- vised for noodles, is also applicable to eggs, previously dried at a moderate temperature with sand, and to commercial dried eggs. If desired, the free lecithin, or that present in the ether extract, and the combined lecithin, obtained by extraction w^ith absolute alcohol of the residue after removal of the ether extract, may be separately determined. Detection of Preservatives. — Formaldehyde may be readily detected by heating directly with the acid ferric chloride reagent as described for milk. Boric Acid. See Chapter XVIII. Bertrand and Agulhon * find by their spectroscopic method o.i 16-0. 136 mg. of boron as hydroxide per kilo of egg white and o.co8 mg. per kilo of egg yolk, to which no pre- servative has been added. These amounts are not detectable by ordinary methods. Salicylic Acid. — Froideaux f proceeds as follows: Mix 25 grams of desiccated or 30 grams of liquid egg with 250 cc. of water, stir in 125 cc. of 8% sodium hydroxide solution, and warm for 45 minutes on a water-bath. Break up the mass with a rod and filter. Acidulate the filtrate with hydrochloric acid, precipitate proteins with sodium phospho- molybdate, filter, extract the filtrate with ether, and proceed as usual. EGG SUBSTITUTES. There have been many preparations in powdered form sold under this name, nearly all claiming to contain all the ingredients of eggs, but most of them falling far short of these claims. Some of them, as, for instance, those made from desiccated skimmed milk, do contain nitro- genous matter, but as a rule little, if any, fat. Two samples of "egg substitute" sold in Massachusetts were anal- yzed with the following results :t A. B. Protein 16.94 18.72 Fat 3.43 3.40 Water 6.71 7.01 Corn starch, salts, and coloring matter. 72.92 70.87 * Compt. rend., 1913, 156, p. 2027. t Jour, pharm. chim., 10, p. 18. X An. Rep. Mass. State Board of Health, 1895, p. 675. EGGS. 279 A ten-cent package of sample A, weighing about 2 ounces, was alleged to be equivalent to 12 eggs. Starch furnished the chief ingredient in both samples. One of the most flagrant examples of fraud in this connection was a product sold under the name " N'egg," advertised to contain the nutritive equivalent of the whites and yolks of a dozen eggs, " their composition being based on careful scientific analysis of natural eggs." It was put up in two small boxes, one containing a white and the other a yellow dry powder. Both were entirely devoid of nitrogen, and consisted of nearly pure tapioca starch with a little common salt, the color of the "yolk" being due to Victoria yellow. Some egg substitutes are sold under the name of " custard powders," and are alleged to take the place of eggs in cooking. These are variously made up of mixtures of skim-milk powder, coloring m.atter, and baking powder ingredients as shown from the following analyses : * CUSTARD POWDERS. Starch Albuminous compounds Soluble coloring matter Baking soda Tartaric acid Phosphates Carbonates of lime and magnesia . Water Ash 86 25 o 59 0.88 11.83 0.45 ^•45 '58 13.69 0.38 51 03 6.01 15 33 13.69 o. 24 2.70 II 00 26.38 2.96 50.70 10.33 9 63 52.32 6.00 22. II "■37 8.20 53 82 5.06 26.71 6.19 8.22 Food and Sanitation, Nov. 25, 1893. CHAPTER X. CEREALS AND THEIR PRODUCTS, VEGETABLES, FRUITS, AND NUTS. The chief points of difference in composition between the animal foods already treated of, and those of the vegetable kingdom, are apparent in the relative amounts of proteins and carbohydrates. The proteins present in the cereals differ materially both in character and amount from those in the flesh foods, being, as a rule, present in much smaller amount. The leguminous foods, such as peas, beans, and lentils, and nuts as a rule, are, however, comparatively high in nitrogenous content. The carbohydrates, which in the flesh foods are almost entirely lack- ing, and in milk in the form of lactose make up about one-third of the solid matter, constitute the greater part of the cereals and legumes, being present chiefly in the form of starch. In nuts, with few exceptions such as the chestnut and peanut, starch is absent. The composition of the principal cereal grains is tabulated as follows by Villier and ColHn: Wheat. Barley. Rye. Oats. Rice. Com. Millet. 13-65 13-77 15.06 12.37 13. II 13.12 11.66 12.35 II. 14 11.52 10.41 7-«5 9-85 9-25 1-75 2.16 1-79 5-32 0.88 4.62 3-50 1-45 1.56 0-95 1. 91 ' 2.46 1 2.38 1.70 4.86 1-79 I 16.52 3-3« 65-95 64.08 61.67 62.00 54.08 62.57 J 2-53 5-31 2.01 II. 19 0.63 2.49 7.29 1. 81 2.69 1. 81 3.02 1. 01 1-51 2-35 Buck- wheat. Water Nitrogenous substances Fat Sugar Gum and dextrin Starch Cellulose Ash 12.93 10.30 2.81 55-81 16.43 2.72 The following results of the analyses of cereal grains are summarized from the work of the Division of Chemistry, United States Department of Agriculture : * * Bulletin 13, part 9. 280 d CEREALS, VEGETABLES, FRUITS, AND NUTS. CEREAL GRAINS. 281 Barley: Mean Buckwheat: Mean Corn, domestic: Maximum Minimum Mean Oats, domestic : Maximum . Minimum . Mean Rice: Unhulled Unpolished . . . Polished* Rye, domestic : Maximum Minimum Mean Wheat, domestic: Maximum , Minimum. Mean Wheat, foreign: Maximum Minimum. ... Mean Num- ber of Analy- ses. 14 Weight of 100 Ker- nels, Grams. Moist- 4 6 14 -533 .069 .312 .608: -979: 2.038: 2.918, 2.929 2.466 2.132 Pro- teins. 4- 201 932 493 ).i9o !-I25| 5.866 ;-723 — 250] 1-076, 6.47 12.31 12.32 9-58 10.93 13.02 7.87 10.06 12.34 11-45 9-54 10.62 14-53 7. II 10.62 12.97 8.52 11.47 11.52 10.86 11-55 8.58 9.88 15-05 9.10 12.15 7-95 8.02 7.1! 18.99 8.40 12.43 17-15 8.58 12.23 14-52 8.58 12.08 Ether Ex- tract. Crude Fiber. Ash. 2.67 2.06 5.06 2.94 4.17 6.14 0-93 4-33 1.65 1.96 0.26 2-30 1. 16 1-65 2.50 0.28 1-77 2.26 0.73 1.78 3.81 10.57 2.00 1 .00 1. 71 16.65 8-57 12.07 10.42 0-93 0.40 2.50 1.65 2.09 3-72 1.70 2-36 1.87 2.28 2.87 1-85 1-55 1. 19 1.36 4-37 2.47 3-46 4.09 1-15 0.46 2.41 1. 71 1.92 2-35 1.40 1-82 2- 04 1.67 1-73 5fl fe ■a S"^ Wet Gluten. 72.66 63-34 75-07 68.97 71-95 61.44 53-70 58.75 65 - 60 76.05 79.36 75.36 63-61 71-37 76.05 39.05 66.67 12.33 71.18 26.46 Dry Gluten. 76.14 67.01 70.66 32-57 18.72 25-36 14.65 4-70 10.31 12.33 7.00 9.82 * Polished rice in the United States is commonly coated with gluccse and talc, ostensibly as a pro- tection against dust and the ravages of insects. Such coating is alowed if declared on the label and directions for its removal are also given. Balland f gives the following percentage composition of beans, lentils, and peas: Beans. Lentils. Peas. Min. Max. Min. Max. Min. Max. Water. , 10.10 13.81 0.98 52-91 2.46 2.38 20.40 25.46 2.46 60.98 4.62 4.20 11.70 20.42 0-58 56.07 2.96 1-99 13-50 24.24 1-45 62.45 3-56 2.66 10.60 18.88 1.22 56.21 2.90 2.26 14.20 22.48 1.40 61.10 5-52 3-50 Nitrogenous substances Fat Sugars and starches. Cellulose Ash f Jour. Pharm. Chem., 1897, pp. 196, 197. 282 FOOD INSPECTION AND ANALYSIS. The composition of potatoes, according to Balland,* is as follows: Water. Nitroge- nous Sub- stances. Fat. Sugar and Starch. Cellulose. Ash Normal state — minimum . . maximum. . Dried — minimum . . 66. 1 o 80.60 1-43 2.81 5-98- 13-24 0.04 0.14 0.18 0.56 15-58 29.85 80.28 89.78 0-37 0.68 1.40 3.06 0.44 1. 18 1.66 maximum. . 4.38 The composition of the common vegetables, fruits, and berries is thus given by Atwater and Bryant.f VEGETABLES. Asparagus — Beans, dried — • BeanSjfresh Lima Beets, fresh — Cabbage — Carrot, fresh — Celery — Cauliflower — Cucumber — Lettuce — Mushrooms — Onion, fresh — Parsnip — Pumpkin — Radish — Rhubarb — Squash — Tomato, fresh — Turnip — as purchased. . . as purchased. . . -edible portion . . as purchased. . . edible portion. . as purchased. . . edible portion . . as purchased. . . edible portion. . as purchased edible portion . . as purchased as purchased. . . edible portion. . as purchased . . . edible portion . . as purchased. . . as purchased edible portion. . as purchased edible portion. . as purchased. . . edible portion . . as purchased edible portion. . as purchased. . . edible portion. . as purchased. . . edible portion. . as purchased. . . as purchased. . . edible portion. . as purchased 12; 24 II 15 10 27 19 55-0 15-0 20.0 20.0 15-0 15-0 10. o 20.0 50.0 30.0 40.0 50.0 30.0 94 22. 5 7-1 3-2 1.6 1-3 1.6 1-4 3-5 1.6 1-4 1.6 1-3 i.o -5 1-3 -9 .6 -4 1-4 -7 -9 1-3 -9 03 >> .2 .8 3- 59- -7 22. •3 9- .1 9- .1 7- -3 5- .2 4- .4 9- .2 7- .1 3- .1 2- •5 4- .2 3- .2 2. -3 2. .2 2. -4 6. -3 -3 9- 8. -5 13- -4 10. .1 5- .1 2. -3 8. .1 5- -7 3- -4 2. -5 9- .2 4- .4 .2 3- 8. .1 5- 4-4 1-7 .8 -9 I.I I.I 2-5 1.2 -7 -7 i-i .6 1-3 * Jour. Pharm. Chem., 1897, pp. 298-300. t Bui. 28, Office of Exp. Station U. S. Dept. of Agriculture. c3 C (D _ o ty .1176 .1110 .0976 .1223 .1076 .117 .0634 -1347 .1185 .1119 .0984 •1233 .1085 .118 .0640 -1358 -1 195 .1128 .0992 •1243 .1094 .119 .0645 .1369 .1204 •I 137 .1000 •1253 .1103 .120 .0650 .1380 .1214 .1146 .1008 .1263 .nil .121 -0655 ■I391 .1224 -I155 .1016 -1273 .1120 .122 .0660 .1402 -1233 .1164 .1024 .1283 .1129 .123 .0665 -I413 -1243 -I173 .1032 .1293 .1138 .124 .0671 .1424 •1253 .1182 .1040 •1303 .1147 .125 .0676 -1435 .1263 .1192 .1049 •I314 .1156 .126 .0681 .1446 .1272 .1201 -1057 -1324 .1165 .127 .0686 -1457 .1282 .1210 .1065 •1334 • I174 .128 .0691 .1468 .1292 .1219 ■1073 .1044 .11S3 • I 29 .0697 -1479 .1301 .1228 .1081 •1354 .1192 • 130 .0702 .1490 .1311 •1237 .X089 •1364 .1201 .131 .0707 .1501 .1321 .1246 .1097 •1374 .1210 .132 .0712 .1512 .1330 -1255 .1105 .1384 .1219 .133 .0717 -1523 -1340 .1264 .1113 •1394 .1227 .134 .0723 -1534 •1350 ■1273 .1121 .1404 .1236 .135 .0728 •1545 .1360 .1283 .1129 .1414 .1244 .136 •0733 ■1556 .1569 .1292 -II37 .1424 •1253 .137 .0738 -1567 .1379 .1301 -II45 -1434 .1262 .138 •0743 -1578 .1389 .1310 •II53 .1444 .1271 • 139 .0748 .1589 .1398 -I319 . I161 -1454 .1280 .140 -0754 .1600 .1408 .1328 .1169 .1464 .1288 .141 .0759 .1611 .1418 -1337 .1177 .1474 .1297 .142 .0764 .1622 .1427 .1346 .1185 .1484 .1306 .143 .0769 ■^^33 -1437 .1355 -1 193 .1494 •1315 .144 .0774 .1644 .1447 .1364 .1201 • 1504 •1324 .145 .0780 .1655 .1457 -1374 .1209 •I515 •^333 .146 .0785 .1666 .1466 ■1383 .1217 •1525 • 1342 .147 .0790 .1677 .1476 .1392 .1225 •1535 •1351 .148 •079s .1688 .i486 .1401 .1233 .1545 .1360 " .149 ,0800 .1699 •1495 .1410 .1241 .1555 .1369 300 FOOD INSPECTION AND ANALYSIS. KROBER'S TABLE FOR DETERMINATION OF PENTOSES AND PENTOSANS FROM PHLOROGLUCID— (Con/i«Me(f). I 2 3 4 S 6 7 8 Phloroglucid Furfural. Arabinose. Araban. Xylose. Xylan. Pentose. Pentosan. 0.150 0.0805 0.1710 0-1505 0.1419 0.1249 0.1565 0-1377 .151 .0811 .1721 -1515 .1428 -1257 -1575 .1386 •152 .0816 .1732 .1524 -1437 .1265 .1585 •1395 •153 .0821 •1743 .1534 .1446 -1273 .1595 .1404 .154 .0826 .1754 -1544 .1455 .1281 .1605 .1413 .155 .0831 .1765 -1554 .1465 .1289 .1615 .1421 .156 .0837 .1776 •1563 .1474 .1297 .1625 .1430 -157 .0842 .1787 •1573 .1483 -1305 -1635 •1439 .158 .0847 .1798 ■1583 .1492 ■ ^3^3 .1645 .1448 .159 .0852 .1809 •1592 .1501 .1321 -1655 .1457 .160 .0857 .1820 .1602 .1510 .1329 .1665 -1465 .161 .0863 .1831 .1612 -1519 -1337 -167s 1474 .162 .0868 .1842 .1621 .1528 -1345 .1685 .1483 .163 .0873 -1853 .1631 -1537 -1353 .1695 .1492 .164 .0878 .1864 .1640 .1546 .1361 .1705 .1501 .165 .0883 .1875 .1650 -1556 .1369 .1716 .1510 .166 .0888 .1886 .1660 .1565 •1377 .1726 .1519 .167 .0894 .1897 .1669 • 1574 -1385 -1736 .1528 .168 .0899 .1908 .1679 .1583 .1393 .1746 •1537 .169 .0904 .1919 .1688 -1592 .1401 .1756 .1546 .170 .0909 .1930 .1698 .1601 .1409 .1766 .1554 .171 .0914 .1941 .1708 .1610 .1417 .1776 .1563 .172 .0920 •1952 .1717 .1619 .1425 .1786 .1572 .173 .0925 .1963 .1727 .1628 -1433 .1796 .1581 .174 .0930 •1974 .1736 -1637 .1441 .1806 •1590 •175 •0935 .1985 .1746 .1647 .1449 .1816 .1598 .176 .0940 .1996 •1756 .1656 • 1457 .1826 .1607 .177 .0946 .2007 ■1765 .1665 -1465 .1836 .1616 .178 •0951 .2018 .1775 .1674 -1473 .1846 .1625 .179 .0956 .2029 .1784 .1683 .1481 .1856 .1634 .180 .0961 .2039 -1794 .1692 .1489 .1866 .1642 .181 .0966 .2050 .1804 .1701 -1497 .1876 .1651 .182 .0971 .2061 .1813 .1710 ■ 1505 .1886 .1660 .183 .0977 .2072 .1823 .1719 ■1513 .1896 .1669 .184 .0982 .2082 .1832 .1728 .1521 .1906 .1678 .185 .0987 .2093 .1842 •1738 .1529 .1916 .1686 .186 .0992 .2104 .1851 -1747 -1537 .1926 .169s .187 .0997 .2115 .1861 ■1756 -1545 .1936 .1704 .188 .1003 .2126 .1870 -1765 .1553 .1946 .17I8 .189 .1008 .2136 .1880 •1774 .1561 .1955 .1721 CEREALS, VEGETABLES, FRUITS, AND NUTS. 301 KROBER'S TABLE FOR DETERMINATION OF PENTOSES AND PENTOSANS FROM Pm^OROGLUCIB— (Continued). I 2 3 4 5 6 7 8 j'hloroglucid Furfural. Arabinose. Araban. Xylose. Xylan. Pentose. Pentosan. 0.190 0.1013 0.2147 0.1889 0.1783 0.1569 0.1965 0.1729 .191 .1018 .2158 .1899 .1792 -1577 -1975 -1738 192 .1023 .2168 .1908 .1801 .1585 .1985 .1747 .193 .1028 .2179 .1918 .1810 .1593 .1995 .1756 .194 -1034 .2190 .1927 .1819 ,1601 • 2005 .1764 .195 .1039 .2201 .1937 .1829 .1609 .2015 -1773 .196 .1044 .2212 .1946 .1838 .1617 .2025 .1782 .197 .1049 .2222 .1956 .1847 .1625 •2035 .1791 ,198 .1054 .2233 .1965 .1856 •^^33 .2045 .1800 .199 .1059 .2244 •1975 .1865 .1641 •2055 .1808 ,200 .1065 .2255 .1984 .1874 .1649 .2065 .1817 ,201 .1070 .2266 .1994 .1883 .1657 .2075 .1826 ,202 -1075 .2276 .2003 .1892 .1665 .2085 .1835 ,203 .1080 .2287 .2013 .1901 .1673 .2095 .1844 .204 .1085 .2298 .2022 .1910 .i68r .2105 .1853 .205 .1090 .2309 .2032 .1920 .1689 .2115 .1861 ^^06 .1096 .2320 .2041 .1929 .1697 .2125 .1869 .^07 .1101 .2330 .2051 .1938 -1705 -2134 .1878 .;o8 .1106 .2341 .2060 -1947 -1713 .2144 .1887 .^09 .IIll .2352 .2069 .1956 .1721 -2154 .1896 ,210 .1116 .2363 .2079 .1965 .1729 .2164 .1904 ^211 .1121 -2374 .2089 -1975 -1737 • 2174 -I913 212 .1127 .2384 .2098 .1984 -1745 .2184 .1922 .213 .1132 -2395 .2108 ■1993 .1753 .2194 •1931 .214 -"37 .2406 .2117 .2002 .1761 .2204 .1940 .215 .1142 .2417 .2127 .2011 .1770 .2214 .1948 .216 .1147 .2428 .2136 .2020 .1778 .2224 -1957 .217 .1152 .2438 .2146 .2029 .1786 .2234 .1966 .218 .1158 .2449 .2155 .2038 .1794 .2244 .1974 .219 .1163 .2460 .2165 .2047 .1802 -2254 .1983 .220 .1168 .2471 -2174 .2057 .r8io .2264 .1992 .221 -1173 .2482 .2184 .2066 .1818 .2274 .2001 .222 .1178 .2492 .2193 .2075 .1826 .2284 .2010 .223 .1183 -2503 -2203 .2084 .1834 .2294 .2019 .224 .1189 .2514 .2212 .2093 .1842 .2304 .2028 .225 .1194 .2525 .2222 .2102 .1850 .2314 .2037 .226 .1199 -2536 .2232 .2111 .1858 .2324 .2046 .227 .1204 .2546 .2241 .2121 .1866 -2334 .2054 .228 .1209 .2557 .2251 .2130 .1874 .2344 .2063 .229 .1214 .2568 .2260 .2139 .1882 .2354 .2072 302 FOOD INSPECTION AND ANALYSIS. PROBER'S TABLE FOR DETERMINATION OF PENTOSES AND PENTOSANS FROM PHLOROGLUCID— (CoK/i«Med). I 2 3 4 5 6 7 8 Phloroglucid Furfural. Arabinose. Araban. Xylose. Xylan. Pentose. Pentosan. 0.230 0.1220 0.2579 0.2270 0.2148 0.1890 0.2364 0.2081 .231 .1225 .2590 .2280 .2157 .1898 •2374 .2089 .232 .1230 .2600 .2289 .2166 .1906 -2383 .2097 .233 .1235 .2611 .2299 •217s .1914 •2393 .2106 .234 .1240 .2622 .2308 .2184 .1922 ,2403 .2115 •235 .1245 .2633 .2318 .2193 .1930 -2413 .2124 .236 .1251 .2644 .2327 .2202 .1938 .2423 .2132 .237 .1256 .2654 ■2337 .2211 .1946 •2433 .2141 .238 .1261 .2665 .2346 .2220 -1954 .2443 .2150 .239 .1266 .2676 .2356 .2229 .1962 .2453 .2159 .240 .1271 .2687 .2365 .2239 .1970 .2463 .2168 .241 .1276 .2698 -237s .2248 .1978 .2473 .2176 .242 .1281 .2708 .2384 .2257 .1986 .2483 .2185 .243 .1287 .2719 .2394 .2266 .1994 •2493 ,2194 .244 .1292 .2730 . . 2403 .2275 .2002 •2503 .2203 .245 .1297 .2741 • 2413 .2284 .2010 .2513 .2212 .246 .1302 .2752 .2422 .2293 .2018 -2523 .2220 .247 •1307 .2762 .2432 .2302 .2026 .2533 .2229 .248 .1312 •2773 .2441 .2311 .2034 -2543 .2238 .249 .1318 .2784 .2451 .2320 .2042 .2553 .2247 .250 .1323 •2795 .2460 •2330 .2050 -2563 .2256 .251 .1328 .2806 .2470 •2339 .2058 •2573 .2264 .252 •1333 .2816 .2479 .2348 .2066 .2582 .2272 .253 •1338 .2827 .2489 •2357 -2074 •2592 .2281 .254 •1343 .2838 .2498 .2366 .2082 .2602 .2290 .255 •1349 .2849 .2508 .2375 .2090 .2612 .2299 .256 -1354 .2860 .2517 .2384 .2098 .2622 .2307 .257 -1359 .2870 .2526 .2393 .2106 .2632 .2316 .258 .1364 .2881 •2536 .2402 .2114 .2642 -2325 •259 .1369 .2892 •2545 .2411 .2122 .2652 •2334 .260 •1374 .2903 •2555 .2420 .2130 .2662 •2343 .261 .1380 .2914 -2565 .2429 .2138 .2672 •2351 .262 .1385 .2924 ■2574 .2438 .2146 .2681 -2359 .263 .1390 •2935 .2584 .2447 .2154 .2691 .2368 .264 •139s .2946 •2593 .2456 .2162 .2701 .2377 .265 .1400 •2957 .2603 .2465 .2170 .2711 -2385 .266 • 1405 .2968 .2612 .2474 .2178 .2721 •2394 .267 .1411 .2978 .2622 .2483 .2186 •2731 .2403 .268 .1416 .2989 .2631 .2492 .2194 .2741 .2412 .269 .1421 .3000 .2641 .2502 .2202 •2751 .2421 CEREALS, VEGETABLES, FRUITS, AND NUTS. 303 KROBER'S TABLE FOR DETERMINATION OF PENTOSES AND PENTOSANS FROM PWLOROGLUCIB— {Concluded). 1 2 3 4 S 6 7 8 Phloroglucid Furfural. Arabinose. Araban. Xy lose. Xylan. Pentose. Pentosan. 0.270 0.1426 0.3011 0.2650 O.2511 0.2210 0.2761 0.2429 .271 ■I431 .3022 .2660 .2520 .2218 .2771 .2438 .272 .1436 •3032 .2669 .2529 .2226 .2781 .2447 .273 .1442 .3043 .2679 • *538 .2234 .2791 .2456 .274 .1447 •3054 .2688 •2547 .2242 .2801 .2465 .275 .1452 -3065 .2698 .2556 .2250 .2811 ■2473 .276 •1457 .3076 .2707 -2565 .2258 .2821 .2482 .277 .1462 .3086 .2717 .2574 .2266 .2830 .2490 .278 .1467 •3097 .2726 -2583 .2274 .2840 .2499 .279 •1473 .3108 .2736 .2592 .2282 .2850 .2508 .280 .1478 -3"9 .2745 .2602 .2290 .2861 .2517 .281 .1483 ■3^3° -2755 .2611 .2298 .2871 .2526 .282 .1488 -3140 .2764 .2620 .2306 .2880 •2534 .283 •1493 .3151 .2774 .2629 .2314 .2890 ■2543 .284 .1498 .3162 .2783 .2638 .2322 .2900 •2552 .285 .1504 •3173 ■2793 .2647 ■2330 .2910 .2561 .286 .1509 -3184 .2802 .2656 -2338 .2920 .2570 .287 .1514 -3194 .2812 .2665 .2346 • .2930 .2578 .288 •I519 -3205 .2821 .2674 .2354 .2940 .2587 .289 .1524 .3216 .2831 .2683 .2362 .2950 .2596 .290 •1529 •3227 .2840 .2693 .2370 .2960 .2605 .291 .1535 .3238 .2850 .2702 .2378 .2970 .2614 .292 ,1540 .3248 .2859 .2711 .2386 . 2980 .2622 •293 -1545 •3259 .2868 .2720 ■2394 .2990 .2631 .294 •1550 .3270 .2878 .2729 .2402 .3000 .2640 .29s -1555 .3281 .2887 .2738 .2410 .3010 .2649 .296 .1560 .3292 -2897 •2747 .2418 .3020 .2658 .297 .1566 •3302 .2906 .2756 .2426 .3030 .2666 .298 .1571 .3313 .2916 .2765 .2434 .3040 .2675 .299 -1576 .3324 •2925 .2774 .2442 •3050 .2684 .300 .1581 •3335 •2935 .2784 .2450 .3060 .2693 304 FOOD INSPECTION AND ANALYSIS. SEPARATION AND DETERMINATION OF THE VARIOUS CARBOHYDRATES OF CEREALS, ETC. STONE'S METHOD. Stone has thus tabulated the results of a series of analyses of various samples of wheat, flour, corn, and bread, in which he has separated the principal carbohydrates.* PERCENTAGES OF VARIOUS CARBOHYDRATES IN CERTAIN FOODSTUFFS. Crude Fiber. 2.68 2-51 0.25 0.25 1-99 1. 00 2.70 2.02 0.34 0.17 2.22 Whole wheat, I. . . Whole wheat, II. . Wheat flour, I. . . , Wheat flour, II. . . Corn Sugar-beet Bread (wheat, I). Bread (wheat, II). Bread (flour, I). . , Bread (flour, II). . Corn cake (maize) Sucrose. Invert Dextrin. Soluble Pento- Sugar. Starch. sans. 0.52 0.08 0.27 0.00 4-54 0.72 0.00 0.41 0.00 4-37 0.18 0.00 0.90 coo coo 0.20 0.00 1.06 coo 0.00 9.27 COO 0.32 0.00 5-14 8.38 0.07 0.35 coo 4.89 0.05 0.32 0.68 1-37 4.16 0.06 0.37 0.23 2.36 4-34 O.OI O.IO 0.27 1.99 0.00 o-iS 0.38 0.91 1.74 coo 0.16 0.19 0.00 2.80 3-54 Determination of Cane Sugar. — 100 grams of the finely ground ma- terial are extracted by boiling under a reflux condenser with 506 cc. of 95% alcohol for three hours, the alcoholic extract is filtered, evaporated nearly to dryness, and then taken up with a small amount of water, to separate the sugar from the oils and waxes dissolved by the alcohol. This aqueous solution is invariably dextro-rotary, and seldom contains any reducing sugar. If the latter is present, it is determined in an aliquot part of the aqueous solution with Fehling's solution, the result being calculated to dextrose. The remainder of the aqueous sugar solution, or the whole of it, if, as is almost always the case, dextrose is absent, is then inverted by heating with hydrochloric acid in the usual manner (page 611) and the sugar is estimated with Fehling's solution, calcu- lating the result to sucrose (page 642). Determination of Dextrin. — Digest the residue from the above alco- holic extraction from eighteen to twenty-four hours with 500 cc. of cold distilled water, shaking frequently. On filtering, a clear solution is ob- ♦ Jour. Am. Chem. Soc, 19, 1897, P- 183, and U. S. Dept. of Agric, Off. of Exp. Sta., Bui. 34. The percentages of normal starch found by Stone are obviously erroneous, and are for this reason excluded from the table as here given. CEREALS, VEGETABLES, FRUITS, AND NUTS. 305 tained, which should be tested with iodine for soluble starch. If the latter is not found (which is nearly always the case), the solution is con- centrated to a small volume, avoiding a temperature higher than 80° to 90°, and this is boiled under a reflux condenser for two hours with one- tenth its volume of hydrochloric acid (specific gravity 1.125). Deter- mine the dextrose by Fehhng's solution and calculate to dextrin by the factor 0.9. Or, instead of submitting the concentrated aqueous extract to hydrolysis as above, the dextrin may be roughly determined gravimetrically therein by treating with several volumes of strong alcohol until no further precipitation is produced. The flocculent precipitate thus obtained is collected, dried, and weighed. Determination of Starch. — Dry in an oven the residue from the pre- ceding treatment and determine its quantitative relation to the original sample ; 2 grams are then accurately weighed and subjected to the dias- tase method of starch determination (page 292). Determination of Pentosans and Hemicelluloses. — The washed resi- due, left after fikering off the starch-containing solution from the process of heating with malt extract in the preceding starch determination, is boiled for an hour with 100 cc. of 1% hydrochloric acid, which converts all the pentosans into sugar. Filter, and wash the residue thoroughly, make up the solution to 200 cc, and determine the sugar with Fehling's solution, calculating the resuks for xylan, assuming that the chief sugar formed is xylose. The reducing power of xylose is assumed to be 4.61 milHgrams for each cubic centimeter of Fehling's solution. If the volu- metric Fehhng method is used, 10 cc. of Fehling's solution are thus equivalent to 0.046 gram xylose. Xylose X 0.88 = xylan. Crude Fiber {Cellulose, etc.). — The residue from the last dilute acid hydrolysis is boiled with 200 cc. of 1.25% solution of sodium hydroxide for half an hour, filtered, dried, and weighed. It is then ignited, and the weight of the ash deducted from the first weight. PROTEINS OF CEREALS AND VEGETABLES. Different cereal and vegetable foods present considerable variations in the character and extent of their protein constituents, and by no means all of the common vegetable foods have been studied in detail. Osborne, in connection with Voorhees and Chittenden, has made a careful study of the proteins of many of the cereals, of potatoes, and of peas. A brief outline only will be given in what follows of methods 306 FOOD INSPECTION AND ANALYSIS. for separation of the vegetable proteins. For fuller details the reader is referred to the work of Osborne et al. in the American Chemical Journal, Vols. "" 14, and 15, and to the Journal of the American Chemical Society, Vols. 17, i8, [9, and 20. Proteins Soluble in Water and Dilute Salt Solution. — By the action of various solvents it is possible to separate the different classes of pro- teins for examination or analysis. Thus water at first applied extracts certain of the soluble proteins, as does a weak salt solution. Osborne and Voorhees recommend the use of a 10% solution of sodium chloride as the first solvent to apply for separating vegetable proteins, shaking the finely ground material with twice its weight of the salt solution. The salt solution, after filtering, is then subjected to dialysis, the protein matter thus separated out being a globulin, while that not precipitated on dialysis is assumed as the protein matter of the substance soluble in water. Two albumins and a proteose are found in wheat to be thus soluble in water. 1\ the proteins soluble in salt solution are to have their total nitrogen determined, they are completely precipitated from the solution by satu- rating with zinc or ammonium sulphate. There are thus two classes of proteins soluble in 10% salt solution: (a) globulins, insoluble in water alone, and {h) albumins and proteoses, which are soluble in water. Separation of Albumins, Proteoses, and Globulins. — Starting with the aqueous solution containing the albumins and proteoses, if present, the former are best separated according to Osborne and Vorhees by fractional coagulation, effected by heating at different temperatures, those that precipitate out at a temperature under 65° being first filtered out, and the filtrate submitted to a higher temperature not. exceeding 85°. The two portions thus separated may be collected in filters, and their nitrogen separately determined. The proteose may be precipitated from the filtrate by saturating with ground salt, or by adding, first salt to the extent of 20%, and finally acetic acid. The globulins, precipitated in the original 10% salt solution by the process of dialysis as described, may themselves be separated by employing salt solution of varying strength as solvents.* Proteins Soluble in Dilute Alcohol, but Insoluble in Water. — The residue from the treatment with 10% sodium chloride is digested with 75% alcohol at about 46° C. for some time and filtered. The residue is further * Am. Chem. Jour., 13, p. 464. CEREALS, VEGETABLES, FRUITS, AND NUTS. 307 digested at about 60° with 75% alcohol three separate times. The evapo- rated filtrates contain the alcohol-soluble proteins. In this class are the hordein of barley, the gliadin of wheat and rye, and the zein of corn. Proteins Insoluble in Water, Salt Solution, and Dilute Alcohol. — It is customary to determine the nitrogen in the final residue without further attempt to separate the remaining protein matter. It is, however, possi- ble to further extract with alkaline and acid solvents, if desired, which process, however, changes the nature of the proteins from that in which they originally exist in the substance. Character and Amount of Proteins in Wheat.*— The proteins of wheat, according to Osborne, are five in number, as follows: Amount Present, Per Cent. Soluble in water: / Albumin (leucosin) 0.3 to 0.4 I Proteose 0.3 Soluble in 10 per cent NaCl: Globulin (edestin) 0.6 to 0.7 Soluble in dilute alcohol: Gliadin 425 Insoluble in above: Glutenin 4 . 00 to 4 . 5 The term gluten is applied to the protein content of wheat flour insoluble in water, the value of flour for baking bread depending on the amount present. Gluten contains the two definite proteins, gliadin and glutenin. Crude gluten, as obtained by washing the dough in the analytical process (page 331), is a complex mixture of many bodies, containing, besides the two proteins above named, small quantities of cellulose, mineral matter, lecithin, and starch. Separation and Determination of Wheat Proteins. — Teller's Method.f — Non-gluten Nitrogen. — Two grams of the finely divided sample are mixed with about 15 cc. of 1% salt solution in a 250-cc. flask. The flask is shaken at intervals of ten minutes during one hour, after which it is filled to the mark with the salt solution and allowed to stand two hours. The super- natant liquid is then filtered through a dry filter into a dry flask, leaving most of the solid material 'n the flask, passing the first part through twice, if necessary, for a clear filtrate. With a pipette, exactly 50 cc. of clear filtrate are run into a 500-cc. Kjeldahl digestion-flask, 20 cc. of the usual reagent sulphuric acid for the Gunning process (p. 58) are added, and the contents of the flask brought to a gentle boil. After the water has * Am. Chem. Jour. XV, 392-471; XVI, 524. t Ark. Exp. Sla. Bui. 42, p. 96. 308 FOOD INSPECTION AND ANALYSIS. been driven off and the acid has stopped foaming, the potassium sul- phate is added and the digestion completed. From the per cent of nitrogen thus obtained 0.27% is deducLed, this figure corresponding to the amount of gliadin soluble in 1% salt solution under the above con- ditions. The remainder is the percentage of non-gluten nitrogen. Cduten Nitrogen. — This is obtained by difference between the total nitrogen and the non-gluten nitrogen as above obtained, or by deducting the combined nitrogen of the edestin, leucosin, and the amido-nitrogen from the total nitrogen. Edestin and Leuco:dn. — Edestin is a globulin belonging to the vegetable vitelHns, and is precipitated from salt solutions by dilution, or by satu- ration . with magnesium or ammonium sulphate, but not by saturating with sodium chloride. It is not coagulated below 100° C, but is partly precipitated by boiling. Leucosin is an albumin, coagulating at 52°, but precipitates from salt solution by saturating with sodium chloride or magnesium sulphate. To 50 cc. of the clear salt extract, obtained as described under non- gluten nitrogen, 250 cc. of pure 94% alcohol are added in a Kjeldahl 500-cc. digestion-flask, the contents thoroughly mixed, and allowed to stand over night. The precipitate is collected in a lo-cm. filter, which is returned to the flask and the nitrogen determined. This represents the nitrogen of the combined edestin and leucosin. These proteins may, however, be separated by coagulating the leucosin at 60°, and pre- cipitating the edestin by adding alcohol to 50 cc. of the clear filtrate, determining the nitrogen separately in each precipitate. Amido-nitrogen. — Allantoin, asparagin, cholin, and betaine are nitrog enous bases present in wheat. Ten cc. of a 10% solution of pure phosphotungstic acid are added to 100 cc. of the clear salt extract as above obtained, thus precipitating all the proteins, which are allowed to settle preferably over night. Fil- ter, and determine the nitrogen in the clear filtrate. The filtrate should be tested with a little of the phosphotungstic acid reagent to make sure that all the proteins have been separated. In some cases, as in bran for instance, more than 10 cc. of the reagent are necessary. Gliadin is dissolved most readily from flour by hot dilute alcohol, but is entirely insoluble in absolute alcohol. One gram of the mate- rial is extracted with 100 cc. of hot 75% alcohol, by shaking the mixture thoroughly in a flask, and heating for an hour at a temperature just below CEREALS, VEGETABLES, FRUITS, AND NUTS. 309 the boiling-point of alcohol, with occasional shaking. After standing for an hour, the hot liquid is decanted upon a lo-cm. fiher, and 25 cc. of the hot alcohol are added to the residue and shaken, after which the residue is again allowed to settle, and the liquid decanted. This is repeated six times. The remainder of the alcohol is then driven off by evaporation, and the nitrogen determined in the residue. The difference between the total nitrogen and the nitrogen thus obtained, gives the nitrogen of the alcoholic extract, which includes the amides. Subtracting the latter, or amido-nitrogen, the remainder is the gliadin nitrogen. Glutenin Nitrogen.— This is the difference between the gluten nitro- gen and the gliadin nitrogen. The factor by which the nitrogen should be multiplied in determin- ing the various proteins, according to Osborne and Voorhees, is 5.7 for wheat. Proteins of the Common Cereals and Vegetables.— Osborne and his coworkers have made a detailed study of the protein constituents not only of wheat as above outlined, but of other common grains and vegeta- bles, and the results of these investigations may be thus briefly sum- marized : Proteins of rye:* Insoluble in salt solution ^^^ ^"** Soluble in alcohol, gliadin ]\\ ^-44 Soluble in water, leucosin Soluble in salt solution: (f^l 'zzz:::::::::::;::::;:^^^ 8.63 Proteins of barley:! ( T »,.-. c- 1 Per Cent. Soluble in water: \ Leucosin / rroteose \ 0.3 Soluble in salt solution, edestin Soluble in dilute alcohol, hordein !!!!!!!!!!! ^ '^^ Insoluble in water, salt solution, and alcohol 4" ro Proteins of corn:| Soluble in water: Proteose ^ ^ , ,, ( Very soluble globulin ...[ o" . Soluble in salt solution : < Maysin. ^ i Edestin ' ^^ Soluble in dilute alcohol: Zein Insoluble in above, but soluble in two-tenths "per cent potash "solution. .' .' .' ." .' ," .* ." .' 3 .' 15 Protein of pea:§ Soluble in sah solution: Globulins] Lfgumin ^^^^ Soluble in water: Albumin, legumelin, proteose.'.'.*.','.'. '. '. '. '. '. '. '. '. *.'.'.' .' ^'°° * Jour. Am. Chem. Soc, 17, page 429. f Ibid., 17, p, 539 t Ibid., 19, p. 525. 5 Ibid, 18. p. 583; 20, pp. 348 and 410. 310 FOOD INSPECTION AND ANALYSIS. MINERAL CONSTITUENTS OF CEREALS AND VEGETABLES. The food analyst often finds the determination of one or more of the mineral constituents of a food product of value as a means of detecting adulteration, since the addition of foreign material may alter materially the composition of the ash. The following table * shows the composition of the pure ash of common cereals. COMPOSITION OF ASH OF CEREALS. K2O. NaaO. CaO. MgO. Fe203. P2O0 SO3. CI. Si02. Wheat (Canada) Rye (Minnesota) Barley (U. S.) Oats (U. S.) Corn (U. S.) Rice, polished (Guatemala) Buckwheat (U. S.) 24 03 27 24 35 15 9 55 4.64 6.42 438 7.72 13.98 2. 26 3-50 5.56 2.44 4.09 3.18 4.48 6.62 13 24 11-73 8.23 7.18 17.99 9.60 20.55 0.52 5- 23 0-33 o. 20 0.50 46.87 41.81 35-47 24-34 35-25 43-21 24.09 O.OI 0.52 0.22 0.48 0.44 0.24 3-59 0.00 0.58 0.56 1 .02 0.00 0.80 0.67 2.28 2-45 22.30 42,64 1 .00 6. 14 5-54 Snyder t obtained the following average results in the analysis of the ash of 12 samples of wheat: Potash (K2O) 30-2% Soda (NaaO) 0.7 Lime (CaO) 3.5 Magnesia (MgO) 13.2 Ferric oxide (Fe203) 0.6 Phosphoric acid (P2O5) 47-9 Sulphuric acid (SO3) o.i Silica (Si02) 0.7 Chlorine (CI) 0.2 The average amount of ash in the grain was 2.0 07 /o- Konig gives the following analyses of the ash of various leguminous and other vegetables : * U. S. Dept. of Agric, Bur. of Chem., Bui. 13, part 9, p. 1212. t Minn. Agric. E.\p. Sta., Bui. 29, 1893, p. 149. CEREALS, VEGETABLES, FRUITS, AND NUTS. 311 Beans. . . Peas. . . . Potatoes . Beets . . . Carrots. . Turnips . *4-l tfl >>S o oj .2 TD jD ca .S^ ji: y^fii^ Fig. 70. — Heidenhain's Apparatus for the'Determination of Carbon Dioxide. Scale, i : 18. R. Safety bottle to receive water which may be sucked back from the aspirator. S. The aspirator, which is a Mariette's bottle of about 4 liters capacity. Tubes M and N should hold about 20 grams, making the capacity of M for carbon dioxide nearly i gram and of N for moisture 0.2 gram. They should be refilled when they have gained 0.75 and o.i gram respect- ively. Use best rubber connections lubricated with a trace of castor oil. Boil connections for the weighed tubes in dilute alkali, wash and dry. Wire or tie all joints. Before using pass carbon dioxide through H and K for several hours and exhaust. CEREALS, VEGETABLES, FRUITS, AND NUTS. 355 Reagents. — i. Calcium Chloride. — This should be dehydrated at 200" C, not fused. Grind so as to pass a No. 18 mesh and reject what passes a No. 30 mesh. The tubes should be filled from the same lot so that the air leaving the apparatus shall have the same moisture content as as that which enters. 2. Soda Lime.^ — To a kilogram of commercial sodium hydroxide add 500 to 600 cc. of water and heat in an iron kettle to form a thin paste. While still hot add a kilogram of coarsely powdered quicklime and stir with an iron rod to mix, break up lumps and facilitate the escape of moisture. When cool grind and sift as in the case of calcium chloride, place in wide-mouthed bottles, and seal with paraffin. To give the best results the product should not be too dry. Process. — Weigh tubes M and N after they have reached the room temperature, opening the cocks for a moment to insure equalization of pressure. Connect tubes with the apparatus and make sure that all joints are tight by closing A at the bottom, opening all cocks, starting the aspirator, and observing P in which the liquid must soon come to a standstill. Then disconnect the aspirator, close B, remove F and introduce the material (using about i gram of carbonate or 2 grams of baking powder), connect F and start the cooler. Introduce hydrochloric acid (sp.gr. i.i) and carbon dioxide-free water through D, lifting E slightly. Heat to boiling and lower the flame to keep just at boiling. If no more air passes P start the aspirator. When water stops running, open B carefully and adjust the outflow of the aspirator by raising or lowering the syphon to half the safe speed. To find the safe speed charge the apparatus as for an analysis, omitting the carbonate, aspirate at the rate of 50 cc. per minute until 2 liters of air have passed through the system, and weigh the tubes. If together they have lost weight reduce the rate until constant weights are secured. Tube M should lose as much as N gains. After M has become cool, increase the current to full safe speed and aspirate altogether 3 liters, continuing boiling to the end. After the tubes have reached the room temperature open for a moment and v/eigh. Determination of Residual and Available Carbon Dioxide. t — Weigh 2 grams of baking powder into a flask suitable for the subsequent deter- mination of carbon dioxide, add 20 cc. of cold water, and allow to stand * Benedict and Tower, Jour. Am. Cham. See, 21, 1899, p. 396. t Conn. Agric, Exp. Sta., Rep., 1900, p. 169. 356 FOOD INSPECTION AND ANALYSIS. twenty minutes. Place the flask in a metal drying cell surrounded by boiling water and heat, with occasional shaking, for twenty minutes. To complete the reaction and drive off the last traces of gas from the semi-solid mass, heat quickly to boiling and boil for one minute. Aspirate until the air in the flask is thoroughly changed, and determine the residual carbon dioxide by absorption, as described, under total carbonic acid. The process described, based on the methods of McGill * and Catlin,t imitates as far as practicable the conditions encountered in baking, but in such a manner that concordant results may be readily obtained on the same sample and comparable results on different samples. To obtain the available carbon dioxide subtract the residual from the total carbon dioxide. Detection of Tartaric Acid-I — In the absence of starch, mix a little of the dry powder in a test-tube with a bit of dry resorcin, add a few drops of concentrated sulphuric acid, and heat slowly. A rose-red color indicates tartaric acid or a tartrate, the color being discharged on dilu- tion with water. In case of baking powder, or a cream of tartar substitute containing starch, shake repeatedly from 3 to 5 grams of the sample with about 250 cc. of cold water in a large flask, allowing the insoluble portion to subside. Decant the solution through a filter, and evaporate the filtrate to dryness, after which test the dried residue or a portion thereof with resorcin and sulphuric acid as above described. Determination of Total Tartaric Acid. — Modified Heidenhain Method.^ — Applicable only in the absence of phosphates and salts of aluminum and calcium. Into a shallow porcelain dish, 6 inches in diameter, weigh out 2 grams of the material and sufficient potassium carbonate to combine with all tartaric acid not in the form of potassium bitartrate. Mix thoroughly with 15 cc. of cold water, and add 5 cc. of 99% acetic acid. Stir for half a minute with a glass rod bent near the end. Add 100 cc. of 95% alcohol, stir violently for five minutes, and allow to settle at least thirty minutes. Filter on a Gooch crucible with a thin layer of paper pulp, and wash * Lab. Inl. Rev. Dept., Canada, Bui. 68, p. 31. t Baking Powders: A Treatise on their Character, Methods for Determination of the Values, etc., p. 20. X Wolff, Rev. chim. anal., 4, 1899, p. 2631. § U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 104J Bui. 107, p. 175. CEREALS, VEGETABLES, FRUITS, AND NUTS. 357 with 95% alcohol until 2 cc. of the filtrate do not change the color of htmus tincture diluted with water. Place the precipitate in a small cas- serole, dissolve in 50 cc. of hot water, and add standard fifth-normal potas- sium hydroxide solution, leaving it still strongly acid. Boil for one minute. Finish the titration, using phenolphthalein as indicator, and correct the reading by adding 0.2 cc. One cc. of fifth-normal potassium hydroxide solution is equivalent to 0.026406 gram tartaric anhydride (C^H^OJ, 0.03001 gram tartaric acid (HjC^H^Oe), and 0.03763 gram potassium bitartrate (KKCJip^). The standard of the potassium hydroxide solution should be fixed by pure dry potassium bitartrate. The accuracy of this method is indicated by the agreement of the percentages of potassium bitartrate in cream of tartar powders containing no free tartaric acid, obtained by calculation from the tartaric acid, with those obtained by calculation from the potassium oxide. In presence of phosphates or of aluminum and calcium salts, the only satisfactory method of arriving at the amount of tartaric acid present is by difference, having determined or calculated the other ingredients. Kenrick's Polariscopic Methods. — Method i. {Applicable to Cream of Tartar). — The method is based on the fact that in the presence of excess of ammonia, the rotation of the solution is proportional to the concentration of the tartaric acid, and is independent of the other bases and acids present. (a) The Substance is Completely Soluble in Dilute Ammonia. — A weighed quantity of the material containing not more than i gram tartaric acid is placed in a 25 cc. measuring flask, moistened with 3 or 4 cc. of water, and concentrated ammonia (sp. gr. 0.880) added in quantity suf- ficient to neutralize all acids that may be present, and leave about i cc. in excess. The actual amount of the excess is not of importance, but a greater quantity than i cc. of free ammonia should be avoided. The solution is then made up to 25 cc. with water, filtered, if necessary, through a dry filter, and measured in a 20 cm. tube in the polarimeter. The amount of tartaric acid (CiHgOg) in grams iy) in the material taken is given by the formula: y =0.005 1 9^, where x is the rotation in minutes. {b) The Substance is not Completely Soluble in Dilute Ammonia. — In this case calcium tartrate is probably present, and may be determined as follows: Treat i gram of the substance (or an amount containing 358 FOOD INSPECTION AND ANALYSIS. not more than i gram of tartaric acid) in a small beaker with 15 cc, of water, and 10 drops of concentrated hydrochloric acid. Heat gently till both the potassium and calcium tartrates have passed into solution, and then, while still hot, add 2 cc. of concentrated ammonia (or enough to produce an ammoniacal smelling liquid), and about o.i gram of sodium phosphate dissolved in a little water. Transfer to a 25-cc. measuring flask, cool, make up to the mark with water, filter through a dry filter, and polarize the filtrate in a 20-cm. tube. The tartaric acid is calculated from the formula given under (a). The precipitation of the calcium by means of sodium phosphate is not absolutely necessary, but when this is not done, in cases where the proportion of calcium in the sample is high, there is a great tendency for the calcium tartrate to crystallize out from the ammoniacal solution before the reading is made. The tartaric acid present as bitartrate of potash may be determined by proceeding as in (a), the calcium tartrate being practically insoluble in cold ammonia solution. The tartaric acid present as calcium tartrate is given, with sufficient accuracy for most purposes, by the difference between the results of (a) and (b). If more accurate results are required, the residue insoluble in ammonia in (a) may be dissolved in a little hydrochloric acid and treated as above with sodium phosphate and ammonia. Method 2. {Applicable to Baking Powder and Cream of Tartar mixed with Substitutes). — Direct readings of rotation in ammoniacal solution are inadmissible in analyses of the substances of this class, on account of the influence of iron and aluminum on the rotation of tartaric acid, and on account of the small but unknown rotation of the trace of inverted starch. Accurate determinations, however, may be made in the presence of excess of ammonium molybdate in neutral solution. The latter substance has the property of greatly increasing the rotation of tartaric acid, so that by its use the small rotation of the inverted starch is made insignifi- cant. It is to be noted, however, that this increased rotation is very sensitive to the presence of alkali and acid, and is, moreover, modified by phosphates. It is therefore necessary, in the first place, to remove the phosphoric acid, and, secondly, to bring the solution to a definite state of neutrality. Both these results are attained by the following procedure, the details of which must be carefully adhered to: (a) Reagents. — The following solutions must be prepared, but need not be made up very accurately: CEREALS, VEGETABLES, FRUITS, AND NUTS. 359 Molybdate solution: 44 grams ammonium heptamolybdate in 250 cc. Citric acid solution: 50 grams citric acid in 500 cc. Magnesium sulphate solution: 60 grams MgS04 . 7H2O in 500 cc. Ammonia solution: 80 cc. concentrated ammonia (sp. gr. 0.880) in 500 cc. Hydrochloric acid: 60 cc. concentrated hydrochloric acid in 500 cc. Methyl orange solution: {b) Process. — An amount of material containing not more than 0.2 gram tatraric acid, not more than 0.3 gram alum, and not more than 0.3 gram calcium superphosphate, is accurately weighed, and placed in a dry flask. To this, 5 cc. of citric acid and 10 cc. of molybdate solution are added, and allowed to react with the substance for 10 or 15 minutes (with an occasional shake). Next, 5 cc. of magnesium sulphate solution are added, and 15 cc. of ammonia solution stirred in. After a few minutes (not more than one hour), the solution is filtered through a dry filter, a slight turbidity of the filtrate being disregarded. To 20 cc. of the filtrate are then added a few drops of methyl orange and hydrochloric acid, from a burette, till the pink color appears (2 or 3 drops too much or too little are of no consequence). Finally, 10 cc. more of the molybdate solution are added to the pink solution, which now becomes colorless or pale yellow, and water is added to make up the volume to 50 cc. This solution, after filtering if necessary, is polarized in a 20-cm. tube. The amount of tartaric acid in grams (y) in the weight of substance originally taken is given by the following formula, in which jc is the rotation in minutes: y = 0.00 io36.v + 0.00 i6oiv'-V- But if the rotation is not less than 40', the simpler formula, y = 0.0075 +0.001 168.V, may be employed. The following table gives the tartaric acid in grams for every 10 minutes rotation : Rotation in Minutes. Grams Tartaric Acid. Rotation in Minutes. Grams Tartaric Acid. 10 0.016 0.029 0.0415 0.0535 0.0657 0.0776 0.0895 O.1013 0.1130 0.1246 0.1365 0.1479 0.1595 O.1710 0.1825 20 30 40 50 60 70 80 100 1 10 1 120 130 140 150 360 FOOD INSPECTION AND ANALYSIS. Determination of Starch. — McGiWs Method* {Modified). — Digest I gram of the sample with 150 cc. of a cold 3% solution of hydrochloric acid during twenty-four hours, with occasional shaking. Filter through a tared Gooch crucible, wash first with water until neutral, then once with alcohol, and finally with ether. Dry at 110° C. for four hours, cool, and weigh. Burn off the starch, and again weigh. The difference in the two weights indicates the weight of the starch. The purity of the starch is insured by examination with the microscope. Acid Conversion Method. -f — If the sample contains lime, mix 5 grams in a 500-cc. flask with 200 cc. of 3% hydrochloric acid, and let the mixture stand an hour with frequent shaking. Filter through a wetted 11 -cm. filter, wash with water, and transfer the starch by a wash-bottle from the filter-paper back into the original flask, using 200 cc. of water. If the sample be free from lime, weigh 5 grams directly into the 500-cc. flask with 200 cc. of water. In either case add 20 cc. of hydrochloric acid (specific gravity 1.125) and heat the flask in boiling water for 2^ hours, the flask being provided with a reflux condenser. Determine the dextrose, and from this the starch in the regular manner. Detection of Aluminum Salts. { — (a) In Baking Powder. — Appli- cable in presence of phosphates. Burn to an ash about 2 grams of the sample in a platinum dish. Extract with boiling water and filter. Add to the filtrate sufficient ammonium chloride solution to produce a distinct odor of ammonia. A flocculent precipitate indicates aluminum. In igniting, as above directed, sodium aluminate results from the more or less complete fusion. The reaction which occurs may be repre- sented as follows: Na^Al^O^-f 2NH,Cl-f 4H2O = Al2(OH)e-f- 2NH,OH-f 2NaCl. Sodium Ammonium Aluminum Ammonia Salt aluminate chloride hydroxide If any phosphate of lime be present, it will be insoluble in the solution of the ash. If phosphate of sodium or potassium be present, it will go into solution, but will only precipitate out when an aluminum salt is also present on the addition of the ammonium chloride reagent. (b) In Cream 0} Tartar. — Mix about i gram of the sample with an equal quantity of sodium carbonate, bum to an ash, and proceed as in the case of baking powder (a). * Canada Inland Rev. Bui. 68, p. 7,^. •f U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 105; Bui. 107 rev., p. 176. X Leach, 31st An. Rep. Mass. State Board of Health, 1899, p. 638. CEREALS, VEGETABLES, FRUITS, AND NUTS. 361 Determination of Alumina. — The above qualitative method with am- monium chloride may be made quantitative in presence of phosphates as follows: After carrying out the qualitative method as above directed, filter off the final precipitate, dissolve it in nitric acid, and test it for phos- phate with ammonium molybdate. If phosphates are found absent, proceei as before with a weighed amount of the sample and wash, ignite, and weigh the residue as AI2O3. If phosphate is found present in the ammonium chloride precipitate, proceed as before, igniting and weighing the total residue. Then deter- mine the P2O5 in the latter and subtract from the total. The difference will be the AI2O3. Determination of Lime. — 5 grams of the sample are treated in a 500-cc. graduated flask with 50 cc. of water and 25 cc. of concentrated hydrochloric acid. Add water to the mark, shake, and allow the starch to settle. Decant through a dry filter, and to 50 cc. of the filtrate add ammonia nearly to neutralization, an excess of ammonium acetate solution, and 4 cc. of 80% acetic acid, and heat at 50° C. Filter if necessary, and precipitate the lime with an excess of ammonium oxalate. Filter, wash, and ignite over a blast-lamp. Weigh as CaO. Determination of Potash and Soda.* — Weigh out 5 grams into a platinum dish, and incinerate in a muffle at a low heat. The charred mass is well rubbed up in a mortar, then boiled fifteen minutes with about 200 cc. of water, to which has been added a little hydrochloric acid. The whole is transferred to a 500-cc. flask, and, after cooling, made up to the mark and filtered. Of the filtered liquid 100 cc, representing i gram of the sample, are measured out, heated to boihng, and a shght excess of barium chloride solution added; then without filtering barium hydroxide is added in slight excess, the precipitate filtered off, and washed. To the filtrate is added a little ammonium hydroxide, and ammonium carbonate solution until the barium is pre- cipitated. This precipitate is filtered and washed, the filtrate evapo- rated to dryness, and carefully ignited below redness until all volatile matter is driven off. The residue is dissolved in a few cc. of water, and a few drops of ammonium carbonate solution added. The precipitate, if any, is removed by filtering and washing, and the filtrate evaporated in a small tared platinum dish, ignited below redness, and weighed. * Conn. Agric. Exp. Sta. Rep., 1900, p. 178. • 362 FOOD INSPECTION AND ANALYSIS. This gives the weight of the mixed chlorides. The residue is taken up with hot water, from 5 to 10 cc. of a loSc- solution of platinic chloride added, and the whole evaporated to a sirupy consistency on the wat.r- bath; it is then treated with 80% alcohol, the precipitate washed with 80% alcohol by decantation, transferred to a Gooch crucible, dried l'c icx)° C, and weighed. The weight of the precipitate, multiplied by 0.19308, gives the weight of K2O, and by 0.3056 the equivalent amiount of KCl. The weight of KCl found is subtracted from the weight of the mixed chloride, the remainder being NaCl, which, multiplied by 0.5300, gives the weight of Na^O in the sample. Determination of Phosphoric Acid. — Mix 5 grams of the material with 10 cc. of magnesium nitrate solution, prepared by dissolving cal- cined magnesia in nitric acid, adding magnesia in excess, and filtering, dry, ignite, and dissolve in hydrochloric acid. Remove an aliquot part of the solution, corresponding to 0.25 gram, 0.50 gram, or i gram, neu- tralize with ammonia, clear with a few drops of nitric acid, and proceed according to the usual method, precipitating successively with molybdic solution and magnesia mixture. Determination of Sulphuric Acid. Boil 5 grams of the powder gently for ih hours with a mixture of 300 cc. of water and 15 cc. of concentrated hydrochloric acid. Dilute to 500 cc, draw off an aliquot portion of ico cc, dilute considerably, precipitate with barium chloride, filter through a Gooch crucible, ignite, and weigh. Direct solution of the material without burning the organic matter was proposed by Crampton.* Determination of Ammonia (present in the form of ammonia alum or ammon'um carbonate). Mix 5 grams of the sample with 200 cc. of water, and add an excess of sodium hydroxide. Distil into standard acid, and determine the ammonia by titration. Detection and Determination of Arsenic. — Proceed according to the Marsh or Sanger-Black-Gutzeit method without preliminary treatment (page 64). Determination of Lead. — Method of the Victor Chemical Works. — In the case of phosphate and alum phosphate powders and of acid phosphate weigh I to 2 grams of the material into a small beaker, add 10 to 15 cc. of water and 2 to 3 cc. of concentrated sulphuric acid. Bring to a boil and if starch is present continue the heating on a water bath until the starch is hydrolized, replacing the water lost by evaporation. Cool, * U. S. Dept. of Agric, Div. of Chem., Bui. 13, part 5, p. 596. CEREALS, VEGETABLES, FRUITS, AND NUTS. 363 add 30 to 40 cc. of 95% alcohol, stir and allow to stand over night. If a precipitate of sodium aluminum sulphate appears, due to an excess of alcohol, add water in small amounts until dissolved. Filter and wash with 75 to 80 cc. of alcohol until free from acid. Dry, transfer the bulk of the precipitate to a crucible, digest with hot alkaline ammonium acetate solution (390 grams of ammonium acetate in 1800 cc. of water and 150 cc. of concentrated ammonium hydroxide), filter through the paper previously used, and wash with small portions of the hot solution. After coohng, make up to 50 cc, add i cc. each of 10% potassium, cyanide solution, 1% gelatine solution, and colorless ammonium sul- phide solution. Compare with standard lead solution prepared from a stock solution of 0.160 gram of lead nitrate (dried over sulphuric acid) in 1000 cc. of water (i cc. = 0.0001 gram Pb) and the quantities of alkaline acetate, cyanide, gelatine and sulphide already given. In the case of tartrate powders and cream of tartar shake 10 grams of the material with 50 cc. of water and 40 cc. of 2N ammonia water. Make up to 100 cc, mix and filter through a dry filter. Determine lead colorimetrically in 50 cc. of the filtrate as above, omitting the preliminary precipitation as sulphate. The standard lead solution should be made up using about the same amount of lead-free cream of tartar as in the solution of the material. SEMOLINA AND EDIBLE PASTES. Semolina is the coarse meal ground from certain varieties of hard or " durum " wheats, grown originally in Italy, Sicily, and Prussia, but at present in France and certain parts of the United States and Canada. This hard wheat is high in gluten, and especially adapted for the prepara- tion of macaroni and the various pastes. A peculiar process is employed in preparing the wheat, whereby the husk is removed by wetting, heating, grinding, and sifting, the resulting meal or semolina, being in the form of small, round, glazed granules. Italian Pastes. — Semolina furnishes the basis of the Italian edible pastes, being mixed with warm water, kneaded, and molded into various forms, either by pressure through holes in an iron plate, or otherwise, and finally dried. In parts of Italy juices of carrots, onions, and other vegetables are said to be mingled with the paste, but for local consumption 364 FOOD INSPECTION AND ANALYSIS. only. Saffron is sometimes added to pastes for the purpose, so it is claimed, of imparting a spicy flavor, although the quantity used is often so small as to be apparent only to the eye, thus indicating that the real object of its addition is to impart a color in imitation of an egg paste. Macaroni is the larger of the slender-tube or pipe-shaped products; vermicelli is the worm-shaped variety, produced when the holes in the plate are very small; spaghetti is the term applied to the cord-hke paste intermediate in size between the others. A variety of Italian pastes or pates is made by rolling the kneaded semolina into thin sheets, and cutting out in shapes of animals, letters of the alphabet, etc. The composition of some of these products is as follows: No. of Samples. Water. Protein. Fat. Total Carbohy- drates. Crude Fiber. Ash Fuel Value per Pound. Cal's. Semolina *.. Macaroni f - Noodles t- - - Spaghetti t - Vermicelli f. 3 15 10.50 10.3 10.7 10.6 II. o 11.96 13-4 II. 7 12. 1 10.9 .60 ■9 0.4 2.0 75-79 74-1 75-6 76-3 72.0 0.50 0.4 0.4 0.65 1-3 i.o 0.6 4-1 1665 1665 1660 1625 ♦Balland. t Atwater and Bryant. Noodles are a strap-shaped form of paste made in German households as well as in factories. True, or egg-noodles, contain a certain percentage of eggs, while water-noodles are practically the same in composition as Italian pastes. The difference in composition between water-noodles and noodles made with different numbers of eggs or egg yolks per German pound of flour, is shown by the analyses of Juckenack and Pasternack * given in the following table: f u Composition of the Dry Matter. Composition of the Dry Matter. K^ 0° 4) C c Ash. Total Phos- phoric Acid. Lecithin Phos- phoric Acid. Ether Extract Protein NX6i V 6.. Ash. Total Phos.- phoric Acid. Lecithin Phos- phoric Acid. Ether Extract Protein NX6i ^ ^2i % % % % % % % % % % 0.460 0.2300 0.0225 0.66 12.00 0.460 0.230c 0.0225 0.66 12.03 I 0-565 0.2716 0.0513 1.56 12.99 I 0.488 0.2720 0.0518 1-57 12.37 2 0.664 0.3110 0.0786 2.42 13.92 2 0.516 0.3127 0.0801 2.47 12.73 3 * 0-758 * 0.3482 * 0.1044 * 3-24 * 14.81 * 3 * 0.542 * 0.3520 * 0.1075 * 3-33 * 13.07 * 12 1.426 0.6123 0.2875 7-94 21.09 12 0.745 0.6533 O.3171 8.64 15-71 *Zeits. Unters. Nahr. Genussm., 3, 1900, p. 13; 8, 1904, p. 94. t The German pound is 500 grams; the avoirdupois pound is 454 grams. CEREALS, VEGETABLES, FRUITS, AND NUTS. 365 From these results it appears that the percentages of ash, total phos- phoric acid, and protein are appreciably increased by the addition of each egg or egg yolk, while the percentages of lecithin-phosphoric acid and ether extract are more than doubled by the addition of the first egg, and are increased in corresponding proportion by the addition of two or more eggs. The German Association of Food Chemists require that commercial egg-noodles contain at least 0.045% ^^ lecithin-phosphoric acid, and 2.00% of ether extract, corresponding to the minimum in noodles with two eggs per half kilogram of flour. Spaeth * considers that if the ether extract of noodles has an iodine number over 98, it is safe to assume that they contain no eggs or only traces. Farcy f determines the nitrogen soluble in hot and cold water. In flour or noodles made from flour alone he found about 0.3%, irrespective of whether hot or cold extraction was followed, while with pastes containing 3-5 eggs, the amount soluble in cold water was the same as for water- noodles, but that soluble in hot water was 0.45-0.48%. In interpreting the results of analysis it should be remembered that fat may have been introduced in some form other than in eggs, and that the lecithin-phosphoric acid diminishes somewhat on long standing, although results obtained by Nochmann % indicate that the loss is slight when care is taken to avoid exposure to warm moist air. Allowance should also be made for the variation in composition of the eggs and flour. Of 22 brands of American noodles examined by Winton and Bailey, § only 5 appeared to be made with eggs; the lecithin-phosphoric acid in these ranged from 0.036 to 0.058, and the ether extract from 1.83 to 2.33 per cent, while in the other samples the lecithin-phosphoric ranged from 0.015 to 0.032 and the ether extract from 0.28 to 2.50%. Adulteration of Pastes. — Rice, corn, and potato flours have been used in the preparation of the cheaper varieties of semolina, but rarely in this country. A more common form of adulteration is the substitution of water-noodles for egg-noodles, artificial colors being used to carry out the deception. Substitutions of this kind are detected by determina- * Forschber. Lebensm., 3, 1896, p. 47. t Ann. fals., 7, p. 183. t Zeits. Unters. Nahr. Genussm., 25, 1913, p. 717. § Conn. Agric. Exp. Sta. Rep., 1904, p. 138; Jour. Amer. Chem. Soc, 37, 1905, p. 137. 366 FOOD INSPECTION AND ANALYSIS. tions of lecithin-phosphoric acid and ether extract, supplemented by tests for artificial colors. ANALYSIS OF PASTES. Determination of Lecithin-phosphoric Acid. — Juckenack's Method* — Extract 30 grams of the finely ground material for 10 hours with abso- lute alcohol in a Soxhlet extractor at a temperature inside the extractor not below 55^-60° C. The extraction flask should be provided with a small quantity of pumice stone to prevent bumping during the boiling, and the extractor enclosed by asbestos paper, if the desired temperature is not readily maintained. After the extraction is completed, add 5 cc. of alco- holic solution of potash (prepared by dissolving 40 grams of phosphorus- free caustic potash in 1000 cc. alcohol), and distil off all the alcohol. Transfer the residue to a platinum dish by means of hot water, evaporate to dryness on a water bath, and char over asbestos. Treat the charred mass with dilute nitric acid, filter, and wash with water. Return the residue with the paper to the platinum dish, and burn to a white ash. Treat again with nitric acid, filter and wash, uniting the filtrates. De termine phosphoric acid by the usual method. Determination of Nitrogen Soluble in Hot and Cold Water. — Farcy Method.-^ — Heat 10 grams of the powdered sample and 150 cc. of water in a 200-cc. graduated flask in a boiling water-bath for 2 hours with occasional shaking, cool, make up to the mark, centrifuge, filter, and determine nitrogen in 50 cc. of the clear filtrate. Repeat the operation, digesting at room temperature. Precipitin Test for Eggs. — Arragon and Bornand | proposed the antiserum method of detecting eggs or parts of eggs and Gothe § has de- veloped details for conducting the test. While the test is doubtless valuable in the hands of a trained serologist, the chemical methods seem more practicable for ordinary use. Detection of Artificial Colors in Pastes. — The following colors have been used in noodles and other pastes: turmeric, saffron, annatto, naphthol yellow (Martius yellow), naphthol yellow S, picric acid, aurantia, Victoria yellow, tartrazine, metanil yellow, azo yellow, gold yellow, and quinoline yellow. Of these naphthol yellow, picric acid, metanil yellow, * Zeits. Unters. Nahr. Genussm., 3, 1900, p. 13. t Loc. cit. X Chem. Ztg., 37, 1913, p. 1345- § Zeits. Unters. Nahr. Genussm., 30, 1915, p. 389. CEREALS, VEGETABLES, FRUITS, AND NUTS. 367 and Victoria yellow are injurious to health, and their use is illegal in European countries as well as in the . United States. Fortunately, they are rarely found in the products now on the market. The detection of artificial colors is complicated by the presence of the natural coloring matter of the flour and the lutein of eggs. These are conveniently extracted by ether, which does not remove the artificial colors, although most of them unmixed dissolve freely in this solvent. Juckenack's Method.^ — Thoroughly shake two portions of the finely ground material, each of about lo grams, in test tubes with 15 cc, of ether and 15 cc. of 70% alcohol respectively, and allow to stand 12 hours. {a) If the ether remains uncolored or only slightly tinted and the material below it remains yellow, while the alcohol is distinctly colored and the material is decolorized, a foreign dye is indicated. {h) If both ether and alcohol are colored, either (i) lutein (egg color) alone, or (2) this with a foreign dye is present. 1. Treat a portion of the ether solution with dilute nitrous acid, according to Weyl. If the ether is not completely decolorized, a foreign dye is present. 2. If the deposit of material below the alcohol is decolorized, while that below the ether is colored, tests should be made for foreign dyes as follows:. Shake the portion previously treated with ether with three or more fresh portions of the same solvent, until no more color is extracted, and then shake the residue with 70% alcohol and allow to stand 12 hours. After filtering, concentrate the solution slightly, acidify with hydrochloric acid, boil with sensitized wool, and identify the color in the usual manner (Chapter XVII). SchlegePs Method. -f — Extract 100 grams of the finely powdered material with ether in a continuous extraction apparatus, and shake the residue at frequent intervals for half a day with a mixture of 140 cc. of alcohol, 5 cc. of ammonia, and 105 cc. water. Filter, evaporate to remove alcohol and ammonia, acidify slightly with hydrochloric acid, and again filter. Boil the filtrate with sensitized wool, and identify the color on the dyed fiber by the usual tests (Chapter XVII). Freseniiis Method.X — Extract 20 to 40 grams of the powdered material with ether in a continuous extraction apparatus. Dry the residue to remove ether, shake for 15 minutes with 120 cc. of 60% acetone, and * Zeits. Unters. Nahr. Genussm, 3, 1900, p. i. t Untersuchungsanstalt, Niirnberg, Ber., 1906, p. 34 X Zeits. Unters. Nahr. Genussm., 13, 1907, p. 132. 368 FOOD INSPECTION AND ANALYSIS. allow to stand 12 to 24 hours. Filter, evaporate, until the acetone is removed, and divide into two portions, a larger and a smaller. To the larger portion add sufficient acetic acid to dissolve flocks, and boil with sensitized wool. Remove natural coloring matter from the wool by boiling in dilute acetic acid. If after this treatment the wool is dyed the presence of a foreign color is indicated, which may be identified by the usual tests. To the smaller portion of the aqueous solution, obtained after removal of the acetone as above described, add an equal volume of alcohol, heat to dissolve flocks, divide into four portions, and apply special tests to three of these, reserving the fourth for comparison. The natural color of the flour is decolorized by hydrochloric acid, intensified by ammonia, but not affected by stannous chloride, even on heating. Saffron reacts in a similar manner, but is only slightly bleached by the acid, and is not affected by the other two reagents. Piutti and Bentivoglio Method.^ — This method is especially designed to detect the four colors forbidden by Italian law, and to distinguish these from naphthol yellow S. Add 50 grams of the paste to 500 cc. of boiling water, made alkaline with 2 cc. of concentrated ammonia water, add 60 to 70 cc. of alcohol, and continue the boiling 40 minutes. After filtering, acidify the Ij^^uid with 2 to 3 cc. of dilute hydrochloric acid and boil with 5 to 6 strands of sensi- tized wool, each strand weighing about 0.5 gram. Wash the wool, dissolve the color in dilute ammonia, and repeat the dyeing. After dissolving a second time '11 ammonia, evaporate the solution of the dye to dryness, avoiding as far as possible the formation of a skin, and take up the residue in water. If a skin has formed, filter and test the insoluble matter for metanil yellow with dilute hydrochloric acid, and for picric acid with ammonium sulphide. To I cc. of the filtrate add stannous chloride solution and a little sodium hydroxide, or preferably sodium ethylate. If no red color forms, nitro-colors are absent; if, also, in another portion dilute hydrochloric acid produces no violet color, thus showing the absence of metanil yellow, no further test is necessary. In the presence of these colors, acidify the remainder of the solution with acetic acid, shake violently with carbon tetrachloride, and identify the color according to the following scheme: A. Color dissolves in carbon tetrachloride to colorless solution. Extract with very dilute ammonia, concentrate and divide into two parts. * Gaz. chim. ital. 36, II, 1906, p. 385. CEREALS, VEGETABLES, FRUITS, AND NUTS. 369 1. Acidify with hydrochloric acid, and add i to 2 drops of stannous chloride and ammonia in excess. A rose colored solution and precipi- tate form Naphthol yellow. 2. Acidify slightly with hydrochloric acid, add a little zinc dust and stir. Solution becomes rose-violet Victoria yellow. B. Color is insoluble in carbon tetrachloride. Evaporate to dryness on water-bath, take up in water and divide into three parts. 1. Hydrochloric acid produces a violet coloration Metanil yellow. 2. Ammonium sulphide produces a red brown coloration. Picric acid. 3. Stir on a water-bath with zinc dust and ammonia, filter, treat with zinc dust and hydrochloric acid and again filter, (a) Potassium hydroxide produces a yellow coloration, and {h) ferric chloride an orange coloration. Naphthol yellow S. Schmitz-Dumont Test for Tropeolins.* — Moisten a small portion of the material with a few drops of dilute hydrochloric acid. The formation of a reddish or bluish color shows the presence of an azo color or some other coal-tar color. Martini Test for Saffron.-\ — Tx-eat 50 grams of the finely powdered material in the cold for 24 hours with 100 cc. of 70% alcohol, shaking occasionally, or reflux for 15 minutes. Filter the extract, concentrate to a paste on the water-bath, and extract the residue with ether, thus re- moving interfering colors. Heat the residue on the water-bath until all ether is removed, then add 98% alcohol and continue the heating thus gradually dissolving the saffron color. Filter the alcoholic solution, evaporate on the water-bath, and test the residue which in the presence of saffron takes on a blue color changing to violet, green, and brown with concentrated sulphuric acid and a transient green color with concentrated nitric acids. Test for Turmeric. — Extract the color from the ground material by alcohol and identify by the boric acid test (Chapter XVII). CEREAL BREAKFAST FOODS. The large number and variety of these preparations now on the market testify to the fact that breakfast cereals form a most important, as well as considerable, portion of our food supply. These foods are generally prepared from wheat, oats, corn, and rice, and are, as a rule, remarkably * Zeits. off. Chem., 8, 1902, p. 424. t Bol. chim. farm., 52, p. 37. 370 FOOD INSPECTION AND ANALYSIS. pure and free from adulteration, though the food value of different varieties is often grossly misstated by their manufacturers. Formerly the break- fast food consisted entirely of the coarsely ground, generally decorticated, raw cereal grain, and required a long period of cooking to prepare it for use. At present many of the oat products, and to some extent also those of com, rice, and w^heat, are subjected to a more or less preliminary cook- ing and drying, whereby they are capable of being prepared for use in a much shorter time, and their keeping qualities are enhanced. The so-called rolled oats are prepared by softening the grains through steam- ing, after which they are crushed between rollers and afterwards dri^d. The steaming process is a typical one for various other cereals, though in some cases the heating consists in baking or kiln drying. The effect of the preliminary cooking on the finished product varies somewhat according to whether dry or moist heat has been applied, and is chiefly noticeable in the altered character of the carbohydrates. In all cases the starch is rendered more soluble, whether by the conversion of a portion into dextrin and dextrose, or by a simple breaking down of the starch grains, as in the case of bread in baking. In spite of the seemingly endless variety of the package cereals, they divide themselves as a matter of fact into a very few well-defined classes, the members of which differ but little from each other except in name. First there are the raw cereal grains of the oat, wheat, and corn, pre- pared by simple crushing to various degrees of fineness, after decorticating; next comes the classes of partially cooked preparations of each of these grains, appearing in various forms of "flakes," "granules," "puffs," etc., and again a class known as malted cereals, in which the moist, ground grain is mixed with malted barley, and, by controlling the temperature, a portion of the starch is converted to maltose and dextrin., after which the mixture is crushed between hot rollers and dried. In the preparation of most of the corn breakfast products, such as samp and hominy, it is customary to remove the germ, which contains the oil and fat, lest the tendency of the latter to become rancid should result in the deterioration of the food. In wheat foods the germ is less often removed, and rarely, if ever, in oat preparations. The amount of fat found in the prepared cereal food as compared with that in the whole grain is of interest in this connection. Composition of Some of th,e Common Breakfast Cereals.— The analyses below by Baird * will serve to typify the various classes of these prepara- * N. Dak. Agric. Exp. Sta., Spec. Bui. Food Dept., 3, 1915, p. 395. CEREALS, VEGETABLES, ERUITS, AND NUTS. 371 tions as they appear on the market. Where more than one sample was analyzed the samples were of different brands of the same or different ■manufacturers: AVERAGE COMPOSITION OF BREAKFAST FOODS (BAIRD). No. of Anal- yses. Water. Protein NX6.25 Fiber. Nitrogen free Extract. Fat. Ash. Fuel Value per Lb. Cal. Wheat Products: Farina Rolled Wheat Shredded Wheat .... Flaked Wheat Puffed Wheat Oat Products: Rolled Oats Corn (Maize) Products: Hominy Corn Flakes Corn Puffs Miscellaneous: Force Grape Nuts 8.10 8.97 6.30 6.8s 6.99 6.55 9.48 5 42 6-33 6. 17 2-59 o. 22 2. 26 1. 91 1-45 2. 12 36 1.38 0.41 0.38 0.96 0.91 1.63 80 1.78 1 .40 1. 17 2.06 6.49 •43 .82 0.58 1-59 1 .62 2.65 1.40 0.56 I 0.39 0.25 i 2.76 0.31 ! 0.50 307 1.80 1719 1562 1709 1685 1712 1832 1683 1692 1723 1705 1769 The methods of analysis employed for these preparations are the same as for ordinary cereals (p. 285), the sample being ground fine enough to pass through a i-mm. sieve. PREPARED FOOD FOR INFANTS AND INVALIDS. In dealing with the composition and analysis of this class of proprie- tary foods more than ordinary care is necessary, in view of the fact that one or another of these preparations is frequently prescribed for the exclusive diet of those whose very life may depend on the character and suitability of the food to the case in hand. Many of these foods do, as a matter of fact, honestly fulfil the claims of their manufacturers, but others fall far short of so doing, so that it is hardly safe to use them unless some intelligent idea of their composition can be gained. It is not, as a rule, within the province of the analyst to furnish an opinion regarding the adaptability of a certain food to the requirements of an infant or invalid, but rather to provide the necessary data whereon such an opinion may be intelligently based. 372 FOOD INSPECTION AND ANALYSIS. A simple statement of moisture, fat, protein, carbohydrates (by dif- ference), and ash, which in the case of ordinary foods would often be sufficient, would be obviously inadequate in expressing the analysis of an infant food, since it is of much more vital importance than in other foods to know the solubility of the food itself, and, to as great an extent as possible, the character of the carbohydrates. The chief ingredients of many of these preparations are wheat or mixed cereals high in starch. Many of the foods are, according to the directions, to be used practically without cooking, but by simply mixing with milk or water, and, in some cases, bringing to the boiling-point. Hence the degree of conversion which the raw starch has undergone in the process of manufacture of the food should, if possible, be ascertained as a prime factor in judging of its character and adaptability to the needs of the young child and of the sick. Incidentally it should be said that few if any of the infant foods, even those whose high character has long been established by continued trial, conform very closely to the composi- tion of woman's milk, which was long accepted as the true standard on which to base their efficiency. Hence it is no easy task to pass judgment on a particular food from its chemical composition alone without trial, nor is it right to unqualifiedly condemn in all cases food high in insoluble carbohydrates, since there are undoubtedly many instances in which such foods are successfully used. Preparation. — The soluble farinaceous foods are usually prepared somewhat as follows: A mixture of ground wheat and barley malt (with sometimes a little wheat bran) is mixed with water to form a paste, and a little bicarbonate of potash r.dded. The mixture is heated at 65° C. for sufficient time to convert the starch, after which it is exhausted with warm water, the extract being strained, and the filtrate evaporated to dryness to form the food. The sugars of such foods consist largely of maltose mixed with dextrin. The farinaceous foods, which depend for the conversion of their starch on the method of cooking or heating before serving, are usually mixtures of wheat or other cereal flour with malt or pancreatic extract. The milk foods are variously prepared, either by the simple desicca- tion of cow's milk (usually previously skimmed), or, when whole milk is used, by mingling the desiccated milk with sugars or baked cereal flour. Sometimes desiccated milk is used in mixture with a dried extract of malted cereals. In fact all sorts of mixtures are found on the market, CEREALS, VEGETABLES, FRUITS, AND NUTS. 373 involving, however, in nearly all cases, one modification or another of the above general processes of preparation. Composition. — Few complete analyses of these classes of foods have recently been made. Among the best are those of McGill,* from whose work the following figures have been selected, illustrating typical examples of foods on the market. Robinson's Patent Barley... Ridge's Patent Food Mellin's Infant Food Gristle's Food Benger's Food Allenbury's Malted Food.. . Horlick's Malted Milk Nestle's Food Allenbury's Milk Food No. i Allenbury's Milk Food No. ; Lactated Food Wampole's Milk Food Ekkay's Albuminized Food.. Num- ber of Anal- yses. Water. 9 8 9 6 3 O S 8 8.0 S3 3 I Pro- tein NX 6.25. 7 o 13 2 10.8 6.8 II. 7 lo. I 14.8 Ii-S Total Car- bohy- drates. Cold Water Extract. 81.6 76.0 82.8 83.2 79.1 83.1 70.9 80.2 65.9 68.4 83.6 72.0 87.9 Starch etc. by Diflfer- ence. Q + 76 9t 74 4 4* 46 9 67 3t 6S 3* 8* LS .■? 5* 0* S3 6 8t 35 Fat. 0.9 0.8 0.3 0.7 8.0 Ash. Kind of Starch. Barley Wheat None Wheat Wheat Wheat None Wheat None None Wheat None Arrowroot * Two analyses. t One Analysis, Street f in 1907 -1908 analyzed single samples found on sale in Con- necticut, representing most of the products since analyzed by McGill, but those included in the following table were not apparently found on sale in Canada in 1914. The figures for water extract and starch (direct determination) are not strictly comparable with those for cold water extract, starch, etc. (by difference) as obtained by McGill. Water. Pro- tein NX 6.25. Fiber. Nitro- gen- free Ex- tract. Reduc- ing Sugar as Dex- trose. Starch Water Ex- tract. Fat. Ash. Kind of Starch. 5 9 5 4 3 I 2 S 13.1 13 4 12 3 II. 4 I 0.2 o.S 80.1 71.7 81.0 80.9 37.1 18.8 SI. 4 74.0 0.6 16.2 2.8 3 3 88.4 48.9 79.7 0.4 6.1 1. 1 2.3 o.S 3-2 2.0 2.9 Wheat None Borden's Malted Milk, . . . Carnrick's Soluble Food . Carnrick's Lacto-preparata Diabetic Foods. — Gluten flour and similar preparations are primarily intended for the use of diabetics, from whose dietary carbohydrates must be excluded. * Canadian Dept. of Inland Rev., Bui. 278, 1914. t Conn. Agric. Exp. Sta. Rep., 1907-8, p. 599. . 374 FOOD INSPECTION AND ANALYSIS. The following analyses of commercial gluten preparations were made by Woods and ^lerrill.* "Cooked gluten" Whole-wheat gluten . . "Glutine" Breakfast cereal gluten Plain gluien flour .... Self-raising flour Many brands of gluten flour are put on the market by dealers in so- called " health foods," and in many cases are represented to be practically free from starch. Thirteen samples of gluten flour were analyzed by the author in 1899, varying in price from 11 to 50 cents per pound. Of these, 3, the product of one manufacturer, contained less than i^ of starch, 3 contained from 10 to 2o9c, while 7 contained from 56 to 70*^^ of starch, the substance which, of all others, the diabetic patient tries to avoid. Some of these preparations were little more than whole- wheat flour. An analysis of one of them, known as " Pure Vegetable Gluten," and sold for 50 cents per pound, and of two similar diabetic flours re- ported by Winton, follows: '• Pure Vegetable " Diabetic " Diabetic Gluten." Food." Flour." Moisture 10.78 12.67 9.26 Ash 2.20 0.43 1.30 Fat 3.25 0.90 2.21 Protein 14-25 11.37 14-25 Crude Fiber 0.25 i .03 Sugars I - 70 1 Dextrin 2.551 71-51 66.63 Starch 5^-55 J Undetermined 8.72 2.87 5.32 100.00 100. CO 100.00 Analyses of other preparations have been reported by Street f and vIcGill.t * Maine Exp. Sta. Buls. 55 and 75. t Conn. Agric. Exp. Sta. Rep., 191 2, p. 107. X Lab. Inl. Rev. Dept. Canada, Bui. 354, 1916. CEREALS, VEGETABLES, FRUITS, AND NUTS. 375 Winton has reported the following analyses of flours and meals well suited for the preparation of diabetic biscuit, and of the biscuit made from two of these by a cook in the family of a diabetic patient: Gluten flour Gluten biscuit. In original Calc. water-free. In original Calc. water-free. In original Calc. water-free. Soja bean meal Soja bean biscuit { r- ^ . Calc. water-free. Casoid flour I r^ , ° ': ' : ' Laic, water-free. Almond meal . . 25-58 7-75 27.66 In original j 8.51 Calc. water-free. . . 1 0.24 2-35 3.16 4-38 4-75 5-33 7-37 2.46 2-73 6.42 7.02 85-38 95.00 50-91 68.41 39-87 43.22 16.71 23.10 85-56 95.08 50.62 55-32 J3 Sf^ &H •a a i3W ^ •z u* -03 3-69 0.56 -03 4. II 0.62 .64 3-18 17-34 .86 4-27 23-30 3 -85 25.09 19.06 4 -17 27.20 20.66 I -55 12.84 35-91 2 .14 17-75 49-64 0.50 0-56 15-63 2 .86 15.96 3 .12 17-45 17.09 n! n bo-" 46 96 8-95 9.70 none none .18 ■85 In the analysis of diabetic foods, the determination of starch, sugar and dextrin together is of greater value than of starch alone, since all three classes of carbohydrates are about equally injurious to diabetics, the starch and dextrins being converted into sugars by the digestive fluids. The nitrogen-free extract of cereal preparations corresponds closely with the sum of the starch, sugar and dextrin, but in the case of soja bean meal, almond meal and other products of legumes and oil seeds, as well as vegetables, it is considerably greater, as it includes pentosans and other substances. METHODS OF ANALYSIS. Preparation of the Sample.— Grind sufficiently fine in a mortar or mill to pass through a i-mm. sieve. Determination of Water, Protein, and Ash.— Follow the regular methods for cereal products (pages 285-287). Determination of Fat. — Owing to the presence of gelatinized starch, sugars, and similar incrusting constituents direct ether extraction is usually not admissable. Proceed as with bread, page 343. 376 FOOD INSPECTION AND ANALYSIS. Separation of the Carbohydrates can be effected by Stone's method (pages 304, 305), but a very satisfactory idea of the solubility of these foods, which is of chief importance, can be gained by the determination of the cold water extract and reducing sugars. Determination of Starch, Sugar, and Dextrin.— Determine together in diabetic preparations by the diastase method (page 292) omitting the preliminary washing with dilute alcohol. The results thus obtained with cereal products agree fairly well with the nitrogen-free extract calculated by difference in the usual manner, but this is not true of meal or biscuit made from soy beans, almonds, etc. Determination of Cold-water Extract— McGill Method*— Weigh the equivalent of 10 grams of the moisture-free substance, finely ground, into a tared flask, and add water in several portions with gentle shaking till the contents of the flask weigh no grams. Cork the flask, then vig- orously shake at intervals during 6 or 8 hours and allow to stand over night. Decant the supernatant liquid into the large tubes of a centrifuge and whirl till the sediment settles out. Filter the comparatively clear liquid, transfer 20 cc. of the filtrate, corresponding to 2 grams of the original sample, to a tared dish, evaporate to dryness and dry to constant weight, as in the determination of the total solids. Additional information may be gained from the specific gravity of the 10% solution of the cold-water extract, best obtained by means of a pycnometer. Determination of Reducing Sugars. — Determine in an aliquot part of the above 10% solution, diluted to proper strength. Effects of Subsequent Heating. — It is hardly fair in the case of those farinaceous foods which, according to directions, are to be subsequently subjected to heating, or boiling with water or milk, to condemn them as containing much insoluble matter, without comparing the figures express- ing results of the analyses of the raw foods, calculated to the water- free basis, with those obtained on analyzing the food after boiling or otherwise cooking with pure distilled water, for a length of time specified in the directions, and afterwards drying. It is possible that the presence in the food of diastase, or other ferment, may be depended on to hydrolyze a whole or a portion of the starch, and only by such comparison will this be shown. Lab. Inl. Rev. Dept. Canada, Bui. 59, if CEREALS, VEGETABLES, FRUITS, AND NUTS 377 Microscopical Examination of the food is of value in determining its general character, showing especially whether or not starch is present in its original form, or has been converted in whole or in part. The par ticular varieties of cereal grain employed are generally evident, as well as the presence and proportion of the different tissues of the grain! CHAPTER XI. TEA, COFFEE, AND COCOA. TEA. Nature and Classification. — Tea consists of the prepared leaves or leaf buds of Camellia Thea also known as Thea chinensis. The best teas are made from young leaves only, the Chinese teas being classified with reference to the age and position of the leaf on the young shoot. Thus, the very choicest Chinese tea, rarely found outside of China, is prepared from the youngest or end leaves of the shoot, which are scarcely more than buds, and form the tea known as pekoe tip, or flowery pekoe. The next leaves are the orange pekoe and pekoe, which produce a very high grade of tea, while next in order as to age, size, and grade of leaf are the souchong ist and 2d, and the congou, producing teas called by the same names. More than 50% of the tea consumed in the United States comes from China, and over 40% from Japan, the remainder being derived largely from India, Ceylon, and other East Indian ports. In the manufacture of tea the fresh leaves, which are nearly 80% water, are rolled, withered by exposure to light, heat, and air, and finally dried or "fired" by treatment with artificial heat over charcoal fires, or in properly constructed furnaces. Teas are divided into two groups, black and green, which differ from each other, not as formerly supposed in being derived from different plants, but in their process of manufacture, the same species of plant furnishing both varieties. Genuine green tea is prepared by first steaming and afterwards drying the leaves while still fresh, thus retaining the bright color. Black tea is allowed to undergo oxidation or fermentation by exposure to the sun, which gradually turns the leaves black. Less tannin is present in black tea than in green. 378 TEA, COFFEE, AND COCOA. 379 Composition of Tea. — Konig gives the following composition of fully developed tea- leaves, being the mean of 50 to 70 analyses : j 1 1 Nitroge- ! Water, nous Sub- Theine. ; stances. Essential Oil. Fat.Chlo- rophyl, and Wax. Dextrin, Tannin. ^^^^'"■ etc. 1 ^^'^• Crude Fiber. Ash. 9-51 24-50 3-58 0.68 6-39 6.44 15-65 16.02 11.58 5-65 Though the nitrogenous substances of tea predominate in amount over any other class of constituents, yet, with the exception of theine or Fl«. 72. — a, Flowery Pekoe; h, Orange Pekoe; c, Pekoe; d, Souchong, ist; e, Souchong, 2d; /, Congou; a, b (when mixed together), Pekoe; a, b, c, d, e (when mixed together). Pekoe Souchong. If there be another leaf below /, it is termed Bohea. At base of leaves are buds i, 2, 3, 4, from which new shoots spring. (After Money.) caffeine, they have been little studied. Theine, tannin, and essential oil give to the infusion of tea its chief characteristics. Zollinski * gives the following summarized results of analyses of a number of the cheaper grades of Chinese black tea: * Zeits. anal. Chem., 1898, 37, 365. 380 FOOD INSPECTION AND ANALYSIS. Water. Total Nitrogen. Albumin- oid and Amido- nitrogen. Protein, NX6.2S. Theine. Ash. Soluble Ash. Insoluble Ash. Maximum. Minimum . Average 11-57 9.96 10.58 4.12 3-76 3-93 3-78 3-37 3-52 23-83 21.06 2.06 1. 14 1-55 6.78 4-79 5-94 31-17 28-13 29.67 61.03 57-74 59-75 A very complete series of analyses of tea was made by Joseph F. Geiss- ler in 1884,* from which the following summaries are taken: eg 1 to It 4J c 'S G c Hx. 2 ^< S w« £^ ^ ^< &< G< u5 C Indian: Maximum. . 6 6.1939-66 45-64 53-07 18.86 3-3 5-79 3-68 2.22 .296 Minimum . . 5-56,37-80 41-32148-53 13-04 1.8 5-42 3-24 1-93 -137 Average. S-81 38.7742.94 51-24 14-87 2-7 5.62 3-52 2.12 .178 Oolong: Maximum. . 13 6.88 44.0248.87 53-15 20.07 3-50 6. II 3-71 3-17 .838 Minimum . . 5-09 34.10I40.6 44-8 11-93 I -15 5-44 2.60 1.84 .266 Average S-89 37-8843-32 50-7 16.38 2.32 5.81 3-2 2.68 -507 Congou: Maximum.. 9-15 32.1437.06 63-85 13.89 2.87 6.48 3-52 3-86 1-31 Minimum . . 7-65 23.48127.48 54-5 8.44 1.70 5-52 2.28 1.90 -32 Average 8.37 28.4034.35 57-2 11-54 2-37 5-75 3.06 2.68 ■425 Kenrick f gives the following averages of a series of analyses of tea made by him in 1891: Congou tea. — Assam tea Ceylon tea . Unclassed black Japan Gunpowder . . . Young Hyson. . O t/l IS 10 3 13 Substances Extracted by 10 Minutes' Infusion. 23- 38. 27. 23- 30. 28. 34- -37 5- -53 7- -45 7- .76 5- .07 9- -55 8. .22 10. -65 2.82 2-45 2-39 2.52 3-55 3-69 3-34 3-53 3.62 3-36 3-83 2.2» 2.16 1.88 2-37 2-73 3-70 2.1C 83 4-51 3-81 3-50 The ash of many genuine teas has been examined by Battershal t with the following results: * Am. Grocer, Oct. 23, 1884. ■\ Canada Inland Rev. Dep. Bui. 24. X Food Adulteration and its Detection. TEA, COFFEE, AND COCOA. 381 Oolong. Average of 5° Samples. Japan. Spent Black Tea. Total ash 6.04 3-44 57.00 5-55 3.60 64.55 2.52 28 Soluble in water Per cent soluble Silica Chlorine Potash Soda Ferric oxide Alumina Manganic oxide. Lime Magnesia Phosphoric acid. Sulphuric acid . . Carbonic acid. . , COMPOSITION. 11.30 1-53 37-46 1.40 1.80 5-13 2. 10 9-43 8.00 12.27 4.18 5-40 9-30 1.60 41.63 I. 13 I. 12 4.26 1-30 8.18 5-33 16.62 3-64 5-9° 27.75 0.79 16.00 19.66 11.20 15.80 1. 10 6.70 99.00 Kozai * gives the following as the results of analyses made by him of Japanese teas: Unprepared Leaves. Caffeine or theine Ether extract Hot-v/ater extract Tannin (as gallotannic acid) Other nitrogen-free extract . Crude protein Crude fiber Ash Albuminoid nitrogen Caffeine nitrogen Amido-nitrogen Total nitrogen 3-3° 6.49 50-97 12.91 27.86 37-33 10.44 4-97 4. II 0.96 0.91 5-97 Green Tea. 3.20 5-52 53-74 10.64 31-43 37-43 10.06 4-92 3-94 0-93 1-13 5-99 Black Tea. 3-30 5.82 47-23 4.89 35-39 38.90 10.07 4-93 4. II 0.96 1. 16 6.22 PROXIMATE COMPONENTS AND ANALYTICAL METHODS. Preparation of Sample. — Grind the material so as to pass a sieve with holes 0.5 mm. in diameter. Moisture, Ether Extract, and Crude Fiber are determined in the same weighed portion of 2 grams, by methods described under cereals (p. 285). Acidity determination by hydrogen electrode is described on p. 1035. Bui. 7, Imperial College of Agriculture, Japan. 382 FOOD INSPECTION AND ANALYSIS. Determination of Protein.— Determine total nitrogen by the Kjeldahl or Gunning method; from this subtract the nitrogen due to caffeine (obtained by dividing by 3.464) and multiply the difference by 6.25. Determination of Total Ash. — Burn 2 grams of the material to a white ash in a platinum dish at a faint red heat. The total ash of pure tea should not be less than 4 nor more than 7'^"^. Determination of Soluble and Insoluble Ash.^Transfer the total ash, as obtained above, to a beaker with 50 cc. of hot water, boil, collect the insoluble ash on a Gooch crucible, wash with hot water, dry below redness, and weigh. To obtain the soluble ash subtract the insoluble from the total ash. Determination of Ash Insoluble in Acid. — Proceed as in the deter- mination of water-insoluble ash, using, however, 25 cc. of 10% hydro- chloric acid instead of water for the boiling. Determination of Alkalinity of Ash.* — This is expressed in terms of cc. of tenth-normal acid required for the ash of i gram of sample. Soluble Ash. — Cool the filtrate from the determination of insoluble ash, as described above, and titrate with tenth-normal hydrochloric acid, using methyl orange as an indicator. Insoluble Ash. — Add excess of tenth-normal hydrochloric acid (usually 10 to 15 cc.) to the ignited insoluble ash as obtained above in the platinum dish, heat to the point of boiling over an asbestos plate, cool, and titrate excess of hydrochloric acid with tenth-normal sodium hydroxide, using methyl orange as an indicator. Determination of Essential Oils. — Distil 100 grams of the tea with 800 cc. of water, and shake out the distillate with several portions of ether. The residue from the combined ether extracts contains the volatile oil. Determination of Insoluble Leaf. — Winton, Ogden, and Mitchell Method.-\ — Boil 2 grams of the unground tea for 30 minutes with 200 cc. of water, taking care to so adjust the flame as to avoid appreciable con- centration. Collect the insoluble leaf on a tared filter, d?y on a watch glass until no moisture is apparent, then transfer to the weighing bottle and complete the drying in a boiling water-oven. If the amount of insoluble leaf is above 60^, the presence of spent or exhausted leaves may be suspected. * U. S. Dept. of Agric, Bur. of Chem., Bui. 107 (rev.), p. 69. t Conn. Exp. Sta. Ann. Rep., 1898, p. 132. TEA, COFFEE, AND COCOA. 383 Doolittle and Woodruff * boil for i hour, but in other respects follow the above method. Determination of Extract. — By this term is meant the total amount of water-soluble matter in tea, including such compounds as tannin, caffeine, albuminous matter, dextrin, gum, certain parts of the ash, etc. The value of a tea from a food standpoint depends obviously upon the character and amount of the extract, rather than on the composition of the dry tea. The relative composition of the extract and of the in- soluble leaf, as found by Eder, is given in the following table: Extract. Insoluble Leaf. Dry matter Per Cent. 40. 12. Per Cent. 60. 12.7 7-2 10. 2-3 0.29 0.58 1.03 0.68 Nitrogenous substances Theine Tea oil 2. 0.6 Resin, chlorophyll, etc. 10. 12. 1-7 C.94 0.04 0.13 0.21 Tannin Extractives Ash Potash Lime Phosphoric anhydride Silica The sum of the percentages of insoluble leaf and moisture subtracted from 100 gives the percentage of extract. Determination of Tannin. — Lowenthal- Proctor Method.^ — i. Reagents: {a) Potassium permanganate solution containing about 1.33 grams per liter. Q}) Tenth-normal oxalic acid solution (6.3 grams per liter) . (c) Indigo carmine solution, containing 6 grams indigo carmine (free from indigo blue) and 50 cc. concentrated sulphuric acid per liter. {d) Gelatin solution, prepared by soaking 25 grams gelatin for an hour in a saturated sodium chloride solution, heating till the gelatin is dissolved, and making up to a liter after cooling. (e) Mixture of 975 cc. saturated sodium chloride solution and 25 cc. concentrated sulphuric acid. (/) Powdered kaolin. * U. S. Dept. of Agric, Bur. of Chem., Bui. 150, 1907, p. 48. t Jour. See. Chem. Ind., 3, 1884, p. 82; U. S. Dept. of Agric, Div. of Chem., Bui. 13, )2, p. 890. 384 FOOD INSPECTION AND ANALYSIS. Obtain the value of the potassium permanganate solution in terms of the tenth-normal oxalic acid solution. 2. Process. — Boil 5 grams of the powdered tea for half an hour with 400 cc. of water, cool, and make up to 500 cc. in a graduated flask. To 10 cc. of the infusion (filtered if not clear) add 25 cc. of the indigo car- mine solution and about 750 cc. of water. Then add from a burette the potassium permanganate solution, a little at a time while stirring, till the color becom'^s light green, then cautiously drop by drop till the color changes to bright yellow, or further to a faint pink at the rim, matching in any event the color adopted in standardizing. The volume in cubic centimeters of permanganate furnishes value a of the formula. Mix 100 cc. of the clear infusion of tea with 50 cc. of gelatin solution, 100 cc. of salt acid solution, and 10 grams of kaolin, and shake several minutes in a corked flask. After settling, decant first the clear super- natant liquid through a filter, and finally bring the precipitate upon the filter. Mix 25 cc. of the filtrate (corresponding to 10 cc. of the original infusion) with 25 cc. of the indigo carmine solution, and about 750 cc, of water, and titrate with permanganate as before. The volume in cubic centimeters of permanganate used gives value h. a = quantity of permanganate solution required to oxidize all oxidiz- able substances present. 6 = quantity of permanganate solution required to oxidize substances other than tannin. .'. a — b = c, permanganate required for the tannin. Assuming that 0.04157 gram tannin (gallotannic acid) is equivalent to 0.063 gram oxalic acid, the tannin in the tea h readily calculated. As recommended by Doolittle and Woodruff* the determination may be conveniently made on aliquot portions of the solution obtained in the determination of insoluble leaf. Method of Fletcher and Allen.-\ — This method depends upon the pre- cipitation of the tannin and other astringent matters in tea infusion by lead acetate, the point of complete precipitation being indicated by an ammoniacal solution of potassium ferricyanide. Five grains of neutral lead acetate are dissolved in water, made up to I liter, and after standing the solution is filtered. As an indicator, 0.05 gram of pure potassium ferricyanide is dis- solved in 50 cc. of water, and an equal volume of concentrated ammonia- * U. S. Dept. of Agric, Bur. of Chem., Bui. 105, 1907, p. 49. t Chem. News, 29, pp. 169, 189. TEA, COFFEE, AND COCOA. 385 water is added. This indicator produces a red coloration with tannin, gallic acid, or gallotannic acid in solution, being so sensitive that a drop of the indicator will detect i part of tannin in 10,000 parts of water. Three separate quantities of 10 cc. each of the standard lead acetate solution, as above prepared, are measured into as many beakers, and each diluted to 100 cc. with boiling water. Two grams of powdered tea are boiled in 250 cc. of water, and varying quantities of this decoction are measured from a burette or pipette into the beakers containing the lead solution, the first beaker receiving, say, 12 cc, the second 15 cc, and the third 18 cc, in the case of black tea, and, with green tea, 8, 10, and 12 cc, respectively. About I cc of each of these trial quantities is removed from the various beakers by means of a pipette, passed through small filters, and tested with the ammoniacal ferricyanide indicator, the drops of filtered solution being allowed to fall directly on spots of the indicator, previously placed on a white slab or plate. It is thus easy to ascertain the approximate amount of tea solution which it is necessary to add to produce a pink coloration with the indi- cator, so that by repeated tests, nearly the right amount may be added at once. If no coloration in a given case is produced when a drop of the filtrate from the solution in the beaker is allowed to fall on the drop of indicator solution, a little more of the tea decoction is added, and this process is repeated until the pink color is apparent. It should be noted how much of the tea decoction is necessary to add to 100 cc of pure water, that a drop of the solution may produce the pink coloration with the ferricyanide, and this amount should be subtracted from the amount of decoction found necessary to add to the known lead solution in the beaker. It was found by repeated experiment that 10 cc of lead solution would precipitate 0.0 1 gram of pure gallotannic acid; hence, carrying out the process exactly as above described, 125 divided by the number of cubic centimeters of tea decoction required gives the percentage of tannin in the sample.* Theine or Caffeine (C8H10N4O2). — This alkaloid when pure exists in white silky needles. It is odorless and sparingly soluble in cold water, but more so in hot. It is less soluble in alcohol, and almost insoluble in ether. It readily dissolves in chloroform. It is present * This process estimates the total astringent matter, all of which is counted in as tannin. 386 FOOD INSPECTION AND ANALYSIS. in tea, coffee, and kola. Graf* has shown that the amount of caf- feine present in tea is in most cases proportional to the commercial value and quality. Detection. — Caffeine may be detected, if present in a suspected residue, by the so-called " murexid test," which is made with the material in a solid state, or with the residue from the evaporation of a liquid. A small quantity of the solid or powdered material is heated in a white porcelain dish and covered with a few drops of strong hydrochloric acid, after which a fragment of potassium chlorate is immediately added. The mixture is then evaporated to complete dryness on the water-bath, whereupon, if caffeine is present, a reddish-yellow or pink color is produced. After coohng, the residue is treated with a very little ammonia water apphed on the point of a stirring-rod. In the presence of caffeine, a purple color (that of murexoin) is produced on application of the ammonia. Determination of Theine or Caffeine. — Dvorkovitsch Method. ■\ — Digest ID grams of the powdered tea with 200 cc. of boiling water for 5 minutes and decant the solution; repeat the treatment twice, and boil the residue with 200 cc. of water. Make up the combined solutions to 1000 cc. and extract a portion with petroleum ether to remove fat, etc. To 600 cc. of the fat-free solution (equivalent to 6 grams of tea) add 100 cc. of 4% barium hydroxide solution, mix and filter. To 583 cc. of the filtrate (equivalent to 5 grams of tea) add 100 cc. of a 20% solution of sodium chloride, and extract three times with chloroform. Distil the greater part of the chloroform from the combined extracts, place the residue in a tared dish, evaporate the remainder of the chloroform, dry at 100° C, and weigh. The caffeine is usually of sufficient purity to render a nitrogen determination unnecessary. Doolittle and WoodruffX proceed as follows: Extract in a separating funnel with petroleum ether 225 cc. of the filtrate from the determi- nation of insoluble leaf (p. 382) made up to 500 cc. To the fat-free portion add 50 cc. of a 4% barium hydroxide solution, shake well, and filter. To the filtrate add 50 cc. of a 20% sodium chloride solution and proceed as above described. * Forsch, Ber., 4, 1897, pp. 88, 89. fBer. d. chem. Ges., 24, 1891, p. 1945; U. S. Dept. of Agric, Bur. of Chem., Bui. 107 (rev.), p. 150. X Loc. cit. TEA, COFFEE, AND COCOA. 387 Stahhchmidt Method * Modified by Spencer. '\ — Boil gently 5 grams of the ikicly po.vdered tea in a flask with 420 cc. of water for 30 minutes, cool, add sufficient lead subacetate (solution or powder) to remove pre- cipitable substances, make up to 500 cc, and filter through a dry paper. Delead an aliquot of 400 cc, equivalent to 4 grams, with hydrogen sul- phide, • boil off the excess of hydrogen sulphide, filter, wash with hot water, and evaporate the filtrate to about 50 cc. Shake out the solution in a separatory funnel with several portions of chloroform until all the theine has been extracted, evaporate off the chloroform from the com- bined extracts in a tared flask, and dry the theine 2 hours or to constant weight at 75° C. Bartlett J has found that the Stahlschmidt method in essentially the form given by Spencer gives satisfactory results. Facing. — The most common form of tea adulteration, if such it may be called, is the practice of " facing " the dried leaves, or treating them with certain pigments and coloring materials to impart a bright color or gloss to the tea, thus causing an inferior grade to appear of better quality than it really is. This practice is more often applied to green tea. The materials for facing include such substances as Prussian blue, indigo, plumbago, and turmeric, often accompanied by such minerals as soapstone, gypsum, etc. Only a small amount of foreign material is actually added to the tea, but the adulteration consists in the deceptive appearance imparted thereto. Battershal has examined various samples of the preparations used in Japan for facing tea. He found in one case the following compo- sition: Soapstone, 47.5%; gypsum, 47.5%; Prussian blue, 5%. An- other sample consisted of soapstone, 75%; indigo, 25*^. A third was composed of soapstone, 60%, and indigo, 40%. In applying the facing to the tea, the latter is first heated in an iron pan over the fire, the facing mixture is then added while still hot, and the whole is stirred briskly till the desu-ed color is imparted. The Chinese and Japanese do not face the tea which they themselves consume, but only that intended for export trade. Detection of Facing. — The most delicate test for facing is to examine under the microscope, or lens, the dust obtained by sifting the leaves or the sediment obtained after shaking them with water. Plumbago appears * Pogg. Ann., 112, p. 441. t Jour. Anal. Chem., 4, 1890, p. 390. X Jour. Assn. Off. .A.gric. Chem., 5, 191 7, p. 21. 388 FOOD INSPECTION AND ANALYSIS. glossy black, soapstone gray, gypsum white, Prussian blue, ultramarine and indigo shades of blue, and turmeric yellow, Prussian blue is decolorized by sodium hydroxide solution. Ultramarine is not affected by alkali but is decolorized by hydrochloric acid. Indigo is not decol- orized by either reagent. Read * rubs the siftings with a spatula on sheets of white and black paper and removes the loose dust. The colors after this treatment are recognized under the lens as streaks on the paper. West f detects Prus- sian blue by the blue spots formed by sprinkling the ground tea on filter paper moistened with oxaHc acid solution and drying. Prussian blue if present in considerable amount may be detected in the sediment, as above obtained, by the blue precipitate which forms after dissolving in hot alkali, filtering, acidifying with hydrochloric acid, and then adding a drop of ferric chloride. If the residue on the paper after treatment with hot alkali, on removal to a porcelain dish and treatment with concentrated sulphuric acid, yields hydrogen sulphide (recognized by its odor or by the blackening of lead acetate paper) ultramarine is indicated. Such minerals as gypsum and soapstone are readily separated as a sediment by shaking the leaves in water, and the sediment is examined by the appropriate qualitative methods for these substances. Spent or Exhausted Leaves. — These consist of leaves of tea that have been previously steeped or infused, and afterwards rerolled and dried. Such leaves are sometimes mixed with tea as an adulterant. Any con- siderable admixture of spent leaves is evident, both by the extremely low ash, and the abnormally small proportion of water-soluble ash in the sample. It is rare that the total ash of genuine tea is under 5%, while the soluble ash is seldom less than 3%. The ash of spent tea leaves sometimes runs as low as 2.5%, of which generally not more than 0,3 to 0.8 per cent is soluble. Spent leaves are also naturally low in tannin and in extract. If the extract is much below 32%, spent leaves may be suspected. Allen determines the per cent of spent leaves by subtracting the per cent of extract from 32, multiplying by 100 and dividing by 30. The use of spent or exhausted leaves as an adulterant is very rare at present, though formerly of common occurrence. Foreign Leaves as a Substitute for Tea. — This sophistication is not common, but the detection of leaves other than tea is readily accom- * U. S. Treasury Decision, No. 32322. t Jour. Ind. Eng. Chem., 4, 1912, p. 528. TEA, COFFEE, AND COCOA. 389 plished by a careful examination of the shape and character of the leaves. For this purpose the dried leaves are opened out by soaking a short time in hot water, after which they are spread upon a glass plate, and examined by the aid of a magnifying-glass. The genuine tea leaf (Fig. 73) is very characteristic, and is readily distinguished from other leaves. It is oval or lanceolate, 5 to 8 cm. long and 2 to 3 cm. wide. It is short-stemmed, somewhat thick and fleshy, attenuated at the bottom and usually pointed at the top. At a certain height from the base, from a third to a quarter up, the smooth or wavy border be- comes peculiarly, though not deeply, serrated in a regular manner, the serrations, which are hook-shaped, continuing to the tip of the leaf. Mature leaves always show these serrations, but they are somewhat obscure in young leaf buds. The latter, however, are rarely found in this country. The veins extend outward from the central rib nearly parallel to each other, but before reaching the border, each bends upward to form a loop with the one above. Foreign leaves, said to be used as aduher- ants, are those of the willow, poplar, elder, birch, elm, and rose, but the writer has never found any of these in tea. All of them differ materially from the genuine tea leaf, and if foreign leaves are apparent in a sample under examination, they should be compared with various leaves collected by the analyst for the purpose. Stems and Fragments.-These, as well as '' tea dust," are apparent by an examination of the leaves, opened out in hot water as explamed above. The ash of tea stems and dust is abnormally high. Besson * and Deuss t oppose fixing a maximum limit for stems on the ground that the more expensive sorts often contain more stems than the cheaper. This is due partly to methods of gathering and partly to the presence of sittings with low stem content in the cheaper grades.^ The term " lie tea " is applied to an imitation of tea, consistmg of The Leaf of Fig. 73 Genuine Tea * Chem. Ztg., 39, 1915, P- 82. t Chem. Weekbl., 13, 1916, p. 66. 390 FOOD INSPECTION AND ANALYSIS. fragments, stems, and tea dust, mixed with foreign leaves, mineral matter, gum, etc. The ash of such " tea " has been found as high as 50%. Such imitations are now almost unknown. Make-weight substances, such as brick-dust, iron salts, metallic iron, sand, etc., have been found in tea. If present, they are to be found in the sediment, obtained on shaking out the tea in water. Added Astringents. — Catechu is sometimes said to be added to tea to give it increased astringency, especially to such tea as has been adulter- ated by the addition of exhausted tea. Hagar's method for detecting catechu is as follows: A hot-water extract of the tea (i to 100) Is boiled with an excess of litharge and filtered. To a part of the filtrate, which should be perfectly clear, nitrate of silver is added. If catechu be present, a yellow floc- culcnt precipitate, rapidly becoming dark-colored, is formed. Pure tea treated in like manner gives a gray precipitate. Spencer * adds, instead of silver nitrate, a drop of ferric chloride to the clear filtrate. With catechu a green precipitate is formed. As a matter of fact the worst forms of tea adulteration, such as the actual substitution of foreign leaves, once so commonly practiced, are now extremely rare in this country and have been for some years, by reason of the careful system of government inspection in force at the various ports of entry. The greater portion of the tea on our market to-day is genuine, but fraud is practiced to l considerable extent by the substitu- tion of inferior grades for those of good quality. This form of deception is in many cases beyond the power of the analyst to detect, and properly comes within the realm of the professional tea-taster. Tea Tablets. — Finely ground tea of varjdng quality is sometimes pressed into tablets, to be used by travelers and campers for preparing a beverage, by simply dissolving in hot water. The composition of one of these preparations sold under the name of Samovar Tea Tablets, analyzed by the Mass. State Board of Health, is as follows: Water 8.7 Theine 2.25 Extract 54.4 Ash 5.4 Soluble ash 2.8 Insoluble ash 2.6 * U. S. Dept. of Agric, Div. of Chem., Bui. 13, p. 885. TEA, COFFEE, AND COCOA. 391 Microscopical Structure of Tea. — The powdered tea may be examined directly in water-mount. Schimper recommends treating the powdered tea with chloral hydrate or potash lye, to render it more transparent. By far the most characteristic element is the peculiarly shaped sclerenchyma, or stone cell, st, Fig. 74, entirely unlike anything to be found in other leaves. These cells are very irregular in form, being sometimes star-shaped, sometimes branched, almost always with deeply wrinkled sides, Fig. 74. — ^Powdered Tea under the Microscope. Xi6o. g, end of leaf nerve; p, chloro- phyll parenchyma; st, stone cells; h, hairs. The tissues were warmed in potash to render transparent. (After Moeller.) and often with sharp points. In most foreign leaves such sclerenchyma cells are lacking, but they are abundant in all genuine tea leaves, excepting rarely in the very young leaves, where they are sometimes not fully devel- oped. They are especially numerous in the main vein and in the stem. They may be seen to best advantage in a section of the stem, or midrib, made parallel to the surface of 'he leaf. To make such a section, soak the leaf first in water, and afterwards dry in alcohol. The interior of the leaf is composed chiefly of ground tissue, having rounded cells full of chlorophyll grains and the fibro-vascular bundles of the veins. Other important characteristics are the peculiar hair growth on the under epidermis, B, which is apparent in nearly all teas, also crystal rosettes of calcium oxalate, which are nearly always present, even in fragments of tea leaves, but not in all foreign leaves. The peculiar structure of the lower epidermis, B, with its numerous stomata is also to be noted. See Figs. 189 and 190, PI. XVIII. 392 FOOD INSPECTION AND ANALYSIS. COFFEE. Nature of Coffee. — Coffee is the seed of the Coffea arabica, a tree which, when under cultivation, is not allowed to exceed twelve feet in height, but when wild sometimes reaches a height of twenty feet. It is indigenous in Southern Abyssinia, and was cultivated in Arabia in the sixteenth century, and in the East Indies in the seventeenth, afterward being introduced into the West Indies and South America. The coffee- beans are usually inclosed in pairs in the berry, being plano-convex with their flat sides together but in " pea berry " coffee only a single, rounded bean is present. When the ripe fruit is gathered, it is first dried and then freed from the hulls, usually by machinery, or, in the West Indies, the green berries are " pulped " or " hulled " under water by a peculiar macerating machine. The raw beans are roasted, and afterwards ground for preparing the infusion. The principal varieties now on the market are true or Arabian Mocha produced in the Yemen district and shipped from the port of Aden, Abys- sinian or long berry Mocha, Java produced on the island of Java under government supervision, Rio and Santos, the leading Brazilian varieties shipped from the ports of Rio Janeiro and San Paulo respectively, Mara- caibo a Venezuelian coffee, and Bogota produced in Colombia. Porto Rican and other West Indian varieties, also the product produced in the islands of the Pacific, often shipped under the name of Java, and various African coffees, are of considerable importance. Brazil furnishes more than half the world's supply of coffee, and nearly 75% of that consumed in the United States. Constituents of Coffee. — Most of the coffee in the retail market is roasted, being sold either in the whole bean or ground. The chief constituents of raw coffee, besides water, are oil, cellulose, sugar, pentosans, dextrins, " caff e tannic acid " (chlorogenic and coffalic acids), protein, caffeine, coffearine (an alkaloid), and ash. During roasting the sugar is largely caramelized, the caffetannic acid reduced, the bean rendered less brittle, and certain flavors are developed. Various substances have been named as products of roasting. Of these caffeol, a volatile oily substance, has long been considered the chief aro- matic constituent, but its identity is now disputed. Several authors have detected pyridine. There is a slight loss of caffeine during roasting. TEA, COFFEE, AND COCOA. 393 The following summary of analyses of coffee of various kinds made by Konig show in general its composition: Raw CofEee. Roasted Coffee. Minimum. Maximum. Minimum. Maximum. 8.0 12.0 0.4 4.0 0.8 1.8 0.8 1.8 II. 4 14.2 10-5 16-5 S-8 7-8 0.0 I.I i6.6 42.3 26.3 51.0 I.I 2.2 1-3 2.7 3-5 4.0 4.0 5-0 Water Caffeine Fat Reducing sugar, Cellulose Total nitrogen. Ash The change in composition that takes place in roasting coffee is well shown by the following figures, which give the mean of analyses by Konig of four samples of coffee before and after roasting: Water Caffeine Fat Sugar Cellulose Nitrogenous substances Other non-nitrogenous matter Ash Raw Coflee. Roasted Coflee 11.23 I-15 1. 21 1.24 12.27 14.48 8-55 0.66 18.17 10. 8g 12.07 13.98 32-58 45-09 3-92 4-75 COMPOSITION OF THE ASH OF COFFEE.* Constituents. Sand Silica (SiOj) Ferric oxide (Fe20J. . . Lime (CaO) Magnesia (MgO) Potash (K„0) Soda (NaoO) Phosphoric acid (P2O5). Sulphuric acid (SO3). . . Chlorine (CI) Mocha. Maracaibo. Java. Riu. 1-44 0.88 0.89 7.18 10.68 59-84 0.48 12.93 4-43 1.25 0.72 0.88 0.89 5.06 11.30 61.82 0.44 13.20 5-10 0-59 0.74 0.91 1. 16 4-84 11-35 62.08 14.09 4.10 0-73 I 00 . 00 1.34 0.69 1-77 4.94 10.60 63.60 0.17 11-53 4.88 0.48 The following are analyses of common varieties of roasted coffee, also of coffee substitutes and adulterated coffee made by Lythgoe:t * U. S. Dept. of Agric, Div. of Chem., Bui. 13, p. 904. t An. Rep. Mass. State Board of Heahh, 1904, p. 3r!o. U. S. Dept. of Agric, Bur. of Chem., Bui. 90, pp. 43-45- 394 FOOD INSPECTION AND ANALYSIS. COMPOSITION OF ROASTED COFFEE. Alka inity (cc. M/io < Add) of A J2 c .2 22, E« .c S Variety. 6 '3 'o < 1 M _c 2^ CM a Oc/3 < < E 2 d "0 w Ji 1 c W a, •3 ^A 1 .40 4.16 3-46 0.00 0.023 2.97 71.4 0.319 0.346 14-58 1-4754 2.26 Santos E 1.87 4 31 3.62 .00 .023 3-3b 75-7 .286 -295 13-84 1-4754 2.26 ,C I-3I 3 80 3.00 .00 .019 3-35 85.6 -273 -295 13.86 1.4750 2-39 Porto A 1.29 4 05 3-30 .00 .016 3-53 87.2 -305 -337 13.00 1-4752 2.28 Rico B 1.26 4 Ob 3-27 .00 .020 3-72 92.6 .226 -351 13-34 1.4750 2.26 C 1.48 4 12 3-32 .00 .016 3.66 88.8 •333 -328 14.12 1.4760 2-33 A 1.76 4 06 3-40 .00 .020 4.16 102.3 .213 .166 13-38 1.4758 2.14 Rio a 2.34 3 Qi 3-24 .00 .021 3-17 81.2 .356 .227 13-71 1.4753 2.18 ■i c 2.10 3 74 3.06 .00 .023 3-22 86.6 .363 -236 13-53 1.4756 2.26 A 2.05 4 05 3-25 .00 .016 3-94 97-4 .282 -351 14.84 *i.4737 2.28 Mocha B 2-95 3 H5 3-07 .00 .021 3.26 84-7 ■333 -364 14.47 *i.4743 2.00 [c 2.40 3 80 3.00 .00 .012 3-54 93-3 -337 -545 15.18 *i.4740 2.02 A 3-34 4 oq 3-27 .00 .016 3.88 95-0 -^58 .421 12.61 1.4752 2.48 Java B 3-35 4 3« 3-56 .00 .019 3-54 80.8 .194 .3S8 12.28 1.4758 2.35 c 3-44 3 q6 3.10 .00 .oil 2-95 74.5 -235 -3H3 13-54 1-4752 2.56 Highest- .. 3-44 4 3« 3.62 .00 .023 4.16 102.3 .424 - 545 15.18 1.4760 2.56 Lowest. . 1.26 3 74 . 3-00 .00 .011 2^95 71.4 .194 .166 12.28 1-4750 2.00 Average . 2.16 4 03 3.26 .00 .018 3-55 87.1 .285 ■329 13-75 1-4754 2.27 Ten Per Cent Extract. 4.1 u ■«-> 6 >^ 1 X a 0) N Variety. u 2 w "0 M M M 5 Xi a > in « M E c •0-2 •d 3 •0 ^ •d S^ c ca u ££°o 3 J3 D. s < O^H w M w < 'A 20.80 16.8^ 0.52 2.28 13-41 1-25 I. 0107 26.7 1.33770 2.64 0.40 Santos \ a 22.72 17. II .68 I. 00 II .02 I. 10 I. 0108 26.9 1.33777 2.66 .39 c 21.70 17. So .75 2.32 14-71 1.20 I.OIOI 26.0 1.33743 2.46 .30 Porto Rico 1 A 22.48 15-70 .50 2.17 13. II 1-38 I. 0107 26.6 1.33766 2.60 .37 ^ 21.76 16.36 -63 1-58 12.93 I. 21 I. 0104 26.3 1-33754 2.50 -3t> [c 24.44 16.91 -54 2.62 12.50 1.32 I.OII3 27.6 1.33804 2-77 .30 A 22.66 17.00 .68 2.82 14.08 I. II I. 0103 25-5 1-33724 2.48 .40 Rio i^ 22.61 17-34 .78 1-47 13.10 I. 10 I.OIOI 25-8 1.33735 2.46 -36 c 22.75 17-37 .61 2.62 II. 91 I. 17 I.OIOI 26.0 1.33743 2.46 .30 A 24.00 18.01 1.78 2.30 11.22 I. 16 I. 0106 26.4 1.33758 2.65 .40 Mocha ■ i^ 20.27 17.96 .94 1.8s 12.34 I. 10 I.OIOI 26.3 1.33754 2.47 .36 c 24.18 19-55 1.42 2.90 13.20 I. 18 I.OIII 27-3 1.33793 2.72 .40 A 23.85 15-95 .32 2.95 13.43 1-34 I.OIIO 29.6 1.33777 2.63 .39 Java \ ii 22.19 15-45 .42 2.32 13-77 1.30 I. 0107 26. e; 1.33762 2.58 .38 c 23.20 16.21 .66 3-34 14-75 1.27 I. 0108 26.6 1.33766 2.62 .38 Highest. . 24.44 19-55 1.78 3.34 14-75 1.34 I.OII3 27.6 1.33804 2.77 .40 Lowest. . 20.27 16.45 .32 1. 00 11.02 1. 10 I.OIOI 26.0 1-33743 2.46 •30 Average . 22.63 17-03 -75 2.30 13-03 I. 20 I. 0105 26.6 1.33766 2.72 -37 * Omitted from average. TEA, COFFEE, AND COCOA. 395 COMPOSITION OF COFFEE SUBSTITUTES AND OF ADULTERATED COFFEE. 6 o 4 < J3 < _2 •J} Id C G Alkalinity (cc. N/io Acid) of d 3 3 c5 a, C .0 2 '^ ^! -22 c Variety. M < < B ca 2 •3 Roasted wheat. Roasted chicory Coffee and chicory Coffee, chicory and pea hulls 5.60 5-55 5.08 3-64 5-71 4-37 3-96 4.97 2.82 2.27 3-14 4-05 0.00 .81 .06 -24 0.080 .026 *.284 0.34 -95 3-05 2.60 6.0 21.8 77.0 65.6 0.64Q .277 .286 .472 I .460 -314 -323 .740 2.40 .88 8.32 9-56 1-4745 1.84 1. 10 1.89 2.17 1 w u u 2 X w ■3 < !3 G '3 3 •a 0) s p u 0) 3 •V c 'S Ten Per Cent Extract. Variety. 1 C JJ DO .2 E c i) u a ^1 -3-2 (U g c ■a 1 Roasted wheat 25-88 72.92 31-79 25.00 10.72 34-39 21.66 14-25 4.10 19-34 5.06 3.00 28.58 2.10 2.21 3-78 6.23 5-91 14-31 17.87 0.00 .00 ■95 1. 00 Roasted chicory Coffee and chicory Coffee, chicory and pea hulls 1.0307 I. 0142 45-0 30-5 1-34463 I -33915 7-44 3.62 0.26 .29 * Admixture of salt. METHODS OF ANALYSIS. Preparation of the Sample. — Grind so as to pass a sieve with holes 0.5 mm. in diameter. Determination of Moisture, Ether Extract, Fiber, Protein, and Ash (including total, water-soluble, water-insoluble, acid-insoluble and alka- linity) is carried out as in the case of tea pp. 381 and 382). Starch, Re- ducing Matters by Acid Conversion, Sucrose, and Reducmg Sugars may be estimated as in cereals, Acidity as described on page 1035. Determination of Ten per Cent Extract. (See page 403). Determination of Caffetannic Acid. — Krug Method* — Although so- called caffetannic acid has been shown to be a mixture of chlorogenic * U. S. Dept. of Agric, Div. of Chem., Bui. 13, p. 908. 396 FOOD INSPECTION AND ANALYSIS. and coffalic acids, the method of determining this mixed substance is still retained. Two grams of the coffee are digested for 36 hours with 10 cc. of water, after which 25 cc. of 90% alcohol are added, and the digestion continued for 24 hours more. The Hquid is then filtered, and the residue washed with 90% alcohol on the filter. The filtrate, which contains tannin, caffeine, fat, etc., is heated to boiling and a boiling concentrated solution of acetate of lead is added, which precipitates out a caffetannate of lead, Pb3(Ci5H 1508)2, containing 49% of lead. When this has become flocculent, it is separated by filtra- tion, and washed on the filter with 90% alcohol, till the washings show Mk II. Fig. 75. — Coffee. I. cross-section of berry, natural size. Pk outer pericarp; Mk endocarp; £)fe spermoderm; 5(1 hard endosperm; 5/* soft endosperm. II. Longitudinal section of berry, natural size; Dis bordered disc; Se remains of sepals; Em embryo. III. Embryo enlarged; co/ cotyledon; rad radicle. (Tschirch and Oesterle.) no lead with ammonium sulphide, and afterwards with ether, till free from fat. It is dried at ioo° and weighed. The weight of caffetannic acid is obtained by multiplying the weight of the precipitate by 652, and dividing by 1263 63. Woodman and Taylor's Modification.^ — To 2 grams of finely ground coffee (passing 0.5 mm. sieve), add 10 cc. of water, and shake for an hour in a mechanical shaking device. Add 25 cc. of 90% alcohol and shake again for half an hour. Filter and wash with 90% alcohol. Bring the united filtrate and washings, about 50 cc, to boiling, and add 6 cc. of saturated lead acetate solution. Separate the precipitated lead caffe- tannate by means of a centrifuge, decanting the supernatant liquid through a tared filter. Repeat the centrifugal treatment twice with 90% alcohol, decanting each time through the filter. Transfer the precipitate to the filter, and wash free from lead. Wash with ether, dry at 100°, and U. S. Dept. of Agric, Bur. of Chem., Bui. 122, p. 82. TEA, COFFEE, AND COCOA. 397 weigh. The weight of the precipitate multipUed by 0.516 gives the weight of caffetannic acid. Caffeine. — Gorter Method* — Moisten 11 grams of the finely powdered coffee with 3 cc. of water, allow to stand for half an hour, and extract for 3 hours in a Soxhlet or Johnson extractor with chloroform. Evaporate the extract, treat the residue of fat and caffeine with hot water, filter through a cotton plug, and wash with hot water. Make up the filtrate and washings to 55 cc, pipette off 50 cc, and extract four times in a separatory funnel with chloroform. Evaporate this chloroform extract in a tared flask, dry the caffeine at 100° C, and weigh. Calculate the caffeine also from the nitrogen content. Lendrich and Notthohm Method.^ — This method is recommended by Murray % for the examination of decaffeinated coffee and other prepara- tions containing small amounts of caffeine, as it yields lower and more accurate results than the Gorter method. Moisten 20 grams of the sample, ground to pass a i-mm. mesh, with 10 cc of water, stir occasionally for 1-2 hours, and extract 3 hours with carbon tetra-chloride in an extraction thimble. To the extract add I gram of paraffin, distil off the solvent, and exhaust the residue with I portion of 50 cc. and 3 of 25 cc. of boiling water. Cool the combined aqueous extract, filter through a moistened paper, wash with hot v/ater, add 10-30 cc. of 1% potassium permanganate solution, and allow to stand 15 minutes. Precipitate the excess of manganese as peroxide by means of a little 3% hydrogen peroxide solution containing 1% oi glacial acetic acid added drop by drop, heat 15 minutes on a boiling water- bath, filter, wash with boiling water, evaporate the filtrate to dryness, and dry further in a boiling water-oven. Exhaust the dry residue with warm chloroform, decanting into a tared dish, remove the chloroform by evapora- tion, dry the residue 30 minutes in a boiling water-oven, and weigh the caf- feine. Murray recommends that nitrogen be determined in the weighed residue as in the Gorter method. ADULTERATION OF COFFEE. According to the U. S. Standard roasted coffee is coffee which, by the action of heat, has become brown and developed its characteristic aroma, and contains not less than 10% of fat, and not less than .3% of ash. * Annalen, 1908, 358, p. 327. t Zeits. Unters. Nahr. Genussm., 17, 1909, p. 241. X Jour. Ind. Eng. Chem., 5, 1913, p. 668. 398 FOOD INSPECTION AND ANALYSIS. Imitation Coffee. — Formerly, artificial coffee-beans containing no coffee whatever, but cleverly molded to imitate the original, were occa- sionally to be found, mixed with genuine, whole coffee. " Coffee pellets " are occasionally sold in bulk to dealers as an adulter- ant of whole coffee. These do not closely resemble the real berries in appearance, but are approximately of the same size, and are not apparent to the purchaser when the whole coffee is ground at the time of purchase. A sample of these " pellets " examined recently was found to consist of roasted wheat mash, colored with red ocher. Coloring Coffee Beans. — The practice of treating raw coffee beans in a manner somewhat analogous to the facing of tea leaves has been sometimes practiced, with a view to giving to cheaper or inferior grades the appearance of high-priced coffee. For this purpose various pigments have been employed, such as yellow ocher, chrome yellow, burnt umber, Venetian red, Scheele's green, iron oxide, turmeric, indigo, Prussian blue, etc., the coffee beans being first moistened with water containing a little gum, and shaken with the pigment. As a rule such pigments, especially when inorganic, are best sought for either in the ash, or in the sediment obtained by shaking the coffee beans in cold water, using the ordinary qualitative chemical methods. Organic coloring matters can be best extracted with alcohol. Prussian blue and indigo are tested for as in the case of tea leaves (p. 387). Glazing. — This is a more recent form of treatment of the whole bean, which consists in coating the beans by dipping in egg or sugar, or a mix- ture of the two, sometimes using various gums. Such glazing is alleged to improve the keeping qualities of the coffee, as well as to aid in clarify- ing the infusion, and if this is the sole purpose, the practice cannot be condemned as a form of adulteration. If, however, it is done to give inferior varieties of coffee a better appearance, in order to deceive the consumer, it clearly constitutes adulteration within the meaning of the law. Adulterants of Ground Coffee. — Of the adulterants used in ground coffee the following have been found in Massachusetts: Roasted peas, beans, wheat, rye, oats, chicory, brown bread, pilot bread, charcoal, red slate, bark, and dried pellets, the latter consisting of ground peas, pea hulls, and cereals, held together with molasses. Methods of Detecting Adulterants. — These methods are, as a rule, physical rather than chemical. A rough test of the genuineness of ground coffee consists in shaking some of the sample in cold water. Pure coffee. TEA, COFFEE, AND COCOA. 399 under these conditions, usually floats on the surface, while the ordinary adulterants, such as cereals, chicory, mineral ingredients, etc., sink, th? grains of chicory coloring the water a brownish-red as they subside. Macfarlane recommends the use of a saturated solution of common salt, in which a portion of the suspected sample, divided in small grains, is shaken in a test-tube. If the liquid is colored pale amber, while all or nearly all the material floats, the coffee is pure. Any considerable sediment at the bottom of the tube, accompanied by a dark-yellow to brown color imparted to the liquid, indicates adulteration by roasted cereals, or chicory, or both. A careful examination of the coarsely crushed grains of a ground sample with the naked eye will often serve to detect, and in some cases identify, certain adulterants, such as chicory and ground peas or beans. A magnifying-glass will aid in such an examination, and the observer can often separate the various ingredients of a coffee mixture, first spread- ing a small portion of the sample on a sheet of white paper. The chicory grains are apparent from their dark and somewhat gummy appearance, and can usually be recognized by crushing them between the teeth. Their soft consistency and sweetish bitter taste are very distinctive. The dull outer surface of the crushed coffee grains is in marked contrast to the polished appearance of the surface of the broken peas or beans, often to be found as adulterants, while fragments of broken cereal grains are readily distinguished from coffee with a low-power magnifier, though perhaps not easily identified by the eye alone. Determination of Added Starch. — Starch is determined in the finely powdered sample as directed on page 292. Microscopical Examination of Coffee. — By far the best means of detecting adulteration is furnished by the microscope. The individual grains of coarsely ground coffee and adulterants, separated by the cold water test or by picking over the mixture, are identified by microscopic examination either after sectioning with a razor or crushing to a powder. In addition, examination is made of a. small portion of the sample pulver- ized in a mortar to a degree fine enough to allow the cover-glass to lie flat on the wetted powder, yet not so fine that it ceases to feel granular when rubbed between the fingers. The writer finds it sufficient to examine this powder in water without further treatment, although Schimper recommends maceration for twenty-four hours with ammonia, in order to render the tissues more transparent, using this reagent also as a mountant. 400 FOOD INSPECTION AND ANALYSIS. In general the interior of the coffee tissue or endosperm consists of polygonal cells with highly characteristic, knotty, thickened walls, which are best seen in razor sections, Fig. 76, 2. These cells contain brilliant, colorless, spherical oil drops, and also proteins. The seed coat is also very characteristic, showing in the powder as occasional delicate silver-like patches, with peculiar, spindle-shaped, thick-sided cells, some of which are loosened from the tissue. Plates XIV and XV illustrate photomicrographs of pure and adulter- ated coffee. Fig. 174 shows genuine coffee, with its loose mesh of irreg- ularly polygonal cells, thick-walled, and inclosing oil drops with amor- phous material. It is not to be expected that every pulverized sample of genuine coffee, mounted as above, will show in every microscopic field the even, continuous structure that Fig. 174 illustrates, but careful examination will show in nearly every field fragments, and more or less disjointed por- tions of the polygonal cells, grouped in the form so characteristic of coffee. See Fig. 176. Chicory under the Microscope. — Fig. 77, after Moeller, shows struc- tural features of chicory. The most striking elements are the fine, thick- walled, long-celled, parenchyma of the. bark rp and hp with its delicate tracery, and the vcssils or ducts g of the wood fibers. These ducts are tubular, resembling jointed cyhnders, often with overlapping joints. Less distinct, but very characteristic of certain roots of the composite family, are the narrower branching milk ducts sch which do not exist in beets and turnips, which are sometimes substituted for chicory. Fig. 178, PL XV, is a photomicrograph of an adulterated sample of coffee, showing in this particular field chicory alone. It is a mass of con- fused cellular tissue, traversed by two broad bands of the vessels, with their striking, transverse, dotted markings. Fig. 177, PL XV, shows a sample of coffee adulterated with roasted peas and pea hulls. No genuine coffee appears in this field. The chief masses in the center are characteristic aggregations of the round starch granules of the roasted pea. The rectangular billets, like bunches of matches, are from the outer or palisade layer of the pea. Fig. 164, PL XI, and Fig. 154, PL IX, show the close resemblance between the starches of the pea and bean, both of which are commonly used in coffee. The palisade structures of the hulls of these legumes also bear a close resemblance, but the cells of the next layer in the pea are hour-glass TEA, COFFEE, AND COCOA. 401 Fig. 76.— -Powdered Coffee under the Microscope. X125. (After Moeller.) i, seed coat (surface). 2, endosperm parenchyma. qic 'T WWim Fig. 77. — Chicory Root in Tangential and Radial Sections. X160, g, reticulated ducts with perforations qu; hp, wood parenchyma; /, wood fibers; rp, bark parenchyma; sch, milk ducts; bp, bast parenchyma; nt, medullary rays. (After Moeller.) 402 FOOD INSPECTION AND ANALYSIS. shaped, while in the bean they are not remarkable for their shape, but for the single crystal of calcium oxalate contained in each. The effect of roasting on starches used as adulterants of coffee is to twist and distort the granules, in some cases destroying largely the even structure of the raw starch. Starch granules of wheat, barley, and rye, for example, are almost perfect circular disks in the case of the raw starch, while in roasted products, such as pilot biscuit and stale bread, the granules are twisted and distorted, sometimes almost forming the letter " S." Use of Chicory in Coffee. — Chicory is a perennial herb {C'.c'iorium intyhus) of the same family {Composite) as the dandelion. The roasted and pulverized chicory root is so much used in ground coffee to impart a peculiar flavor thereto, that by many it is considered as not strictly an adulterant. The taste imparted to coffee by a small admixture of pure chicoiy is to some desirable, but if its unrestricted use is sanctioned in this manner, the door would soon be opened to a more unlimited form of adulteration, wherein the chicor}^ might predominate. It is, therefore, best to regard chicory as an adidterant, and to require the package con- taining a mixture of coffee and chicory, if sold legally, to have plainly printed thereon the percentage of chicory in the mixture. Chicory, when roasted, consists of gum, partly caramelized sugar,, and insoluble vegetable tissue. Common adulterants of chicory are dried beets and other roots, also cereal matter. Villiers and Collin * give the following analyses of two samples of chicory. See also analysis of roasted chicory on page 395. Soluble in water: Insoluble in water: Water (loss at ioo° to 103°) Weight of total matter soluble in water. Reducing sugar Dextrin, gum, inulin Album inoids Mineral matter . Coloring matter ' Albuminoids Weight of the total insoluble matter. . .. •| Mineral matter Fat [ Cellulose In Large Granules. 16.28 57-96 26. 12 9-63 3-23 2.58 16.40 3-15 25.76 4-58 5-71 12.32 In Powder. 16.96 56.90 23-79 9-31 3.66 2-55 17-59 2.98 26.14 5-87 3-92 13-37 * Falsifications et Alterations des Substances Alimentaires, p. 234. TEA, COFFEE, AND COCOA. 403 Detection and Estimation of Chicory. — Various chemical tests for detection of chicory in coffee infusions have been suggested, depending on color reactions,* but these are, as a rule, unreliable. By far the best means for detecting chicory in cofifee is furnished by the microscope. In mixtures containing coffee and chicory only, the approximate amount of the latter can be obtained by McGill's method,t as follows: Weigh a quantity of the pulverized sample, corresponding to lo grams of the dry substance, into a counterbalanced flask, and add water till the weight of the contents is no grams. Bring to boiling in ten to fifteen minutes and continue the boiling for an hour under a reflux condenser. Cool for fifteen minutes, pass through a dry filter, and determine the specific gravity at 15°. McGill found the average specific gra\ity of a 10% decoction as above carried out to be, in the case of pure coffee 1.00986, and in the case of chicory 1.0282 1, the difference being 0.01835. The specific gravity of the 10% decoction of the suspected sample at 15° being d, the per cent of chicory, c, can be calculated roughly by the formula: (1.02821 —d)ioo c= 100 — — . 0.01835 As a means of detecting chicory in the beverage La Wall J determines the amount of extract and the percentage of reducing sugars in the extract. The latter in genuine coffee ranged from 1.92 to 2.64%, whereas in two samples of chicory it was over 25%; consequently addition of 5 parts of chicory to 100 parts of the coffee showing the highest ratio, increased the percentage of reducing sugar in the extract to 4.6. Date Stones, roasted and ground, have been used to some extent as a coffee adulterant. Fig. 78 shows the structural features of date stones under the microscope. End represents a fragment of endocarp with its elongated, thick-walled cells, peculiarly arranged as shown, adjacent cells often lying with axes at right angles to each other. The more evenly formed episperm cells, e, are thin-walled and of a brown color. The albumen, a, is made up of very thick-walled, somewhat regularly arranged cells, indented from within with deep channels. Date stones are readily distinguished from coffee by these features. * See Allen's Commercial Org. Analysis, 4 Ed., Vol. VI, pp. 671, 672. t Trans. Royal Soc. of Canada, 1887. t Am. J. Pharm., 1913, p. 535. 404 FOOD INSPECTION AND ANALYSIS. Hygienic Coffee. — Various processes have been devised for removing the caffeine from coffee. One of these, patented in Germany, has recently come into extensive use, as the flavor of the beverage is not greatly injured by the treatment. In follow^ing out this process the whole beans are first exhausted vi^ith water in a vacuum, and the infusion extracted with a suitable solvent for caffeine. The exhausted beans are then impregnated with the decaffeinated infusion and dried in a vacuum. This treatment, as shown by the investigations of Lendrich and Murdfield,* does not Fig. 78. — Powdered Date Stones under the Microscope, end, endocarp; e, episperm; a, albumen in cross-section; a' , albumen in longitudinal section. (After Villiers and Collins.) completely remove all the caffeine, the quantity remaining being from 0.14 to. 0.26%, or about one-sixth of that in the untreated coffee. Further effects of the treatment are a decrease in the water extract and an increase in the fat. The following are the average of analyses, made by these authors, of caffeine-free and untreated coffee : 0) ■(3 c < Analysis of the Dry Substance. 3 of Ash I HCl grams e). i if 3 u •5^ u E 3 6 u 3 S < Alkalinity (cc. N/ per 100 of Coflfe w Co .S2 % % % % % % % "Caffeine-free Coffee". .. 14 2.13 4-23 3.22 47-72 21.30 17-13 0. 22 11.83 Untreated coffee 9 1.46 4.71 3-77 56-43 26.17 15-73 I. 19 11-75 Zeits. Unters. Nahr. Genussm., 15, 1908, p. 705. TEA, COFFEE, AND COCOA. 405 Several brands of coffee advertised to be free from tannin and in some cases also from caffeine, have been placed on the market in the United States. Some of these consist merely of ground coffee from which the chaff (which is represented to contain not only the tannin but also most of the caffeine) has been removed by mechanical means. The absurdity of the claims of the manufacturers is shown by the following analyses made in New Hampshire by C. D. Howard.* Water. Ash. Fat. Fiber. Caffeine. 2.70 4.10 13.18 18.46 1. 17 2.70 4-05 14.12 15-70 ^■33 2.26 3-6i 12.55 22.70 0.87 3-13 4-13 14.10 15-50 1.29 2.60 5.65 9-30 26.50 0.40 Caflfe- tannic Acid. Tanninless coffee No. i. . . Tanninless coffee No. 2. . . Tanninless coffee No. 3. . . Java and Mocha Coffee chaff 10.76 11.04 7.61 II. 17 5-98 The following analyses made at the Connecticut Station by E. Shanley,t corroborate those of Howard: Caffeine in the Coffee. Caffetannic Acid in the Coffee. Caffetannic Acid in the Chaff. Per Cent of Chaff in the Coffee. Tanninless coffee A 1. 14 1. 11 1. 12 1. 13 1.26 I-I3 9.89 9-45 9-96 9-51 9.96 9-47 5-46 7-55 6.79 Tanninless coffee B Tanninless coffee C Java coffee I 80 Mocha coffee 2-38 1-77 Rio coffee The Asa process consists in treating the raw coffee with water vapor under a pressure of 4.5 atmospheres and distilling in vacuo, thus removing, it is claimed, volatile toxic substances. Vacuum packed coffee has been extensively advertised as being free from the objectionable qualities of ordinary coffee. Gould's experiments J indicate that the composition of the vacuum-packed coffee is not quite the same as that of ordinary coffee, nor is the gas given off the same, but whether these changes render the coffee more wholesome appears uncertain. * U. S. Dept. of Agric, Bur. of Chem., Bui. 105, p. 41. t Ann. Rep. Conn. Exp. Sta., 1907, p. 141. X Eighth Int. Cong. App. Chem., 26, 191 2, p. 389. 406 FOOD INSPECTION AND ANALYSIS. Coffee Substitutes. — A large number of preparations sold as " cofifee substitutes " or " cereal co£fee " are now on the market in the United States, most of which are composed, as alleged on the labels, of cereals, ground peas, etc. Some contain roasted wheat, malt or some other cereal alone, others are mixtures of cereals or cereal products and peas, and a few contain chicory. Some of these preparations have labels calling attention to the evil effects of coffee, and one of the latter class, extensively advertised, and purporting to contain nothing but the entire wheat kernel roasted and ground, was found to contain peas, and aboui 30% of that " most harmful ingredient " coffee itself. Various substitutes are also made from dried fruits such as figs, prunes and bananas. In addition to the materials named the following have been used in Europe: beans, lupine seeds, cassia seeds, astralagus seeds, Parkia seeds, chick peas, soy beans, dried pears, carob bean pods, date stones, ivory nuts, acorns, grape seeds, fruit of the wax palm, cola nuts, false flaxseed, dandelion roots, beets, turnips and carrots.* As in the case of coffee the analyst must depend chiefly on the micro- scope in identifying the constituents of coffee substitutes. Coffee itself should properly be considered in the light of an adulterant. COCOA AND COCOA PRODUCTS. Nature of the Cocoa Beans. — The various chocolate and cocoa prep- arations are made from the bean of the tree Theohroma cacao, of the family of ByitneriacecB. This tree averages 13 feet in height, and its main trunk is from 5 to 8 inches in diameter. It is a native of the American tropics, where it is still most successfully grown for supplying the world's market. The cocoa beans of commerce are derived chiefly from Ariba, Bahia, Caracas, Cayenne, Ceylon, Guatemala, Haiti, Java, Machala, Mara- caibo, St. Domingo, Surinam, and Trinidad. Besides these, the Sey- chelles and Martinique furnish a small amount. The plant seeds, or beans, grow in pods, varying in length from 23 to 30 cm., and are from 10 to 15 cm. in diameter. The beans, which are about the size of almonds, are closely packed together in the pod. Their color when fresh is white, but they turn brown on drying. * Winton's Microscopy of Foods, p. 435. TEA, COFFEE, AND COCOA. 407 The gathered pods are first cut open, and the seeds removed to undergo the process of " sweating " or fermenting, which is carried out either in boxes or in holes made in the ground. This process requires great care and attention, as upon it depends largely the flavor of the seed. The sweating operation usually takes two days, after which the seeds are dried in the sun till they assume their characteristic warm red color, and in this form are shipped into our markets. Manufacture of Chocolate and Cocoa. — For the production of choc- olate and cocoa the beans are cleaned and carefully roasted, during which process the flavor is more carefully developed, and the thin, paper-like shell which surrounds the seed is loosened, and is very readily removed. The roasted seeds are crushed, and the shells, which are separated by winnowing, form a low-priced product, from which an infusion may be made, having a taste and flavor much resembling chocolate. The crushed fragments of the kernel or seed proper are called cocoa nibs, and for the preparation of chocolate they are finely ground into a paste and run into molds, either directly, or after being mixed with sugar and vanilla extract or spices, according to whether plain or sweet chocolate is the end product. For making cocoa, however, a portion of the oil or fat known as the cocoa butter is first removed, by subjecting the ground seed fragments to hydraulic pressure, usually between heated plates, after which the pressed mass is reduced to a very fine powder, either directly, or by treat- ment with anmionia or alkalies, to render the product more " soluble." It is held that the large amount of fat contained in the cocoa seeds (vary- ing from 40 to 54%) is difficult of digestion to many, such as invalids and children, and hence the desirability of removing part of the fat. Composition of Cocoa Products. — The chief constituents of the raw cocoa nib are fat, starch, pentosans, proteins, theobromine, caffeine, tan- nin, and mineral matter. Minor constituents are oxalic acid (combined), acetic and tartaric acids. During roasting there is reason to believe a volatile substance is developed much in the nature of an essential oil, which gives to the product its peculiar flavor, and is somewhat analogous to the caffeol of coffee. Tannin, the astringent principle of cocoa, exists as such in the raw bean, but rapidly becomes oxidized to form cocoa red, to which the color of cocoa is due. Weigmann gives the following results of analyses of cocoa niljs and shells: 408 FOOD INSPECTION AND ANALYSIS. COMPOSITION OF COCOA NIBS. Commercial Vajieties. U Caracas 7 Trinidad 7 Surinam ! 7 Port au Prince 7 Machata 8 Puerto Cabello 8 Ariba 8 14-13 14.06 13.69 14.56 14.06 13-50 15-37 1-31 1.66 1-51 45-54 44.62 44-74 46-35 45-93 46.61 45-15 1 9. -40 25-30 26.45 5-97 5-69 22.9 5-83 15-53 17-50 16.96 6.19 4-55 4-30 5-19 4-36 4-43 4.48 4.91 3-48 3.16 4-iS 4.09 4.28 3 88 2.06 o.io 0.13 1.48 0.22 0.18 0.14 COMPOSITION OF COCOA SHELLS. p V Commercial Varieties. 1 1 (1) "3 T) "3 c i3 :3 (U ■4J .c c S gc/. H fe gW 6 < u^ Caracas 12.49 13.18 14.62 0.58 0.74 0.78 0.75 2-38 40.30 16.33 9.06 6.26 2.11 Trinidad. 14.64 3-45 44-89 15-79 6.19 0.42 2-34 Surinam 13-93 14.89 16.25 16.18 2-54 42.47 17.04 6.63 0.85 2.60 Puerto Cabello 2.01 43-32 15-25 8.08 0.27 2-59 On page 409 are the summarized results of the analyses of seventeen varieties of cocoa seeds and shells, made by Winton, Silverman, and Bailey.* According to Bell f the ash of cocoa nibs has the following composition: Per Cent. Sodium chloride o-57 Soda 0.57 Potash 27 . 64 Magnesia 19.81 Lime 4 . 53 Alumina 0.08 Ferric oxide 0.15 Carbonic acid 2.92 Sulphuric acid 4.53 Phosphoric acid 39 - 20 100.00 * Ann. Rep. Conn. Agric. Exp. Sta., 1902, p. 270. t Analysis and Adulteration of Foods. TEA, COFFEE, AND COCOA. 409 Roasted Cocoa Nibs. Air-dry Material. Maxi- mum. Mini- mum. Mean. Water- and Fat-free Material. Maxi- mum. Mini- mum, Mean. Water , Total ash , Water-soluble ash Ash insoluble in acid Alkahnity of ash , Theobromine Caffeine Other nitrogenous substances Crude fiber , Crude starch (acid conversion) Pure starch (diastase conversion) Other nitrogen-free substances Fat Total nitrogen Constants of fat (ether extract) : Melting-point, degrees C Zeiss refractometer reading at 40° C Refractive index at 40° C Iodine number Per cent of nibs in whole bean " " "shells " " " 3.18 4-15 1.86 0.07 3-35 1.32 0-73 13.06 3.20 12.37 8-99 21.07 52-25 2.54 35-0 48.00 [-4579 37-89 92.90 13.88 2.29 2.61 0-73 0.00 1-5° 0.82 o. 14 II .00 2.21 9-30 6.49 17.69 48.11 2.20 32-3 46.00 r-4565 33-74 86.12 8.83 2.72 3-32 1. 16 0.02 2-51 1.04 0.40 12.12 2.64 II. 16 8.07 19-57 50.12 2.38 33-3 47-23 1-4573 34-97 88.46 11-54 3-96 o. 14 7.12 2.92 1-55 28.05 6.56 25.68 18.61 44.08 5-41 5-76 1.60 3-29 1.66 0.31 23-37 4.70 19.80 13.82 38.78 4-74 7.04 2.46 0.05 5-32 2.21 0.86 25.69 5-61 23.66 17.10 41.49 5-05 Roasted Cocoa Shells. Air-dry Material. Maxi- mum. Mini- mum. Mean. Water- and Fat-free Material. Maxi- mum. Mini- mum. Mean. Water Total ash Water-soluble ash Ash insoluble in acid Alkalinity of ash Theobromine Caffeine Other nitrogenous substances Crude fiber Crude starch (acid conversion). . Pure starch (diastase conversion) Other nitrogen-free substances. . Fat.. Total nitrogen 6-57 20.72 5-67 II. 18 5-92 0.90 0.28 18.06 19.21 13.89 5.16 51.86 5-23 3-17 3-71 7.14 2.02 0.05 5-02 0.20 0.04 10.69 12.93 9.87 3-36 43-71 1.66 1-74 4-87 10.48 3-67 2-51 5-52 0.49 0.16 14-54 16.63 11.62 4.14 46.40 2.77 2.34 21.97 6. II 11.86 6-47 0.97 0.31 19.40 20.72 15-42 5-59 55-84 3-41 5-63 2.16 0.05 5-32 0.22 0.04 11-34 13-71 10.47 3-65 47.04 1.87 11-33 3-97 2.70 5-97 0.52 o. 17 15-70 18.01 12.59 4-47 50.08 2.54 410 FOOD INSPECTION AND ANALYSIS. Theobromine (C7H8N4O2), the chief alkaloid of cocoa, when pure, forms a white, crystalline powder, having a bitter taste. It is slightly soluble in water and alcohol, very slightly soluble in ether, insoluble in petroleum ether, but readily soluble in chloroform. It sublimes at 290° to 295° C. It is a weak base, and much resembles caffeine. A small amount of caffeine has also been found in cocoa, but in most analyses is reckoned in with the theobromine. The Nitrogenous Substances of Cocoa, aside from the alkaloids, have been little studied. Stutzer has, however, separated them roughly as in the following analyses of four samples, of which A was manufactured without chemicals, B with potash, and C and D with ammonia : Total nitrogen Theobromine Ammonia Amido compounds Digestible albumin Indigestible nitrogenous substances Containing nitrogen Proportion of total nitrogen indigestible A. B. c. 3.68 3-30 3-95 1.92 1-73 . 1.98 0.06 0.03 0.46 1-43 1-25 0-31 10.25 7.68 10.50 7.18 9.19 7.68 I-I5 1-47 1-23 31.2 44.5 31.2 3-57 1.80 0-33 1-31 7.81 8.00 1.28 35-8 Pentosans. — Several authors have called attention to the value of these substances as a means of detecting added shells in cocoa products. Liihrig and Segin * found in cocoa nibs from 2.51 to 4.58% of pentosans calculated to the dry, fat-free substance, and in the shells from 7.59 to 11.23% calculated to the dry substance. Milk Chocolate, a product of comparatively recent introduction, consists of a mixture of chocolate, sugar, milk powder, and cocoa butter. It is especially prized by travelers and others who desire a concentrated, and at the same time palatable food. The following analyses by Dubois f show the composition of three of the leading brands on the market, and also illustrate the accuracy of Dubois' method of determining sucrose and lactose given on page 415. Various Compounds of chocolate or cocoa with other materials have been placed on the market. Zipperer | gives formulas or analyses of seventy-four such preparations, containing one or more of the following ingredients: oatmeal, barley meal, malt, malt extract, wheat flour, potato * Zeits. Unters. Nahr. Genussm., 12, 1906, p. 161. t Jour. Am. Chem. Soc, 29, 1907, p. 556. t The Manufacture of Chocolate and Cacao Preparations, 2d ed., 1902. TEA, COFFEE, AND COCOA. 411 Polarization. Su- crose, Per Cent. Lac- tose, Per Cent. Reich- ert- Meissl Num- ber of Fat. Approx. Per Cent Direct. After Inver- sion. Temp. At 86°. Fat in Total Fat. Commercial milk chocolate: A + 21. OO + 23.22 + 23.88 + 19.00 — 2.00 — 2.22 — 2.20 -1.50 24 23 23 20 + 1.36 + 1.50 + 1-36 + 1.40 40.90 45-73 46.78 35-99 35-82 39-84 39.80 8.24 9.12 8.24 8.52 8.82 6.03 5-88 5-3 5-5 5-8 4-83 3-48 B 22.9 24.2 c Milk chocolate made in the laboratory: J-. / Found \ Calculated ■p f Found + 19.70 — 2.20 21 + 0.99 14.5 ^ \ Calculated flour, rice, peas, peanuts, acorns, cola nuts, sago, arrowroot, Iceland moss, gum Arabic, salep, dried meat, meat extract, peptones, milk powder, plasmon (a preparation of casein), eggs, saccharin, vanilla, spices, and inorganic salts. Certain medicinal preparations also contain cocoa products. Cocoa Butter. — See Chapter XIII. METHODS OF ANALYSIS. Preparation of the Sample.— Cocoa is usually in a fine powder, and needs merely to be put through a sieve, to break up lumps, and mixed. Chocolate should be grated or shaved so as to permit mixing. It can- not be ground, as the heat of grinding reduces it to a paste. Determination of Moisture. — Dry 2 grams of the material to con- stant weight at 100° C. in a current of dry hydrogen. Somewhat lower results are obtained by drying in a dish in air. Determination of ksh..~Total, Water-soluble, and Acid-soluble. — Pro- ceed as described under tea (page 382), Alkalinity {Ewell Method^). — To the ash of 2 grams of the sample add 100 cc. of water, an excess of N/io sulphuric acid, and boil until carbon dioxide is removed. Titrate the excess of acid with N/io alkali, using phenolphthalein as indicator. Calculate the number of cubic centimeters of N/io acid required to neutralize the ash from i gram of the sample. This method was used by Winton, Silverman, and Bailey, in the U. S. Dept. of Agric, Div. of Chem., Bui. 13, 1892, p. 956. 412 FOOD INSPECTION AND ANALYSIS. analyses as summarized on page 409. It is essentially the same as the French official method* and differentiates cocoa and chocolate from cocoa shells more sharply than the A. O. A. C. method employing methyl orange as indicator. Determination of Protein. — Determine total nitrogen by the Kjeldahl or Gunning method. From the percentage of total nitrogen subtract the nitrogen of the theobromine and caffeine, obtained by multiplying the percentages found by 0.3 11 and 0.289 respectively, and multiply the remainder by 6.25. Fig. 79. — Cocoa. / entire fruit, Xi; II fruit in cross-section; 777 seed (cocoa bean) natural size; IV seed deprived of seed coat; V seed in longitudinal section, showing radicle (germ) ; VI seed in cross-section. (Winton.) Determination of Casein. — Hammarsten Method Modified by Baier and Neumann.1[ — Extract 20 grams of the sample with ether, dry at room temperature, and weigh. Rub up 10 grams of the dry fat-free material with a small quantity of 1% sodium oxalate solution, wash into a 250-cc. graduated flask with about 200 cc. of the oxalate solution, heat to boiling, and make up nearly to the mark with boiling oxalate solution. Allow to stand 18 hours with occasional shaking, fill to the mark with cold oxalate solution, and filter through a dry paper. Pipette off 100 cc. of the filtrate, add 5 cc. of 5% uranium acetate solution and 30% acetic acid, drop by drop with constant stirring until a precipitate of casein begins to form, * Ann. fals., 4, p. 417. t Zeits. Unters. Nahr. Genussm., 18, igog, p. 13. TEA, COFFEE, AND COCOA. 413 then add 5 additional drops of the acid. Centrifuge, filter, wash free from oxalate with a solution containing in 100 cc. 5 grams of uranium acetate and 3 cc. of 30% acetic acid, and determine nitrogen in the filter and precipitate by the Kjeldahl or Gunning method. Calculate casein using the factor 6.37. Bolton and Revis * and Lythgoe f have found this method satisfactory. Determination of Theobromine and Cafifeine (Decker-Kunze MetJwd).X — This combination of the Decker and the Kunze methods was first em- ployed by Winton, Silverman, and Bailey, and afterwards adopted by the Assn. of Official x\gricultural Chemists. Boil 10 grams of the powdered material and 5 grams of calcined magnesia for 30 minutes with 300 cc. of water. Filter by the aid of suction on a Biichner funnel, using a round disk of filter paper. Transfer the material and paper to the same flask used for the first boiling, add 150 cc. of water, and boil 15 minutes. Filter as before, and repeat the operation of boiling with 150 cc. of water and filtering. Wash once or twice with hot water. Evaporate the united filtrates (with quartz sand if sugar be present) to complete dryness in a thin glass dish of about 300 cc. capacity. § Grind to a coarse powder in a mortar provided with a suitable cover to prevent loss by flying. Transfer to the inner tube of a continuous fat extractor, and dry thoroughly in a water oven. Extract with chloro- form for 8 hours, or until the theobromine and caffeine are completely removed, into a weighed flask. It is important that the material be thoroughly dry, that an extractor be used that permits of a hot extraction, and that a considerable volume of chloroform passes through the material. Distil off the chloroform, and dry at 100° C. to constant weight. If the material be pure chocolate or cocoa, the extract thus obtained is practically pure theobromine and caffeine, but if the material is cocoa shells or a cocoa product mixed with a large amount of shells, the extract may be brown in color, due to the presence of considerable amounts of impurities. In either case, separate the caffeine by treating the extract in the flask at the room temperature for some hours with 50 cc. of pure benzol. * Fatty Foods, Phila., 1913, p. 317. t Jour. Assn. Off. Agric. Chem., i, 1915, p. 200. X Schweiz. Wchschr. Phar., 40, 1902, pp. 527, 541, 553; Conn. Agric. Exp. Sta. Rep., 1902, p. 274. §A "Hoffmeister Schalchen" may be used, or dishes may be made from broken flasks by making a scratch with a diamond and leading a crack from this scratch about the flask by means of a glowing springcoal. 414 FOOD INSPECTION AND ANALYSIS. Filter through a small paper into a tared dish, evaporate to dryness, and dry to constant weight at ioo° C, thus obtaining the amount of caffeine. Determine theobromine by Kunze's * method, as follows: Add to the residue and paper 150 cc. of water, enough ammonia water to make the liquid slightly alkaline, and an excess of decinormal silver nitrate solution. Boil to half the original volume, add 75 cc. of water, and repeat the boiling. The solution should be perfectly neutral. If it contains the slightest amount of free ammonia, add water and boil until it is completely removed. Filter from the insoluble silver theobromine compound, and wash with hot water. In the filtrate determine the excess of silver nitrate by Vol- hard's f method as follows: Add 5 cc. of cold saturated solution of ferric ammonium sulphate (ferric-ammonium alum), and enough boiled nitric acid to bleach the liquid. Titrate with decinormal ammonium sulphocyanide solution until a permanent red color appears. One cc. of decinormal AgNOa solution is equivalent to 0.01802 gram of theobromine. If the mixed alkaloids were colorless, the theobromine obtained by subtracting the weight of caffeine from the weight of the mixed alkaloids will usually agree closely with that obtained by silver titration. Determination of Crude Fiber. — Proceed as in the analysis of cereal products, using the residue from the ether extraction. Determination of Reducing Matters by Acid Conversion (Crude Starch). — Winton, Silverman, and Bailey % proceed as follows: Weigh 4 grams of the material into a small Wedgwood mortar, add 25 cc. of ether, and grind with a pestle. After the coarser material has settled out, decant off the ether with the fine suspended matter on an ii-cm.- paper. Repeat this treatment until no more coarse material remains. After the ether has evaporated, transfer the fat-free residue from the filter to the mortar by means of a jet of cold water, and rub to an even paste. Filter the liquid on the paper previously employed. Repeat the process of transferring from the filter to the mortar, grinding, and filtering, until all sugar is removed. In the case of sweetened cocoa products, at least 500 cc. of water should be used. * Zeits. anal. Chem., 2^, 1894. p. i. t Ibid., 13, i874,p. 171. t Conn. Agric. Exp. Sta., Rep., 1902, p. 275. TEA, COFFEE, AND COCOA. 415 Transfer the residue to a 500-cc. flask by means of 200 cc. of water, and convert the starch into dextrose by Sachsse's method (page 292). Cool the acid solution, nearly neutralize with sodium hydroxide solu- tion, add 5 cc. of lead sub-acetate solution (page 610), make up to 250 cc. and filter through a dry filter. To 100 cc. of the filtrate, add i cc. of 60% sulphuric acid, shake thoroughly, allow to settle, and filter through a dry filter. Determine reducing matters by Allihn's method (page 632). Dubois,"^ instead of treating with ether as above described, shakes 4 grams of the unsweetened product or 8 grams of the sweetened with 100 cc. of gasoline, and whirls in a centrifuge to separate from the insoluble matter. After decanting off the gasoline layer, sweetened products are treated in like manner with two portions of 100 cc. of water to remove the bulk of the sugar, and finally washed on the paper. Determination of Pure Starch. — Diastase Method. — Remove the fat and sugar from 4 grams of the material by treatment with ether and water, as described in the preceding section, and determine starch in the residue by the diastase method (page 292). Revis and Burnet ff employ a method with the following features: (i) taka-diastase is substituted for malt extract, (2) the solution containing dextrose and maltose into which the starch has been converted is cleared with acid mercuric nitrate, the excess being removed by sodium phosphate solution, (3) the copper-reducing power and polarization of the solution are determined without acid conversion, and (4) the dextrose and maltose and from these the starch are calculated by appropriate formulae. The authors obtain by this method lower results on cocoa shells than by the diastase method, which is consistent with the absence of starch as shown by microscopic examination. Determination of Pentosans.— See page 294. Determination of Sucrose and Lactose. — Dubois Method. % — Place 26 grams of the material in an 8-ounce nursing bottle, add about 100 cc. petroleum ether and shake for 5 minutes. Whirl in a centrifuge until the solvent is clear, draw off the same by suction and repeat the treatment with petroleum ether. Keep the bottle containing the defatted residue in a warm place until the petroleum ether is practically expelled. Add ICO cc. water and shake until all the chocolate is loosened from the sides * U. S. Dept. of Agric, Bur. of Chem., Bui. 122, p. 214. t Analyst, 40, 1915, p. 429. X U. S. Dept. of Agric, Bur. of Chem., Circ. 66, p. 15. 416 FOOD INSPECTION AND ANALYSIS. and bottom of the bottle and continue the shaking for 3 minutes longer. Add 10 cc. of lead subacetate solution (page 610), mix thoroughly and filter through a folded filter. Make the direct polariscopic reading (a) in a 200-mm. tube, then precipitate the excess of lead by dry potassium oxalate. Invert by one of the methods given on page 611, polarize, and multiply the invert reading by 2 to correct for dilution {b). Calculate the approximate percentages of sucrose (5) and lactose (L) by the follow- ing formulas: (a — b)Xiio (aXi.io)— 5 142.60 — — 2 From the sum of 5 and L calculate the approximate number of grams of total sugar G present in the 26 grams of sample taken and determine the factor X thus: X=iio + (GXo.62), in which 0.62 is the volume in cc. displaced by i gram of sugar in water solution. Applying this correction, SX ^ ^ LX True per cent sucrose = — -. True per cent lactose = . ^ no ^ no The following method of solution may be substituted for that given above : Transfer 26 grams to a flask, add 100 cc. water, cork, and heat in steam-bath for twenty minutes, releasing the pressure occasionally during the first five minutes. Twice during the twenty minutes shake thor- oughly so as to emulsify completely. Finally cool to room temperature, add 10 cc. lead subacetate solution, mix, and filter. Determination of Cocoa-Red. — Blyth Method.^ — Make 2-3 grams of the fat-free sample into a paste with hydrochloric acid, add sufficient silver oxide to fix the hydrochloric acid, and extract in a Soxhlet extractor with 100 cc. of absolute alcohol. Cool, filter the alcoholic liquid, pre- cipitate with an alcoholic solution of lead acetate, collect the purple-black precipitate on a filter, and wash well with boiling water. Transfer the precipitate to a small flask, add 70% alcohol, and decompose the lead * Blyth, Foods: Their Composition and Analysis, London, 1909, p. 368. TEA, COFFEE, AND COCOA. 417 salt with hydrogen sulphide. Drive off the excess of hydrogen sulphide by heating, filter, evaporate the filtrate, dry, and weigh. Purify by con- verting again into the lead salt and decomposing with hydrogen sulphide. Zipperefs Method is more elaborate and requires correction for resin and phlobophene formed by the decomposition of the cocoa-red. Ulrich Method.'^ — Boil for 3 hours i gram of the dry, fat-free, finely powdered sample with 120 cc. acetic acid (50-51%) in a 300-cc. Erlen- meyer flask having a reflux condenser. Cool, make up to 150 cc. with water, shake, and allow to stand 12 hours. Filter through dry paper and boil 135 cc. of the filtrate with 5 cc. of concentrated hydrochloric acid and 20 cc. of a 20% ferrous chloride solution under a reflux condenser for 10 minutes. Cool quickly, pour into a beaker, allow to stand 6 hours, and filter through a weighed paper, washing with hot water until free from iron, dry 6 hours at 105° C, and weigh. ADULTERATION OF COCOA PRODUCTS AND STANDARDS OF PURITY. The following are the U. S. standards : f Standard chocolate should contain not more than 3% of ash insoluble in water, 3.5% of crude fiber, and 9% of starch, nor less than 45% of cocoa fat. Standard sweet chocolate and standard chocolate coating are plain chocolate mixed with sugar (sucrose), with or without the addition of cocoa butter, spices, or other flavoring material, containing in the sugar- and fat-free residue no higher percentage of either ash. fiber, or starch than is found in the sugar- and fat- free residue of plain chocolate. Standard cocoa should contain percentages of ash, crude fibe^, and starch corresponding to those of plain chocolate, after correcting for fat removed. Standard sweet cocoa is cocoa mixed with sugar (sucrose) containing not more than 60% of sugar, and in the sugar- and fat-free residue no higher percentage of either ash, crude fiber, or starch than is found in the sugar- and fat- free residue of plain chocolate. The removal of fat, or the addition of sugar beyond the above pre- scribed limits, or the addition of foreign fats, foreign starches, or other foreign substances, constitutes adulteration, unless plainly stated on the label. *Inaug. Dis. Detmold, 191 1; Arch. Pharm., 249, p. 524; Jour. Assn. Off. Agric. Chem., I, 1916, p. 550. t U. S. Dept. of Agric, Off. of Sec, Circ. 19. 418 FOOD INSPECTION AND ANALYSIS. The most common adulterants of cocoa are sugar and various starches, especially those of wheat, corn, and arrowroot. Starch is sometimes added for the alleged purpose of diluting the cocoa fat, instead of remov- ing the latter by pressure, thus, it is claimed, rendering the cocoa more digestible and more nutritious. Unless its presence is announced on the label of the package, starch should be considered as an adulterant. Cocoa shells are also commonly employed as a substitute for, or an adul- terant of, cocoa. Other foreign substances found in cocoa are sand and ground wood fiber of various kinds. Iron oxide is occasionally used as a coloring matter, especially in cheap varieties. Such adulterants as the starches and cocoa shells are best detected by the microscope. The presence of any considerable admixture of sugar is made apparent by the taste. Mineral adulterants are sought for in the ash. Addition of Alkali. — The amount of water soluble matter in cocoa is very small (about 20 to 25%), and in preparing the beverage, the desideratum aimed at is to produce as perfect an emulsion as possible. The legitimate means of accomplishing this is by pulverizing the cocoa very fine, so that particles remain in even suspension and form a smooth paste. Another means sometimes resorted to for producing a so-called " soluble cocoa " is to add alkali in its manufacture, the effect being to act upon a part of the fat, and produce a more perfect emulsion with less separation of oil particles. Such treatment with alkali is regarded with disfavor, even if not considered as a form of adulteration. Cocoa thus treated is generally darker in color than the pure article. The use of alkali is usually rendered apparent by the abnormally high ash, and by the increased alkalinity of the ash, the latter constant being expressed in terms of the number of cubic centimeters of decinormal acid necessary to neutralize the ash of i gram of the sample. In pure, untreated cocoa, the ash rarely exceeds 5.5%, and the alkalinity of the ash is generally not more than 3.75. In cocoa treated with alkali, the ash sometimes reaches 8.5%, with the alkalinity running as high as 6 or even 8. Microscopical Structure of Cocoa. — Fig. 80 shows elements of the powdered cocoa bean, both of the shell and of the kernel. The powder of the latter should constitute pure cocoa, with occasional fragments only of the shell. The irregular lobes constituting the kernel are each inclosed in a membrane made up of angular cells, filled with granular matter. (4), (5), and (6) show elements of the powdered cotyledons, TEA, COFFEE, AND COCOA. 419 or seed kernels. The polygonal tissue of the cotyledon is shown in cross- section at (4). In the powder one finds also dark granular matter, bits of debris, and fragments, with masses of yellow, reddish-brown, and sometimes violet coloring matter, together with numerous starch granules and aleurone grains. The starch granules are nearly circular, with rather indistinct central nuclei, and range in size from 0.0024 to 0.0127 mm., averaging about 0.007 ™^- They are more often found in single detached grains, but sometimes in groups of two or three. Occasional ^spiral ducts, sp, are seen, but these are not abundant in the pure cocoa. Fig. 80. — Cocoa under the Microscope. A. Powdered Cocoa under the Microscope. X125. (After Moeller.) i, cross-section through shell parenchyma; 2, thick-walled cells; 3. epidermis of shell (surface section); 4, cross-section of cotyledon tissue; 5, 6, cotyledon parenchyma; 7, starch. B. Cocoa Shell in Surface Section. X160. ep, epicarp; p, parenchyma of the fruit; qu, layer of transverse cells. (After Moeller.) The masses of color pigment are shown up with striking clearness, according to Schimper, by applying a drop of sulphuric acid to the edge of the cover-glass and allowing it to penetrate the tissue. The bits of coloring matter are for a short time colored a brilliant red, which, how- ever, soon fades. Ferric chloride colors them indigo blue. Schimper recommends mounting the powder in a drop of chloral hydrate, which soon renders most of the tissues transparent. It is some- times necessary to allow the chloral to act on the powder in a closed 420 FOOD INSPECTION AND ANALYSIS. vessel for twenty-four hours, before all the elements of pure cocoa are rendered transparent. If after that time opaque masses are still found, these are due to foreign material. Ammonia may be used instead of chloral with even better results, but this reagent requires longer treatment, soaking for several days or a week being sometimes necessary. Fig. 185, PI. XVII, shows the microscopical appearance of genuine powdered cocoa .with its variously sized starch grains and the debris of the ground cotyledons. Fig. 186 shows cocoa adulterated with arrowroot. Cocoa Shells. — A cross-section of the shell parenchyma and the stone- cell layer, also some of the numerous spiral ducts, all characteristic of the ground shell, are shown at i. Fig. 80. The thick-walled stone-cells are shown in surface view at 2, and the spongy, outer seed-skin, composed of two layers, with elongated cells running crosswise to each other in striated fashion, and with the underlying hairs or so-called " Mitscherlich bodies," is shown at 3. The presence of an abnormally large number of yellow and brown frag- ments in the water-mounted cocoa specimen, even under small magnifi- cation, arouses suspicion of the presence of shells, the most distinctive elements of which are the spongy tissue, the stone-cells, and the abundant spiral ducts, the latter being scarce in pure cocoa powder. Cocoa shells are indicated on chemical analysis by the abnormally high ash, crude fiber and pentosans. Added Starch. — This can only be approximately determined by a careful examination with the microscope. Long experience will enable the analyst to familiarize himself with the appearance and abundance of starch grains of various kinds in a series of fields, so that he can roughly estimate the amount of each starch present in the mixture, by careful comparison with mixtures of known percentage composition. If the amount of starchy adulterant is considerable, evidence may be secured by determinations of starch by the diastase method and reducing matters by acid conversion. Added Sugar.— Any appreciable amount of added cane sugar is shown by the sweet taste. The amount of cane sugar may be determined by means of the polariscope, as described on page 415. An abnormally low ash is indicative of the addition of starch or sugar or both. Foreign Fat.— Certain mnaufacturers have found it profitable to remove a portion of the cocoa butter from chocolate and substitute for TEA, COFFEE, AND COCOA. 421 it a cheaper fat, such as cocoanut oil, tallow or even paraffine. Such adulteration is detected by determination of the physcial and chemical constants of the fat obtained by extraction with ether. Dyes and Pigm3nts, such as Bismarck brown and Venetian red, have been employed to hide the presence of diluents. They are detected by dyeing tests, and by examination of the ash. CHAPTER XII. SPICES. These aromatic vegetable substances are classed as condiments, and depend for their use on the pungency which they posses in giving flavor or relish to food. As such seasoning or zest-giving substances, they are of considerable importance dietetically, but from the fact that they are used in comparatively insignificant amount, the determination of their chemical composition or actual value as nutrients per se is of little im- portance to the food economist. Adulteration. — Formerly ground spices were subject to the grossest forms of adulteration, all kinds of cheap material being reduced to powders for the purpose, the aim being to match the genuine spice in color and general appearance. The foreign materials were for the most part de- tected by microscopic examination although chemical analysis furnished valuable corroboratory evidence. At present such frauds have for the most part disappeared in the United States, and the analyst is called on chiefly to examine spices for an excess of shells or fibrous material, dirt, and similar impurities, the presence of which indicates a low grade rather than intentional adulteration, or for exhausted spices. In a few instances the substitution of the products of inferior species or varieties belonging to the same family as those which yield the standard spice is still practiced. Examples are Bombay and Macassar mace sub- stituted for true or Banda mace, the seed of charlock substituted for the seeds of the more valuable species of the mustard family, and Spanish red pepper or pimiento substituted for the Hungarian product known as paprika. Microscopic and chemical examination is still necessary partly to detect the occasional fraud of the old type, which still may be practiced, and partly to distinguish varieties and grades and detect an excess of natural impurities. General Methods of Proximate Analysis. — The following methods common to all the spices are specially designed to determine quality or grade, or to detect adulteration. Methods of analysis peculiar to individual spices will be treated 422 1 SPICES. 423 under the discussion of the spice in question. For these determinations the spices should be powdered fine enough to pass through a 6o-mesh sieve. Determination of Moisture. — Richardson'' s Method.^ — Two grams of the sample are weighed in a tared platinum dish and dried in an air-oven at iio° to a constant weight, which generally requires about twelve hours. The loss in weight includes the moisture and the volatile oil. The latter is determined from the ether extract, as described on page 424, and deducted from the total loss to obtain the moisture. McGill t determines the moisture by exposure of a weighed portion of the sample in vacuo over perfectly colorless sulphuric acid. The spice gives up its moisture before the volatile oil comes off, and any appreciable amount of the volatile oil, when absorbed by the acid, causes the latter to be discolored, so that by carefully observing the beginning of the dis- coloration, and removing the sample, the loss due to moisture may be obtained by weighing at the proper stage. The abstraction of the mois- ture in ihis manner requires about twenty-four hours. Determination of Ash. — Two grams of the spice are burned in a platinum dish heated to faint redness on a piece of asbestos paper by means of a Bunsen burner. The burning is best finished in a muffle furnace. If the ash contains an appreciable amount of carbon, it is exhausted on a filter with hot water, and the filter with the residue is burnt in the dish previously used. After adding the aqueous extract and a few drops of ammonium carbonate solution, the whole is evaporated to dryness and ignited at a faint red heat. The Water-soluhle Ash % is found by boiling the total ash as above obtained with 50 cc. of water, and filtering on a tared Gooch crucible, the insoluble residue being washed with hot water, dried, ignited, and weighed. The insoluble ash, subtracted from the total, leaves the water- soluble ash. Sand. — This is assumed to be the percentage of ash insoluble in hydrochloric acid. The ash from 2 grams of the substance, obtained as above described, is boiled with 25 cc. of 10% hydrochloric acid (specinc gravity 1.050) for five minutes, the insoluble residue is collected on a tared Gooch crucible, thoroughly washed with hot water, and finally dried and weighed. * U. S. Dept. of Agric, Div. of Chem., Bui. 13, pt. 2, p. 165. t Canada Dept. of Inland Rev., Bui. 73, p. 9. X Conn. Agric. Exp. Sta., Rep. 1898, p. 186. 424 FOOD INSPECTION AND ANALYSIS. Lime is determined from the ash as directed on page 312, having first separated the iron and phosphates. The sulphuric acid due to calcium sulphate (added as an adulterant) is determined by precipitation with barium chloride of a very weak hydro- chloric acid solution of the ash, the separated barium sulphate being washed, dried, ignited and weighed. Ether Extract. — Total, Volatile, and Non-volatile* — Two grams of the air-dry, • powdered substance are placed in some form of continuous extraction apparatus, such as Soxhlet's or Johnson's (Chapter IV), and are subjected to extraction for sixteen hours with anhydrous, alcohol- free ether.t The ether solution is then transferred to a tared evaporating- dish, and allowed to evaporate spontaneously at the temperature of the room. After the disappearance of the ether, the evaporating-dish is placed in a desiccator over concentrated sulphuric acid and left over night, or for at least twelve hours, after which it is weighed, the residue in the dish being regarded as the total ether extract. The dish and its contents are then subjected to a heat of about 100° C. for several hours, taking a long time to bring the temperature up to that point so as to avoid oxidation of the oil. Finally heat at 110° C. till the weight is constant. The final residue is the non- volatile, and the loss in weight the volatile ether extract. Alcohol Extract. — Method 0} Winton, Ogden, and Mitchell.X — Two grams of the powdered sample are placed in a loo-cc. graduated flask, which is filled to the mark with 95% alcohol. The flask is stoppered and shaken at half-hour intervals during eight hours, after which it is allowed to stand for sixteen additional hours without shaking, and the contents poured upon a dry filter. Of the filtrate, 50 cc. are evaporated to dry- ness in a tared platinum dish on the water-bath, and heated at 110° C. in an air-oven to constant weight. This method, while only approxi- mate, is so much simpler than the tedious operation of continuous extrac- tion, considering the long time required, that it is regarded as preferable for ordinary work, and, unless great care is taken, is nearly as accurate. Determination of Nitrogen. — This, in spices other than pepper, is best done by means of the Gunning or Kjeldahl method. * Richardson, U. S. Dept. of Agric, Div. of Chem., Bui. 13, p. 165. t Petroleum ether may be used, yielding results which differ but slightly from those obtained with ethyl ether. As the latter has been used in the analyses of a large number of samples of spices, if these analyses are to be taken for standards of comparison it is evi- dent that the same solvent should be used. X Conn. Agric. Exp. Sta., Rep. 1898, p. 187. SPICES. 425 Determination of Starch. — In spices like white pepper, ginger, and nutmeg that normally contain a high content of starch and very little other copper-reducing matter, the direct acid conversion process of starch determination is satisfactory. In spices normally free from starch, such as cloves, mustard, and cayenne, vv^here a starch determination indicates the amount of a foreign starch present as an adulterant, it is safer to use l^he diastase process. Four grams of the powdered sample are extracted on a filter-paper (fine enough to retain all starch particles) first with five successive por- tions of ID cc. of ether, then with 150 cc. of 10% alcohol. Owing to difficulty of filtering in the case of cassia and cinnamon, Winton recom- mends that all washing in the determination of starch in these substances be omitted. The residue is washed from the filter-paper by means of a stream of water into a 500-cc. flask, if the direct acid conversion method is used, using 200 cc. of water; 20 cc. of hydrochloric acid (specific gravity 1.125) are added, and the method from this point on followed^ as detailed on page 292. If the starch is to be determined by the diastase method, wash the residue from the filter-paper into a beaker with 100 cc. of water, and proceed as on page 292. Determine the dextrose in either case by the Defren or Allihn method* or volumetrically, and convert dextrose to starch by the factor 0.9. Determination of Crude Fiber. — Two grams of the substance are extracted with ordinary ether (or the residue left from the determination of the ether extract may be taken) and subjected to the regular method for determining crude fiber, by boiling successively with acid and alkali (page 286). McGill recommends the use of the centrifuge in separating the crude fiber, after boiling with the alkaline solution. Determination of Volatile Oil. — Method 0} Girard and Dupre* — The spice is mixed with water and subjected to distillation, receiving the distillate in a graduated cylinder. The volume occupied by the essential oil (which is immiscible with water) can be thus rea-d off and its content roughly determined. If the volatile oil is slightly soluble in water, separate out the water layer, having first read the volume of the oil layer, and extract the aqueous solution with petroleum ether. Evaporate the petroleum ether extract to dryness at room temperature * Analyse des Matieres Alimentaires, 2nd ed., p. 787. 426 FOOD INSPECTION AND ANALYSIS. in a tared dish, and add the volume due to the weight of the residue to the volume read off in the graduate. Microscopical Examination of Powdered Spices. — As a rule few microscopical reagents are necessary in the routine examination of powdered spices for adulteration, unless a more careful study of the structure than is necessary to prove the presence of adulterants is desir- able. The simple water-mounted specimen is usually sufficient to show the purity or otherwise of the sample. If in doub. as to the presence oi starch in small quantities, iodine in potassium iodide should be apphed to the specimen, well rubbed out under the cover-glass. The tissues may be cleared by adding to the water mount a small drop of 5% sodium hydroxide, or by soaking a portion of the spic? for a day in chloral hydrate solution. A valuable means of clearing dense tissues is to boil about 2 grams of the material successively with dilute acid and alkali as in the crude fiber process (p. 286), decanting (not filtering) the solution after each boiling. The presence of occasional traces of a foreign substance, when viewed under the microscope, is hardly sufficient to condemn the sample as adulterated, since such traces are apt to be accidental. Composition of Miscellaneous Spice Adulterants. — The chemical analyses of various spice adulcerants commonly met with are given on page 427. CLOVES. Nature and Composition. — Cloves are the dried, undeveloped flowers of the clove tree {Caryophyllus aromahcus or Eugenia caryo phyllata) , which belongs to the myrtle family {Myrtacece). The tree is an evergreen, from twenty to forty feet in height, cultivated extensively in Brazil, Cey- lon, India, Mauritius, the West Indies, and Zanzibar. Its leaves are from 7.5 to 13 mm. long, and its flowers, of a purphsh color, grow in clusters. The green buds in the process of growlih change to a reddish color, at which stage they are removed from the tree, spread out in the sun, and allowed to dry, the color changing to a deep brown. Each whole clove consists of a hard, cylindrical calyx tube, having at the top four branching sepals, surrounding a ball-shaped casing, which consists of the tightly overlapping petals, and within which are the stamens and pistil of the flower. In taste the clove possesses a strong and pecuhar pungency. One of its most valuable ingredients is the volatile clove oil. This is composed largely of eugenol (CioHijOj), which forms 70 to i SPICES. 427 COMPOSITION OF SPICE' ADULTERANTS. English-walnut shells*. Brazil-nut shells * Almond shells * Cocoanut shells * Date stones * Spruce sawdust * Oak sawdust * Linseed meal * Cocoa shells * Red sandalwood * Ground olive stones f . Buckwheat hulls Ash. 1.40 1-59 2.86 0-54 1.24 0.23 1.22 5-72 8.40 0.70 0.88 1.84 1^ 0.77 1.06 2-39 0.50 0.76 o. 16 0.32 1-74 4.66 0.28 0.24 i.r4 0.00 0.17 0.05 0.00 0.04 0.00 0.02 0-55 0.83 0.07 0.44 0.00 Ether Extract. 0.07 0.16 0.00 0.36 0.07 0.07 0.04 1. 00 I .21 0.06 0.07 C.2 0-55 0-57 0.64 0.25 8.38 0.77 C.84 6.58 2.99 11.47 0.24 0.38 1.84 1. 01 5.16 1. 12 16.72 1.50 6.25 9.46 4-77 19-37 2.17 English-walnut shells *. Brazil-nut shells * Almond shells * Cocoanut shells * Date stones * Spruce sawdust * Oak sawdust * Linseed meal * Cocoa shells * Red sandalwood * Ground olive stones f . Buckwheat hulls Sf 5 >.i? crx 0-53 0-33 0.40 0.47 0.61 0.30 1. 00 1 .26 0-59 S-0-? O' 1.30 1.56 1.82 2.34 1. 17 12.22 3-90 4-94 2.29 0.27 0.67 0.28 C.18 0.85 0.09 0.26 5-09 2-59 0.49 0.17 0.49 85 per cent of the oil, and a sesquiterpene known as caryophyllene. There are also in cloves a notable amount of fixed oil and resin, and also a peculiar form of tannin. Very few complete analyses of cloves are on record. Richardson f seems to have been the earliest worker in the field to give anything at all satisfactory in the way of a number of determinations of value. The following are maximum and minimum figures from the tabu- lated results of Richardson's analyses: * Winton, Ogden, and Mitchell, Conn. Exp. Sta. An. Rep., 1898, p. 210. t Doolittle, Mich. Dairy and Food Dcpt. Bui. 94, 1903, p. 12. J U. S. Dept. of Agric, Div. of Chem., Bui. 13. 428 FOOD INSPECTION AND ANALYSIS, Whole cloves (7 samples): Maximum Minimum Stems ( I sample) Ground cloves (9 samples): Maximum Minimum 10.67 2.90 10. 1 13-05 5-50 6.96 9-5810.73 5-93 5-79 0.23 4.40 13-93 3-94 Oii 10.24 7- 4-03 7-44 4.02 9-75 6.18 13-58 13.80 9-38 7- 4-73 5-78 6.48 4.20 1. 12 .76 .92 1.04 .70 5-43 3.00 5-96 6.20 22.13 11.70 23.24 24.18 McGill * gives tables of analyses of pure and adulterated samples of cloves. Analyses of upwards of twenty samples of genuine cloves, both whole and ground, from these tables show the following maximum and minimum figures: Moisture Volatile oil Total volatile matter Fixed oil Total extraction Ash Maxi Minim-iim. 11.80 19.63 30.68 10.23 31-40 7.00 5-05 9.24 16.25 0.94 22.23 5-03 McGill also made analyses of whole cloves of several varieties, the fcilowing table being a summary of his results: No. of Analyses. Total Moisture. Volatile Matter. 7-4 24-3 5-0 20.7 6.2 22.4 6-7 25-9 5-S 23-5 6.1 24.6 6.7 23.6 4.1 18.6 5-7 21.7 Volatile Oil. Total Extract- ive Matter. Fixed Oil. Penang cloves: Maximum Minimum. Mean \mboyna cloves: Maximum Minimum. Mean Zanzibar cloves: Maximum Minimum. Mean. 17.2 14.8 16.2 19.2 18.0 18.5 18.3 12. 1 16.0 28.2 24.4 27.0 29.2 26.5 27-5 28.1 21.3 25-5 9-5 10.8 9-0 10.7 8.0 Maximum and minimum figures of thirteen samples of unadulterated cloves, as purchased from retail dealers in Connecticut and analyzed by Winton and Mitchell,! are as follows: * Canada Inland Rev. Dept. Bui. 73. \ Conn. Exp. Sta. Rep., 1898, pp. 176-177 SPICES. 429 Maximum. Minimum. Ash total . . . 7.92 18.25 7.19 5-99 11.03 4.87 Ether extract, volatile ......... Winton, Ogden, and Mitchell * give more complete analyses of eight samples of whole cloves of known purity, representing Penang, Amboyna, and Zanzibar varieties, and two samples of clove stems, as follows: Moisture. Ash. Ether Extract. Total. Soluble in Water. Insoluble in HCl. Volatile. Non- volatile. Extract. Maximum 8.26 7-03 7.81 8.74 6.22 5.28 5-92 7-99 3-75 3-25 3-58 4.26 0.13 0.00 0.06 0.60 20.53 17.82 19.18 5.00 6.67 6.24 6.49 3-83 is-58 Minimum 13-99 14.87 Clove stems, mean 6.79 Reducing Matters by Acid Conver- sion, as Starch. Starch by Diastase Method. Crude Fiber. Nitrogen, X6.2S. Oxygen Absorbed by Aque- ous Ex- tract. Querci- tannic Acid. Total Nitrogen. Maximum ............ 9-63 8.19 8-99 14-13 3-15 2.08 2-74 2.17 9.02 7.06 8.10 18.71 7.06 5-88 6.18 5.88 2.63 2.08 2-33 2.40 20-54 16.25 18.19 18.79 I-I3 M inimum 0.94 Mean 0.99 Clove-stems, mean 0.94 The Tannin Equivalent in Cloves. — The amount of tannin in cloves was shown by ElUs to be so constant as to be of valuable assistance as a guide to their purity. The actual determination of tannin is, however, a long and difficult proceeding, and Richardson f has pointed out that it is not necessary, but that simply using the first part of the Lowenthal tannin process, and noting the "oxygen absorbed" as expressed by the oxidizing power of permanganate of potash on the material after extrac- tion with ether, is quite as useful as determining the tannin, and is in effect proportional to the tannin present. The result is sometimes expressed as in Richardson's figures above, as the oxygen equivalent, or as quercitannic acid. Determination of Tannin Equivalent.^ — Reagents: Indigo Solution. — Six grams of the indigo salt § are dissolved in 500 cc. of water by heat- * Conn. Exp. Sta. Rep., 1898, pp. 206, 207. t U. S. Dept. of Agric, Div. of Chem., Bui. 13, p. 167. X U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 60; Bui. 107 rev., p. 164. § The quality of the indigo used is of great importance since with inferior brands it is 430 FOOD INSPECTION AND ANALYSIS. ing. After cooling, 50 cc. of concentrated sulphuric acid are added, the solution made up to a liter and filtered. Standard Permanganate Solution. — Dissolve 1.333 grams of pure potassium permanganate in a Hter of water. This should be standardized by titrating against 10 cc. of tenth-normal oxaHc acid (6.3 grams pure crystalHzed oxahc acid in 1,000 cc), diluted to 500 cc. with water, heated to 60° C, and mixed with 20 cc. of dilute sulphuric acid (i : 3 by volume). The permanganate solution is added slowly, stirring constantly, till a pink color appears. Two grams of the material are extracted for twenty hours with pure anhydrous ether. The residue is boiled for two hours with 300 cc. of water, cooled, made up to 500 cc, and filtered. Twenty-five cc. of the filtrate are pipetted into a 1200-cc. flask, 750 cc. of distilled water are added and 20 cc. of indigo solution. The standard permanganate solution is then run in from a burette a drop at a time with constant shaking, until a bright golden yellow color appears, which indicates the end-point. Note the number of cubic cen- timeters required, represented by {a). In a similar manner determine the number of cubic centimeters of standard permanganate solution consumed by 20 cc. of the indigo solu- tion alone, represented by (ft), and subtract this from (a). The oxygen equivalent, or, as it is sometimes called, the "oxygen absorbed," is calculated from the equivalent in tenth-normal oxalic acid of the number of cubic centimeters of standard permanganate repre- sented by a — h. 10 cc of tenth-normal oxalic acid are equivalent to 0.008 gram of oxygen absorbed, or 0.0623 gram of quercitannic acid. Microscopical Examination of Cloves. — Unless the finely powdered, water-mounted sample is well rubbed out under the cover-glass, many of the masses of cellular tissue will be too dense to recognize. With a little care, however, it is possible to make a very satisfactory water mount, though by soaking for twenty-four hours in chloral hydrate solution the more opaque masses are rendered very translucent. Fig. 81, from Moeller, shows some of the characteristics of p-^wdered cloves. The outer skin of the calyx tube is shown at (i) with its polyg- onal cells and large oil spaces showing through them; (2) shows the epidermis of the outer part of the lobes or wings of the calyx, with stomata impossible to get a sharp end-point. The indigo solution should be made from the very best variety of sulphindigotate, which may be obtained from Grueber & Co., of Leipzig, or Gehe & Co., of Dresden, under the name of canniniuni cceruleum. SPICES. 431 surrounded by irregularly shaped cells; (3) represents the epidermis of the petals, with crystals of calcium oxalate; a cross-section of the epi- dermis of the calyx is shown at (4); (5) shows the parenchyma, with calcium oxalate crystals and with one of the slender spiral ducts; (6) and (7) represent in cross-section and longitudinal section respectively the parenchyma of the middle layers of the ovary, one of the rounded, triangular pollen grains being shown at (12). 5 ' ^ KJ^-J Fig. 8 1 .—Powdered Cloves under the Miaroscope. X125. (After Moeller.) Characteristics of clove stems, which are frequently used as adulter- ants of cloves, are found in (8), (9), (10), and (11). Stone cells of the outer skin and the inner portion of the clove stem are shown at (8) and (9) respectively; (10) shows one of the vascular ducts, and (11) two of the bast fibers. Both the vascular ducts and the stone cells are very characteristic of clove stems. Pure cloves have no stone cells and comparatively few bast fibers. Stemj under the micro- scope show a large number of bast fibers and frequent stone cells, the latter being of a distinctly yellow color. A plain water-mounted slide rarely shows all the structural details depicted in Fig. 81, but is nearly always sufficiently characteristic to 432 FOOD INSPECTION AND ANALYSIS. prove the purity of the sample. Fig. 220, PI. XXV, shows the actual appearance of powdered cloves, mounted in water and examined under a magnification of 130. The general appearance of the cellullar tissue is that of a loose, spongy mass filled with brown, granular material. Throughout the masses of tissue are to be seen small oil globules. Cloves have no starch whatever. Aside from the stems, cloves are sometimes adulterated with clove fruit or " mother cloves," which have a small amount of a sago-like starch, and also contain some stone cells. The U. S. Standard for pure cloves is as follows: Clove stems not more than 5%; volatile ether extract not less than 15%; quercitannic acid, calculated from the total oxygen absorbed by the aqueous extract, not less than 12%; total ash not more than 7%; ash insoluble in hydrochloric acid not more than 0.5%; crude fiber not more than 10%. Adulteration of Cloves. — Clove Stems are frequently present in cloves and possess considerable pungency. They are commonly identified under the microscope by the large number of bast fibers and stone cells. Allspice, being considerably cheaper than cloves, is sometimes used as an adulterant. It is readily recognized by the characteristics described on page 436. O titer Adulterants reported in cloves are cereal products (especially corn and wheat) and ginger (for the most part " exhausted"). Besides the above, pea starch, rice, turmeric, charcoal, sand, pepper, ground fruit stones, and sawdust have been found in samples of cloves examined in Massachusetts. Exhausted Cloves, both whole and in powdered form, are not infre- quently found on the market. These have been deprived of a portion of the volatile oil, and are much less pungent than the pure article, so that the difference in taste between the two varieties is quite marked. It is, however, rare that powdered cloves are sold consisting entirely of the exhausted variety, the more common practice being to mix from 10 to 25% of exhausted cloves with the pure powder, so that the sophistica- tion is less apparent. A determination of the volatile oil is the only reliable means of show- ing whether or not the material has been wholly or in part exhausted, though Villiers and Collin claim that under the microscope an exhausted sample of cloves shows the oil glands to be nearly empty, or to inclose much smaller droplets of oil than the pure variety. SPICES. 433 With the exception of exhausted cloves, the presence of nearly every foreign ingredient is best and most quickly shown by the use of the microscope, though much information as to the purity of the sample can be gained by the ether extract, the percentage of ash, and of crude fiber.* Cocoanut Shells. — Figs. 226 and 227, PL XXVII, show samples of cloves adulterated with ground cocoanut shells. The long, spindle-shaped, yellow- brown and deeply furrowed stone cells of the adulterant with their thick walls and central branching pores are unmistakable. The dark-brown contents of the cells turn reddish brown when treated with potassium hydroxide. The anatomy of the cocoanut, including the shell, has been carefully studied by Winton.f Fig. 82, after Winton, shows elements of powdered cocoanut shell under the microscope, st are the daik, elongated, yellow, porous ston© -^ Fig. 82. — Cocoanut-shell Powder. s(, dark-yellow stone cells with brown contents; t, reticulated trachea; sp, spiral trachea; g, pitted trachea; w, colorless, and br, brown, parenchyma of mesocarp; /, bast fibres, with stegmata (ste). Xi6o. (After Winton.) cells with their brown contents, these stone cells being the most dis- tinctive characteristic of the ground shells. /, sp, and g are the various forms of trachea; w and hr are respectively colorless and brown paren- chyma of the mesocarp or outer coat, portions of which always adhere to the nutshell and are ground with it. * Note especially the sharp distinction between these values in the case of pure cloves and of clove stems in Richardson's table. I The Anatomy of the Fruit of the Cocoanut. Conn. Exp. Sta. Rep., 1901, p. 208. 434 FOOD INSPECTION AND ANALYSIS. Fig. 264, PI. XXXVI, shows a photomicrograph of powdered cocoanut shells, mounted in gelatin. The long, spindle-shaped stone cells are especially apparent, Ground cocoanut shells have been used in various spices besides cloves, especially allspice and pepper. In the following tabulated results of analyses by Winton, Ogden, and Mitchell * are shown the wide deviation between the chemical constants of cocoanut shells and several of the spices in which they appear as adulterants. Water Total ash. Ash soluble in water Ash insoluble in hydrochloric acid Volatile ether extract Non-volatile ether extract Alcohol extract Reducing matters, as starch, acid conversion Starch by diastase method Crude fiber Total nitrogen Oxygen absorbed by aqueous extract Quercitannic acid equivalent Black Pepper. Cloves. Allspice. Nutmeg. 11.96 7.81 9.78 3.63 4.76 5-92 4 47 2.28 2-54 3-58 2 47 0.86 0.47 0.06 03 0.00 1. 14 1Q.18 4 o.S 3.02 8.42 6.49 5 84 36.70 g.62 14.87 II 79 10.77 38.63 8.99 18 03 25-56 34-15 2.74 3 04 23-72 13.06 8.10 22 39 2.51 2.26 0.99 92 1.08 2.33 I 24 18.19 9 71 Cocoanut Shells. 7-36 0-54 0.50 0.00 0.00 0.25 I. 12 20.88 0.73 56.19 0.18 0.23 1.83 ALLSPICE, OR PIMENTO. Nature and Compositicn. — Allspice is the dried fruit of the Eugenia pimenta, an evergreen tree belonging to the same family (MyrtncecB) as the clove. It is indigenous to the West Indies, and is especially cul- tivated in Jamaica. The allspice berry is grayish or reddish brown in color, and is hard and globular, measuring from 4 to 8 mm. in diameter, being surmounted by a short style. This is imbedded in a depression, and around it are the four lobes of the calyx, or the scars left by them after they have fallen off. The berry has a wrinkled, ligneous pericarp, with many small excrescences filled with essential oil. The pericarp is ea.sily broken between the fingers, showing the berry to be formed of two cells with a single, brown, kidney-shaped seed in each, covered with a thin, outer coating, inclosing an embryo rolled up in a spiral. The berries are gathered when they have attained their largest size, but before becoming fully ripe. If allowed to mature beyond this stage, some of the aroma is lost. * Conn. Ag. Exp. Sta. Rep., 1901, p. 225. SPICES. 435 Though considerably less pungent than other spices, allspice possesses an aroma not unlike cloves and cassia. In chemical composition it most resembles cloves, containing both volatile oil and tannin ; but, unhke cloves, it contains much starch, the starch being contained in the seeds. The volatile oil of allspice is very similar to clove oil. It is shghtly laevo- rotary. and is composed of eugenol and a sesquiterpene not determined. It is present in allspice to the extent of 3 to 4.5 per cent. The boiling- point of the oil is 255° C. Authoritative full analyses of allspice are even more meager than of cloves. Analyses of one sample of whole allspice and five samples of the ground spice, made by Richardson,* are thus summarized: c ■d < .5J |5 1° k s ■*-> Tannin Equival Whole 6.19 4.01 5-15 6.15 59.28 14.83 4-38 .70 10.97 2 81 Ground: Maximum 8.82 5-53 7>-^2 6.92 58.24 18.98 5-42 .87 12.74 3-36 Minimum 5-51 3-45 2.07 3-77 56.86 13-45 4-03 .64 8.27 2.12 Seventeen samples of unadulterated allspice, as sold on the Connect- icut market, were analyzed by Winton and Mitchell,! with maximum and minimum results as follows: Ash. Maximum. Minimum. Total 7-51 -95 3-50 6.22 4-34 .40 1-34 3-78 Insoluble in hydrochloric acid (sand) . . Ether extract, volatile Ether extract, non-volatile Three samples of pure whole allspice were more fully analyzed by Winton, Mitchell, and Ogden with the results given on page 4364 The Tannin Equivalent in Allspice. — Tannin is present in allspice, though to a less extent than in cloves. The exact amount present is rarely determined, but rather the " oxygen equivalent," or quercitannic acid, as explained on page 429, the determination being carried out as there detailed. * U. S. Dept. of Agric, Div. of Chem., Bui. 13, p. 229. t An. Rep. Conn. Exp. Sta., 1898, pp. 178, 179. X Ibid., pp. 208, 209. 436 FOOD INSPECTION AND ANALYSIS. Moisture. Ash. Ether Extract. Alcohol Total. Soluble in Water. Insoluble in HCl. Volatile. Non- volatile. E.x tract. Maximum 10.14 9-45 9.78 4.76 4-15 4-47 2.69 2.29 2.47 0.06 0.00 0.03 5-21 3-38 4-05 7.72 4-35 5-84 14.27 7-39 11.79 Minimum Average Reducing Matters by Acid Conver- sion, as Starch. Starch . by Diastase. Crude P'iber. Nitrogen, X0.2S. Oxvgen Absorbed Querci- by Aque- tannic ous Ex- Acid. tract. 1-59 12.48 1.03 8.06 1.24 9.71 Total Nitrogen. Maximum Minimum Average . . 20.65 16.56 18.03 3-76 1.82 3-04 23-98 20.46 22.39 6-37 5-19 5-75 0.83 0.92 Microscopical Examination of Powdered Allspice. — By soaking the powder twenty-four hours or more in chloral hydrate, many of the harder portions are rendered much more transparent than would otherwise be possible. Fig. 83, after Moeller, shows the microscopical structure of various elements that go to make up allspice powder. The epidermis, or outer layer of the berry with its small cells, is shown in cross-section at (la) and in surface view at (2). Just beneath the outer coat are the large oil spaces (ih) and still further below the stone- cells (ic)- The fruit parenchyma (3) has vascular tissues running through it. (4) and (5) arc the inner epidermis and stone cells of the dividing partitions between the seeds. Small hairs connected with the outer epidermis arc shown at (6). (7) and (8) show in cross-section a portion of the seed-shell and inclosed seed or embryo, with the starch (8a) and the colored lumps of gum or resin (Sb) of a port- wine color. These colored cells exist in the seed coating, and, although only one is here shown, constitute a very important and striking characteristic of allspice. (9) represents the spongy parenchyma of the seed shell, and (10) shows its epidermis. In the parenchyma of the fruit and of the partitions between the cells arc seen, but not always plainly, minute crystals of calcium oxa- late (see (4) and (5)). These details so closely drawn by Moeller are idealized, but serve well to indicate what should be looked for. In practice the water- mounted specimen shows all the characteristics necessary to identify pure allspice, and most if not all its adulterants. In fact pimento is one of the easiest spices to identify under the microscope, by reason of its striking characteristics. SPICES. 437 Three distinctive features are especially typical, viz. : First, the starch grains, which are very uniform in size, measuring about 0.008 mm. in diameter, being nearly circular as a rule, and often arranged in groups not unlike masses of buckwheat starch. Ordinarily these masses con- tain fewer granules than do those of buckwheat. The granules are Fig. 83 — ^Powdered Allspice under the Microscope. X125. (After Moeller.) smaller and more inclined to the circular than to the polygonal form, while in many cases they have distinct central hila. The starch grains are very numerous and are found in nearly every field. Sec Fig. 195, PI. XIX. A second distinctive feature of allspice is the stone cells, of which there are many. These are more often colorless, and in most cases very large and plainly marked. They are sometimes seen singly and at other times grouped together. Frequently they are attached to pieces of brown parenchyma. 438 FOOD INSPECTION AND ANALYSIS The third and most characteristic feature of allspice powder under the microscope is the striking appearance of the lumps of gum or resin, which are of a more or less deep port-wine or amber color and are con- tained in the middle layers of the seed coat. These cells are very striking, occurring sometimes in isolated bits, and in other cases in aggregations of from 2 to 4 or even 6 to 8 cells. These resinous lumps appear plainly in Fig. 194, PI. XIX. Droplets of oil are occasionally seen, but not in profusion. As a rule the oil is forced out of its large containing cells and into the surrounding tissue by the process of drying. U. S. Standards. — According to the U. S. standard for allspice, quer- citannic acid should not be less than 8%, total ash not more than 6%, ash insoluble in hydrochloric acid not more than 0.4%, crude fiber not more than 25%. Adulteration of Allspice. — The most common adulterants reported in powdered allspice are cocoanut shells and the cereal starches. Besides these the writer has found in Massachusetts, peas, pea hulls, exhausted ginger, cayenne, olive stones, pepper, and turmeric. To this list may be added clove stems, which are on record as a not uncommon adulterant in some localities. All of these are to be readily recognized by a care- ful microscopical examination. CASSIA AND CINNAMON. Nature and Composition. — The terms cassia and cinnamon are inter- changeable in commerce, though, strictly speaking, they represent two separate and distinct species of the genus Cinnamomum, belonging to the laurel family (JLauracecE). True cinnamon is the bark of Cinnamo- mum zeylanicum, a tree from 20 to 30 feet high, having horizontal or drooping branches, and native to the island of Ceylon, but cultivated also in some parts of tropical Asia, in Sumatra, and in Java. The entire yield of pure Ceylon cinnamon is extremely small, and but little of it is found in this country. It is the very thin, inner bark of the tree, and is of a pale, yellowish-brown color, being found on the market in long, cylindrical, quill-like rolls or pieces, the smaller rolls being inclosed in the larger. The outer surface is marked by round dark spots, corre- sponding to points of insertion of the leaves, and it is also furrowed length- wise by somewhat wa\'y, light-colored lines. The inner surface of the bark is darker colored, and has no lines. In thickness the bark varies from 1.5 to 3 mm. Both the inner and outer coatings of the bark of Ceylon cinnamon are usually removed in the process of preparation, so SPICES. 439 that it is of a much cleaner and more even texture than the cassia bark, which is thicker and heavier by reason of the outer cork layer usually left on it. The cheaper and more common cassia is the bark of the China- momum cassia, w^hich comes from China, Indo-China, and India. It is of a darker color than that of cinnamon, of coarser texture, and as a rule about four times as thick. Most varieties of cassia bark are less tightly rolled than cinnamon, and are not arranged one within the other in layers. The outer surface is marked by elHptical spots left by the leaves, and by small, dark-brown, wart-Hke protuberances. Cassia does not have the wavy, hght-colored lines found in the cinnamon. Both cinnamon and cassia barks are very aromatic in taste, somewhat astrin- gent, and slightly sweet. Cassia buds are the dry flower buds of China cassia, and are found m the market both in whole and in powdered form. Powdered cassia often consists of a mixture of several varieties of bark, while the cheaper grades sometimes contain an admixture of the ground buds. The best grade of cassia is that from Saigon, a much cheaper, from Batavia, while the cheapest is the China cassia. The odor of cassia and cinnamon bark is due to the volatile oil, of which from i to 2 per cent is usually found. Cassia and cinnamon oil greatly resemble each other, the principal constituent in either case being cinnamic aldehyde, CeH^CH: CH.CHO. Besides this, one or more esters of acetic acid are present. Both oils are very pungent and intensely sweet. Starch is present in cassia to the extent of from 16 to 30 per cent. A very small amount of tannin is found, as well as cinnamic acid and mucilaginous matters. Cassia buds are somewhat similar in com- position to the bark. They have, however, less starch and crude fiber, and higher contents of volatile oil and nitrogen than the bark. Richardson * has made analyses of a few samples of pure whole cinna- mon and cassia, from which the following are taken: fe ^:2 Ceylon cinnamon i Cassia bud'^ Cassia bark (4 samples) : Maximum Minimum 5-40 7-43 4-79 17-45 9-32 4-55 3-40 5-58 8.23 2.48 1.05 .82 3-59 3-51 -55 1.66 1.58 5-21 2.38 -74 33-08 25-63 8.60 26.29 14-33 3-80 7.00 4-55 2-63 51.28 56.84 65-23 6^-33 48.65 .62 1. 12 •73 .42 * U. S. Dept. of Agric., Div. of Chem., Bui. 13, p. 221. 440 FOOD INSPECTION AND ANALYSIS. Winton, Ogden, and Mitchell's * results of analyses of whole samples of cinnamon, cassia, and cassia buds are thus summarized: Moisture. Ash. Total. Soluble in Water. Insoluble in HCl. Ether Extract. Volatile. Non- volatile. Ceylon cinnamon (6 samples) Maximum Minimum Average Cassia bark (20 samples): Maximum Minimum Average Cassia buds (2 samples): Average 10.48 7-79 8.63 11.91 6-53 9.24 7-93 5-99 4.16 4.82 6.20 3.01 4.73 4-64 2.71 1.40 1.87 2.52 0.71 0.58 0.02 0.13 2.42 0.02 0.56 0.27 1.62 0.72 1-39 5-15 0-93 2.61 1.68 I-3S 1-44 4-13 1.32 2.12 5-96 Alcohol Extract. Reducing Matters by Acid Conversion, as Starch. Crude Fiber. Nitrogen, X6.2S. Total Nitrogen. Ceylon cinnamon (6 samples) : Maximum Minimum Average Cassia bark (20 samples): Maximum Minimum Average Cassia buds (2 samples): Average 13.60 9-97 12.21 16.74 4.57 8.29 22.00 16.65 19.30 32.04 16.65 23-32 10.71 38.48 34-38 36.20 28.80 17-03 22.96 13-35 4.06 3-25 3-70 5-44 4-34 7-53 0.65 0.52 0-59 0.87 0-53 0.69 Structure of Powdered Cassia under the Microscope. — Fig. 84, from Moeller, shows various elements of cassia bark as veiwed microscop- ically, (i) shows in cross-section a portion of the cork and outer layer of the bark rind, with flat cells nearest the surface, having somewhat thick walls and reddish-brown contents, and, farther in, the cells s, with mucilaginous material. The stone cells of the intermediate layer of bark are shown at (2). Here the tendency of the stone cells is to be thicker on one side than on the other, as is plainly shown. (3) represents the structure of the inner layer of the bark, showing bast fibers b cut across, and more of the so- called mucilaginous cells 5 of large size, which normally contain the ethereal or volatile oil. The starch granules (4) are contained in great abundance in the polygonal cells of the parenchyma of the intermediate * Twenty-second Annual Report Conn. Exp. Sta., 1898, pp. 204, 205. SPICES. 441 and inner bark layers. (6) represents a fragment of a bast fiber, which is often shown in cassia powder with connecting parenchyma. The slone-cells cf the cork are shown in plan view at (7). Very small, needle- like crystals of oxalate of calcium are occasionally to be seen if looked for carefully. They occur in the parenchyma cells of the inner and inter- mediate layers of the bark. The microscopical structure of Ceylon cinnamon much resembles that of cassia. Cassia starch grains measure from 0.0132 to 0.0222 mm., Fig. 84.^— Powdered Cassia under the Microscope. X125. (After Moeller.) being considerably larger and more abundant that those of true cinnamon. As a rule the bast fibers of cassia are larger, but shorter, than those of cinnamon, and provided with thicker walls. Figs. 203 and 204, PL XXI, show various phases of pure cassia bark as photographed from water-mounted specimens of the powder. Cassia starch somewhat resembles that of allspice, but it is not as a rule found in masses containing as many granules as does the allspice starch. Very commonly two or three of the starch granules are arranged together in 442 FOOD INSPECTION AND ANALYSIS. such a manner that at first sight they appear to form a single large granule, but on more careful examination are seen to be two- and three-lobed, consisting of several smaller grains. Stone cells, which are very abundant in the powdered cassia, do not happen to be included to any extent in the photographed fields. Cassia stone cells are generally more oblong than those of allspice, and are more often brown in color, while the all- spice stone cells are generally colorless. A distinctive feature of powdered cassia consists in the long-amber- colored wood fibers, some distributed in bundles, and others arranged singly. These are very clearly shown in Figs. 204 and 205. Yellow patches of cellular tissue with starch grains interspersed among them are very abundant in the powder. The U. S. Standards place limits as follows: Total ash not to exceed 5%; sand not to exceed 2%. Adulteration of Cinnamon and Cassia. — The commonest adulterants are cereal products and foreign bark. Besides these, the writer has found, in samples sold in Massachusetts, leguminous starches, pea hulls, nut- shells, turmeric, pepper, olive stones, ginger, mustard, and sawdust. Much of the China cassia when imported contains an inexcusably large amount of dirt. In one sample Winton, Ogden, and Mitchell found over 15% of sand. Ground Bark of the Common Trees, especially that of the elm, resembles in physical appearance ground cassia, and is to be looked for as an adulterant. Fig. 265, PI. XXXVII, shows the appearance of ground elm bark. The fibers of cassia bark have starch granules as a rule interposed among them, while the foreign bark, usually of a much coarser texture, shows no starch connected with its structure. Fig. 206, PI. XXII, shows a water-mounted specimen of adulterated cassia powder, chosen from samples purchased in the Massachusetts market. Nothing but the adulterant (a foreign bark) shows in the field. The tissue is loose and considerably coarser than that of cassia bark. PEPPER. Nature and Composition. — Pepper is the dried berry of the pepper plant {Piper nigrum), a climbing shrub belonging to the family Pipe- racecB, native to the East Indies, but cultivated in many tropical countries. The height of the pepper plant is from twelve to twenty feet. When the fruit begins to turn red, it is gathered and then dried, by which process it turns black and shrivels up, forming the black peppercorns of com- merce. They are spherical single-seeded berries, about 5 mm. in diam- SPICES. 443 merce. They are spherical single-seeded berries, about 5 mm. in diam- eter, covered with a brownish-gray epicarp, and having on the under side the remains of a short stem. At the top of the berry is an indistinct trace of a style, and of a lobed stigma. Varieties of black pepper are named from the localities in which they are grown or from which they are shipped, as Singapore, Lampong, Sumatra, Tellicherry, Malabar, Acheen, Penang, Alleppi, Trang, Man- galore, etc. White pepper is obtained by decorticating the fully ripened black peppercorns, or removing the dark skin. This is accomplished by mac- erating them in water to loosen the skin, which is then removed readily by drying and rubbing between the hands. White whole pepper grains are grayish white, and a trifle larger than the black pepper berries. They are nearly spherical in shape, and have a number of light-colored lines that, like meridians, run from top to bottom. The common varieties are Siam, Singapore and Penang, the latter being coated with lime. The pungent taste of pepper is due in great part to its essential oil, a hydrocarbon of the formula CioHie, present in amounts varying from 0.5 to 1.7 per cent. Pepper oil contains phellandrene and a terpene. Other important constituents of pepper are piperidine, and the crys- talline base piperin, C17H19NO3, insoluble in water, but soluble in ether, and in alcohol. Starch is present in pepper to a large extent. Burcker gives the following average percentage composition of black and white pepper: Black pepper . White pepper. 4-57 12.45 1.80 6.08 12.50 13-56 1.36 0.94 6.85 7. II $0. 42.90 56-04 C 3 o o 2; C c^ ^•sl 7-39 3-35 Richardson's * analyses of three samples of whole black and two samples of whole white pepper, all pure, are as follows: Black pepper: West coast. Acheen. Singapore. , White pepper: West coast. Singapore . Water. 8.91 8.29 9-83 9-85 10.60 Ash. 4.04 4.70 3-7° 1. 41 1-34 Volatile Oil. .70 1.69 1.60 -57 1.26 Piperin and Resin. Alcohol Extract. 7-29 7-72 7-15 7-24 7-76 6.06 5-74 2-57 Starch (Acid Con- version) . 36.52 37-50 37-30 40.61 43.10 * U. S. Dept. of Agric, Bur. of Cham., Bui. 13, part 2, p. 206. 444 FOOD INSPECTION AND ANALYSIS. Undeter- mined. Crude Fiber. Albumin- oids. Total NX6.2S. Total N. Black pepper: West coast Acheen. . . Singapore . White pepper: West coast Singapore , 24.62 13-64 17.66 23.28 19-55 10.23 10.02 10.02 7-r3 4.20 7.69 10.38 10.00 9-31 9.62 9.«i 12.60 12.08 11.48 11.90 1-57 2.02 1-93 1-83 1.90 Richardson gives the following variations in the constituents of pure pepper: Black. V^hite. Water 8.0 to II.O 2.75 to 5.0 .50 to 1.7s 7.0 to 8.0 32.0 to 38.0 8.0 to II.O 7.0 to 12.0 8.0 to II.O 1.0 to 2.0 .50 to 1.75 7.0 to 8.0 40.0 to 44.0 4. 1 1 to 8.0 8.0 to 10. Ash Crude fiber McGill's * analyses of six samples of whole black, and five samples of whole white pepper, all genuine, are thus summarized: Moisture, etc., Lost at 100° C. Ash. Soluble in Hot Water. Insoluble in Water. Total. Insoluble in Hydro- chloric Acid. Sand Expressed as Per Cent of Total Ash. Alcohol Extract. Black: Maximum Minimum Mean 14.10 10.62 12.03 13.00 11.30 12.34 2.64 2.07 2.41 0.72 0.14 0.54 3.06 1.46 2.05 3-04 1-50 2.46 5.16 3-98 4-47 3-65 1.64 3.00 1.08 .06 0.36 0.88 0.26 0-55 21 2 8 42 9 21 9.06 8.28 8.71 White: Maximum Minimum Mean 8.92 7.00 7-73 Winton, Ogden, and Mitchell's, and Winton and Bailey's f analyses of whole black pepper and whole white pepper, rc] resenting the leading varieties imported into the United States, also of pepper shells and long pepper, are summarized in the following table: ♦Canada Inl. Rev. Dept. Bui. 20, 1890. t An. Rep. Conn. Exp. Sta., 1898, pp. 198-199; 1903, pp. 158-164. SPICES. 445 lOBJixa J3q;a M to ro l^ looo Oi ?o 95 M Tt ov to^to C) li- Ov P« 1 ro N rO r*^ ro rO ©^ "3^ SO rorON (mOOSvJSO m O " ■ g ajpBIOA-UO^ UJ ddddddddd 6666':6,'^<^666 \o looo M Ti-ioeoGo^o 00 H O H &:] l^i ";J->o « 00 % •Flox rOM O H P) ro'iiO®^ q M q q>-;OiO roM m ■£c-9X w OnOoO 0^|^)'^0^^ rovO OvCO<3i^05 osw to t^r^OoO t^roQO'CiOi q qooo-^^oo « row N' S9I 'uaSoj;!f,j l^^bx rJ M d d M M GO O '-i w M d o-^^cJo •4p< m •^0 t^t^O On^*^®* O O N O'O^^+vot^-.vO o o oo vOO^OO►-^^'*^^OOto asBjsBiQ Xq qojBjg rororOPOoo'N©o<3^l^ HH 00 M O to ■^^^ ^^ ro fO to vototoio<;o^o'Oi-i "^ •qojB^s SB O t^Ot^H r^f^'^OO UOM M t^^GoN. O\fO00 oq^qvq m w c^^■^©< 00 r~-0 MOi~^>-i\o •'too I 10ISJ3AU03 ppv M w d\o6 i^M(3oooQo' Tt\d dvt^^tooi M H PI OnG m t^vO ioto>-H^ rOlOvO o'^lOito O f^ 0000 'to comOoGO^ 00 't m po^ >-H to (-0 vo •jOBrixa loqooiv CO o6 6^ 6 <5> d ■~^' oo oi r^oo r^t^ooJ^f^vd 'too o fO"*r^r^ONON^to*~i 'tOv'tPl^to'^ t^Tt-M ca •aillBJOA-UOfsI r^C^iOM u-)C)(3000~-^ PI 00 vO roOi e^ Ol 0\ O vO livdoo 6^o6 dM;::J0 •an^^PA ooo M o ■'tvo^'to©? lOOvvO t^Os^^to OvO lO W MdlHMMM©JO->~; dddd ooomo'm « Mvooooo loGoOO H OsO voOOO O POPi "lOH "? aiqniosui w q q ^ q q to O ^-; O q H M©}0'-H toVO N d d d d o o* o 't oJ d J3 d d H d M w" >-^ o o O lor^oo moO>CO r^ POOO loO 00 fo 00 O •ja^BjVi UT aiqnpg M r-.ror--q\q"^?^to •* PO rovO QO ®i ■vf- P< PI P< < N oJ oJ N N roGo >~! e-< q ro'toqOiOts. (^„ qs MMMpi^>~I>~I|.JO''' M M o^o^ ovMoo^'^oto OvIoPOOOf^^f^vO P« lo ■ajnjsioi^ q to Tj- q •^ r~-Oi to oq 00 't>qvq^?>;^vq ^ •^ m' M M cs w M Qci ci >~; pj rOPOPr>^©j<30 d d d\ MMMMHM-^^T-^-^^ ■saidmBg JO jaquinj^i lO CI t M ro lO O P» PI PO PO O f^ w M 0) O (U M bO bO U K j- (-1 bjO bC S E bObObObc^S eg Avera Avera n! d 3 :i dj ciSnJ(33rt;33il)33 Aver Aver axim inim ('erag ^ ^ Si ^ .S E rt .5 c § %< % ^<% § nO NO to o M t^NO 1 tT O •* 00 >o t^ rotoroONOO MiONOf^to On 00 to •SC-9X 'U330J1IN t^ rl- lO \0 ■* to toNNOrt-wro MNOOONOto to to M M H M M H ^ MMMMMM CSMMMM M M M ro O M t— f^ r-~ mnOOOnOO mOn-<^moO Tf t^ On 00 H ro ro !^ r<- nOnOIOMOOO MMt^O'^ t-~ Tj- On ■jaqij apnJ3 Os lo lo lo tn i/- rONOONtoTj-to or^oO'^O M Tt On M H W M H ^ MMMMMM MMMNM t>l VO "* M <>> r^ mnOOnOnono nOnOOO"" P) ■qojB^g SB tt to Tj- LO l/- \r lO M On On On 0^ M ro nO m m M •UOTSJOAUOQ PPV NO ^MroONONON OOr^ t^ NO NO NO o Aq sa3iiT3i\[ aupnpa^ M M M M M M CSWNmmm mmmmm 00 ro O w "~ ro Ot^MOOO '^NCOror^M 00 jaqia an^BiOA \0 O fOO ■* to OOt^rOr^OM toQrorOO N 1^ ro ro ro r^ r<" fO cowrorororo rorOfOf^^*~0 to -uo^ JO -o^ auipoj M Ht M l-t M " ^ " On P) o a On OnmoOnOOOM •^nOmOOnO t 00 1 1 — 1 ■4-* O-^rorororO ^ooOt^'tNO roOfOOOO-^ On On V^ •airttJjoA-uofvi H t^ O O O NO'^tO'^'^-4- ni^OOnoO On m O 1 p tH MM C) M (N M M M y, < to t^ to 00 oc on 0'*00mio OtoO to nC H 00 On .C •sn^^PA N M 00 M M M MTfoO'^toON OnOniomioOn •*« 1 Pi w M O M M M mOOmOO mQmWm M O 3 < «4-l O J^ rt- OtoroOOto OOmOO rO NO O NO O O t^ M On MOOtoONt^ro OQtot^OOC ro 'to ^* -aa^B^ m Tt Tt to •^ Tf NO -^ to NO to NO ro M c^ ro M M 00 M Ph^ N to O O O OONQtoto OOtoOO r^ t-- Ci^ ^ •l^^ox O CI O On M nOOnOnO\no-* OO'^oO'^Onm M w <; 00 NO t^ f>.NO t^ OOtONOOOt^OO NOrO'^rtro'* •*■<*■ | Ph M M Ph NtoONQi^to oOfOtootoM ONtor^MTj-NO Tj-NO 'lOH N O M O c c 000 a < fe ^ > OH -G lu b X. -Ob -c I- -C hole P Hunga Spanis oj rt \fi c cu ^ ds (S Hung Spani eds a Hung Spani 1^ Cu rn 1 SPICES. and pimiento they determined the percentage of the different part follows: 457 ;s as Paprika (21 Samples). Pimiento (18 Samples). Shells. Seeds and Placentae. Stems. Shells. Seeds and Placentae. Stems. Maximum 63.7 50.5 56.4 43-2 28.1 36.1 9-4 6.0 7-5 58.1 531 55-3 37-4 34-9 36.0 10.9 6 Minimum Average 8.7 Analyses were reported of each of the above separately as well as of the whole product and of the whole product less the stems as follows: COMPOSITION OF RED PEPPER (TOLMAN AND MITCHELL). Ash Ether Extract Non-vol. Ether Ext. *M W d 6 (Cont Ext.). (Shaking Method). ji d c •5 Xi to 3< 1^ a c u •d c > c 2 J H w > Z eu oi fe Mombassa Chillies 26 Maximum 8.41 3.03 6.41 1.72 19.00 28.70 Minimum S 34 0.44 4-73 0.28 15.88 24.98 Average 6 31 1.24 5 07 0.81 17 26 26.86 Japan Chillies. . . . 17 Maximum 6. 20 1.07 5-50 I 59 23 21 25.96 Minimum 5-08 0.31 4-52 0.09 17.10 22.82 Average 5. 52 0.53 4.99 0.56 19.94 24.25 Cherry Chillies . . I 6.62 1.23 5-39 1. 18 16.17 26.20 Hungarian Papriks i With stems . . . 7 Maximum. . . 3.76 6.03 0.33 5-73 0.89 16.43 15.00 134-0 1.4854 22.76 Minimum . . . 3 29 5.08 0.24 4.82 0.08 12.21 10.86 129 8 1-4758 20.69 Average 3-47 S 63 0.28 5. 36 0.42 14.04 12.61 132-6 I .4806 21.93 Without stems. 7 Maximum. . . 4. 16 5.56 0.31 5.2s 0.90 17-35 15.08 133.2 1-4834 23.18 Minimum . . . 3. II 4.66 0.20 4.41 0.07 13-94 12.64 129.0 I -4756 20.47 Average 3 SI 5.22 0.26 4.96 0.34 15-28 13.91 131-9 1-4799 21.56 Spanish Pimiento: With stems. . . . 7 Maximum . . . S.98 7.86 0.48 7.54 0.69 12.58 10.81 137.3 I. 4818 20.59 Minimum . . 4 31 6.98 29 6.69 0. 10 11.30 9.81 136.0 1-4776 19.53 Average 5 06 7-39 35 7.04 0.47 11.87 10.34 136.7 I -4805 20.13 Without stems. 8 Maximum . . . 5-09 7 35 0.40 6.98 0.60 13.34 11.30 137.2 I. 4810 20.34 Minimum. . . 452 6.60 0.24 6.26 0.2s 11.58 9.80 134-5 1.4792 18.76 Average 4-83 6.98 0.32 6.66 0.44 12.47 10.67 136 -I I. 4801 19.49 Boyles' * analyses of red peppers appear in the following table. South Carolina capsicums were grown under the indirect supervision of the Bureau of Plant Industry from Hungarian paprika seed, but in that climate be- * Loc. cit. 458 FOOD INSPECTION AND ANALYSIS. came so hot as to be classed, when ground, with cayenne. He believes that the United States standards for cayenne should be revised as follows: Total ash increased to 7.5%, ash insoluble in 10% hydrochloric acid (sand) to 1.0%, fiber to 20%, and non-volatile ether extract lowered to 14%. COMPOSITION OF RED PEPPER (BOYLES). Number of Analyses. Mombassa Chillies. . Maximum Minimum Average Japan Chillies So. Carolina Capsi- cums Maximum Minimum Average Bombay Capsicums Maximum Minimum Average Japan Capsicums. . . Maximum Minimum Average Korean Capsicums. . Maximum Minimum Average Niger Capsicums . . . Maximum Minimum Average African Capsicums. . Bombay Cherries. . . Maximum Minimum Average Ash. 17 35 19 Total. 9 40 4 36 6 08 4 63 7- 75 4- 82 5- 98 9 35 5 56 6 95 6 84 4 90 6 05 7 70 6 20 6 94 6 17 S 27 5 72 5 05 5 .67 5 ■35 5 •51 Insol. in HCl (Sand). 1.77 0-3S I .06 0.18 0.25 0.78 1-75 o. 14 0.76 1.17 o. 14 0.39 0.75 0. 20 0-5I 1 . 27 0.60 0.83 0.95 0.82 0.65 0.74 Ether Extract. Volatile.* (3) 0.32 0.15 0.23 I. 85 0.15 0.60 (7) o. 72 0.25 0.45 (3) 0.40 0.30 0.35 (2) 0.60 0.45 0.53 (2) 0.85 0.25 O.S5 (i) 0.30 0.30 0.30 Non-vol."* (6) 25-49 1575 20.06 22.50 15-70 10.75 13.92 (12) 20.40 12.35 16.57 (5) 17.03 12.80 15-56 (2) 22.25 19.77 21.01 21.96 18.22 19-53 19-45 17-55 15.60 16.57 Fiber.* (6) 30.45 22.63 26.25 24.02 30.48 20.07 25.48 (8) 32.30 25.00 28.08 (5) 26.64 22.50 23.84 (2) 26.02 25-85 25-94 27.77 22.82 24-93 28.76 29. 20 27-45 28.33 * Figures in parentheses are number of samples. Microscopical Structure of Red Pepper.— Fig. 86, from Moeller, shows the appearance under the microscope of various elements of powdered red pepper, (i) is a sectional view through the outer portion of the fruit SPICES. 459 shell or pod, showing the epidermis (a), and beneath this the collenchyma layer. The inner epidermis is shown at (2) with its cells thick-walled in places and inclosing brilliant, red oil drops of coloring matter, (3) represents the outer and (4) and (5) the inner epidermis in surface view. The outer epidermis of cayenne, which is the element of chief value in distinguishing this from paprika, is shown at (6). Fig. 86. — Powdered Red Pepper under the Microscope. Xi2s. (After Moeller.) A cross-section through the seed shell is shown at (7); a being the epidermis of the seed, b the parenchyma layer directly beneath, and c the tissues of the endosperm. (8) shows in surface view the peculiar seed epidermis, the appearance of which Moeller compares with that of intestines. At (9) is shown one of the isolated cells of this epidermis more highly magnified, while (10) shows the epidermis of the calyx. Figs. 211 and 212, PI. XXIII, show photomicrographs of powdered cayenne. In Fig. 211 is shown a large bit of the outer epidermis of the fruit pod, while in Fig. 212 appears a smaller portion of this same kind 460 FOOD INSPECTION AND ANALYSIS. of epidermis, and next to this the characteristic skin of the seed shell, with its striking markings suggestive of the convolutions of the intestines. Yellow or yellowish-red droplets of oily coloring matter are distributed through the field. Starch grains are absent. U. S. Standards. — Cayenne: Non-volatile ether extract, not less than 15%; total ash, not more than 7%; ash insoluble in hydrochloric acid, not more than 1%; starch, not more than 1.5%; and crude fiber, not more than 28%. Paprika: Total ash, not more than 8.5%; ash insoluble in hydro- chloric acid not more than 1%; iodine number of extracted oil, between 125 and 136. Rosenpaprika : Non- volatile ether extract, not more than 18%; total ash not more than 6%; ash insoluble in hydrochloric acid, not more than 0.4%; crude fiber, not more than 23%. Konigspaprika : same as rosenpaprika in limits, except that for total ash is 6.5%, and for ash insoluble in hydrochloric acid is 0.5%. Pimiento: non- volatile ether extract, not more than 18%; total ash, not more than 8.5%; ash insoluble in hydrochloric acid, not more than 1%; crude fiber, not more than 21%. The most common adulterants ot cayenne are the starches of the cereal grain?, corn and wheat. Ground pilot bread and crackers are especially common. Besides these the writer has found in the routine examination of cayenne samples in Massachusetts, ginger, nutshells, turmeric, rice, gypsum, buckwheat, olive stones, mustard hulls, ground redwood, red ocher, and coal-tar dyes. Fig. 213, PI. XXIV, shows a sample adulterated with wheat, corn, and cocoanut shells. Mineral Adulterants, such as gypsum, ^nd red ocher and other pigments, are all to be looked for in the ash by methods of qualitative analysis. An abnormally high ash is suggestive of adulteration. According to Vedrodi, the ash of genuine cayenne should not exceed 5.96. The presence of red ocher is rendered apparent by the high content of iron. Salts of lead and mercury are rarely if ever now used for color. Ground Redwood. — Numerous varieties of redwood are commonly used to intensify the color of cayenne, especially when otherwise highly adulterated with colorless materials, such as the starches. The redwood is sometimes used alone, and sometimes in mixture with turmeric. Both redwood and turmeric are readily recognized under the microscope. Fig. 214, PI. XXIV, shows a cayenne sample adulterated with corn starch and red sandalwood, a mass of the latter filling the center of the field. The wood fibers of the dyestuff, even when finely ground, are very striking under the microscope, showing a brick-red color. SPICES, 461 Detection of Coal-tar and Vegetable Colors.— Oil-soluble coal-tar and vegetable colors may be tested for in cayenne and paprika by an adaptation of Martin's butter-color method, shaking the ether extract of the sample with the alcohol and carbon bisulphide mixture, page 557. The carbon bisulphide dissolves the oil and natural color, while the over- lying alcohol layer holds in solution many of the artificial coloring matters that may be employed. The natural colors of cayenne and paprika are sparingly soluble in alcohol, but readily soluble in carbon bisulphide. The separated alcohol is examined for colors by methods given elsewhere. Tests for coal-tar dyes should also be made by Sostegni and Carpen- tieri's, or Arata's method (Chapter XVII). Szigeti * treats the suspected sample with water acidified with acetic acid, and boils in this solution a bit of wool, which, if carotin or a coal-tar dye be present, is colored red. If the color is carotin, it will be removed from the wool by treatment with petroleum ether, or by heating at 100° C. for some hours, but if a coal-tar dye, it will still remain fixed thereon. Detection of Olive Oil in Red Pepper.— The color of paprika and pimiento is sometimes intensified by grinding with olive oil. This form of adulteration is detected by determination of the iodine number of the non-volatile ether extract. The usual method of determining the non- volatile ether extract having been found unsatisfactory for the purpose, Wintont suggested a method analogous to that employed by him and co-workers in determining alcohol in water extracts. The following details of the process, elaborated by Seeker,f have been adopted by the Association of Official Agricultural Chemists: Dry 5 grams on a watch-glass over sulphuric acid for at least twelve hours. Measure 250 cc. of anhydrous alcohol-free ether into a dry graduated flask with the mark near the lower end of the neck, and brush the paprika into it. Place a mark on the neck of the flask at the meniscus, and allow to stand for one hour, shaking at twenty-minute intervals during that time. Bring the meniscus back to the mark either by cooling if the level has risen, or by adding absolute ether if it has fallen, and let settle. Pipette off 100 cc. of the supernatant liquid, filter through an ii-cm. close-textured paper into a tared, air-dry glass-stoppered 250-cc. Erlenmeyer flask previously counterpoised against a similar flask, wash * Zeits. landw. Versuchs. Oesterreich, 5, 1902, pp. 1208, 1222. t U. S. Dept. of Agric, Br. of Chem., Bui. 122, 1909, p. 38. X Ibid., Bui. 132, 1910, p. 114; 137, 1911, p. 81. 462 FOOD INSPECTION AND ANALYSIS. with a little absolute ether, and distil off the solvent until the ether ceases to come over. Lay the flask on its side in a water-oven, heat for thirty minutes, cool the open flask for at least thirty minutes in the air and weigh. Repeat this heating and weighing until the weight is constant to within i milligram, two heatings usually being sufficient, and calculate the per cent of ether extract. If more than il hours' heating is required to obtain constant weight or if the ether extract becomes colorless it should be rejected, and a new determination started with freshly purified ether. Dissolve the ether extract in the flask in lo cc. of chloroform, add 30 cc. of Hanus solution, and proceed as described for the Hanus method. The iodine number thus determined should not be less than 125. GINGER. Nature and Composition. — Ginger as a spice is the ground root- stock of the Zingiber officiiiale, an annual herb of the family Zingiber- acecB, growing to a height of from 3 to 4 feet. It is a native of India and China, but is cultivated quite extensively in tropical America, Africa, and Australia. The root is dug when the plant is a year old, and when the stem has withered. If the root, when freshly dug and scalded to prevent sprout- ing, is dried at once, it forms the so-called black ginger, of which Calcutta and African are the common varieties. When decorticated, the product is known in commerce as white ginger, the chief varieties being Jamaica, Cochin, and Japan. The best variety is Jamaica ginger. The scraped root is sometimes bleached to make it still whiter, or sprinkled with carbonate of lime. In commerce whole or black ginger appears in " hands " 4 to 10 cm. long, and from 10 to 15 mm. in diameter. These usually have three or four various-sized, irregular branches, some short and thick, others elongated. The epidermis is gray or yellowish gray in color, more or less wrinkled, and beneath it is a reddish-brown layer. The inner portion of the dried root is white or yellowish. The root is hard, and of a com- pact, horny structure. White or decorticated ginger appears in " hands " of smaller diameter than the black, and yields a lighter colored powder on grinding. Preserved ginger root is prepared by boiling the root in water, and curing with sugar or honey. Much of the preserved ginger comes from Canton. SPICES. 463 The distinguishing features of ginger are its large content of starch, its volatile oil, and its resinous matter. Inasmuch as the epidermis con- tains a large amount of pungent resin, it is easy to see how the peeled or decorticated variety is inferior. Oil of ginger is very aromatic, and of a greenish- yellow color. Its specific gravity ranges from 0.875 '-O 0-885. It is slightly soluble in alco- hol. Of its composition little is known. Richardson's analyses in full of five samples of whole ginger-root are as follows: .- a! Calcutta Cochin Unbleached Jamaica Bleached Jamaica, London. . " " American 9.60 9.41 10.49 II .00 10. II 7.02 3-39 3-44 4-54 5-58 2.27 1.84 2.0:5 1.89 2-54 4-58 4.07 2.29 3-04 2.69 49-34 53-33 50-58 49-34 50.67 7-45 •05 74 70 65 6.3c 7.00 10.85 9.28 9- 13-44 18.91 15-58 19.21 11.66 1. 01 1. 12 1-74 1.48 1.46 Summaries of Winton, Ogden, and Mitchell's analyses of eighteen samples of whole ginger, representing the common white and black varieties, as well as of two samples of exhausted ginger, are as follows; Ash. u g '►J Ether Extract. > h "o > 1- Ginger: Maximum 11.72 8.71 10.44 10.61 8.02 9-35 3.61 5-27 2.12 5-05 4.09 1-73 2.71 0-59 3-55 2.29 0.02 0.44 0.18 1.50 3-53 0.20 0.80 3-09 0.96 1.97 1. 61 0.13 5-42 2 82 Minimum Average 4.10 3-86 0-54 Exhausted ginger from English ginger- ale works E.xhausted ginger from extract works . . Ginger: Maximum Minimum Average Exhausted ginger from English gin- ger-ale works. Exhausted ginger from extract works. 6.58 5.18 4.88 1-52 Reducing Matters by Acid Con- version, as Starch. Starch by Diastase. Method. il urr, 62.42 53-43 57-45 59.86 60. 31 1 5.50 49-05' 2.37 54-53' 3-91 54-57. 5-17 9-75 4.81 7-74 6.94 2T^ 17-55, 1-55 10.92 0.77 13-42, 1.23 6-15' 16.42J I. II 464 FOOD INSPECTION AND ANALYSIS. McGill * records the analyses of ninety-eight samples of ground ginger as sold in the Canadian market. Of thirty-two of these, pronounced pure on analyses, the following is a summary: Moisture or Loss on Dry- ing at IOO°. Petro- leum- ether Extract. Cold- water Extract. Ash. Total. Soluble. Insoluble. Alkalin- ity of Soluble Ash as K2O. Maximum 12.00 9-50 6.13 2.78 15-48 14.04 7.84 3-67 3-15 2.28 3-99 1.96 •133 .103 Minimum According to Vogl, the proportion of ginger ash varies quite widely according to the kind, but should never exceed 8%. Exhausted Ginger and Methods of Detection. — There are two kinds of exhausted ginger commercially available for admixture with ground spice, as an adulterant. One is the product left after extraction with strong alcohol in the making of extract of Jamaica ginger, and the other the residue from extraction with either very dilute alcohol, or with water, in the manufacture of ginger ale. Ground, exhausted ginger is rarely substituted wholly for the pure variety, since, from its lack of pungency, the sophistication would be too apparent. It is rather used to mix with the latter in varying proportions, and as an adulterant of other spices. Ginger that has been exhausted by extraction with alcohol has been deprived of most of its volatile oil, which is found in the "extract," while for the manufacture of ginger ale, a water extract, or at most a very dilute alcoholic extract is best adapted. Such a water extract does, as a matter of fact, remove much of the valued pungency, so that the residue, or exhausted ginger, is rather inert. Either the alcohol- or the water-extracted variety of exhausted ginger, when present in considerable amount, would be apparent, one by the alcohol and ether extract, and the other by the abnormally low cold- water extract, and water-soluble ash. Dyer and Gilhard f first called attention to the water-soluble ash as a reliable means of indicating exhausted ginger. Six samples of ginger of known purity were analyzed by them, their results being summarized as follows: * Dept. Inl. Rev. Canada Bui. t Analyst, 18, 1893, p. 197. pp. 10, II. SPICES. 465 Pure ginger (6 samples): Highest Lowest. Average Exhausted ginger (6 samples) : Highest Lowest. Average Water- Total Ash. soluble Ash. 4-1 3- 3-1 1.9 3-8 2-7 2-3 o-S I.I 0.2 1.8 0.35 Alcohol Extract, after Ether Extract. 3-8 2.1 2.8 1-5 0.8 Allen and Moor* pointed out the value of the cold-water extract as a help in detecting exhausted ginger, especially when taken in con- nection with the soluble ash, showing that the presence of this adulterant is assured, when the soluble ash is as low as i% and the cold-water extract is less than 8%. Determination of Cold-water Extract. — Winton, Ogden, and MitcheWs Melhod.-f — Four grams of the ground sample are placed in a 200-cc. graduated flask, and the latter is filled to the mark with water, and shaken at half-hour intervals during eight hours, after which it is allowed to stand at rest for sixteen hours in addition. The contents are then filtered, and 50 cc. of the filtrate evaporated to dryness in a platinum dish. It is then dried at ico° to constant weight and weighed. Microscopical Structure of Ground Ginger. — Fig. 87, from Moeller, shows elements of ginger root, from which the epidermis has not been removed. A bit of the large-celled cork (or dead protective tissue of the epidermis) is shown in surface view at (i); at (2) is shown in cross- section the parenchyma in which the starch is contained, h being an oil- cell; (3) shows the parenchyma in longitudinal section, with bast fibers. Fragments of spiral ducts are shown at (4), and starch grains at (5). (6) is a cross-section in the extreme interior of the root. The most prominent feature of powdered ginger is the starch grains (5), which Moeller compares#in shape to tied sacks. Fig. 228, PI. XXVII, is a photomicrograph of pure, ground ginger, mounted in water, showing the starch grains inclosed in the cells of the parenchyma. Fig. 231 shows the starch grains alone. The granules of ginger starch are ellipsoidal, and as a rule very clear and transparent, being for the most part entirely devoid of either hilum or concentric rings. Occasionally granules are to be found, however, with faint concentric * Analyst, 19, 1894, p. 194. t Conn. Agric. Exp. Sta. Rep., 1898, 190. 466 FOOD INSPECTION AND ANALYSIS. markings, and even with an apparent hilum. The characteristic form of the ginger starch granule is more or less egg-shaped, with a small protu- berance near one end. This protuberance serves to readily distinguish the starch granules of ginger from those of wheat, with which ginger Fig. 87. — Powdered Ginger under the Microscope. X125. (After Moeller.) is frequently adulterated. While wheat granules are of various sizes, the grains of ginger starch are as a rule much more uniform. U. S. Standards. — Ginger: Starch, not less than 42%; crude fiber, not more than 8%; lime (CaOj, not more than 1%; cold-water extract, not less than 12%; total ash, not more than 7%; ash insoluble in hydro- chloric acid, not more than 2%; ash soluble in cold water, not less than 2%. Jamaica ginger: cold-water extract, not less than 15%, other- wise as for ginger. Limed ginger: calcium carbonate, not more than 4% ; total ash, not more than 10% ; otherwise as for ginger. Adulteration. — Besides exhausted ginger, the common adulterants re- ported in powdered ginger are turmeric, wheat, corn, rice, and sawdust. Sawdust of soft wood was a not uncommon adulterant, and care should be taken to distinguish between the wood fiber natural to the ginger root, and that of the foreign variety. A careful study should be made of finely ground, soft-wood sawdust, with its long spindle cells and lateral SPICES. 467 pores, as shown in Fig. 266, PI. XXXVII, and the wood fiber of the genuine ginger root. A large admixture of sawdust would materially increase the percentage of crude fiber. Fig. 234, PI. XXIX, shows a sample of ginger adulterated with corn and wheat. Fig. 232 shows a mass of wheat bran in an adulterated sample. Fig. 233 shows ginger adulterated with turmeric* TURMERIC. Nature and Composition. — Turmeric, while largely used as an adul- terant of other spices (especially of ginger and mustard), possesses some value as a condiment in itself, forming, for instance, the chief ingredient of curry powder, f Turmeric {Curcuma Ion go) belongs to the same family {Zingiberacece) as ginger, having a perennial rootstock, and an annual stem. It is a native of the East Indies and Cochin-China. Its chief ingredients are starch, a volatile oil, a yellow coloring matter (cur- cumin), cellulose, and gum. Curcumin (C14H14O4) is insoluble in cold water, but readily soluble in alcohol. It is extracted from powdered turmeric by boiling the latter with water, filtering, and extracting the residue with boiling alcohol. The alcohol solution is filtered, evaporated, and the residue extracted with ether. The ether extract contains the curcumin, together with a small amount of volatile oil. Curcuma oil is an orange-yellow, slightly fluorescent liquid, its specific gravity being 0.942. The following analyses of turmeric were made in the writer's labo- ratory : Variety. China. . Pubna. . Alleppi. Average Mois- ture. 9-03 9.08 8.07 8.73 Total Ash. 6.72 8.52 5-99 7.07 Ash Soluble inWater. 5.20 6.14 4-74 5-3^ Ash Insoluble in HCl. Total Nitrogen. 1-73 0.97 1.56 1.42 Protein. NX6.2S. 10.81 6.06 9-75 Total Ether Extract. 10.86 12.01 10.66 11.17 * This photomicrograph is very disappointing, in that it fails to show the intense yellow of the central mass of turmeric. t Curry powder consists of a mixture of turmeric, cayenne, and various pungent spices. 468 FOOD INSPECTION AND ANALYSIS. Variety. Volatile Ether Extract. Non-vol- atile Ether Extract. Alcohol Extract. Crude Fiber. Reducing Matter by Acid Con- version , as Starch. Starch by Diastase Method. China. . Pubna. . Alleppi. Average 2.0I 4.42 3.16 3-19 8.84 7.60 7-51 7.98 9.22 7.28 4-37 6.96 4-45 5-84 5-83 5-37 48.69 50.08 50-44 49-73 40.05 29.56 33-03 34.21 Microscopical Structure of Turmeric. — Moeller's representation of characteristics of powdered turmeric is reproduced in Fig. 88. The Fig. ■Powdered Turmeric under the Microscope. X125. (After Moeller.) epidermis is shown at (i) with one of the numerous, one-celled hairs that grow from it, also the scar left after one of the hairs has been removed; (2) shows in plan view the cork immediately under the epidermis. The tender-celled parenchyma is shown in cross-section at (3), and in longi- tudinal section at (4). In some of the cells of the parenchyma are found dark-yellow lumps of resin {h), and vascular ducts (g), but by far the most numerous and striking contents of the parenchyma-cells are the bright- SPICES. 469 yellow masses of " paste balls " (^a) and the starch granules, one of which is shown in (3). See also Plate XIII. The starch grains in the water- mounted powder show under the microscope in masses, usually of a deep- yellow color, unless very finely rubbed out, when they appear for the most part in fragments. The whole starch granule appears somewhat in the form of a clam-shell, with very distinct markings. When fragments of the starch granules are carefully examined, these distinct markings are so strongly characteristic, even in the smallest pieces commonly found in the powdered sample, as to nearly always serve to identify them. See Fig. 171, Plate XIII. Turmeric as an Adulterant. — Turmeric is a material especially adapted by its deep-yellow color to intensify mustard and ginger, especially when these spices are adulterated with the lighter-colored cereal starches, hence formerly it was used in these spices, both with and without other adulterants. It was also frequently used in small quantities in adulterated cayenne, mace, and various -spices, to counteract the colors of other dyestuffs, such as ground redwood, which in itself would sometimes be too intense if used alone. MUSTARD. Nature and Composition. — Mustard is the seed of the mustard plant, an annual belonging to the family CrucifercB, and to the genus Sinapis, or Brassica, as it is now generally known. The mustards include wild and cultivated species all with yellow flowers and Ijn-ate leaves. The common species are black, sometimes called brown, mustard (B. nigra), brown or Serepta mustard (B. Besseriana), white or yellow mustard, {B. alba), and Indian mustard {B. jimcea). The seeds of char- lock {B. arvensis), growing wild in the grain and flax fields of the North- west, together with brown mustard, are separated from the grain by in- genious machines and constitute the so-called wild mustard of commerce.* The seeds of all varieties are globular, those of the black mustard being smaller than those of brown, and both smaller than those of white mustard. As seen under the lens the surface of black, brown, and Indian mustard is reticulated, while that of white mustard and charlock is smooth. Most of the seeds of charlock are of a deep black color. Both black and white mustard contain from 27 to 38% of fixed oil, a soluble ferment known as myrosin, and a sulphocyanate of sinapin. Mustard seeds contain no starch, and very little volatile oil as such. Black * Jour. Ind. Eng. Chem., 7, 1915, p. 684. 470 FOOD INSPECTION AND ANALYSIS. mustard seed contains sinigrin, or myronate of potash (not found in the white seed), which, when moistened with water, forms by hydrolysis the volatile oil of black mustard, otherwise known as allyl isothiocyanate, in accordance with the following equation: KC10H16NS2O9 +H2O = CeHisOe +C3H5CNS +KHSO4. Potassium Glucose Mustard Potassium myronate oil bisulphate Mustard Oil (volatile) is a colorless, or slightly yellow, highly refrac- tive liquid of a very strong odor, and capable of blistering the skin when brought in contact with it. It is optically inactive. Its specific gravity varies between 1.016 and 1.030. It boils between 148° and 156°. It turns reddish brown by exposure to light. Volatile oil of black mustard forms thiosinamine with ammonia, as follows : CaH.CNS +NH3= CS.NH2.NH.C3H5. Thiosinamine is soluble in hot water, from which it crystallizes in tufts of monoclinic crystals, having a melting-point of 74° C. It is pre- cipitated by silver nitrate, mercuric chloride, and Mayer's solution. White mustard differs from the black in containing a sulphur com- pound, sinalbin, C30H42N2S2O15. This is a glucoside. Sinalbin by hy- drolysis forms an oil of white mustard, in a somewhat similar manner to the potassium myronate of black mustard, and according to the follow- ing equation: C3oH,2N2S30i5+ H,0 = C,H,ONCS + CeH^^O^ + C.eH^.NO.HSO,. Sinalbin Sinalbin Glucose Sinapinacid mustard oil sulphate Sinalbin Mustard Oil cannot be obtained by the distillation of white mustard, being sparingly volatile with steam. Sinalbin mustard oil somewhat resembles that from black mustard, being quite as pungent, but less strong in odor when cold. It is soluble in dilute alkali. Fixed oil of mustard is a bland, tasteless, and nearly odorless oil, its specific gravity at 15° varying between the hmits of 0.914 to 0.918. It is said to be used to some extent as an adulterant of table oils, being separated by pressure from the crushed mustard seeds before the latter are ground into "flour." The chief use of mustard oil is in mixture with other oils as an illuminant. MUSTARD Flour. — In the process of preparing the ground spice com- monly known as mustard "flour," the seeds are first crushed and sepa- SPICES. 471 rated by winnowing from the hulls, the latter being incapable of the fine grinding necessary to produce a smooth flour. The yellow hulls are, however, found in the cheaper grades of ground mustard, and both varieties of hull are frequently used in the wet mustard preparations, sold in bottled form. In order to produce an even, dry powder, free from lumps, it is necessary to remove a large portion of the fixed oil, which is indeed of no value in the final product, and this is done by subjecting the crushed material to hydraulic pressure, during which process the mustard is molded together into thin, hard plates, called "mustard cake." This is then broken up and reduced to fine powder by pounding. Richardson's* analyses of whole-seed flour, prepared by himself without the removal of the fixed oil, are as follows: c4^ .d t^ CO u- 00 ■* t^ 1 M o M m w o voo r* o- fO >n->to.o t^-*'*^ COO M ©■ 0. r~ 0.00 tf) 1 "00 CO r~o t 1 0) 1 1 W 0) Ph >> u Q d O corocO«f)MHN « -uoisaaAU03 pioy -Aci sja^i -VBI^I 3,onpa-a « oo moo ro in o -^ m trj 0\ m t^ 0» ^O Nr^^fANf^OM CO TJ-00 •* M .^00 0> « -^ -^ t^OO ■^ 00 ir^^O r.. 0\ t^oO t^ 0> cO"PJ-<(-mN^Ti. CO \-i " •jaqig apnao \0»>^0r^'-'0io O -tCO « tN t o >o t-NOOMl-ONM m't^oo CM o 00 CO Tj- coo CO Tfoo m OOCSmcOfOcowco .*t^rOrO«rON n t^ t^ r* t^ t^oooo 00 'Hsy l^^ox ot-OOcooO'^ t^ ^00 •-' moo worn cOTfOiMNinTtrO CO«N«T)-MCOOO CO e^ 00 M t^ 00 t^vO t^ t^ »o^o \o o t'-o t^o 00 •ua3 -oj^iN iB'iox t^O M 00 o o o o> « c^O O N O M fno Nooo -to •* 00 O inO ro ■* t^ rt \r, t ><> n -^ m r^ OOcoOOwOmOO c^ t- m r^ m cooo O ooo^O'0^c^O'C^ o* t^ r- r^ t^O t^O t^ -xg ijou^ooiv oc^oor^OHO CO OiNO O'O-'-'mM 00 m r^ r^co fo tJ- m CO CO m -cj-coo OOO 00 ■>)■ Tt Tj-o CO Tf .* m .>t •asBisBiQ Aq sjan^I^ Suionpa-jj Mrv,oO>tO0N 00 0%OC0MM-tH.!l- CO Ooor^m««mco 00 r^ f^ t^ Tj-OO Ov H CO Tt 6 „„„„„ „„ H £ o o.-*o ovtn-t 0-<+H o ot^o* Tj. Tt Tt mo C4 M CO Oi H CO ^0 CO M -^ I/) t^vO »/) lo vO t^O r^ O* CO O- Ov N 't fixed oil remov inner seed adhe oi! and hulls. WINNCSMNN « Tt Tt ■* Tto •* mm m •no an^^FA inOiiflro ... . t^ N o fO lO O ro • • • • t^vO t^ MHHM... . OOO ■*ao • oi a o> ; ; ooooooo- •ua3oj:tiM Ib;ox I^inrOlD'tM'O 00 oooao«>oovM CO ■* KOvo t~>o r~o-o o •ct'^trnTj-coTj-Tj. ^ ■B ^ ° •10Bj:>xa loqootv wNOOr-MCOO O (MMMO-*mom •"t-^rfw 00000 Oi r^ NOir^OcOMN m inaMN-tOM « Ttcor^Ttooo m S (U c -1^8 •^oBj^xg jatHa an^BioA-uofsi <5 ■*00 o. in in o O. « MO rvlf^Ot^O oomMOOJ-MOv ro N t~0 t»>0>0 00 00 0>oo.-*mT}-co M coo M 00 •'fo m N r-O-OOONWO. 00 mo t^ t^oo 00 M -xg jaq^a ain^PA 0000000 00000000 d OOOOOOO- OOOOOOO- ooooooo 111 naBj-v -xg Jaq^a iB^ox >0 -too OMn lo O Oi M -0 fOfnoM^o 00mM0<5r^tHOv CO « t^^o t^O^O 00 00 CO OOO-ctm-rj-co c^ coo MOO -"J-o m N j^O'OOOWmO\ CO mO t^ t^oo 00 M COCO(NCOC4MC1 CO ;3 (U ya S - '10 H ui a^qn^osui qsy OO'OO'tinO.N t^ OMinwr^NfO « ^ fo 0> m w m ^On MtHMOMOOO 2 n HMO COO N t^ M NiNmw>w-*co CO 03-^ ^ j: -o •? " § S.S 2 Ph H •qs-v a^qnios-aaiBj^ r^ PO CK O>co MO O mo M r.^ M 00 m ■* ^0 t^ m mo m •qsy Flox 00 "1 Tt- ro 0>0 ^ CO CO coo m 00 m -^t r* mo mo m ■* -^ •* •* •*■*-* 00 cooo CO CO « VOTtlOlO'+'t.* U- coco-t^t^»nO lO ooomooo Mustard "flour" as pre- pared commercially: * English brown California brown Av. of brown flours. . German yellow California yellow Av. of yellow fi9urs. . Average of all varieties of flonr. . . >y • •d S'M 3 a > >■ •■ <<: 2 _c ^ > c 2 3r "p. a H bo; •d i s 1 (u-d/r :-3 : ■ 0) • . (0 • d " * alls Top English yellow California yellow Av. of yellow seeds. . Average of all six sam- ples of seeds SPICES. 473 Piesse and Stansell give the following composition of mustard ash: White Seeds. Brown Seeds. Yorkshire. Cambridge. Cambridge. Potash 21.29 0.18 13-46 8.17 1. 18 7.06 O.II 32-74 1. 00 1.82 12.82 18.88 0.21 9-34 10.49 1-03 7.16 0.12 35-00 1. 12 1-95 15-14 21 .41 0-35 13-57 10.04 1.06 5 -56 0.15 37.20 1. 41 1.38 7-57 Soda Lime Magnesia I ron oxide Sulphuric acid Chlorine Phosphoric acid Silica Sand Charcoal 99-85 100.48 99.70 Determination of Potassium Myronate, Sinapin Thiocyanate, and Myrosin. — Leeds and Everhart Method.^ — Dry 10 grams of the sample at 105° C, remove the fat with absolute ether, and extract the potassium myronate and sinapin sulphocyanate from the residue in a continuous extractor with a mixture of equal parts of alcohol and water. Evaporate the extract in a tared dish, and dry the combined sulphur compounds at 105° C. to constant weight. Incinerate at a temperature sufhciently ligh to transform the potassium bisulphate, resulting from the decom- position of the myronate, into the neutral sulphate. Multiply the weight of the ash by 4.77, thus obtaining the weight of potassium myronate. This, deducted from the total weight of the dried alcoholic residue, gives that of the sinapin sulphocyanate. Remove the alcohol from the residue after the alcoholic extraction, as above described, and treat with 0.5% sodium hydroxide solution, thus dissolving the myrosin. Filter, nearly neutralize the filtrate with dilute hydrochloric acid, add 50 cc. of Ritthausen's copper sulphate solution, and nearly neutralize with dilute sodium hydroxide solution. Collect the heavy green precipitate of copper myrosin on a tared filter, dry at 110° C, and weigh. Ignite, weigh again, and deduct the weight of the ash from the total weight, thus obtaining the weight of the myrosin. Determination of Volatile Mustard Oil. — Roeser Method.f — Mix 5 grams of the sample with 60 cc. of water and 15 cc. of 60% alcohol, and *Zeits. anal. Chem., 21, 1882, p. 389. t Jour, pharm. chim, [6], 15, 1902, p. 361. 474 FOOD INSPECTION AND ANALYSIS. let stand for 2 hours. Distil into a flask containing 10 cc. of ammonia, and, after about two-thirds of the solution have been distilled off, mix the ammoniacal distillate with 10 cc. of tenth-normal silver nitrate solu- tion, and allow the mixture to stand for 24 hours, after which make up with water to 100 cc. Filter, and treat 50 cc. of the filtrate with 5 cc. of tenth-normal potassium cyanide solution. Titrate the excess of cyanide with the tenth-normal silver nitrate, using as an indicator a 5% solution of potassium iodide, made slightly ammoniacal. Calculate the percentage of mustard oil, containing 93% of allyl iso- thiocyanate, (P), by the following formula: * ^^^Xo.oo4957X2Xioo^^^^^ 0.93X5 "* in which A = t\ie number of cc. of N/io silver nitrate required for the final titration and 0.004957 = the weight of allyl isothiocyanate corre- sponding to I cc. of N/io silver nitrate. To obtain the results in terms of allyl isothiocyanate, as recommended by Boutron,t omit 0.93 from the above formula or employ the factor 0.1983 instead of 0.2132. The Kimtze Method, like that of Godamer and others, employs am- monium thiocyanate for the titration. The method, as applied to mus- tard oil, J was adopted by the committee on the ninth revision of the United States Pharmacopoeia and, as applied to mustard seed, by the Bureau of Chemistry. § In details of distillation, it is the same as the Roeser method, except that 5 grams of the sample are macerated for 2 hours at 37° C. with 100 cc. of water, 20 cc. of 95% alcohol are used, and the distillation is begun at once and continued until 60 cc. have passed over. To the distillate 20 cc. of N/io silver nitrate are added and, after standing over night, the mixture is heated to boiling to cause the silver • * The conversion factor given in former editions of this work, taken from an abstract of Roeser's paper published in the Analyst (27, 1902, p. 197), was nearly three times too high. Attention to this error was directed by Mr. M. C. Albrech, chemist of the R. T. French Co., mustard makers, Rochester, N. Y., and Mr. A. E. Paul, of the U. S. Food Laboratory, Chicago. This same erroneous factor is given in the fourth edition of Allen's Commercial Organic Analysis and other works, and appears to have vitiated the results of several in- vestigations. In the present edition the analytical results by Leach and by Winton and Bornmann, as well as the factor itself, have been corrected. A. L. W. t Bui. sci. pharm., July, 191 2; Ann. chim. anal., 18, 1913, p. 61. X Arch, pharm., 246, 1908, p. 58; Allen's Coml. Org. Anal., 4 ed., 7, 1913, p. no. § Service and Regulatory Announcements, 20, 1907, p. 59. SPICES. 475 sulphide to flock, cooled, made up to loo cc, shaken, and filtered. Fifty cc. of the filtrate are mixed with 5 cc. of concentrated nitric acid, titrated with N/io ammonium thiocyanate solution, using 5 cc. of 10% ferric ammonium sulphate solution as indicator. Microscopical Characteristics of Powdered Mustard.— The principal features of powdered black mustard are represented in Fig. 89- The seed shell or hull is shown in cross-section at (i), a being the polygonal-celled epi- dermis, h a layer of palisade-shaped cells, and c a thin pigment layer, the brown coloring matter of which is colored blue by iron salts; d is the aleurone layer and ob- scure parenchyma, and e the small-celled tissue of the cotyledons, containing fixed oil and albumen. (2) shows in surface view the various layers of the seed shell, the letters of reference corresponding to those of (i). (3) shows in surface view a bit of the extreme outer mucilaginous layer of the seed- hull. Fig. 247, PI XXXII, shows the ap- pearance in water- mount of pure ground mustard. This is a photomicrograph of the ground hulled seed with- out the extraction of the oil, and should not be taken as a standard for commercial mustard "flour," from which, as a rule, a large por- tion of the oil has been removed. The cellular tissue of the mustard shows in the form of granular masses of loose, fine gray texture; the globular bodies are oil drops. Here and there through the field of ordinary ground mustard are to be seen patches of the yellowish layer 3f the seed skin of the brown mustard, a mass of which is shown in Fig. 248, with dark-brown spots distributed regularly through it. This is the layer shown at (2) h, Fig. 89. The hull of the yellow seed, also common in powdered mustard, is similar in appearance, having dark- brown spots, but with nearly colorless or gray cell walls, instead of yellow. Patches of the outer hull layer represented by (3) in Fig. 89 are also very common in the commercial mustard flour. Mustard contains no starch. Fig. 89. — Powdered Mustard under the Microscope. X12S. (After Moeller.) 476 FOOD INSPECTION AND ANALYSIS. U. S. Standards for mustard flour are as follows: Starch, by diastase method, should not exceed 1.5%, and total ash should not exceed 6%. Mustard seed should not contain more than 5% of total ash nor more than 1.5% of ash insoluble in hydrochloric acid; black mustard seed and related types yield not less than 0.6% of volatile mustard oil. Adulteration of Mustard. — It is difficult to draw the line between the amount of mustard hulls which may naturally occur in ground mustard, and the excess amount which is sometimes added as an adulterant. In determining starch in mustard, it should be borne in mind that mustard hulls have considerable reducing matter by the diastase process, although no true starch is evident by microscopic examination or the iodine tests. At one time much of the mustard in the American market contained cereal flour, gypsum, or other makeweights, artificial colors, notably turmeric, being used to cover the fraud. Pure uncolored mustard is now everywhere obtainable. Wild Mustard, consisting of charlock and brown mustard, grows luxuriantly in the grain fields of the Northwest and the seed is a common impurity of the uncleaned wheat from that region. It is an important constituent of wheat screenings, from which it is separated and placed on the market under such names as " Dakota mustard," " Domestic mustard," etc. The brown mustard has been shown by Kate Barber Winton * to be B. Besseriana and not as has been generally believed B. juncea. The product also contains other weed seeds, notably those of the mustard family, and also a certain amount of broken wheat. The following table by Winton and Bornmann f gives botanical anal- yses and results of determinations of volatile mustard oil in samples of pure mustards and wild mustard separated from screenings. In addition to percentages of volatile oil by Roeser's method are given figures obtained by calculation from the botanical analyses by the following formula: F = 0.00825 4- 0.0005C, in which V is percentage of volatile oil, B is percentage of brown mustard, and C is percentage of charlock. * Winton's Microscopy of Vegetable Foods, 2 ed., New York, 1916, 183. t Jour, Ind. Eng. Chem., 7, 1915, p. 684. SPICES. 477 BOTANICAL ANALYSES AND VOLATILE OIL CONTENT OF CULTIVATED AND WILD MUSTARD SEED. As Separated. Botanical Analysis. Calculated Free of Foreign Seeds. Botanical Analysis. Volatile Oil. Charlock. Brown Mustard. Foreign Seeds. Charlock. Brown Mustard. Actual Deter- mination. Calc. from Botanical Analysis. Pure charlock. Pure brown mustard Pure black mustard . Pure white mustard. Commercial wild mustard Separated from— Flaxseed Barley Wheat. Unknown . ICO I CO o IOC 99-5 4-7 10.7 9.0 12.9 8-5 18.2 35-8 27.6 24-5 2-5 9.0 28.5 18. 1 4.8 1-3 5-8 50 4.0 6.1 16.4 iS-i 2.0 10.9 2.0 5-3 0.8 100 100 o o.S 95 I 89.1 90.4 86.4 91 . 2 80.6 57-3 67-5 75-0 97.2 90.8 69.9 99- 5 4-9 10.9 9.6 13.6 8.8 19.4 42.7 32.5 25.0 2.8 9.2 30.1 II. 9 0.05 0.09 0.98 1-57 0.05 0.82 0.08 0.13 o. 12 o. 14 O. II o. 19 0-39 0.32 0.31 0.06 015 0,31 o. 16 0.09 o. 14 0.13 0.16 O. 12 0.20 0.38 0.30 0.24 0.07 0.12 0.28 0.14 Mustard flour is often made from wild mustard or a mixture of mustard seeds containing wild mustard. If the latter consists in large part of charlock, the product is doubtless inferior, since this seed has a rank flavor; on the other hand, if wild mustard shows a preponderance of brown mustard, it is well adapted for use as a spice. Charlock is identified by the presence in the palisade cells of a black substance which on heating in various acid reagents (such as chloral hydrate, glycerine, or zinc chloride, acidified with hydrochloric acid, syrupy phosphoric or citric acid), becomes bright carmine. A satisfactory reagent is a solution of 16 grams of chloral hydrate in 10 cc. of water and I cc. of concentrated hydrochloric acid. Mount 10 mg. of the material in a drop of the reagent, heat gently and examine under a lens. 478 FOOD INSPECTION AND ANALYSIS. Detection of Coloring Matter. — Turmeric is best detected by the microscope (see pages 468 and 469). Oil-soluble coal-tar dyes should be tested for as in the case of cayenne. Nitro colors, such as naphthol yellow (Martius yellow) and naphthol yellow S, are detected by dyeing tests, with subsequent examination of dyed fabric according to directions given in Chapter XVII. Prepared Mustard. — This product consists of a mixture of ground mustard seed or mustard flour with salt, spices, and vinegar. The U. S. standards require that it should contain not more than 24% of carbo- hydrates calculated as starch, not more than 12% of crude fiber, and not less than 5.6% of nitrogen. Most of the product consumed in the United States is of domestic manufacture, although until the passage of the federal food law it was customary to designate it German or French mustard, or label it in a foreign language. Composition and Adulteration. — The common admixtures are wheat flour, maize flour, and other starchy matter, mustard hulls, sugar, chemical preservatives, and artificial colors. Of 28 brands examined in Connecticut in 1905 by Winton and Andrew,* 13 contained cereal flour (wheat or corn), 4 salicylic acid, and 25 artificial color (turmeric, nitro-color or azo-color). A summary of the analyses of those brands free from cereal flour and those containing it follows: In the Material as Sold. Water. Acid- ity Calcu- lated as Acetic Acid. Total Solids. Total Ash. Com- mon Salt. Ash other than) Salt Pro- tein. Crude Fiber. Reduc- ing Matters by Acid Conver sion, as Starch. Nitro- gen- free Ex- tract. Fat. Prepared mustard free from cereal flour ; Maximum Minimum Average Prepared mustard con- taining cereal flour : Maximum , Minimum , 83.68 73-OI 78.59 85.63 70.44 3.66 2.74 3.05 3 54 1.86 23.67 13-32 18.36 37 . 70 9.89 4-79 2.60 3.38 3 69 1.78 2.32 3-39 1.51 1-31 0.82 1 .06 I. 16 0.48 6. 12 3.62 4.71 6.38 I 53 1.68 0.77 I. 17 1-59 o. 22 2 .92 1.83 2 . 40 13.69 15.35 3.82 7.23 2 . 12 4 . 12 3.2s o. 76 Ann. Rep. Conn. Exp. Sta., 1905, p. 123. SPICES. 479 In the Dry, Fat, and Salt-free Material. Ash. Protein. Crude Fiber. Reducing Matters by Acid Conver- Nitrogen- free Extract. Prepared mustard free from cereal flour: Maximum Minimum Average Prepared mustard containing cereal flour: Maximum Minimum Whole mustard sood (analyses by the author See page 472): Maximum Minimum Average 10. 66 7-3S 8.94 0.68 4.84 7.64 6.28 6.83 43-94 32 .01 39-44 33-89 21-37 48.31 37.50 44>3I 14.12 7-77 9-89 18.44 0.4S IO-33 7.24 S.Oj 24-37 16.82 20. 1 1 59-22 24-51 IS-9I 11-94 13-82 44 76 34.98 41-73 66.42 41.79 48. ss 37.84 40.81 The following methods for the analysis of prepared mustard were used by Winton and Andrew, and afterwards adopted by the Association of Official Agricultural Chemists: Determination of Solids, Ash, and Salt is carried out in one portion of 5 grams of the thoroughly mixed material, following the usual methods. The salt is calculated from the percentage of chlorine. Determination of Ether Extract.— Place lo grams of the material and about 30 grams of sand in a capsule, and dry on a water bath with stir- ring. Grind the dried residue and extract with anhydrous ether in the usual manner. Determination of Reducing Matters by Acid Conversion. — Treat the material directly, without previously washing, as described on page 425- Determination of Fiber. — Treat 8 grams of the material (equivalent to about 2 grams of dry matter) as described on page 286, except that (i) the boiling 1.25% acid is added directly to the material without previous extraction, taking care to introduce it in small portions and shake thoroughly until all lumps are broken up, and (2) the fiber after collecting on the weighed paper is washed twice with alcohol and finally with ether until all fat is removed. If these precautions are not followed the results will be high. Determination of Protein. — Nitrogen is determined by the Kjeldahl or Gunning method, and the result multiplied by 6.25. Detection of Dyes and Preservatives. — See chapters XVII and XVIII. 480 FOOD INSPECTION AND ANALYSIS. NUTMEG AND MACE. Nature and Production. — Both nutmeg and mace occur in the fruit of several varieties of trees of the genus Myristica, especially of Myris- tica fragrans or Myristica moschata, belonging to the family Myristi- cacecE. The nutmeg tree is a native of the Malay archipelago, and grows from 20 to 30 feet high, somewhat resembling the orange tree in appear- ance. It does not produce flowers till its eighth or ninth year, after which it bears fruit constantly for many years. The fruit is a globular, pendant drupe, about 5 cm. in diameter, of a yellowish-green color, the pericarp of which, when ripe, splits in two, showing within it the seed, completely surrounded by a fleshy, fibrous aril, or covering of a crimson color. This covering, when dried, furnishes the mace of commerce, while the kernel of the hard, brown seed is the nutmeg. The seed as separated from the fruit is surrounded by a thick tegu- ment, marked with depressions corresponding to the lobes of the aril or mace, and by a second thin, inner envelope, closely adhering to the seed. The whole seed is dried in the sun for about two months, or by the aid of heat, the tegument becoming separated from the kernel, and, by breaking with a hammer, is readily removed. The kernels are then commonly washed in milk of lime, and again dried, or they are sometimes treated with dry, powdered, air-slaked lime. Liming is alleged to prevent sprouting and ward off the attacks of insects. The so-called brown nutmegs of commerce are those which have not been treated or coated with lime. Nutmegs. — True nutmegs, the seed kernel of M. fragrans, are spher- oidal, sometimes nearly spherical, from 20 to 25 mm. long and 15 to 18 mm. in diameter. The outer surface is somewhat furrowed. A cross- section of the kernel shows the grayish-brown, starchy endosperm, mottled with the dark-brown, resinous veins of the perisperm. These veins on pressure with the finger nail present an oily appearance. Near the end of the nutmeg which is attached to the stem, is a small cavity, in which is the undeveloped embryo with two cotyledons. Macassar, or long nutmegs, the seed kernel of M. argentea, are more elongated than true nutmegs and are inferior in flavor. Nutmeg contains a considerable amount of fixed oil, a volatile oil, starch, and albuminous matter. Its volatile oil is colorless, and is soluble in three parts of strong alcohol. The specific gravity of nutmeg oil varies between 0.865 and 0.920,, and its specific rotary power (a')z)= 14 to 28. SPICES. 481 Richardson's analyses of three samples of nutmeg are as follows: Water. Ash. Volatile Oil. Fixed Oil or Fat. Starch, etc. Crude Fiber. Albu- minoids. Nitro- gen. Whole limed , , 6.08 4.19 6.40 3-27 2.22 3-15 2.84 3-97 2.90 34-37 37-30 30.98 36.98 40.12 41-77 11.30 6.78 9-55 S-16 S-42 5-25 •83 .87 .84 Ground limed Ground Konig gives the following minimum and maximum composition of nutmeg : Minimum, Maximum. Water 4.2 5-2 2-5 31.0 29.9 6.8 2.2 12.2 6.1 4.0 37.3 41.8 12.0 3-3 Albuminoids Volatile oil Fat Carbohydrates Cellulose Ash Winton, Ogden, and Mitchell analyzed four samples of nutmeg of known purity, the following being maximum and minimum results: Moisture. Ash. Ether Extract. Total. Soluble in Water. Insoluble in HCl. Volatile. Non-vola- tile. Maximum 10.83 5-79 3.26 2.13 1.46 0.82 O.OI 0.00 6.94 2.56 36-94 28.73 Minimum Alcohol Extract. Reducing Matters by Acid Con- version , as Starch. Starch by Diastase. Crude Fiber. Nitrogen X6.2S. Total Nitrogen. Maximum , 17-38 10.42 25.60 17.19 24.20 14.62 3-72 2.38 7.00 6.56 Minimum .............. 1.05 Microscopical Structure of Nutmeg. (Fig. 90.)— The thin- walled cells of the parenchyma of the endosperm or albumen are shown at (i), with starch grains. Simple and compound granules of the starch are shown at (2). Aleurone grains appear as shown at (3), and (4) represents in surface view the epidermis, or brown seed coat, with its numerous layers of flat cells. Powdered nutmeg under the microscope in water- mount shows most commonly a sponge-like, loose meshwork of bruised 482 FOOD INSPECTION AND ANALYSIS. Fig. go. — Powdered Nutmeg under the Microscope. X 1 25 . (After Moeller.) or broken cellular tissue, with many starch granules, and occasional fragments of the epidermis. Fig. 240, PI. XXX, is a photomicrograph of a water-mounted sample of pure nutmeg. The starch granules of nutmeg are different from other starches in appearance, being almost circular as a rule, quite uniform in size (averaging 0.006 mm. in diameter), and having very distinct central hyla. The U. S. Standards for nutmegs are as follows: Non- volatile ether extract should be not less than 25%; total ash should not exceed 5%; ash insoluble in hydrochloric acid should not exceed 0.5%; crude fiber should not exceed 10%. Adulteration of Nutmeg. — Nutmegs are usually sold whole, since the housewife much prefers to grate the whole nutmeg, rather than to use the ground material. It is hence less liable to adulteration than the other spices, though of late more of the ground nutmeg is being sold in packages. Samples of ground nutmeg have been found in Massa- chusetts adulterated with wheat and nutshells. One sample was found to contain at least 25% of ground cocoanut shells. Nutmegs which have become mouldy, or have been eaten out by insects, have been imported for grinding, as sound nutmegs are not readily reduced to a powder. Such a product is obviously unfit for consumption. An inferior variety is known as the Macassar nutmeg. This lacks much of the agreeable pungency of the better grades. Mace. — The crimson-colored aril that surrounds the nutmeg kernel within the pericarp, as above described (p. 480), has many narrow, flattened lobes. In the process of drying to form the mace of commerce, it loses its brilliant red color, and turns a yellowish brown. When dried, it is brittle, somewhat translucent, and of a pungent odor. Whole mace appear on the market in the form of flat membranous masses, 3 to 4 cm. long. Macassar mace has a characteristic wintergreen taste. Bombay mace is lacking in spicy flavor. Mace contains no starch as such, but a modified form of starch known as amylodextrin. This is a carbohydrate, C36H62O31 +H2O, which pro- duces with iodine a red coloration. Mace has a large amount of fixed oil, as well as considerable resinous and albuminous matter, and a vola- tile oil which much resembles that of nutmeg. SPICES. 483 The specific gravity of volatile oil of mace is rather higher than that of nutmeg oil. Its specific rotary power, («)o= lo to 20. Konig's figures for the composition of mace are as follows: Water Protein (iVX6.25) Volatile oil Fat Carbohydrates . .. Cellulose Ash Alcoholic extract . Minimum. Maximum. 4-9 17.6 4-6 6.1 4.0 8.7 18.6 29.1 41.2 44-1 4-5 8.9 1.6 4-1 45-1 55-7 Richardson gives the following as the results of analyses of three samples made by him : Water. Ash. Volatile Oil. Resin. Unde- ter- mined. Crude Fiber. Protein (ATX 6.25). Nitro- gen. Whole mace . Ground mace, Ground mace. 5-67 4-86 10-47 4-IO 2.65 2.20 4.04 8.66 8-68 27.50 29.08 23-33 41.17 35-50 34-68 8.93 4-48 6.88 4-55 6.13 5.08 •73 .98 .81 Winton, Ogden, and Mitchell's analyses of four samples of pure Banda or Penang mace, as well as of Bombay and Macassar mace, are sum- marized as follows : Moisture. Ash. Ether Extract. Total. Soluble in Water. Insoluble in HCl Volatile. h^°"J°.'^" True mace : Maximum Minimum Average Macassar 12.04 9-78 II-O^ 4.18 0-32 2-54 1. 81 2-01 2-OI 1.98 ^■33 1.06 1-13 I- II 1-37 0,-2 1 0.00 0.07 0.03 0.07 8-65 6.27 7-58 5-89 4-65 23-72 21.63 22-48 53-54 59-81 Bombay (adulterant) Alcohol Extract. Reducing Matters by Acid Con- version, as Starch. Starch by Diastase.* Crude Fiber Nitrogen X6.25. Total Nitrogen. True mace : Maximum Minimum Average Macassar 24-76 22-07 23.11 32.89 44-27 34-42 26-77 31-73 10-39 16-20 30-43 23.12 27-87 8-78 14-51 3-85 2.94 3-20 4-57 3.21 7.00 6.25 6-47 7.00 5.06 I-I2 1. 00 1.03 I . 12 Bombay (adulterant) 0.81 * The figures in this column do not express starch, but amylo-dextrin, which like starch may be determined by the diastase method. 484 FOOD INSPECTION AND ANALYSIS. Fig. the Microscope. Moeller.) ' Microscopical Structure of Mace. — Fig. 91 shows characteristics of mace, (i) being a cross-section through it, (2) a surface view of the epidermis, showing its elongated, often nearly rectangular cells, and (3) the large- celled parenchyma, in which are numerous oil globules. The contents of the paren- chyma cells are for the most part color- less, consisting of protein, fat, and granules of amylodextrin, which are shown at (4). At (5) are shown fragments of vascular tissue. The water-mounted powder of pure mace shows no highly colored fragments, 9i-^Po^fiered Mace under \fxxt as a mass, is white or grayish, and X125. ( ter ^£ loose texture. Occasional pale, yel- lowish, lumpy masses appear, and pale- brown fragments of the seed coating. The amylodextrin granules (which are colored red-brown by solution of iodine) are very small. U. S. Standards. — Mace should contain not less than 20 nor more than 30% of non- volatile ether extract; nor more than 3% of total ash; nor more than 0.5% ash insoluble in hydrochloric acid; nor more than 10% of crude fiber. Adulteration. — Turmeric and cereal starches have been detected in mace, but by far the most common adulterant is the so-called false, or wild mace, otherwise known as Bombay mace. The non-volatile ether extract of both Bombay and Macassar mace is twice as high as that of true mace, and at room temperature the fixed oil of Bombay mace is a thick and viscous fat, while that of true and other maces is a thin oil. The refractive indices of the fixed oils of various species of pure, as well as of Bombay mace, as determined by Lythgoe follow : SPICES. 485 iiD at 35° C. Banda Mace (i) i .4848 " " (2) 1.4747 (3) 1-4829 Batavia Mace (i) 1-4893 (2) 1-4975 Papua Mace (i) i .4816 (2) 1.4795 West Indian Mace (i) 1.4766 Bombay Mace (i) 1.4615 (2) 1-4633 The microscope indicates at once when Bombay mace is present in a sample. The oil glands situated in the outer layers of Bombay mace are strongly colored and contain a reddish resinous substance, while the glands of the more interior layers have balsam-like contents of bright yellow color. Both the red and yellow lumps are visible in water mounts, but a 5% potassium hydroxide solution colors them a brilliant blood-red, making possible an approximate percentage* estimation of Bombay mace in true mace. Hefelmann's Test for Bombay Mace * consists in saturating a strip of filter-paper with an alcoholic solution of the mace, and removing the excess of liquid by pressure between filter-paper. On treating with a drop of dilute sodium or potassium hydroxide solution, a red color is produced in presence of the wild mace. Waage's Test.'f — One part of the mace is extracted with ten parts of alcohol, and potassium chromate solution is added to the extract. If Bombay mace is present, the solution becomes red, and the precipitate, which is at first yellow, becomes red on standing. True mace gives a yellow solution and precipitate, and the latter does not change greatly on standing. * Pharm. Zeit., 36, 1891, p. 122. t Pliarm. Centbl., 33, 1892, p. 372. CHAPTER XIII. OILS AND FATS. Constituents. — The oils and fats are essentially the glycerol salts or triglycerides of the fatty acids. Free fatty acids, lecithin (page 35), and sterols (cholesterol and phytosterol, page 521) are among the minor con- stituents. Vegetable oils owe their yellow color to carotin or related substances. Butter fat also contains carotin derived indirectly from feeds. The greenish color of certain grades of olive and other oils is due to chlor- ophyl. Mono- and di-glycerides are prepared synthetically, but do not exist in natural oils or fats. Solubilities of Oils and Fats. — The edible members of the group are insoluble in water, and are almost insoluble in cold 95% alcohol, though they are somewhat soluble in absolute alcohol. They are readily soluble in ether, petroleum ether, chloroform, carbon tetrachloride, various chloro- compounds of ethylene and ethane (especially trichloro-ethylene) , acetone, amyl alcohol, oil of turpentine, and carbon bisulphide. Fatty Acids. — Following, compiled from Lewkowitsch,* are the fatty acids whose glycerides occur in edible oils and fats, together with their melting- and boiling-points so far as these have been determined. ACIDS OF EDIBLE OILS AND FATS. Name. Formula. Melting- point. Boiling- point. Occurrence in Oils and Fats. Acetic Series Butyric CnH2re02 C4H8O2 C6H12O2 C8H16O2 C10H20O2 Cl2H2402 C14H28O2 Cl6H32C)2 -6.5° 16. 5 31 3 43 6 53.8 62.6 162.3° 202-203 236-237 268-270 176 196.5 215 Butter Caproic Caprylic Butter, cocoanut, palm nut. Butter, cocoanut, palm nut. Butter, cocoanut, palm nut. Cocoanut, palm nut. Cocoanut, palm nut, sesame, butter. Nearly all oils and fats. Capric Laurie Myristic Palmitic * Chemical Technology and Analysis of Oils, Fats, and Waxes, sth ed., London, I, 1913, p. 348. 483 OILS AND FATS. 487 Name. Stearic Arachidic Behenic Lignoceric Oleic Series Hypogaeic Oleic Iso-oleic Rapic Erucic Linolic Series Linolic Linolenic series Linolenic Clupanodonic Series. Clupanodonic . . . . Formula. C18H36O2 C20H40O2 C22H44O2 C24H48O2 CnH27j— 2O2 C16H30O2 C18H34O2 C18H34O2 C18H34O2 C22H42O2 ^nH2n — 4O2 C18H32O2 C0H20— eOa C18H30O2 CnH2o— 8O2 C18H28O2 Melting- Boiling- pomt. pomt. 69 -3° 232.5 77 83-84 81 33 236 14 232.5 44-45 33-34 264 under —18 Occurrence in Oils and Fats. Fats, most oils, except olive and maize. Peanut, butter (trace), rape, cocoa. Peanut. Peanut. Nearly all fats and oils. Rape, mustard. Rape, mustard. Linseed, olive, cottonseed, pea- nut, sesame, maize, cocoa, pop- py seed, soy bean, sunflower. Linseed, poppy seed, soy bean. Whale, cod-liver, fish. Saponification of Fats and Oils. — By this term is meant the decom- position of the glycerides composing the fats or oils, whereby the tri- atomic alcohol glycerol and the fatty acids or their alkali soaps are sep- arated. The saponification process is commonly applied in carrying out many determinations of value on fats and oils, such as those of the soluble and insoluble fatty acids, the Reichert value, etc. As commonly carried out, the tri-glycerides are first split up into glycerol and the soluble soaps of the fatty acids by the action of caustic alkali, usually in solution in alcohol. This part of the process in the case of a given oil, composed, for example, of stearin, olein, and palmitin, is illustrated as follows: (1) C3H5(Ci8H3502)3+3KOH = C3H5(OH)3+3K(Ci8H3502) Stearin or Glycerol Potassium triglyceryl stearate stearate (2) C3H.5(Ci6H3i02)3+3KOH = C3H5(OH)3+3K(C,6H3i02) Palmitin or Potassium triglyceryl p»lmitate palmitate (3) C.3H,5(C,sn3302)+3KOH =C3H5(OH)3+3K(Ci8H3302) Olein or tri- J- Potassium glyceryl oleate oleate 488 FOOD INSPECTION AND ANALYSIS. These " soaps," or potassium salts of the fatty acids, are further de- composed by the action of sulphuric acid into the free fatty acids and potassium sulphate, in the case of potassium stearate, as follows : 2K(Ci8H3502)+H2S04 = K2S04+2H(CikH3502) Potassium stearate Stearic acid The result obtained in the determination of saponification number — the number of milligrams of potassium hydroxide required to saponify I gram of fat — is inversely proportional to the average molecular weight of the glycerides present. Hydrogenation of Oils. — Recently the hardening of oils by hydro- genation, employing nickel (or less often platinum or palladium) as a catalyst, has become of commercial importance. By this process olein and other unsaturated glycerides are more or less completely converted into stearin as is shown by the lowering of the iodine number and the change of the physical constants. Not only are vegetable oils hardened by hydrogenation but also whale oil and other fish oils which may be transformed from inedible products into bland and tasteless fats. Hardened oils are used in lard substitutes in place of natural stearin. Various oxides and salts of nickel have been used in place of the metal in hydrogenation, but the actual catalyst in all such cases, although for some years a matter of dispute, has been shown without question to be the metal. The treatment, unless slight, renders useless the Halphen test for cotton- seed oil and the hexabromide test for fish oils, but does not usually inter- fere with the Baudouin test for sesame oil. Bomer* finds that neither cholesterol nor phytosterol is changed. The table of results by Bomer * on page 489 shows the effects of hydrogenation on the chemical and physical constants of certain oils. ANALYSIS OF EDIBLE OILS AND FATS. Judgment of Purity of fats and oils presents numerous difficulties owing partly to the variation of the physical and chemical constants. Among the influences affecting the constants are, in the case of vegetable oils, the large number of varieties and species of fruits or seeds from which each oil in different localities is obtained, in the case of animal fats, the breed and feed, and in both cases the method of refining, age, and con- ditions of storage. Hydrogenation has added further to the difficulties. * Zeits. Unters. Nahr. Genussm., 24, 191 2, p. 107. OILS AND FATS. 489 EFFECTS OF HYDROGENATION ON THE CONSTANTS OF OILS. Hardness. .Color. Melting Point. Deg. C. Solidi- fying Point. Deg. C. Refract- ometer Reading at 40° C. Acid Number (Mgs. KOH per gram). Saponi- fication Number. Iodine Number. Peanut oil Natural Fluid Soft Medium * Hardf Hardt Medium * Soft Medium * Hard t Yellow White White White White Yellow White White Yellow 44.2 46.1 53-5 62.1 38.5 25.6 44-5 45-4 30.2 32.1 38.8 45-3 25 4 20.4 27.7 33-7 56.8 52.3 50-5 49 38. 4t 53-8 37-4 35-9 49.1 I.I 1-3 0.9 1.2 4-7 0.6 0-3 0.4 1 .1 191 .1 188.3 188.4 189.0 188.9 19s 7 255-6 254-1 193.0 84.4 56.5 54-1 42.2 25-4 69,7 11.8 I.O 46.8 Hardened Sesame oil Hardened Cottonseed oil Hardened Cocoanut oil Natural Hardened Whale oil Hardened •*■ * Consistence of lard. t Consistence of tallow. t Determined at 50° C. It is often difficult to name the adulterant or estimate the "xtent of adulteration. In some cases a large number of tests must be made before one can intelligently form an opinion. It should be borne in mind that skilful manufacturers may adulterate the edible oils and fats with mix- tures intended to confuse the chemist, and yield on analysis constants that are entirely misleading. Information may often be gained by care- fully noting the color, taste, odor, and appearance of the sample. Rancidity should not be confounded with acidity, although rancid oils usually are high in acids. Lewkowitsch holds that fatty acids are liberated by the action of moisture in the presence of enzymes. If in addition the oil is exposed to air and light, the fatty acids are acted on, causing rancidity, which is detected by taste and smell, although chemically little understood. As a rule rancidity develops more readily in liquid oils in which olein predominates than in solid fats. To avoid changes samples should be kept in a dark, cool place in tight containers. Filtering, Measuring, and Weighing of Fats. — A steam- or hot- water- jacketed funnel as represented in Fig. 92 is convenient for filtering fats, or, in the absence of this contrivance for keeping the fat in a molten con- dition, a hot funnel may be employed, the filtering being best conducted in a warm closet or oven. Portions of the fat for the various determinations may be measured off with a pipette while still hot, or, after cooling (over ice if necessary), the desired amounts may be removed in the solid state. 490 FOOD INSPECTION AND ANALYSIS. Specific Gravity. — The specific gravity of liquid oils is most con- veniently taken either at room temperature or at 15.5°, being always best referred to the latter. Either the hydrometer, Westphal balance, Sprengel tube, or pycnometer is employed, according to the degree of accuracy required. If taken at any other temperature than 15.5°, say Fig. 92. — Jacketed Funnel for Hot Filtration, at room temperature, T, the specific gravity may be computed at 15.5° by the formula /-, , t^z-t- \ ± ^ G=G' + KiT-is.s),* in which G is the specific gravity at 15.5°, G' the specific gravity at T°, and K a factor varying with the different oils as follows: FACTORS FOR CALCULATING SPECIFIC GRAVITY. Oil. Correction for 1° C. Observer. Cod-liver oil 0.000646 .000658 .000629 .000655 .000620 .000624 .000629 A. H. Allen C. M. WetheriU C. M. Stillvvell A. H. AUen << Sesame oil * Allen, Com. Org. Anal., 4 Ed.; Vol. II, p. 49- OILS AND FATS. 491 Unless the most accurate work is necessary, it is sufficient to assume in all cases A" ---0.00064, in which case the formula becomes G=G' + o.oco64(r-i5.5). In the case of solid fats, it is most convenient to take the specific gravity of the melted fat. This may be done at any temperature above the melting-point by either of the instruments above described, or at the temperature of boiling water by the Westphal balance or pycnometer. The figures thus obtained may be compared with those for water de- termined in the same apparatus, either at the same temperature or at 15.5°. When the pycnometer is used, it is immersed in a water-bath, the temperature of which is well above the melting-point of the fat, say 35° or 40° or 100°. While still immersed nearly to the neck, it is carefully filled with the melted fat and kept in the bath till the fat has acquired the same temperature, usually about 15 minutes. If the pycnometer is provided with a thermometer stopper, this will serve to indicate the tem- perature; otherwise a separate thermometer is inserted in the bath. The pycnometer is then removed, cleaned, dried, and cooled to the room temperature, at which it is weighed. The factors employed in the above formula for calculation of specific gravity of solid fats at 15.5° are as follows: FACTORS FOR CALCULATING SPECIFIC GRAVITY. Fat. Correction for 1° C. Cocoa butter 0.000717 .000673 . 000650 .000617 . 000674 . 000642 .000657 Tallow Lard Butter fat Cocoanut stearin Cocoanut oil Palm nut oil Either the Westphal balance or the hydrometer may be used directly on the melted fat, carefully recording the temperature and calculating as above. For making the determination with the Westphal balance at the temperature of boiling water, the melted fat is contained in a vessel im- mersed in a boiling water-bath, and kept sufficiently long to acquire that temperature, which is carefully noted. Calculation of Proportions of Two Known Oils in Mixture.* — This may be roughly accomplished from the specific gravity of the mixture and of the oils known to compose it. * Villiers et Collin, Les Substances Alimentaires, Paris, 1900, p. 646. 492 FOOD INSPECTION AND ANALYSIS. Then Let G = specific gravity of mixture, D and D' = specific gravity of the two oils, and X = % oil of specific gravity D. ioo{G-D') D-D' ' SPECIFIC GRAVITY OF EDIBLE OILS AND FATS. Oil. Rape oil Olive oil Lard oil Mustard oil. . . Sesame oil. . . . Peanut oil ... . Cottonseed oil Sunflower oil. . Maize oil Poppyseed oil. Soy oil Linseed oil Specific Gravity, 15-5° 15. 5°' 0.913-0. 917 0.915-0. 918 0.915-0. 918 0.914-0. 919 0.921-0.924 0.917-0.926 0.922-0.926 0.924-0.926 0.921-0.927 0.924-0.927 0.922-0.928 0.931-0. 941 Fat. Specific Gravity, 100° 15.5°' Mutton tallow 0.858-0.860 0.858 0.858-0.862 . 860-0 . 863 0.860-0.863 0.859-0.864 0.864-0.868 0.870 0.870 0.865-0.870 0.859-0.873 0.863-0.874 Cacao butter Oleo stearin Beef tallow Oleo oil ... •. Lard Cottonseed stearin Cocoanut stearin Palm kernel stearin Butter fat Palm kernel oil Cocoanut oil Determination of Viscosity in the case of edible oils, is of less im- portance than in the case of lubricating oils, and gives little insight into the nature or purity of the sample. Its application in the detection of oleo- margarine in butter is discussed by Lewkowitsch.* Descriptions of viscosi- meters are given by the same author. Loc. cit., p. 348. OILS AND FATS. 493 Determination of Refractive Index, and the reading on the arbitrary scale of the butyro-refractometcr, express in two different and interchange- able terms the refraction value, a useful and easily determined constant of fats and oils. For the routine examination of fats and oils the butyro-refractometer is more convenient than the Abbe refractometer, and the readings obtained by the former instrument are less cumbersome than refractive indices. These instruments and details with regard to their manipulation are described in Chapter VI. The readings on the scale of the butyro-refractometer may be readily transformed into refractive indices and vice versa by table or by means of the Leach and Lythgoe slide rule (page 93). Lythgoe's * table on pages 494 and 495 is useful as showing readings on the butyro-refractometer of edible oils and fats at various temperatures. REFRACTION OF EDIBLE OILS AND FATS. Oil. Refractive Index, 25°. Lard oil Olive oil Peanut oil ... . Cottonseed oil . Rape oil Mustard oil . . . Sesame oil ... . Maize oil Sunflower oil . . Soy oil Poppy seed oil . Linseed oil 4620-1 . 4660 4659-1.4680 4691-1.4707 4698-1.4723 4708-1.4723 4688-1.4729 4710-1.4729 4729-1.4734 I • 4735 4729-1,4742 4723-1.4754 4789-1.4824 Fat. Butyro Scale, 40°. Refractive Index, 40°. Cocoanut stearin 33-36 36-39 40.5-46* 40-48 46-48 46-49 49 47-50 X; 48.5-52.5 Cocoanut oil I. 4474-1. 4495 Palm kernel stearin Palm kernel oil I. 4495-1. 45 I 7 1.4527-1.4566! I. 45 24-1. 4580 1.4566-1.4580 I . 4566-1 . 4586 1.4586 I. 45 73-1. 4593 § 1.4583-1.4609 Butter fat Oleo stearin Cacao butter Beef tallow Mutton tallow Oleo oil Lard Cottonseed stearin .7-54.2 at 25°. 1 1.4582-1.4621 at 25° X 55.2-58.2 at 25'= § 1.4627-1.4647 at 25° Tech. Quart., 16, 1903, p. 222. 494 FOOD INSPECTION AND ANALYSIS. CALCULATED READINGS ON BUTYRO-REFRACTOMETER OF EDIBLE OILS AND FATS. Temp. C. 45-0 44-5 44.0 4S-5 43-0 42.5 42.0 41-S 41.0 40-5 40.0 39-5 39-0 38-5 38.0 37-5 37-0 36.5 36.0 35-5 35-0 34-5 34-0 33-5 33-0 32 5 32.0 31-S 31.0 30-5 30.0 29-5 29.0 28.5 28.0 27-5 27.0 26.5 26.0 25-5 25.0 Cocoanut Oil. 31- 31 32 32 32 52 35 33 33 34 34 34 34 35 35 35 35 36 36 36 36 37 37 37 37 38 38 38 38 39 39 39 40 40 40 40 41 41 41 41 42 Butter.* 41 41 42 42 42 42 43 43 43 43 44 44 44 45 45 45 45 46 46 46 47 47 47 47 B ef Stearin. 41.9 42.2 42.4 42.6 42.9 43-2 43-5 43-7 44.0 44.2 44-5 Cacao Butter. 43-7 44.0 44-2 44-5 44-8 45-0 45-3 45-6 45-9 46. 1 46.4 46.6 46.8 47-1 47-4 47-6 47-9 48.2 48-5 48.7 49.0 B f Talli)W. 44-1 44-3 44.6 44-8 45-1 45-4 45-6 45-8 46. 1 46-3 46.6 46.8 47-1 47-4 .17.6 47-8 48. 48. 48. 48- 49- Lard StLarin. 44-9 45-1 45-5 45-7 46.0 46.3 46.5 46.8 47.0 47-3 47-6 47- 48. 48. 48. 48. 49-2 49.4 49-7 50.0 50.2 Beef Oleo. 45-0 45- 45- 45- 46. 46. 46. 47' 47- 47- 47- 48. 48. 48. 48. 49- 49. 49. 50- 50. 50- 50- 51- 5T- 51- 52- 52. 52- 52. 53- S3- 53- 54- 54- 54- 55- 55- 5: 65. 66. Lard.t •3 48. .6 48. -9 49- ). r 49- >-4 49- >-7 49- .0 50. -3 ■;o. .6 50- .8 51- .1 51- -4 51- -7 51- -9 52- .2 52- .5 52- .8 53- .0 53- -3 53- .6 53- -9 54- .2 54- . t; 54- -7 55- .0 55- -3 55- .6 55 -< .8 =;6. .1 S6.. -4 56- - 7 57-c -9 57-. .1 57-' -4 57-J -7 58- .0 58- .2 58. - ■> 59 -c .8 59-, . I 59-< * Butter readings by Zeiss. t Lard readings by Hefelmarm, OILS AND FATS. 495 CALCU LATED READINGS— {ContinMcT). Temp. C. Olive Oil. Peanut OU. Cotton- seed Oil. Rape- seed Oil. Sesame Oil. Yellow Mustard Oil. Black Mustard Oil. Sun- flower Oil. Corn Oil. Poppy- seed Oil. 35-0 57-0 59-8 61.8 62.1 62.3 63.0 64.2 64-5 65.0 -5-5 34-5 57-2 60.0 62.1 62.4 62.5 63-3 64.5 64.8 65-3 6s. 8 34 o 57-4 60.3 62.3 62.7 62.8 63.6 64.8 65-1 65.6 66.1 33-5 57-7 60.6 62. 5 63.0 63.1 63-9 65.1 65-4 65-9 66.4 33-0 58.0 60.9 62.8 63-3 63-4 64.1 65-3 65-7 66.2 66.7 3^-5 58-3 61. 1 63.0 63.6 63-7 64.4 65.6 66.0 66.5 67.0 32.0 58.5 61.4 63.2 63.8 64.0 64.7 65-9 66.3 66.8 67-3 31-5 59-0 61.7 63.6 64.1 64-3 65.0 66.2 66.6 67.1 67.6 31.0 59-2 62.0 64.0 64.4 64.6 65-3 66.5 66.9 67.4 67.9 30-5 59-5 62.2 64.2 64.7 64.9 65.6 66.8 67.2 67-7 68.2 30.0 59-9 62.5 64-5 65.0 65.1 65.8 67.0 67-5 68.0 68.5 29-5 60.1 62.8 64.9 65-3 65-4 66.1 67-3 47-7 68.2 68.7 29.0 60.3 63.1 65.1 65.6 65-7 66.4 67.6 68.0 68.5 69.0 28.5 60.6 63-3 65-3 65-9 66.0 66.7 67.9 68.3 68.8 69-3 28.0 60.9 63.6 65-7 66.1 66.2 66.9 68.1 68.6 69.1 69.6 27-5 61. 1 63-9 66.0 66.4 66.5 67.2 68.4 68.9 69.4 69.9 27.0 61-S 64.2 66.5 66.7 66.8 67-5 68.7 69.2 69.7 70.2 26.5 62.0 64-4 67.0 67.0 67.1 67.8 69.0 69-5 70.0 70-S 26.0 62.2 64-7 67-3 67-3 67.0 68.0 69.2 69.8 70-3 70.8 25-5 62.4 65.0 67-5 67.6 67.7 68.3 69-5 70.1 70.6 71. 1 25.0 63.0 65-3 67.9 67.8 67.9 68.6 69.8 70.4 70.9 71-4 24-5 63-3 65-5 68.2 68.1 68.2 68.9 70.1 70.7 71.2 71.7 24.0 63.6 65.8 68.'? 68.4 68.5 69.2 70.4 71.0 71-5 72.0 23-5 63-9 66.1 68.8 68.7 68.8 69-5 70.7 71-3 71.8 72-3 23.0 64.2 66.4 69.1 69.0 69.1 69.7 70.9 71.6 72.1 72.6 22.5 64-5 66.6 69.4 69-3 69.4 70.0 71.2 71.9 72.4 72-9 22.0 64.8 66.9 69.7 69.7 69.7 70-3 71-5 72.2 72.7 73-2 21-5 65.1 67.1 70.0 70.0 70.0 70.6 71.8 72-5 73-0 73-5 21.0 65-4 67.4 70-3 70.3 70.3 70.9 72.1 72.8 73-3 73-8 20.5 65-7 67.7 70.6 70.6 70-5 71.2 72.4 73-1 73-6 74-1 20.0 66.0 68.0 70.9 70.8 70.8 71.4 72.6 73-4 73-9 74-4 19-5 66.3 68.2 71.2 71. 1 71. 1 71.7 72-9 73-6 74-1 74-6 19-0 66.6 68. c; 71-5 71.4 71.4 72.0 73-2 73-9 74-4 74-9 18.5 66.9 68.8 71.8 71.7 71.7 72-3 73-5 74-2 74-7 75-2 18.0 67.2 69.1 72.1 72.0 72.0 72.6 73-8 74-5 75-0 75-5 17-5 67-5 69-3 72-4 72-3 72-3 72.9 74-1 74-8 75-3 75-8 17.0 67.8 69.6 72.7 72.6 72-5 73-1 74-3 75-1 75-6 76.1 16.5 68.1 69.9 73-0 72.9 72.8 73-4 74-6 75-4 75-9 76-4 16.0 68.4 70.2 73-3 73-2 73-1 73-7 74-9 75-7 76.2 76-7 15-5 68.7 70-5 73-6 73-5 73-4 74.0 75-2 76.0 76-S 77.0 15.0 68.9 70.8 73-8 73-8 73-7 74-3 75-5 76.3 76.8 77-3 496 FOOD INSPECTION AND ANALYSIS. Determination of Melting-point and Solidifying Point. — A piece of small glass tubing is drawn out to a capillary open at both ends, and this is inserted into a beaker of the fat, melted at a temperature slightly above its fusing-point. A portion of the melted fat being drawn up into the capillary, the latter is removed and the fat allowed to solidify spon- taneously. After an interval of not less than twelve hours, the capillary is attached by a rubber band to the stem of a delicate thermometer (pref- erably capable of being read to tenths of a degree) , the portion of solidified fat being opposite the thermometer bulb. A test-tube containing water is held in the neck of a flask in such a manner as to be immersed in water contained in the flask, as shown in Fig. 93, the flask being held on the ring of a stand, with wire gauge interposed between flask and flame. The thermometer with attached capillary is then held immersed Fig. 93. Fig. 94. Fig. 93. — Apparatus for Determining Melting-point. Capillary tube with enclosed fat shown on the right, enlarged. Fig. 94.— Reichert Flask with Card Inserted for Quick Evaporation. in the water of the test-tube and below the level of the water in the flask, as shown. The water in the flask is then heated very gradually, so that the rise of temperature as shown by the thermometer does not exceed 0.5° C. per minute, the exact temperature at which fusion of the fat occurs being recorded as the melting-point. OILS AND FATS. 497 The flame is then removed, and the temperature at which the fat solidifies is noted as the solidifying-point. MELTING AND SOLIDIFYING-POINTS OF EDIBLE OILS AND FATS. Oil. Melting-point. Solidifying-point. Linseed oil -25° — 18 Poppy seed oil Sunflower oil — 19 to —16 -17 to -15 Mustard oil Maize oil Soy oil -15 to - 8 — 5 too — 6 to — 4 oto -f 3 — 10 to +10 — 6 to +10 Cottonseed oil Sesame oil Peanut oil Rape oil Olive oil Lard oil Fat. Melting-point. Solidifying-point. Cocoanut oil 20-28° 28-36 29 23-30 28-35 31-32 30-39 36-46 26-40 42-49 44-49 44-54 14-23° 19-24 Butter fat Cocoanut stearin Palm kernel oil 20-27 21-27 28 Cacao butter Palm kernel stearin Oleo oil Lard 27-30 16-33 27-35 32-41 40-50 Cottonseed stearin Beef tallow Mutton tallow Oleo stearin The mean of two or three determinations is usually taken as the true melting and solidifying-points. Reichert-Meissl Process for Volatile Fatty Acids. — This process has undergone various modifications from time to time. Reichert origi- nally used 2.5 grams of fat, but Meissl, who improved the process, used 5 grams, so that the Reichert-Meissl number is now expressed on the basis of 5 grams of fat. The method is conveniently carried out as follows : Five grams of the fat are transferred to a dry, clean Erlenmeyer flask of about 300 cc. capacity, 10 cc. of 95% alcohol are added, and 2 cc. of 498 ' FOOD INSPECTION AND ANALYSIS. sodium hydroxide solution (prepared by dissolving loo grams of sodium hydroxide in loo cc, of water). The flask with its contents is then heated on a water-bath with a funnel in the neck, which satisfactorily replaces the return-flow condenser originally prescribed. The heating is con- tinued with occasional shaking till saponification is complete. This Fig. 05. — Apparatus for Reichert-Meissl and Polenske Distillation. Stage of the process is indicated by the appearance of the solution, which is then perfectly clear and free from fat globules. The condenser-funnel being removed, the contents of the flask are next evaporated by continued heating over the bath to dryness. This may be hastened by inserting a card in the neck of the flask, as shown in Fig. 94, thus starting a circulatory movement to the air through the flask. The dry soap thus formed is then dissolved by warming on the water- bath with i.:?q cc. of added water, shaking the flask occasionally. After OILS AND FATS. 499 cooling, 5 cc. of dilute sulphuric acid (200 parts sulphuric acid in i liter of water) are added, and the fatty acid emulsion formed is melted by heating the flask on the water -bath, the flask being corked during the heating. The fatty acids are completely mehed when they form an oily layer on the surface of the solution. Scraps of pumice stone joined by platinum wires are next placed in the flask to prevent bumping, and the flask is properly connected with the condenser for distilling, as shown in Fig. 95. A flask graduated at no cc. is used as a receiver, the funnel placed therein being provided with a loose tuft of absorbent cotton to serve as a filter. The distilla- tion is conducted by so grading the heat that the receiving flask is filled with the distillate in about thirty minutes. Finally the entire distillate is titrated with decinormal sodium hydrox- ide, using 0.5 cc. of a solution of phenolphthalein as an indicator. The number of cubic centimeters of decinormal alkali required to neutralize the acidity of the distillate from 5 grams of the fat in the manner described expresses what is known as the Reichert-Meissl number. Lejjmann and Beam's Modification.'^ — Five grams of the fat placed in the flask are treated with 20 cc. of a solution of soda in glycerin (20 cc. of a 50% solution of sodium hydroxide in 180 cc. of glycerin), heating the flask till the contents are completely saponified. The solution becomes perfectly clear, showing complete saponification in about five minutes, after which 135 cc. of water are added to the clear soap solution, at first drop by drop to prevent foaming; 5 cc. of the dilute sulphuric acid are then added, and the distillation conducted at once without first melting the fatty acids. Polenske Number.! — This number represents the volatile fatty acids insoluble in water, and is of value in detecting cocoanut and palm kernel oils in butter and other fats. The details of apparatus and manipulation here described should be closely adhered to in order to secure comparable results. The Reichert-Meissl, Polenske, and Jensen- Kirschner numbers may be determined in one weighed portion of the fat. The method of saponification is that devised by Leffmann and Beam. Place 5 grams of the clear filtered fat in a 300-cc. Jena flask, add 20 grams of glycerine and 2 cc. of a 50% solution of sodium hydroxide. Heat the flask on a wire gauze until the contents are completely saponified, which requires about 5 minutes, and is indicated by the clearing up of the liquid. While still hot add 90 cc. of boiled water, at first drop by drop * Analyst 16, 1891, p. 153. t Polenske, Zeits. Unters. Nahr. Genussm., 7, 1904, p. 274. Fritsche, ibid., p. 193. 500 FOOD INSPECTION AND ANALYSIS. to prevent foaming, and shake until the soap is dissolved. The solution should be completely clear and almost colorless. Rancid or oxidized fats that yield a brown soap solution should not be examined. To the soap solution, warmed to 50°, add 50 cc. of dilute sulphuric acid (25 cc. : i liter) and 0.5 gram of granulated pumice stone with grains I mm. in diameter, then connect with the distilling apparatus shown in Fig. 95. Distil over a 0.5-mm. mesh copper gauze,* using a Bunsen flame so regulated as to give a distillate of no cc. in 19-20 minutes, and a stream of water that will cool the distillate to about 20-23°. The room should have a temperature of about 18-22°. As soon as no cc. have come over, replace the flask by a 25-cc. measuring cylinder. Without mixing the distillate place the flask for 10 minutes in water at 15°, so that the iio-cc. mark is about 3 cm. below the surface of the water. After the first 5 minutes, gently "move the neck of the flask in the water so that the fatty acids floating on the surface come in contact with the glass, noting at the end of 10 minutes the condition of these acids. If the butter is pure, the floating acids are either solid or form a half solid turbid mass, according as the Reichert-Meissl number is high or low; if it is adulterated with 10% or more of cocoanut oil, they form transparent oil drops. Stopper the iio-cc. flask, mix by inverting 4 or 5 times, avoiding violent shaking, filter through an 8-cm. dry filter fitted close to the funnel, titrate 100 cc. of the liquid with N/io barium hydroxide solution, and multiply by i.i, thus obtaining the Reichert-Meissl number. After the last drop of distillate has passed through the filter, wash with three 15-cc. portions of water, each of which has previously been used to rinse the condenser tube, the measuring cylinder, and the iio-cc. flask. Then repeat this treatment, using 15-cc. portions of neutral 90% alcohol. Titrate the united alcoholic washings with tenth-normal barium hydroxide solution, using phenolphthalein as indicator. The number of cc. required is the Polenske number. The following results illustrate the value of the method: Reichert-Meissl Polenske Number. Number. 31 samples of butter (Polenske) 23 . 3-30. i i . 5-3.0 4 samples of cocoanut oil (Polenske). 6.8-7.7 16. 8-17. 8 Oleomargarine (Arnold) 0.5 o. 53 Lard (Arnold) 0.35 0.5 Tallow (.\rnold) o. 55 o. 56 * Lewkowitsch recommends a circular piece of asbestos 12 cm. in diameter with a hole in the center 5 cm. in diameter and warns against overheating. He was unable to secure uniform heating with gauze. OILS AND FATS. 501 Jensen-Kirschner Number.* — This number (" Kirschner value "), which is a measure of the butyric acid content, is recommended by Bolton and Revis f as the only available means of detecting butter in oleomargarine containing cocoanut oil. They give tentatively Jensen-Kirschner num- bers 20-26 for butter as corresponding to Polenske numbers 1.6-3.2, also Jensen-Kirschner numbers 1.6-1.9 for cocoanut oil and i.i for palm oil. Add to the 100 cc. of distillate, neutralized for the determination of the Reichert-Meissl number (page 500), 0.5 gram of powdered silver sulphate, allow to stand for an hour with occasional shaking, filter, pipette 100 cc. of the filtrate into a distillation flask, add 35 cc. of water, 10 cc. of 2,5% sulphuric acid, and a long piece of aluminum wire, then distil as in the Reichert-Meissl-Polenske method, collecting no cc. of distillate in 20 minutes. Titrate 100 cc, correct for a blank determination, and cal- culate the Jensen-Kirschner number by the following formula: i2iA"(ioo + F) 10,000 in which Z = cc. of N/io alkali used in the Jensen-Kirschner titration, corrected for blanks, and Y the cc. of N/io alkali used in the Reichert- Meissl titration. Determination of Soluble and Insoluble Fatty Acids. — Jones Method. t — Soluble Acids. — Five grams are weighed out and transferred to an Erlenmeyer flask of the same size and in the same manner as that used for the Reichert-Meissl process. Fifty cc. of alcoholic potash solution are added (40 grams of potassium hydroxide in i liter of 95% redistilled alcohol) and the flask, provided with a return-flow condenser, is heated on the water-bath till saponification is complete, as evidenced by the clear solution free from fat globules. The alcoholic solution of potash is pref- erably measured from a pipette, from which it is allowed to drain for a noted interval of time, say thirty seconds. After complete saponification, the condenser is removed and the alcohol is evaporated by further heating. One or more blanks are pre- pared at the same time, using the same 50-cc. pipette for measuring, and * Zeits. Unters. Nahr. Genussm., 9, 1905, p. 65. t Analyst, 36, 191 1, p. 333; 37, 1912, p. 183. Fatty Foods, Phila., 1913, p. 120. t Analyst, 3, 1878, p. 19. 502 FOOD INSPECTION AND ANALYSIS. applying the same time limit for draining the pipette. The blanks are first titrated, after evaporation, with half-normal hydrochloric acid, using phenolphthalein as an indicator. Then add to the flask contain- ing the fatty acids i cc. more of the half-normal acid than is found neces- sary to neutralize the alkali in the blanks, after which heat the flask again with a funnel in the neck till the fatty acids have completely separated in a layer on top of the solution. Then cool the flask in ice water till the fatty acids are solidified, after which decant the liquid portion through a filter, previously dried in the oven and weighed, into a liter flask, keeping the solid mass of fatty acids intact. Next add 200 or 300 cc. of hot water to the flask containing the fatty acids, and again melt over the water-bath till they collect as before on top, having again inserted the funnel to act as a condenser, and occasionally shaking the contents of the flask during heating. Cool as before in ice water, after which again decant the liquid from the solid mass through the same filter into the liter flask. Repeat this process of washing, melting, cooling, and decanting three times, receiving all the wash water through the same filter in the same flask. Make up the washings with water to the liter mark, and, after mixing, two portions of 100 cc. each are titrated with tenth-normal sodium hydroxide, using phenolphthalein for an indicator. Each reading is multiplied by ten to represent the total volume, and the figure thus obtained represents the number of cubic centimeters of tenth- normal alkali necessary to neutralize the acidity of the soluble fatty acids, together with the excess of half-normal acid used, amounting to i cc. This I cc. of half-normal acid corresponds to 5 cc. of tenth-normal alkali, hence 5 cc. are to be deducted from the total number of cubic centimeters required for the titration, the corrected figure thus obtained being multi- plied by the factor 0.0088, which gives the weight of soluble fat acids in the 5 grams of the sample, calculated as butyric acid. Hehner Method."^ — Insoluble Acids. — Transfer the fatty acids left in a cake in the flask from the separation of the soluble acids, to a weighed glass evaporating dish, using strong alcohol to wash them out thoroughly. Dry the filter used in the separation, transfer it to an Erlenmeyer flask, and thoroughly wash it with strong alcohol, transferring all the washings to the dish. The alcohol is then evaporated by placing the dish on the water- bath, after which it is dried for 2 hours in the air-oven at 100°, cooled Zeits. anal. Chem., 16, iSyy^j). 145. OILS AND FATS. 503 i.i the desiccator, and weighed. After once heating for 2 hours, cooUng and weighing, heat again for half an hour, cool, and weigh. If a con- siderable loss in weight is found, heat for an additional half-hour. It is best, however, to avoid too prolonged heating, lest oxidation of the fatty acids should produce an increase in weight. INSOLUBLE FATTY ACIDS OF EDIBLE OILS AND FATS. Mustard oil gg 2-95 i Cottonseed oil g6 _g^ Corn oil g6 -g^ Lard g5 _g^ Peanut oil gj 8 Sesame oil g^ _ 7 Beef tallow g^ 6 Mutton tallow g5 . 5 Poppyseed oil 95 . 2-94. 9 Rape oil 95 . i Sunflower oil 95 Olive oil gj Cocoa butter g4.6 Cocoanut oil go -88 . 6 Butter 89 . 8-86 . s Saponification Number.— Koettstorfer's Method.— By the saponifica- tion number is meant the number of milligrams of potassium hydroxide necessary to completely saponify i gram of the fat. Between i and 2 grams of the fat are transferred in the usual manner (see p. 489) to an Erlenmeyer flask, and 25 cc. of the alcoholic potash solution (40 grams of potassium hydroxide free from carbonates in i liter of 95% alcohol redistilled after standing for some time with potassium hydroxide) are added with a graduated pipette, which is allowed to drain for a noted period of time, say 30 seconds. The determination should preferably be made in duplicate. Conduct the saponification as in the case of the soluble fatty acids by heating on the water-bath. After saponification, remove from the bath, cool, and titrate with half-normal hydrochloric acid, using phenolphthalein as an indicator. Titrate also several blanks in which 25 cc. of the alcoholic potash solution are measured out with the same pipette as before, and allow to drain for the same amount of time. Subtract the number of cubic centimeters of half-normal acid necessary to neutralize the alkali in the case of the saponified fat from that necessary to neutralize the blank, multiply the result by 28.06, and divide the product by the number of grams of fat taken. 504 FOOD INSPECTION AND ANALYSIS. SAPONIFICATION NUMBER OF EDIBLE OILS AND FATS. Oil. Saponification No. Mustard oil 170-178 168-179 188-193 188-194 189-194 189-194 191-19S 185-196 186-196 190-196 189-197 190-198 Rape oil Sesame oil Sunflower oil Maize oil Soy oil Cottonseed oil Olive oil Peanut oil Linseed oil Poppyseed oil Lard oil Fat. Saponification No. Mutton tallow 192-195 195 192-197 193-200 192-202 198-202 193-203 220-241 242 242-255 251-257 246-268 Cottonseed stearin Oleo stearin Beef tallow Cacao butter Oleo oil Lard Butter Palm kernel stearin Palm kernel oil Cocoanut stearin Cocoanut oil The Iodine Absorption Number. — This determination is based on the well-known property of the unsaturated fatty acids to absorb a fixed amount of iodine under given conditions of time, strength of reagent^ etc. HiibVs Method.^ — The following reagents are necessary: (i) Iodine Solution, made by dissolving 26 grams of pure iodine in 500 cc. of 95% alcohol, and, separately, 30 grams of mercuric chloride in 500 cc. of the same strength of alcohol. Filter the latter solution, if necessary, and mix the two together, allowing the mixture to stand at least 12 hours before using. As the solution loses strength rapidly, it should not be used in accurate work after it is 24 hours old. (2) Decinormal Thiosulphate Solution, made by dissolving 24.8 grams of the freshly powdered, chemically pure salt in water, and making 'up to I liter. Dingler's Polyt. Jour., 25, li p. 281. OILS AND FATS. 505 (3) Starch paste, prepared by boiling i gram of starch in 200 cc. of water for ten minutes, then cooling. (4) Potassium Iodide Solution, made by dissolving 150 grams of the salt in water, and making up the volume to i liter. (5) Potassium Bichromate Solution for standardizing the thiosulphate, made by dissolving 3.874 grams of chemically pure potassium bichromate in distilled water, and making up the volume to i liter. The sodium thiosulphate solution is standardized as follows: 20 cc. of the potassium bichromate solution are introduced into a glass-stoppered flask together with 10 cc. of potassium iodide and 5 cc. of strong hydro- chloric acid. Then slowly add from a burette the sodium thiosulphate solution, till the yellow color of the solution has nearly disappeared, after which a little of the starch paste is added, and the titration carefully con- tinued to just the point of disappearance of the blue color. The reaction which takes place is as follows: K2Cr207+i4HCl+6KI = 2CrCl3+8KCl+6I+7H20. The equivalent of i gram of iodine in terms of the thiosulphate solu- tion is found by multiplying the number of cubic centimeters of the latter solution required for the above titration by 5. If, for example, 16.4 cc. of the thiosulphate solution are required for 20 cc. of the bichromate solution, then i gram of iodine is equivalent to 16.4X5 = 82.0 cc. of sodium thiosulphate solution, or i cc. of the thio- sulphate solution =^^^ = 0.0122 gram of iodine, i cc. of exactly deci- normal thiosulphate is theoretically equivalent to 0.0127 gram of iodine. The thiosulphate solution may also be standardized by means of iodine. A short tube closed at one end is tared, together with another tube of such a size as to fit over the first. Into the inner tube are introduced about 0.2 gram of resublimed iodine and the tube heated until the iodine melts, after which it is closed by the second tube and the whole cooled in a desiccator and weighed. The iodine is dissolved in 10 cc. of 10% potassium iodide solution, the solution diluted with water, and the thiosulphate solution added with constant stirring until only a yellow color remains. Starch paste is then added, and the titration con- tinued until the blue color disappears. Manipulation. — Place 0.4 to i gram of the solid fat, or from 0.2 to 0.4 gram of oil, in a glass-stoppered flask or bottle of 300 cc. capacity. 506 FOOD INSPECTION AND ANALYSIS. In the case of oils, this may conveniently be done by difference, weigh- ing first a small quantity of the oil in a beaker with a short piece of glass tubing to serve as a pipette, transferring a number of drops of the oil from the beaker to the bottle, and again weighing the beaker and contents. The number of drops of oil required for the desired weight is first ascer- tained experimentally. The material may also be conveniently and accurately weighed in small, flat bottomed cylinders of glass about lo mm. in diameter and 15 mm. high, which may be made by cutting off so-called " shell vials." Fats are introduced while melted, the weight being taken after cooling. The cylinder and fat are transferred together by means of forceps to the glass-stoppered bottle. Dissolve the oil in 10 cc. of chloroform, and after solution has taken place, add 30 cc. of the iodine solution, shake, and set in a dark place for three hours, shaking occasionally. The excess of iodine should be at least as much as is absorbed. When ready for the titration, add 20 cc. of the potassium iodide solution (the purpose of which is to keep in solution the mercuric iodide formed, which would otherwise precipitate on dilution) and 100 cc. of distilled water. Titrate the excess of iodine by the thiosulphate solution, which is slowly added from a burette till the yellow color has nearly disappeared, then add a little starch paste, and finally thiosulphate solution drop by drop until the blue color of the iodized starch is dispelled. Near the end of the reaction the flask should be stoppered and vigorously shaken, in order that all the iodine may be taken up, and sufficient thiosulphate should be added to prevent a reappearance of any blue color in five minutes. Two blanks are conducted at the same time and in similar flasks or bottles, in exactly the same manner as in the case of the above titration, except that the fat is omitted. This is to get the true value of the iodine solution in terms of the thiosulphate solution. Suppose, for example, in the case of the blanks, 30 cc. of the iodine solution required in one instance, 46.2 cc. of sodium thiosulphate solution and in the other 46.4 cc. The mean is 46.3. Suppose 30.7 cc. of thio- sulphate solution were required for the excess of iodine remaining over and above that absorbed by 0.5 gram of the fat in the above process. Then the thiosulphate equivalent to the iodine absorbed by the fat would be 46.3 — 30.7 = 15.6 cc, and the per cent of iodine absorbed would be 11^.6X0.0122X100 „ ^ — = 38.06. OILS AND FATS. 507 IODINE NUMBER OF EDIBLE OILS AND FATS. Oil. Iodine No. Lard oil 67- 88 77- 95 83-105 94-105 103-117 104-117 92-122 I 16-130 120-135 121-143 132-143 170-202 Olive oil Peanut oil Rape oil Sesame oil Cottonseed oil Mustard oil Maize oil Sunflower oil Soy oil Poppyseed oil Linseed oil Fat. Iodine No. Cocoanut stearin 4- 6.6 8 8- 95 13- 18 8- 27 26- 38 32- 41 35- 45 32- 50 40- so 54- 70 88-104 Palm kernel stearin Cocoanut oil Palm kernel oil Oleo stearin Butter fat Cacao butter Beef tallow Mutton tallow Oleo oil Lard Cottonseed stearin The Hijbl method was long almost universally used for estimating the per cent of iodine absorbed, but is open to serious objections, chief of which are the tendency of the iodine solution to lose strength, and the length of time requu-ed to insure saturation of the oil with the iodine. The Wijs and Hanus modifications obviate these defects, the former being quite generally used in Europe and to a considerable extent in America, and the latter being the official method of the A, O. A. C. Tolman and Munson * have shown that with oils and fats having iodine numbers below 100, the three methods give practically identical figures, while with oils having high iodine numbers, the Wijs and Hanus modifications give higher results than the Hiibl method, but are doubt- less more nearly correct. Their results follow: 'Jour. Am. Chem. Soc, 25, 1903, p. 244. 508 FOOD INSPECTION AND ANALYSIS. E 2 2:< t-, M " r^ C 3 E ^ C 3 O 015, f^ o C c! C " m I 2 I 4 2 36 3 S 2 I 3 I 3 Cocoanut oil Butter — minimum maximum, Oleo oil Oleomargarine — minimum maximum, Lard oil — minimum maximum, Olive oil — minimum maximum, average . . Peanut oil — minimum maximum Mustard oil — minimum maximum Rape oil — minimum maximum Sunflower oil Cottonseed oil — minimum maximum Sesame oil Corn oil — minimum maximum Poppyseed oil — minimum maximum 34 35 42 52 66 69 73 79 89 84 94 107 98 113 100 lOI 106 103 106 106 119 123 134 93 9-05 35-9 36.2 43-5 52-9 66.0 70-5 74-5 79-9 91.4 8'5-3 95-2 109.5 104-3 118. 2 104. 1 105-7 109.2 105-3 107-3 107.0 122.2 129.2 135-2 139-1 8.60 35-4 35-3 43-3 52.0 64.8 69.8 73-9 80.6 90.0 84.6 94.1 107.7 103.8 116. 8 102.8 105.2 107.2 105.2 107.8 106.5 119. 6 126.0 132.9 138.4 + 0.12 + 1.1 -f 0.9 4-0.9 -f 0.4 -0.3 + 1.2 -f 0.7 -f 0.7 + 1.6 + 1-3 + 0.7 + 1.8 + 5-9 + 5-2 + 3-9 + 4-4 + 2.8 + 1-5 + 1.1 + 0.6 + i-o + 5-8 + 1.8 + 4-2 -0.33 -f 0.6 -f 0.0 + 0.7 -o-S -i-S + 0.5 -f 0.2 + 1-4 + 0.2 -f 0.6 — 0.1 -f 0.0 + 5-4 + 3-8 -f 2.6 + 3-8 -f 0.8 + 1.4 + 1.6 + 0.1 -f 0.4 + 2.7 -o-S + 3-5 Hanus Modification.'^ — Reagents. — Iodine Solution. — Dissolve 13.2 gms. of pure iodine in i liter of pure glacial acetic acid (99%), and to the cold solution add 3 cc. of bromine, or sufficient to practically double the halo- gen content when titrated against the thiosulphate solution, but with the iodine slightly in excess. Decinormal Thiosulphate Solution, Starch Paste, and Potassium Iodide Solution, as in Hiibl's method. Method of Procedure. — Proceed as in Hiibl's method, substituting 30 cc. of the Hanus iodine reagent for that of Hiibl, stirring the solu- tion before adding the water, and, instead of adding 20 cc. of the potas- sium iodide solution, use only 15 cc. The excess of iodine should be at least 60% of that added. * Zeits. Unters. Nahr. Genussm., 4, 1901, p. 913. OILS AND FATS. 509 Only half an hour is required for full saturation of the oil by the iodine in the Hanus method, as against three hours in the Hiibl. In case of the non-drying oils and fats, the reaction takes place in from eight to fifteen minutes, though it is best to let the flask set for half an hour at least, in all cases. With oils having an iodine number in excess of ICO, Tolman and Munson recommend one hour's standing. On account of the high coefficient of expansion of acetic acid, care should be taken that the temperature is the same when the iodine solu- tion is measured for the blank and for the determination, as otherwise a serious error may be introduced. Wijs Modification.* — Reagents. — Iodine Solution. — Dissolve 13.2 grams of pure iodine in i liter of pure glacial acetic acid, and pass through the larger portion of this solution a current of carefully washed and dried chlorine gas f until the solution is practically decolorized. Finally add enough of the original solution of iodine in acetic acid to restore the iodine color, so that there is a slight excess of iodine. Hunfs Modified Iodine Solution. — Dissolve .10 grams of iodine tri- chloride in I liter of pure glacial acetic acid, and finally add and dissolve 10.8 grams of pure iodine. Other Reagents, as in the Hiibl and Hanus methods. Method 0} Procedure. — Proceed as in the Hanus method, observing the same precautions, the only difference being in the use of the Wijs iodine reagent. Wijs recommends the following periods of time for absorption of the iodine: For non-drying oils and fats, such as peanut, olive, and cocoanut oils, butter fat, lard, and other animal fats, 15 minutes; for semi- drying oils, such as cottonseed, rape, sesame, corn, and mustard, 30 minutes; for drying oils, such as sunflower and poppyseed, I hour. The Bromine Index or Bromine Absorption Number. — The measure of the amount of bromine absorbed by the oils and fats is a useful factor. By the bromine index is understood the weight of bromine which is absorbed by i gram of a given oil. The bromine index of various oils has been determined as follows: * Ber. d. chem. Ges., 31, 1898, p. 750. t The chlorine is conveniently prepared by treatment of bleaching powder with dilute sulphuric acid, using gentle heat, and washing the gas by passing through strong sulphuric acid. 510 FOOD INSPECTION AND ANALYSIS. Bromine Index. Observer. Poppyseed Mustard Sesame 0.835 0.763 0.69s 0.645 0.632 0.530 500 to 0.544 Levallois Girard Levallois Girard Levallois 1 1 Cottonseed Rape Peanut Olive The following methods are at present seldom used : Method of Levallois* — Five grams of the oil are saponified with alco- holic potash in a 50-cc. graduated flask by the aid of a gentle heat. At the end of the saponification and after cooling, the flask is filled to the mark with alcohol, and, after shaking, 5 cc. are removed by means of a pipette and transferred to a flask. A slight excess of hydrochloric acid is added to set free the fatty acids, and from a burette a standardized solution of bromine water is run in till with constant shaking a permanent yellow color persists. The bromine is previously standardized with potassium iodide and sodium thiosulphate. The weight of bromine fixed by i gram of the fat is then calculated. MllPs Method. — Modified.-\ — Dissolve o.i gram of the filtered and dried fat in 50 cc. of carbon tetrachloride or chloroform in a loo-cc. stop- pered bottle. From a burette a standard solution of bromine in carbon tetrachloride, approximately tenth-normal (8 grams to a liter), is slowly added to the oil solution till, after fifteen minutes, a permanent coloration remains. The amount of bromine absorbed is calculated by comparing with the color similarly produced in a blank experiment, or an excess of bromine solution may be run in and the solution titrated back with a standard solution of thiosulphate, using potassium iodide and starch. Thermal Tests. — The rise in temperature produced by the action of certain reagents on various oils and fats, when applied in a definite manner, has been found to be of considerable value, especially in the case of sulphuric acid and of bromine. * Villiers et Collin, Les Substances Alimentaires, p. 680. tjour. Soc. Chem. Ind., 2, 1883, p. 435; 3, 1884, p. 366. Am. Chem. Soc, 16, 1894, p. 275; 21, 1899, p. 1084. See also Mcllhiney, Jour. ^^m OILS AND FATS. 511 ^H The Maumene Test,* or thermal reaction with sulphuric acid, is most ^Wadily carried out in a beaker of say 150 cc. capacity, which is set into a larger beaker or vessel of any kind, the space between the two being packed with felt or cotton waste. The inner beaker is removed, and into it is weighed 50 grams of the oil. It is then replaced and the packing adjusted, if necessaiy, after which the temperature of the oil is noted with a ther- mometer. From a burette containing the strongest sulphuric acid of the same temperature as the oil, 10 cc. are run into the beaker, at the same time stirring the mixture of acid and oil with the thermometer. The temperature rises ?oraewhat rapidly, and remains for an appreciable time at its maximum point, which should be noted. The difference in degrees centigrade between the initial temperature of the oil and the maximum temperature of the mixture expresses the Maumene number. With certain oils, as cottonseed, considsrabb frothing ensues when concentrated acid is employed, making an accurate determination of the Maumene number somewhat difficult. In this case it is better to employ a somewhat weaker acid, and to express results in terms of what is called the "specific temperature reaction." This is the result obtained by dividing the rise of temperature in the case of the oil by the rise of temperature in the case of water, using the same strength of acid, and multiplying the quotient by 100. Indeed, it is of importance in all cases to compare results on oils with those oblained by carrying out the same test on water. Bromination Test. — This test depends upon the avidity with which the oils and fats absorb bromine, the rise in temperature caused by the reaction being measured in this case rather than the actual amount of bromine absorbed, as in the case of the iodine absorption. Indeed, there is such a close relation between the iodine number and the heat of bromination, that when one is determined the other may be calculated quite closely by multiplying by a factor. In view of the fact that the heat of bromination is much more readily determined than the iodine number, it is often convenient to calculate the latter from the former, the result in the case of the edible oils and fats being quite sure to fall within the limits of variation of the iodine number of different oils of the same class. The bromination test was devised by Hehner and Mitchell,t who employed a vacuum jacketed tube for a calorimeter in which to make the test. Various modifications have been suggested both in the * Maumene, Compt. Rend., 35, 1852, p. 572. t Analyst, 20, 1895, p. 146. 512 FOOD INSPECTION AND ANALYSIS. apparatus employed and in the manner of diluting the oil and applying the reagent. The calorimeter employed by Gill and Hatch,* Fig. 96, is conveniently made and is very satisfactory. It consists of a long, narrow, fiat-bottomed tube, held by a cork in a small beaker, in such a manner that it is surrounded by an air jacket. The small beaker is set into one of larger size, the space between the two being packed with cotton waste. Five grams of the oil or fat are dissolved in 25 cc. A. B. Fig. 96. A. Gill and Hatch's Calorimeter for the Bromination Test with Oils. B. Wiley's Pipette for Measuring Bromine in Chloroform. of chloroform or carbon tetrachloride, and 5 cc. of this solution (containing i gram of the oil) are transferred by a pipette to the inner tube of the above calorimeter, being careful not to let it flow down the sides of the tube. The temperature of the oil is then taken by a thermometer graduated to 0.2°. The bromine reagent, which should be freshly prepared, is made up by measuring from a burette one part by volume of bromine into four parts of chloroform or carbon tetrachloride. The reagent is transferred to a measuring-flask devised by Wiley,t consisting of a side-necked filter-flask provided with a per- * Jour. Am. Chem. Soc, 21, 1899, p. 27. Gill, Oil Analysis, p. 50. t Jour. Am. Chem. Soc, 18, i8y6, p. 378. OILS AND I'ATS. 513 forated rubber stopper into which the stem of a 5-cc. pipette is fitted, Fig. 96. A bulb on the side-neck serves to fill the pipette. This pipette, filled to the mark with the bromine reagent (which should be at the same temperature as the oil solution in the calorimeter), is first covered bv the finger and removed, and its contents of 5 cc. allowed to flow down the sides of the inner tube of the calorimeter and mingle with the oil without stirring. The rise in temperature is very quick, and the highest point is noted. The difference between the highest and the initial temperature constitutes the heat-of-bromination number. This number, in the case of Gill and Hatch's calorimeter, is somewhat lower than when a vacuum jacketed tube is employed, and differs some- what with the diluent of the oil and bromine. In spite of these variations and that due to the personal equation, concordant results may be obtained with the vaiious oils, when the method is carried out under precisely the same conditions. The analyst should carefully work out the test several times with a particular oil till the results agree, and should then with equal care determine the iodine number of the same oil. The iodine number, divided by the heat-of-bromination number, gives the factor which is to be employed under the same conditions for calculating one constant from the other. In the case of Hehner and Mitchell's work with the vacuum tube, measuring i cc. of undiluted bromine into i gram of oil dissolved in 10 cc. of chloroform, it was found that the factor to be used in calculating the iodine number was 5.5. The following are some of the results on edible oils obtained by Hehner and Mitchell: Oil. Heat of Bromination. Iodine Number. Calculated Iodine Number. Lard .„ , 10.6 6.6 15 21-S 19.4 57-15 37-07 80.76 122 107.13 58.3 36.3 82.5 118 2 Butter Olive oil. Corn oil Cottonseed oil 106.7 As in the case of the Maumene test with sulphuric acid (wherein the rise in temperature of sulphuric acid and water is taken as a standard), it is convenient to employ some standard for the bromination test, whereby varying results due to difference in apparatus, etc., may be compared. In this case Gill and Hatch found that sublimed camphor may be prepared sufficiently pure to be used for such a standard. Applying the bromination test with their calorimeter, as above described, to 5 cc. of a 514 FOOD INSPECTION AND ANALYSIS. solution of 7 J grams of camphor in 25 cc. of carbon tetrachloride, an average rise in temperature of 4.2° was obtained, and the specific temperature reaction is calculated for each oil by dividing the heat of bromination by this number. Furthermore, by dividing the iodine number of several oils by this specific temperature reaction, the factor to be employed for the calculation of the iodine number was found to be 17.18, as in the fol- lowing cases:* Oil. Specific Tem- perature Reaction. Iodine Number. Calculated. Found. Prime lard No. I lard. Olive Cottonseed Com -705 .096 .762 .667 -381 63.8 70-3 81.8 97-3 109.5 63.8 73-9 82.0 103.0 107.8 The Acetyl Value. — On heating fats with acetic anhydride they become " acetylated " ; i.e., the hydrogen atom of their alcoholic hydroxy! group is exchanged for the acetic acid radicle, in accordance, for example, with the following reaction: C,,H32(OH)COOH+ (C3H30)30 = Ci,H33(0,C2H30)COOH+ C,H,0,. Ricinoleic Acetic anhy- Acetyl-ricinoleic Acetic acid dride acid acid By the actyl value is meant the number of milligrams of potassium hydroxide necessary to neutralize the acetic acid formed by the saponifi- cation of I gram of the acetylated fat. The Lewkowitsch method of procedure follows: t 10 grams of the oil are boiled with twice that weight of acetic anhydride for 2 hours in a flask with a return-flow condenser, and the mixture is then transferred to a large beaker containing 500 cc, of water, and boiled for 2 hours. To prevent bumping, a current of carbon dioxide is slowly passed through it during the boiling, introduced through a finely drawn, bent glass tube reaching nearly to the bottom of the beaker. The mixture on standing separates into two layers, of which the lower, or aqueous layer, is si- * Gill, Oil Analysis, p. 128. t Jour. See. Chem. Ind., 16, 1897, p. 503. OILS AND FATS. 515 phoned off, and the oily layer boiled with fresh portions of water, which are in turn siphoned off, the operation being repeated till the wash water tests free from acid by litmus paper. The acetylated fat is then separated and dried by filtering through a dry paper at ioo° in an oven. If desired, the process may be carried out quantitatively, weighing the acetylated fat on a tared paper or in a tared dish as in the case of the insoluble acids, page 502. About 5 grams of the acetylated fat are weighed into a flask, and saponified with alcoholic potash in precisely the same manner as for the determination of the saponification number. Evaporate the alcohol and dissolve the soap in water. One of two methods may be carried out for freeing the acetic acid for titration, one by distillation and the other by filtration. In either case the water used must be boiled until free from carbon dioxide. For the former or distillation process, acidify the aqueous solution of the soap with i : 10 sulphuric acid, and distil in a current of steam until 600 to 700 cc. of distillate are obtained. The distillate should be received in a funnel with a loose cotton plug, so as to filter it free from insoluble acids mechanically carried over. The filtrate is titrated with tenth-normal sodium hydroxide, using phenolphthalein as an indicator. The number of cubic centimeters of alkali used is multiplied by 5.61, and the product divided by the number of grams of acetylated fat taken. The result is the acetyl value. If the filtration process is used (which is more rapid and should give concordant results with the distillation process), the exact amount of alcoholic potash used in the saponification should be accurately measured in carrying out the former part of the test, and the exact number of cubic centimeters of standard acid corresponding to the amount of alkali em- ployed should be added to the aqueous soap solution. The mixture should be gently warmed, and the fatty acids will gather in a layer at the top. These are filtered off and washed, till free from acid, with boiling water. The filtrate is titrated with tenth-normal sodium hy- droxide, and the acetyl value calculated as in the distillation process. ACETYL NUMBER OF EDIBLE OILS AND FATS. Lard 2.6 Cacao Butter 2.8 Linseed Oil 4.0 Palm Kernel Oil t.q -8.4 516 FOOD INSPECTION AND ANALYSIS.J Butter Fat T.9- 8.6 BeefTallow 2.7- S.6 Peanut Oil 9.1 Olive Oil 10.6 Cocoanut Oil » 0.9-12.3 Rape Oil 14.7 Cottonseed Oil 21 .0-25 .0 Holland * has simplified the process and adopted as the rational acetyl number the milligrams of potassium hydroxide required for the saponification of the acetyl assimilated by i gram of the fat on acetylation (not I gram of the acetylated fat) thus making the number analogous to the other common fat constants. His process is as follows : Heat 5 grams of the sample with 10 cc. of acetic anhydride for 1-1.5 hours in a 300-cc. Erlenmeyer flask under a reflux condenser on a boiling water-bath. Add sufficient ceresine to form a solid disk on cooling (0.4- 0.5 gram for butter, less for hard fats, more for oils), heat on the water- bath with rotation until the mass is homogeneous, add carefully 150 cc. of boiling water and heat further with occasional agitation to remove occluded acetic acid. Cool in water, decant off the solution without disturbing the cake onto a dense ether-extracted filter. Repeat the treatment with water about 6 times or until the final filtrate gives a de- cided color with 2-3 drops of N/io alkali and phenolphthalein. Drain in a cool place, return to the flask small particles adhering to the filter, add 50 cc. of alcoholic potash (50 cc. saturated solution to 1000 cc. of alcohol), 50 cc. of alcohol, a few glass beads, and boil under a reflux condenser on a water-bath for 60 minutes, or to complete saponifi- cation. Place in water at 60° C. and titrate with N/2 hydrochloric acid using as indicator phenolphthalein or preferably i cc. of a solution of alkali blue (6B) prepared by digesting i gram with 100 cc. of alcohol for several days at room temperature in a stoppered flask, with occasional shaking, and filtering. Boil and retitrate if necessary. Conduct blanks without ceresine. Calculate the saponification number of the fat after acetylation from these data. The acetyl number (in the new sense) is the difference between the saponification numbers of the fat before and after acetylation. The Valenta Test, f— This depends upon the solubility of the oil in * Jour. Ind. Eng. Chem., 6, 1914, p. 484. fDingler's polyt. Jour. 252, 1884, p. 296. OILS AND FATS. 517 glacial acetic acid. Pour from 3 to 5 cc. of the oil into a test-tube, and add an equal volume of glacial acetic acid (specific gravity 1.0562). Place a thermometer in the tube and warm gently till the oil goes into solution. Then allow the mixture to cool, and observe the temperature at which the solution begins to appear turbid. Castor oil and oil of the olive kernel are soluble in glacial acetic acid at ordinary temperatures, rape, mustard seed, and other cruciferous oils are partly insoluble even in the boiling acid, while the other edible oils and fats become turbid at temperatures between 23° C. and the boiling- point of acetic acid. Tables have been prepared by Valenta, Allen, and others, showing the turbidity temperatures for different oils and fats, but as these figures are far from concordant, the analyst will do well to establish his own standards. Thompson and Ballantyne * found that the amount of free fatty acids and the specific gravity of the acetic acid exert a marked influence on the results. Fryer and Weston f dry the oil by hot filtration through cotton. The Elaidin Test was first suggested by Poutet in 18 19 and was for- merly much used. It is based on the conversion by nitrous oxide of liquid olein into the solid elaidin, a crystalline compound isomeric with olein, while other common glycerides remain liquid under treatment with this reagent. By the consistency of the final product, when subjected under certain conditions to the action of nitrous oxide, some idea as to the character of the oil may be gained. Manipulation. — To carry out the test according to Poutet (modified), weigh 5 grams of the oil into a beaker, add 7 grams of nitric acid (specific gravity 1.34) and about 0.5 gram of copper wire. Place the beaker in water at 15° and stir thoroughly with a glass rod in such a manner as to make an intimate mixture of the oil and the evolved nitrous oxide gas. After the wire has been dissolved, add another piece of about the same size and again stir vigorously. Set aside for about 2 hours, at the end of which, in the case of pure olive, almond, peanut, or lard oil, it will have been changed into a solid white mass. Nearly all the seed oils, especially cottonseed and mustard, are turned into a pasty or buttery mass. Another modification of Poutet's tests | consists in mixing 10 grams * Jour. Soc. Chem. Ind., 10, 1891, p. 233. t Analyst, 43, 1918, 3. Used in the Paris municipal laboratory. 518 FOOD INSPECTION AND ANALYSIS. of the oil, 5 grams of nitric acid (specific gravity 1.38), and i grain of marcury in a test-tube, shaking for 3 minutes and allowing to stand 20 minutes, when it is again shaken. The behavior of various oils after that time on further standing is as follows: Solidified after Olive oil 60 minutes Peanut oil 80 " Sesame oil 185 " Rape oil 186 " Archbutt * prepares the reagent previous to use by dissolving 18 grams of mercury in 15.6 c.c of nitric acid (sp. gr. 1.42) and uses 8 grams for 96 grams of the oil, shaking every 10 minutes for 2 hours. Determination of Free Fatty Acids. — Weigh 5-20 grams of the oil or fat into a flask, add 50 cc. of neutralized 95% alcohol, warm in the case of fats until melted, shake thoroughly, and titrate with N/io alkali, using phenolphthalein as indicator. The result may be reported in terms of percentage of oleic acid (each cubic centimeter of tenth-normal alkali is equivalent to 0.0282 gram of oleic acid) or as the " acid number," by which is meant the number of cubic centimeters of tenth-normal alkali necessary to saturate the free acid in i gram of the fat or oil. Constants of the Free Fatty Acids. — Often much information as to the character of an oil or fat may be obtained by determining such con- stants of its fatty acids as the melting- and solidifying-point, the iodine number, etc. To prepare the fatty acids or if soluble acids are present the insoluble fatty acids, for examination, saponify a quantity of the oil or fat with al- coholic potash, evaporate the alcohol, and dissolve the soap in hot water. Decompose the soap by the addition of an excess of hydrochloric or sul- phuric acid, heat till the fatty acids rise in a layer to the top of the liquid, cool, remove the fatty acids, boil up again with water, and repeat until the mineral acid is removed. The melting-point, iodine number, etc., are determined as with the oil or fat itself. Solidifying-point of the Fatty Acids, or Titer Test. — Modified Wolfbauer Method. \ — Saponify 75 grams of fat in a metal dish with 60 cc. * Jour. Soc. Chem. Ind., 5, 1886, 304. t A. O. A. C. Method, U. S. Dept. of Agric, Bur. of Chem. Bui. 107, p. 135. OILS AND FATS. 519 of 30% sodium hydroxide (36° Baume) and 75 cc. of 95^0 by volume alcohol or 120 cc. of water. Boil to dryness, with constant stirring to prevent scorching, over a very low flame, or over an iron or asbestos plate. Dissolve the dry soap in a liter of boiling water, and if alcohol has been used, boil for forty minutes in order to remove it, adding sufficient water to replace that lost in boiling. Add 100 cc. of 30% sulphuric acid (25° Baume) to free the fatty acids, and boil until they form a clear, trans- parent layer. Wash with boiling water until free from sulphuric acid, collect in a small beaker, and place on the steam bath until the water has settled and the fatty acids are clear; then decant them into a dry beaker, filter, using a hot-water funnel, and dry twenty minutes at 100° C. When dried, cool the fatty acids to 15 or 20° C. above the expected titer, and transfer to the titer tube, which is 25 mm. in diameter and 100 mm. in length (i by 4 inches), and made of glass about i mm. in thickness. Place in a i6-ouncc saltmouth bottle of clear glass, about 70 mm. in diameter and 150 mm. high (2.8 by 6 inches), fitted with a cork, which is perforated so as to hold the tube rigidly when in position. Suspend the thermometer, graduated to 0.10° C, so that it can be used as a stirrer, and stir the mass slowly until the mercury remains stationary for thirty seconds. Then allow the thermometer to hang quietly, with the bulb in the center of the mass, and observe the rise of the mercury. The highest point to which it rises is recorded as the titer of the fatty acids. Test the fatty acids for complete saponification as follows: Place 3 cc. in a test tube and add 15 cc. of alcohol (95% by volume). Bring the mixture to a boil and add an equal volume of ammonium hydroxide (0.96 sp. gr.). A clear solution should result, turbidity indicat- ing unsaponified fat. The titer must be made at about 20° C. for all fats having a titer above 30° C. and at 10° C. below the titer for all other I fats. The thermometer must be graduated in tenth degrees from 10° to 60°, 1 with a zero mark, and have an auxiliary reservoir at the upper end, also i one between the zero mark and the 10° mark. The cavity in the capillary tube between the zero mark and the 10° mark must be at least i cm. below I the 10° mark, the 10° mark to be about 3 or 4 cm. above the bulb, the i length of the thermometer being about 15 inches over all. The ther- ' mometer is annealed for 75 hours at 450° C, and the bulb is of Jena ' normal 16"' glass, moderately thin, so that the thermometer will be quick acting. The bulb is about 3 cm. long and 6 mm. in diameter. The stem of the thermometer is 6 mm. in diameter and made of the best 520. FOOD INSPECTION AND ANALYSIS. thermometer tubing, with scale etched on the stem, the graduation to be clear cut and distinct, but quite fine.* Unsaponifiable Matter. — x\s will be seen by reference to the table on page 529, the unsaponifiable matter in pure edible oils and fats is comparatively insignificant in amount, consisting largely of cholesterol or phytosterol. A high content of unsaponifiable matter is indicative of adulteration, pointing to the presence of mineral or coal-tar oils, or to paraffin. Determination of Unsaponifiable Matter.f — Weigh 7 to 10 grams of the fat or oil in a 250-cc. flask, and saponify by boiling with 25 cc. of alcoholic potassium hydroxide and 25 cc. of alcohol under a return - flow condenser. After saponification, add 30 to 40 cc. of water, and bring to the boiling-point. Cool and transfer the contents from the flask to a separatory funnel, washing out the flask first with a small amount of 50% alcohol, and finally with 50 cc. of petroleum ether (B.P. 40^-70°), adding both washings to the separatory funnel. Shake the latter thoroughly, but avoid if possible forming an emulsion. If the latter persists in forming, add a volume of water equal to that of the soap solu- tion, which will sometimes break it up. After separation of the petro- leum ether layer, draw off the underlying soap solution into a beaker, and wash the petroleum ether two or three times with 50% alcohol, which is drawn off and added to the soap solution. The petroleum ether is then run into a tared Erlenmeyer flask, and the soap solution extracted twice more with fresh portions of petroleum ether, washing the ether each time with 50% alcohol as before and then transferring the ether to the tared flask. The petroleum ether is then removed by placing the flask on the water-bath, bumping being prevented by means of a spiral of platinum wire weighed with the flask. Finally remove all traces of 'remaining ether by blowing hot air through the flask, or, in the absence of mineral oils (some of which are volatile), dry in the water-oven to con- stant weight, cool in a desiccator, and weigh. Cholesterol and Phytosterol. — These are monatomic alcohols, and combine with the fatty acids forming esters. Both respond to the same reactions, and are separated by the same process from the oils and fats in which they occur. Phytosterol was long thought to be the same as cholesterol, and some confusion seems to have arisen from the fact that early writers purport to have found cholesterol in vegetable oils, when * Tolman, U. S. Dept. of Agric, Bur. of Chem., Bui. 90, p. 75. fHonig and Spitz, Jour. Soc. Chem. Ind., 1891, 1039. OILS AND FATS. 521 in reality the substance was phytosterol. The latter first distinguished from cholesterol by Hesse, who named it. Cholesterol (C26H44O) crystalHzes in white, nacreous, monoclinic laminae, having a melting-point of 145° and specific gravity 1.067. Its reaction is neutral, it is devoid of taste or smell, insoluble in water, sparingly soluble in cold, but readily soluble in boiling alcohol, and soluble in ether, chloroform, methyl alcohol, benzene, and oil of turpentine. It sublimes unchanged at 200°, but at higher temperatures decomposes. Commercial cholesterol is obtained from wool oil and is known as lanolin, being used largely in medicine as a basis for ointment. Cholesterol occurs also in the yolk of eggs, in many animal secretions, and in most animal oils and fats. It separates in laminated, transparent crystals from a mixture of 2 volumes alcohol and i volume ether, and in the form of anhydrous Deedles from chloroform. Phytosterol (C26H440,H20) is most abundantly found in the legu- minous seeds, and is prepared commercially from these, especially from peas and lentils. It is a constituent of most vegetable oils. It crystallizes in slender, glittering plates from chloroform, ether, and petroleum ether, and from alcohol in tufts of needles. In solubility it much resembles cholesterol, but its melting-point from 132° to 134° is lower. Determination of Cholesterol and Phytosterol. — Method of For ster and Reichmann* — 50 grams of the oil or fat are boiled for five minutes in a flask connected with a reflux condenser with two successive portions of 75 cc. of 95% alcohol, and in each case the alcoholic solution is sepa- rated by means of a separatory funnel. The combined alcoholic solutions are then boiled in a flask provided with a funnel in the neck, till one- fourth of the alcohol is evaporated, and then poured into an evaporating dish and brought to dryness. The residue is then extracted with ether, and the ether solution is evaporated to dryness, taken up again with ether, filtered, evaporated once more, and dissolved in hot 95% alcohol, from which it is allowed to crystallize. Cholesterol or phytosterol will crys- tallize out under these conditions, and may be weighed. Distinguishing between Cholesterol and Phytosterol. — It is some- times of importance to determine which of these substances is present in an oil, or whether indeed both occur. Confirmatory proof as to the presence of vegetable in animal oils may, for instance, be established by * Analyst, 22, 1897, p. 131. 522 FOOD INSPECTION AND ANALYSIS. showing whether the unsaponifiable residue in the sample contains choles- terol or phytosterol or both. Hehner * has made use of this test in deter- mining the presence of cottonseed oil in lard. The most ready means of distinguishing between cholesterol and phytosterol is furnished by the marked difference between the form of the ' crystals, the manner of crystallization of the two substances, and the melting points of the acetates. Separation and Crystallization of Cholesterol and Phytosterol. — Bamer^s Method.^ — Saponify loo grams of the fat by heating in a liter Erlenmeyer flask on a boihng w^ater bath with 200 cc. of alcohohc potash S'Dlution (200 grams of potassium hydroxide -fi liter of alcohol). The flask should be provided with a perforated rubber stopper, through which passes a glass tube 700 cm. long, which serves as a reflux condenser. During the flrst part of the heating shake often and vigorously until the solution is clear, after which continue the heating one-half to one hour longer with occasional shaking. While still warm, transfer to a separatory funnel of about 1.5 liters capacity, rinsing the flask with 400 cc. of water. When cool, add 500 cc. of ether, shake vigorously for one-half to one minute, opening the cock repeatedly, and allow to stand for two to three minutes until the liquids separate. Remove the ether solution to a flask, and distil off the ether, using a few pieces of pumice stone to prevent bumping. Shake the soap solution two to three more times in the same manner with 200 to 250 cc. of ether, add the ether solution after each shaking to the residue in the distiUing flask, and distil off the ether. Usually a small amount of alcohol remains in the flask after removal of the ether, which may be removed by heating on a boiling water bath in a blast of air. To saponify any remaining fat, add 20 cc.of the alcoholic potash solution, and heat for five to ten minutes as before. Transfer to a small separatory funnel, rinse with 40 cc. of water, cool and shake with 150-200 cc. of ether from one-half to one minute, allow to stand two to three minutes, and draw off the lower layer. Wash the ether solution three times with 10-20 cc. of water, filter, to remove drops of water, into a smafl beaker, and remove the ether by cautious evaporation on the water bath, thus obtaining the crude cholesterol or phytosterol. The unsaponifiable residue, which may be weighed after drying, in the case of animal fats shows beautiful radiating crystals, and consists * Ibid., 13, 1888, p. 165. t Zeits. Unters. Nahr. Genussm., i, 1898, p. 31. I OILS AND FATS. 523 largely of cholesterol, while in the case of vegetable fats it consists largely of phytosterol. Dissolve the residue in 4-20 cc. of absolute alcohol with the aid of heat, and allow to crystallize slowly in a shallow dish. The crystallization in the case of cholesterol alone begins from the margin of the lif|uid and gradually extends inward toward the center, forming a uniformly bright, thin, colorless film over the whole surface. This film is best removed with a knife or spatula and pressed between filter-paper. The film will be seen, even megascopically, to be composed of large, glossy plates with a silk-like luster. After the removal of the first film a second will form similar to the first, but composed as a rule of smaller crystals. These are removed in hkc manner, dried between filters, and added to the first in a glass. After the second crop, the mother liquid is thrown away. The crystals are then redissolved in absolute alcohol, and again allowed to separate out, being repeatedly recrystallized till the melting-point is constant. In lard and most fats the crystals were found pure by Bomer after the second crystallization. Phytosterol is crystallized with greater difficulty, especially when derived from seed oils, on account of the presence of pigments and other foreign matter. The first procedure is the same as above described for cholesterol, the crystals being allowed to separate slowly out of a solu- tion in absolute alcohol. Unlike cholesterol, no film is formed on the surface, but needles (sometimes i cm. in length) are gradually elim- inated, beginning at the margin and extending inward moslly at the bottom. In concentrated solutions, fine needles would be uniformly deposited through the liquid. These are best separated from the mother liquid by filtration, as they are not easily taken out with a knife. They may be washed on the filter with small amounts of absolute alcohol for microscopical examination, or repeatedly recrystallized, as in the case of cholesterol, till the melting-point is constant. 1. Cholesterol Crystals. — ^When crystahized separately under above conditions, cholesterol crystals viewed under the microscope show generally rhomboidal forms of plates, as in Fig. 97, but sometimes with a reenter- ing angle. The plates are often grown together in masses. The most characteristic forms are found from the first crystallization or from the first film removed. Sometimes quadrilateral crystals predominate among the plates, often also the other shapes shown are found most numerous. 2. Phytosterol Crystals. — Pure phytosterol crystallizes in needles or narrow plates, arranged commonly in star form or in bunches. The 524 FOOD INSPECTION AND ANALYSIS, most common forms are shown in Fig. 98, best conditions as to shape of crystals being obtained from slow crystallization, in which case the needles are finer and more regular. The crystals are commonly in the form of long, narrow plates, thin and slender, often pointed at both ends. Sometimes the points are lacking, or the ends are beveled. The more frequently they are re- crystallized, the larger and more varied are the crj'stal forms. The Fig. 97. — Cholesterol Cr>'stals under the Microscope. (After Bomer.) broad, hexagonal and quadrilateral plates shown are products of re- crystallization; the shorter forms are rarely met with. Sometimes various forms are found side by side in the same cr}'stallizat:on. Ph}'tosterol crv'stals, from a second of third recrj'stallization, some- times grow together in bunches resembling at fitst glance to the naked eye the cholesterol masses. They never do this in the first crj'^staUization, whereas in the case of cholesterol the growing together in masses is very characteristic of the first crj'stallization. V^ Fig. 98. — Phj-tosterol Crj-stals. (.\fter Bomer.) Thus for purposes of distinguishing between the two the product of the first cr}'Stallization is best observed. 3. Crystals of Mixed Cholesterol and Phytosterol. — In mixtures of the two they do not crv^stallize separately, but when in nearly equal propor- tion, or with ph}i;osterol predominating, the crj^stals much resemble phjliosterol. Even when cholesterol predominates to the extent of 20 parts to I of phytosterol, the mode cS cr)'stallization leans most toward OILS AND FATS. 525 that of phytosterol, though the needles are of different shape. Such a mixture, for instance, does not form in a film like cholesterol, but, like ph}tosterol, comes out in needle-like bunches. The needles, however, are more often like those shown in Fig. 99 when viewed under the micro- n Fig. 99. — Characteristic Forms of Crystallization of Mixed Cholesterol and Ph}i;osterol (After Bomer.) scope, sho"\^'ing needles for the most part squarely cut off at the ends, and sometimes placed end to end, and of var}'ing diameter, giving the appearance of a spy-glass. WTien cholesterol predominates over phy- tosterol 50 to I, the plates resemble those of cholesterol. Bomer's Phytosterol Acetate Test for Vegetable Fats.* — Dissolve the crude cholesterol or phytosterol, or the mixture of the two, obtained by Bomer's method, as described on page 522, in the smallest possible amount of absolute alcohol, and allow to crystallize. Examine under the microscope the first crystals that separate, comparing with the cuts and descriptions given in the preceding section. Remove the alcohol completely by evaporation on the water bath, add 2 to 3 cc. of acetic anhydride, cover with a watch glass, and boil for one-fourth minute on a wire gauze; then remove the watch glass, and evaporate the excess of acetic anhydride on the water bath. Heat the residue with sufficient absolute alcohol to dissolve the esters, and add enough more to prevent immediate crystallization on cooling. Cover until the room temperature is reached and allow to crystallize. After one-half to one-third of the liquid has evaporated and the greater part of the esters have crystallized, transfer the crystals to a small filter by the aid of a small spatula, rinsing with two portions of 2 to 3 cc. of 95% alcohol. Return the crystals to the crystallizing dish, dissolve in 5 to ID cc. of absolute alcohol, and again allow to crystallize. After the greater part of the crystals have separated, collect on a filter as before. Repeat the recrystallization several times (5 to 6 is usually sufficient), determining the melting point of the crystals after each recrystallization beginning with the third. Zeits. Unters. Nahr. Genussm., 4, 1901, p. 1070. 526 FOOD INSPECTION AND ANALYSIS. If after the last crystallization the corrected melting-point of the crystals is above ii6°, the presence of a vegetable fat or oil is indicated, if it is II 7° or higher the proof may be regarded positive. The standard thermometer used should be graduated to tenths of a degree. Correct the reading by the following formula: S=T+o.oooi^4n(T —t) in which 6*= the corrected melting-point, T=ihe observed melting-point, w = the length of the mercury column above the surface of the liquid, expressed in degrees, and / = the temperature of the air about the mercury column as determined by a second thermometer. Bomer states that by this method the analyst can detect in edible animal fats i to 2 per cent of oils rich in phytosterol (cottonseed, peanut, sesame, rape, hemp, poppy, and linseed), and 3 to 5 per cent of oils con- taining smaller amounts of this constituent (olive, palm, palm kernel, and probably cocoanut). He found the corrected melting-point of choles- terol acetate to be 114.3° to 114.8° and of phytosterol acetate, 125.6° to 137.0°, according to the source. Klosterman Digitonin Method * Modified by Kiihn, Benger, and Wer- werinke.'f — To the fatty acids, separated from 50 grams of the sample in the usual manner, contained in a beaker, add 25 cc. of a 1% solution of digitonin (crystalline) in 95% alcohol, and heat at 70° C. for 30-45 minutes with occasional stirring until the precipitate of digitonides separates. Add 15-20 cc. of chloroform, filter, using suction, wash successively with chloroform and with ether until all the fat is removed, and dry. Boil the dried precipitate with 3-5 cc. of acetic anhydride for 5 minutes, add while hot 4 volumes of 50% alcohol, and allow the crystals of sterol acetate to separate. Filter, recrystallize from ether, and determine the melting- point as above described. Numerous experiments, made both in Europe and America, show that feeding milch cows and swine with oil cakes does not introduce phyto- sterol into either the fat of the milk or the lard, although both fats may respond to the Halphen test, or give abnormally high Polenske numbers as a result of feeding with cottonseed or cocoanut cake respectively, and although the lard (not the butter fat) may respond to the Baudouin test, owing to feeding with sesame cake. (See pages 552 and 579). * Zeits. Unters. Nahr. Genussm., 26, 1913, p. 433. t Ibid., 28, 1914, p. 369; 29, 191S, p. 321. OILS AND FATS. 527 ParaflSn, sometimes used as an adulterant of fats, is included in the unsaponifiable matter determined as described on page 520. If present in an amount sufficient to indicate substitution for a more valuable fat the hot solution of the soap will be cloudy, showing often oily drops, and the percentage of unsaponifiable matter will be far in excess of normal. The characteristics of the unsaponifiable matter useful in further identification are the iodine and saponification numbers (nearly zero), the refraction, and the melting-point, although the latter will be modified in a degree by the presence of the small amount of sterols. For the detection of minute amounts, said to be used to misguide the analyst in interpreting the results of the phytosterol acetate test, Polenske's method * may be applied. Microscopical Examination of Oils and Fats. — In the examination of lard and butter for adulterants, the use of the microscope is often of great value, and will be described more fully under these special fats. In general, the best fat crystals are obtained by slow crystallization at room tempera- ture from an ether solution, or. from a mixture of ether and alcohol. The first crystals formed may often with advantage be filtered out, and washed with the alcohol and ether mixture on the filter, dissolved finally in ether, and the latter allowed to evaporate spontaneously. The crystals are then examined in a medium of ether. If it is desired to separate the liquid oleins from an oil, so that crystals of the solid fats are left for examination. Gladding f recommends dis- solving the fat in a mixture of two volumes of absolute alcohol and one volume of ether in a test-tube, which is stoppered with cotton and set for half an hour in ice water, during which time the more solid stearin and palmitin will have crystallized out. This portion is then separated from the mother liquor by filtration through an alcohol-wet filter-paper, and the crystals finally treated as in the preceding section, being examined in a medium of olive or cottonseed oil. CONSTANTS AND VARIABLES OF COMMON EDIBLE OILS AND FATS. The tables on pages 528 and 529, based on the results of numerous analysts, are designed merely as a guide. The figures given are not the * Arb. kaisl. Gsndhtsamt., 22, 1905, p. 576. t Jour. Amer. Chem. Soc, 18, 1896, p. 189. I 528 FOOD INSPECTION AND ANALYSIS. (u a " 5 ■ •*'0 o M 00 00 vO 00 III 'I O O 0^ C^ t^ 22 ^ ro O r^O N 00 •* O N t^ ir> lOvO ■^ i/i tt ^ in't Tt I I I I I I ro rfO r*^ ^ o 5 O O t^ o ■ (•lo in N MO I I I I I 00 IN O 00 00 -^ CO g %0 O OO 00 t-H lo ■^ fo -^^o r^ ^00 Ov On r^ r^ t^oo 0^0\00000\ llTVTTi iTl iTl I inooo foo o*M o^oo oo ooo o ooooo t^r~r^O\oooooo Oooco 0\ 00ON-• I sOOOOO r*0 t^o r-00 t>- 00 vO O'O N Os O 00 I I I I I I 2: I I rf t I -^ O O r- t- N III. lOOO ooo C^0\0\'^0 00 O r«^00O ' I ro '^ '^ fO -^ W OOO r-OO PCO r^'i-oo m r^-Ooo C^O>0>O^O^C^O^C^O^C^C^O^O^O^ loli/^OOOOOOOOOOOOOO ■ ■ I I I I I I I I I i I I I I inioiot-fOiOTt-w M tH (-H o) M rt'^io OlO\O^O^O^O^C^O^OlO^O^O^O^O^ OOOOOOOOOOOOOO rfroO^fOOrOfNoO O O oiooOOOOOOOOr-r^ •00 I I I I I I I I I ooco 000000000000000000 GOOOOOOOO •o-H 3 cM \ii ou2mMja. o o O. I- tl 5 g+J-O 3 CO 3 en .— tU 1/1 o «§ o oij i;ii o ooo o E OILS AND FATS. 529 u 1 nf^' \0 M 00 o oi 1/3 COO 1/3 00 cj M ^ ro w CM sO 00 CSNrOfOroroiO O fO NNCMOOCMCO OM I oo 1 1 1 1 r^ 00 00 1 1 1 r^ 1 00 o M ONI^ONNN « « LOMOONOCM MCM 1^ 00 o o o M O M lO 1- -* \ninN O Tt CO v (D 0) o O O c^ " M ^4 M H ro a • M H C^ Q^ M M l-t M « M w N N Ol w CO O CO M- ^ 1 1 CM 1 Ti- 1 in ^ CM^MOOOmcO °^ 3 z 1 1 1 1 1 >0 lO O 0\ 't 1 1 1 P4 1 f<3 1 W ro 0> M 0\ M M- Id 00 0\ o o c\ O M O I> N CO ■ N CM '5 o M M (I M M M M 00 a a , t) ■Isd tH\0 t-i t^O o fo N a " " M- CO t^ o m t^ r^ -^ o o c CO c>5 (N 1-1 w 1 1 1 1 1 rt (N c») 0) CM CH M 1 1 1 1 1 1 1 ^00 rOvO t~ O t^ in c» CM •* •* M- in fO„ CO 1 1 1 1 1 1 1 1 "S : oo •>*'0 00 m lo-o t^ " 00 M PJ M M rO M CM M M CM IH •*CMNCOCO'*t « (M !S S < , ^- nl >■ c vO ro C> O t^ On ^ M M t^cJD w mvo 00 N invO M " t~ 11^ cs C^ MOO M 1 1 1 1 1 t^ CM O O O r<3 " M CM CM M P-. 1 1 1 1 1 1 1 00 ro On CO CO 1/3 I^ mcMCMco^^-* inicM^ in>-cOcO' oi OM> o. oi a

Jo./^^' ^<^ ^.^ii^c^^;^^ in (^£1 C^O\O^C^O\0(O^O^O^O^C^»0 "' • 0\ • 0\ ~-' On ^ 00 vO 00 00 On a >> 13 1^ ot^ m o O o •*^.^ c * 4- -++«» rt (U QJ l/^ ^ t~ 1 1 1 roco 1/3 O o CO t CO 1 • 1 1 O w CM CO O O O ^ mm 1 1 1 00 CO CM (M 1 o 1 d 'c ., t^ c CM O t^ O CO lo o r^ CO ^ c c 1 1 1 " CM «' M (N ^ O 1 1 i 1 1 • 1 O 1 o 1 CI 3 C3 , M- 1/3 l« t^ CM O CO CO O CO r^ CM 13 o o o O 1-1 " O O M o m moo o O CM . • • 4) E "o 3 N M CO o o 1 1 1 1 1 m^ in --^ m o 1 m C1.Z mo "CO o *J ^ W^ 00 0\ t^ 00 invO 00 nO ^ CO *-''[r CJ . . . Tt • • 1/3 • • 1 o o o O lO CM O 1 1 1 1 I> COM 't c Ooot^coOOcoO 1 1 1 1 1 1 '1 CMOO^CMMQCO . . . CM . . O N 1 • f ^ z o o o GO ■* O O CO C g C C d ■si lb & 2-g^: > -4- c 1 c c +-i ■♦J c 'a E > a, 4, > c c c >o to: 1.C 'o ■a CT +-> -1 cj cti O C O CJ w o o c u cs 3 & O "a 4-' 03 O o o ^1 O 5 C5 ^ O O c3 i20fi,rtfflpsuo.^wwhjeL,WH-i *500(a23 1.288 •345 2.485 CANE SUGAR, OR SUCROSE. Nature and Occurrence. — ^This, the most common of all the sugars, is nearly always understood by the unqualified term of sugar. It crys- tallizes in monoclinic prisms. Its specific gravity is 1.595. Its melting- point is about 160° C. Its specific rotary power .[a:]^, in solutions having a concentration of from 10 to 20 grams in 100 cc. is, according to Tollens, 66.48°. Sucrose is extremely soluble in water, which, when cold, will hold in solution twice its weight of the sugar. Cane sugar is ordinarily derived from four sources — the sugar beet, the sugar cane, the maple tree, and the sorghum plant. The first two sources supply the principal output of commercial cane sugar, about half the sugar on the world's market being furnished, by the sugar beet and the other half by the sugar cane. It should be understood that the product sucrose, or cane sugar, is chemically the same whether derived from either of the above sources and thoroughly refined. U. S. Standard Sugar is white sugar containing at least 99.5% of sucrose. Ann. Chim. Phys., 59, 233. 588 FOOD INSPECTION AND ANALYSIS. The Sugar Cane {Saccharum officinarum) is cultivated principally in Louisiana and other southern states, in Cuba and the West Indies, and in the Hawaiian Islands. Its growth and cultivation form an industry in nearly all tropical countries. Allen * has compiled the following table showing the composition of the juice of the sugar cane from different localities: Locality and Kind of Cane. Water. Sugar. Woody- Fiber. Salts. Authority. Martinique 72.1 72.0 77.0 65-9 69.0 76-73 76.08 18.0 17.8 12.0 17.7 20.0 13-39 14.28 9-9 9-8 II. 16.4 10. 9.07 8.87 0.4 I.O •39 •35 Peligot Dupuy Casaseca Guadaloupe Havana. ........... Cuba Casaseca Mauritius ......... leery Avequin Avequin Ribbon cane Tahiti The composition of raw cane sugar ash according to Monier is as follows : RAW CANE SUGAR ASH. Carbonate of calcium 49 .00 " " potassium 16.50 Sodium and potassium sulphate 16.00 Sodium chloride 9 .00 Silica and alumina 9 . 50 100.00 Manufacture of Cane Sugar. — ^The process of manufacturing raw sugar from sugar cane is briefly as follows: The juice is first extracted from the canes by crushing in roll mills and is freed from nitrogenous bodies, organic acids, etc., by the process of defecation, which consists in heating to coagulate the albumin, and nearly neutralizing with milk of lime, the impurities being removed as a scum. The juice is then subjected to evaporation and crystallization, the raw, or muscovado sugar, which contains from 87 to 91 per cent of sucrose, being separated from the molasses, which is the mother liquor, by draining or by centrifugal. Some of the best grade of muscovado, or raw sugar, is used as ' ' brown sugar" without further refining, and much of the molasses is used as a table syrup and for cooking, while the lower grades of molasses are used in the manufacture of rum. * Com. Org. Anal., 4 Ed., Vol. I, p. 359. t SUGAR AND SACCHARINE PRODUCTS. 589 The following table from Thorpe * shows the average comp osition of raw and refined sugar: Cane Sugar. Glucose'. Water. Organic Matter. Ash. RAW SUGAR. Good centrifugal . Poor centrifugal . . Good muscovado. Poor muscovado . Molasses sugar Jaggary sugar Manilla sugar Beet sugar, ist Beet sugar, 2d . . . REFINED SUGAR. Granulated sugar White coffee sugar Yellow X C sugar Yellow sugar Barrel sugar 96-5 92.0 91.0 82.0 85-0 75-0 87.0 95-0 91.0 99.8 91.0 87.0 82.0 40.0 0-75 2.50 2.25 7.00 3.00 11.00 5-50 0.00 0.25 0.20 2.40 4-50 7-50 25.00 1.50 3.00 5.00 6.00 5.00 8.00 4.00 2.00 3.00 0.00 5-5° 6.00 6.00 20.00 0.85 I-7S 1. 10 3-5° 5.00 4.00 2.25 1-75 3-25 0.00 0.80 1.50 2.50 10.00 0.40 0-75 0.65 1.50 2.00 2.00 1.25 1-25 2.50 0.00 0.30 1. 00 2.00 5.00 1 The term "glucose" includes sugars which reduce Fehling's solution, but are not necessarily optically active. The following minimum and maximum figures are taken from analyses made by Babington f of twenty-two samples of brown sugar and thirty- one samples of molasses. BROWN SUGAR. Direct polarization 84 Invert " -27 Sucrose by Clerget 83 . 5 Reducing sugar 3 Moisture 3.5 Ash 0.8 MOLASSES. Direct polarization — 30 Invert " — 10 Sucrose by Clerget 32 Reducing sugar 13 Moisture 29 Ash 0.5 * Outlines of Industrial Chem., p. 383. t Can. Inl. Rev. Dept. Bui. 25. to to 87 29 91-5 6 6 3-0 50 — 21 52 24 32 4 590 FOOD INSPECTION AND ANALYSIS. The Sugar Beet {Beta vulgaris) is grown chiefly in France and Ger- many, and to a lesser extent in Holland and England. The successful growth of the sugar beet in the United States is confined mainly to Cali- fornia, Colorado, Utah, and Nebraska, and the entire output of beet sugar in this country is comparatively small. According to R. Hoffmann, sugar beets have about the following composition, three types being selected — first, those poor in sugar; second, those having a medium sugar content, and third, those rich in sugar: COMPOSITION OF THE SUGAR BEET. First Type. Second Type. Third Type. Water Sugar Nitrogenous compounds Non-nitrogenous compounds Soluble Insoluble (cellulose) Ash 89. 20 4.00 1. 00 4-13 1. 01 0.66 83.20 9.42 1.64 3-34 1.50 0.90 75.20 15.00 2.20 4.23 2.07 1.30 The following is the mean composition of ten samples of California sugar beet : * Per cent juice extracted 61 .38 Specific gravity i .062 to i .075 Per cent of reducing sugar 0.91 Per cent of sucrose 14-38 Total solids calculated 16.58 Total solids weighed 1 7 . 20 Per cent of ash 0-994 The composition of beet sugar ash according to Monier is as follows: RAW BEET SUGAR ASH. Carbonates of potassium and sodium 82 . 20 Carbonate of calcium 6. 70 Potassium and sodium sulphate and sodium chloride. ... 11 .10 100.00 Manufacture of Beet Sugar. — In making raw sugar from sugar beets the latter are first washed and sliced by machinery and the juice extracted * U. S. Dept. of Agric, Div. of Chem., Bui. 27, p. 302. SUGAR AND SACCHARINE PRODUCTS. 591 by diffusion or digestion with warm water. The juice is then clarified or defecated in much the same manner as that from the sugar cane, after which it is usually bleached with sulphur dioxide. The subsequent evaporation and crystallization are carried out usu- ally in vacuum pans, and the sugar separated out by centrifugals. Beet sugar molasses is unfit for food, due to the presence of nitroge- nous bodies, which give it a very unpleasant taste and smell. Process of Refining. — In refining raw sugar, a syrup is made, which is subjected to centrifuging and further defecation, using lime, clay, liquid blood, calcium acid phosphate, and other substances as clarifiers. The syrup is then filtered, first through cloth bags and then through bone char, after which it is evaporated and allowed to crystallize, the resulting granulated sugar being separated, as in the case of raw sugar, by centrifugal machines. Granulated Sugar of commerce is without doubt the purest food product on the market, being generally 99.8% sucrose. It is usually treated with an extremely weak solution of ultramarine to counteract the natural yellow color. The syrup from which the granulated sugar is separated forms the "golden," or "drip," syrup used on the table. Its typical composition •s as follows: Sucrose, 40%; reducing sugars, 25%; water, 20%; organic natter, 10%; ash, 5%. The dry sugars, whether white or brown, are rarely subjected to adulteration. Maple Sap. — The sap of the maple tree, Acer saccharinum, or Acer barbatum, furnishes a sugar considerably prized for its peculiar flavor. The maple sugar industry is largely confined to the northeastern states and to Canada, and the maple sugar season is generally limited to six weeks or two months in the spring. The following are minimum and maximum figures from the analyses of five samples of maple sap made in Massachusetts : Specific gravity i .007 to i .015 Sucrose 0.769 " 2.777 Reducing sugar " 0.012 The ash of maple sap varies from 0.04 to o. i per cent. Albuminoids are present in amount varying from 0.008 to 0.03 per cent. Maple Sugar and Syrup are made by, simply boiling down the sap to the proper consistency, usually in open pans, and removing the scum 592 FOOD INSPECTION AND ANALYSIS. with great care, since this contains nitrogenous matters that would cause fermentation in the finished product. Pure cane sugar is never com- mercially produced from the maple sap, since the refining process would deprive it of the flavor which gives to maple sugar the chief value. McGill gives the following as the average analyses of six samples of maple syrup of known purity: Saccharim- eter Invert. Cane Sugar by Clerget. By Copper. Ash. Water. Saccharim- eter Direct. Reducing Sugar. Cane Sugar. Solids. + 62.2 — 21.2 62.4 .42 63-36 -53 35-7° 64.30 The variation in the composition of pure maple products is shown by the following table compiled by A. H. Bryan * from analyses published by Hortvetjt Jones,{ and Winton§, and some sixty analyses made at the sugar laboratory of the Bureau of Chemistry, U. S, Department of Agriculture. Maple Sugar. Mini- mum. Maxi- mum. Average. Maple Syrup. Mini- mum. Maxi- mum. Average. Water per cent Direct polarization " Invert sugar " Lead number Total ash per cent Soluble ash " Insoluble ash " Alkalinity of soluble ash Alkalinity of insoluble ash Ratio of insoluble to soluble ash Iodine reaction Polarization at 87° after inversion °V. Malic acid value 3-05 72.6 1. 16 1.83 0.64 0-33 0.20 0.40 0-55 0.50 II. o ■87.4 8-37 2.48 1.32 0.67 0.87 0-95 1.72 2.20 - 2.0 0.65 + 2.0 1.67 2.23 0.91 0.46 0.46 0.63 0.94 1. 00 none Not m 51-0 0-34 1. 19 0.46 0.21 0.14 0.26 0.31 0.60 ore tha 62.2 9.17 2.03 1. 01 0.63 0.56 C.68 0.94 0.41 + 2.0 1.76 n 32.00 1-49 0.60 0.38 0.23 0.50 0-S4 1.70 none 0.78 In the table which follows appear the maximum, minimum, and average results obtained in the four most extensive investigations of genuine maple * U. S. Dept. Agric, Bur. of Chem., Circular No. 40, p. 10. t Jour. Am. Chem. Soc, 26, 1904, p. 1523. I Vt. Agric. Exp. Sta. Rep., 1904, p. 446; 1905, p. 315. § Jour. Am. Chem. Soc, 28, 1906, p. 1204. SUGAR AND SACCHARINE PRODUCTS. 593 syrup which have yet been undertaken * as compiled by Snell and Scott. The electrical conductivity and volumetric lead values are not included. (See pages 659 and 661.) SUMMARY OF ANALYSES OF MAPLE SYRUP BY DIFFERENT ANALYSTS CALCULATED TO THE DRY SUBSTANCE. Maximum: Bryan Jones McGill Snell and Scott. Minimum: Bryan Jones McGill Snell and Scott. Average : Bryan Jones McGill Snell and Scott. No. of Sam- ples. Ash. Alkalinity of Ash. Lead No Total. Sol- uble. Insol- uble. Sol- uble. Insol- uble. Cana- dian. Win- lon (25 g. Syrup) Win- ton (25 g. Dry Mat- ter) 481 48 456 126 481 48 456 126 481 48 456 126 1.68 1.32 1.38* 1.58 0.68 0.77 0.69* 0.61 I.oo 0.92 0.89* 0.88 I 23 0.72 0.79* 0.77 0-35 0.45 0.33* 0.30 0.63 58 0.56* 48 1. 01 0.78 075* 0.92 0.23 0.25 12* 0. 16 0.37 0.34 0.33* 0.40 122 102 208 145 4.41 6.56 7.50 2 38t 1.76 4.09 103 41 46 201 41 55 1-37 1-74 lost 2.70 1.41 51 75 79 48 97 83 2.83 3 48 i.75t 2.30 68 116 Malic Acid Value. 1.60 I II I i6t I 46 o 29 0.65 o 3ot 0.38 0.84 o 82 o 77t 0-7S * IIS samples. t 47 samples. J 452 samples. A summary of 363 analyses of authenticated samples of maple sugar by A. H. Bryan f with the collaboration of Straughn, Church, Given, and Sherwood appears in the table which follows. The analyses were made on syrup prepared as described on page 656, but the results are cal- culated to the dry basis. * Bryan, U. S. Dept. of Agric. Bur. of Chem. Bui. 134, 1910; Jones, Vt. Agr. Exp. Sta. Rep., 1904-5, p. 315; McGill, Lab. Int. Rev. Dept. Ottawa Bui. 228, 1911; Snell and, Scott, Jour. Ind. Eng. Chem., 6, 1914, p. 216. t U. S. Dept. of Agric. Bui. 466, 1917. 594 FOOD INSPECTION AND ANALYSIS. Number of Anal- yses. Sucrose. Invert Sugar. Total Ash. Soluble Ash. Insol- uble Ash. _ Undeter- mined Winton Lead No.* Malic Acid Value. United States: Maximum . . 283 98.62 57-04 91.89 96-59 58-92 86.46 37-3° 0.09 5-46 35 26 0.88 8.76 1.66 0.76 0-95 1.70 0. 76 1.06 I. 14 0.37 0.62 0.89 0.31 0.61 0.81 0. 21 0-33 1. 00 0. 24 0-45 5-84 0.00 1.70 8.18 0.02 3-70 4-95 1-85 2.68 4.14 1.86 3-04 1.72 0-51 0.91 1-51 0.62 Minimum . . Average. . . . Canada : Ma.ximum. . 80 Minimum . . Average. . . . I 03 * Determinations on 308 samples by Ross modification: Max. S-90, min. 2.20, av. 3.50. Partial ash analyses of maple products and brown sugar have been made by Jones * with the following maxima and minima results : 100 Parts of Ash Contain Ratio of Number of Analysis. CaO. K2O. SO3. CaO to K2O CaO to SO3 KoQ to SO3 X 100. X 100. Xioo. Maple syrup: Min. . . . 6 18.03 30.00 0.68 ISO 3-4 1-9 Max. .. 23.98 38.98 2.30 181 12.7 7-2 Maple sugar: Min. . . . 4 21.03 18.26 I-51 57 5-2 5-1 Max 31-74 32-95 2.42 153 10.4 9-4 Brown rugar: Min. . . . 4* 4-17 30.72 4-58 257 27 II Max 21.62 55-40 17-78 949 157 58 * Including one analysis by Hortvet. U. S. standards for Maple Products. — Maple Sugar is the solid product resulting from the evaporation of maple sap, and contains in the water-free substance not less than 0.65% of maple sugar ash. Maple syrup is syrup made by the evaporation of maple sap or by the solution of maple concrete, and contains not more than 32% of water and not less than 0.45% of maple syrup ash. Adulteration of Maple Sugar and Syrup. — The chief adulterants of maple sugar are brown, or molasses sugar, and white, or refined sugar, the latter being (5ften used in mixture with burnt or inferior maple stock, which itself would be abnormally dark in color and of a rank taste. Maple syrup is commonly adulterated with a syrup made from refined cane sugar, less often with golden or drip syrup, or molasses. Gluco.se, which formerly was a common adulterant, is now seldom employed. * Loc. cit., 1905, p. 331. SUGAR AND SACCHARINE PRODUCTS/ ^ 595 Refined Sugar or refined sugar syrup added to maple products, while not greatly affecting the polarization, diminishes the percentage of total ash and the lead number, as well as the malic acid value and ash constants. According to analyses by Jones and Hortvet, brown sugar of various grades contains from 0.59 to 4.33% of total ash, some of the grades with low ash content, or syrups made from them, not being distinguishable from maple sugar or maple syrup respectively by this determination alone; the ratio of insoluble to soluble ash, however, is commonly higher in brown sugar than in maple products. It is frequently possible to identify brown, or molasses sugar, especially when it forms the larger portion of the alleged maple sugar or syrup, by the physical sense of taste. When the perfectly characteristic taste of brown, or molasses sugar, or of "drip syrup," so far predominates over the maple flavor as to be unmistakable, especially in cases where the maple flavor is entirely lacking, one need have little hesitation in condemning the product. Glucose in maple products is detected by polarization both before and after inversion. A reading of the inverted solution much in excess of 3° Ventzke at 87° C. furnishes evidence of the presence of this adul- terant. Sorghum {Andropogon sorghum, variety saccharatus) has for many years been grown quite extensively in the southern and western states, and used as a source of syrup which is highly prized because of its distinc- tive flavor. Much experimental work was carried out by Collier * in the early eighties and prior thereto with the belief that the sorghum plant would become an important source of commercial crystallized sugar, but experi- ments were at length abandoned. The composition of the juice of the sorghum plant is shown by the following results of analyses of eleven varieties made by Hardin.| Total solids 15-97 to 18.71 Specific gravity 1.0656 to 1.0775 Solids not sugar 5.02 to 10.63 Cane sugar 2.81 to 8.01 Reducing sugars 3.87 to 7.55 Some varieties of sorghum juice have been known to contain 15 or even 17% of sucrose. * See numerous government reports. t U. S. Dept. Agric. Div. Chem. Bui. 37, p. 75. 596 FOOD INSPECTION AND ANALYSIS. In making syrup from sorghum, the ripe canes are crushed, the juice is heated with milk of Hme, and the scum removed. The juice is then concentrated usually in open pans to the required consistency. The following analysis of sorghum syrup is by Jordan and Chesley.* Total solids 74-63 Sucrose 40 .00 Reducing sugars 28.42 Gums and extractives 4 -03 Ash 2 .82 Acidity as tartaric o - 79 GRAPE SUGAR, OR DEXTROSE. Dextrose (C6H12O6+H2O), designated (/-glucose by Fisher and known in its commercial form as starch sugar, occurs in honey with levulose, and in fruits with both levulose and cane sugar. It is produced by the action of dilute acids or of certain ferments on starch, dextrin, or cane sugar. Grapes contain about 15% of dextrose. Anhydrous dextrose is soluble in 1.2 parts of cold water. It is soluble in alcohol, but less so than cane sugar. It is much less sweet than cane sugar. The specific rotary power of dextrose is [a]o = 52.3, [«];•= 58. A normal solution of dextrose on the Soleil-Ventzke scale polarizes at 78.6°. For the commercial preparation of dextrose see p. 598. U. S. Standards for Various Sugars. — Standard 70 sugar, or brewers^ sugar, is hydrous starch sugar containing not less than 70% of dextrose, and not more than 0.8% of ash. Standard 80 sugar, climax, or acme sugar, is hydrous starch sugar containing not less than 80% of dextrose., and not more than 1.5% of ash. Standard anhydrous starch sugar is anhydrous starch sugar contain- ing not less than 95% of dextrose without water of crystallization, and not more than 0.8% of ash. The ash of these standard products consists almost entirely of chlorides and sulphates of lime and soda. LEVULOSE. Levulose, also known as (/-fructose and /-(^-fructose, occurs in foods as the product of inversion of cane sugar. It is prepared by the action * Jour. Ind. Eng. Chem., 9, 1917, p. 256. SUGAR AND SACCHARINE PRODUCTS. 597 of dilute acids on inulin. Normally it is in the form of a syrup, but with extreme care pure anhydrous levulose can be obtained. Diabetene is a commercial form of dry levulose. Levulose is formed with dextrose in the inversion of cane sugar (page 586), and with dextrose occurs in honey and in many fruits. The specific rotary power of levulose varies with the temperature. At 15° C. [«]z)= -98.8°, decreasing by 0.6385° for each degree increase in temperature. Its left-handed reading on the Ventzke sugar scale at 15° C. is equivalent to 148.6°. Levulose is sweeter than dextrose. Its reducing power on Fehling's solution is assumed to be the same as that of dextrose. MALT SUGAR, OR MALTOSE. Maltose (C,,li,.0,,+ B.,0) is of little importance from the standpoint of the food analyst, excepting as an ingredient of commercial glucose, and as being the sugar produced by the action of ptyaline, the ferment of the saliva on the starch of food in the ordinary process of digestion. When gelatinized starch is subjected to treatment with malt extract at 55° to 60° C, it is converted into dextrin and maltose as follows: ioCi'>H.oOio + 8H20 = 2Ci2H2oOio + 8Ci2H220ii. "starch Dextrin Maltose In its commercial preparation maltose is separated from dextrin by crystallization in alcohol. By the action of weak acids and heat both dextrin and maltose are further converted into dextrose. Maltose usually crystallizes in minute needles, and its molecule of water is expelled at 110° C. It is somewhat less soluble in water than dextrose. It is shghtly soluble in alcohol, though less than sucrose. So- lutions of maltose possess the property of birotation; i.e., when freshly prepared they do not at once assume their true optical activity. The rotation of a freshly prepared solution of maUose increases on standing, requiring several hours to reach its maximum. The specific rotary power, according to O 'Sullivan, of anhydrous maltose is [a]z) = i39-2. [«],.= 154.5. For hydrated maltose [a]o would thus be 132.2. A normal solution of maltose hydrate on the Soleil -Ventzke scale should polarize at 198.8°. DEXTRIN. COMMERCIAL GLUCOSE. DEXTRIN, (CeHioOs)^, possesses more the nature of a gum than of a sugar, and is sometimes called British gum. It is said to occur naturally in the sap of various plants, but this is not definitely assured. 598 FOOD INSPECTION AND ANALYSIS. It undoubtedly occurs in beer and in bread crust, and is one of the constituents of commercial glucose. Like starch, it is convertible by hydrolysis with acid into dextrose. By treatment of starch with malt extract or diastase, starch is converted into dextrin and maltose, these two bodies being separated, in the commercial preparations of dextrin, by repeated treatment with alcohol. Dextrin is an uncrystallized, colorless, tasteless body, capable of being pulverized. It is readily soluble in water, slightly soluble in dilute alcohol, but insoluble in alcohol of 60% or stronger. It is not colored by iodine, and exercises no reducing action on alkaline copper solution. Its specific rotary power is [cx]]j = 2oo, [a]j= 222. Amylodextrin, erythrodextrin and achroodextrin are intermediate products formed in the transformation of starch into dextrose. Amylo- dextrin is colored purple and erythrodextrin red by iodine solution, while achroodextrin produces no coloration. It is probable that some of these dextrins are not simple substances. Commercial Glucose, otherwise known as mixing syrup, crystal syrup, and starch, or corn syrup, is a heavy, mildly sweet, colorless, semi-fluid substance, having a gravity of 40° to 45° Baume. It is largely used as an adulterant of maple syrup, molasses, honey, drip syrup, and jellies and jams, and as an ingredient of confectionery. In France and Germany it is made from potato starch, but in the United States mainly from corn starch. The conversion is effected by boiling with dilute sulphuric or hydrochloric acid, after which the acid is neutral- ized with marble dust, or sodium carbonate respectively, the juice is filtered through bone black, and finally concentrated by evaporation, the degree of conversion and of concentration depending on whether the liquid glucose or the solid dextrose is wanted for the final product. The end product obtained by complete conversion is the dry commercial grape sugar, or dextrose, which is purified by repeated crystallization. Commercial glucose is a mixture of dextrin, maltose, and dextrose cf the following varying composition: Dextriri 29.8% to 45-3% Maltose 4-6% " i9-3% Dextrose 34-3% "36-5% Ash 0.32%" 0-52% Water 14-2% "17.2% SUGAR AND SACCHARINE PRODUCTS. 599 Calcium sulphate is usually found in the ash if sulphuric acid was used for conversion. Solid commercial grape sugar, or dextrose, has the following coni' position : Dextrin o% Q-iVo Maltose o% i .8% Dextrose 72% 99-4% Ash 0.3% 0.75% Water 0.6% 17.5% U. S. Standard glucose, mixing glucose, or confectioners' glucose, is color- less glucose, varying in density between 41° and 45° Baume, at a tempera- ture of 100° F. (37.7° C). It conforms in density, within these limits, to the degree Baume it is claimed to show, and for a density of 41° Baume contains not more than 21% of water, and for a density of 45° not more than 14%. It contains on a basis of 41° Baume not more than 1% of ash, consisting chiefly of chlorides and sulphates of lime and soda. Healthfulness of Glucose. — The analyst alleging commercial glucose as an adulterant is frequently asked in court as to its healthfulness, so that the following conclusions of a committee appointed some years ago by the National Academy of Sciences to ascertain among other things whether there is any danger attending the use of this product in food are in point: "First, that the manufacture of sugar from starch is a long- established industry, scientifically valuable and commercially important; second, that the processes which it employs at the present time are unob- jectionable in their character and leave the product uncontaminated; third, that the starch sugar thus made and sent into commerce is of excep- tional purity and uniformity of composition and contains no injurious substances; and fourth, that though having at best only about two- thirds the sweetening power of cane sugar, yet starch sugar is in no way inferior in healthfulness, there being no evidence before the committee that maize starch sugar, either in its normal condition or fermented, has any deleterious effect upon the system, even when taken in large quan- tities." MILK SUGAR, OR LACTOSE. Lactose (C12H22O11+H2O) is prepared commercially from skim- milk by coagulating with rennet and digesting the whey with chalk and aluminum hydroxide. The insoluble matter is filtered out, and the filtrate is concentrated in vacuo to a syrup, which, on standing, yields 600 FOOD INSPECTION AND ANALYSIS. crystals of lactose. The product is purified by repeated crystalliza- tion. Lactose ordinarily crystallizes in rhombic, hemihedral crystals. Its specific gravity is 1.525. Its water of crystallization is lost by drying at 130° C. It is soluble in 6 parts of cold water, and in 2^ or less of boiling water. It is insoluble in absolute alcohol and ether. It has a very slightly sweet taste. The specific rotary power of milk sugar, after remaining in solution long enough to overcome its birotation, is [«]z) = 52-5- In the ordinary souring of milk the lactose becomes converted into lactic acid. On heating lactose with dilute acids it undergoes inversion, forming dextrose and galactose in accordance with the formula given on p. 565, illustrating the inversion of cane sugar. Milk sugar is of considerable importance by reason of the large amount used of late in the preparation of modified milk for infant feeding. Grape sugar and cane sugar are to be looked for as adulterants of milk sugar. The purity of milk sugar is best established by titrating against Feh- ling's solution, 10 cc. of which are equivalent to 0.067 gram of lactose. RAFFINOSE. Raflfinose, C18H32O165H2O, is a sugar belonging neither to the saccha- rose nor the glucose group, but to the so-called saccharoid group, the other members of which do not occur in foods. Raflfinose occurs in beet root molasses to the extent of from 3 to 4 per cent. It is a crystalline, slightly sweet substance, soluble in water and slightly soluble in alcohol. It does not reduce Fehling's solution, but readily undergoes fermentation with bottom yeast. On inversion it splits up into levulose and melibiose (C12H22O11). The melting-point of raflfinose is 118° to 11*9° C. Its specific rotary power [a:lD== + 104.5 ^-t a temperature of 20° C. THE POLARISCOPE AND SACCHARIMETRY. A full discussion of the principles of polarized light and even a detailed description of their application to the polariscope will not be given here, but the reader who wishes full information along this line is referred to SUGAR AND SACCHARINE PRODUCTS. 601 the various treatises such as those of Browne * Landolt,t Rolfe,t Spencer, § Tucker, 1| and Wiechmann,^ in which ^various forms of polariscopes are described and their underlying principles discussed. The Soleil-Ventzke Saccharimeter is the one most commonly used in this country, being adopted as the standard for all United States govern- ment work. Fig. 102 shows this instrument, known as the half-shadow apparatus, in its simplest form with a single movable wedge in its com- pensating system. An excellent light for work with this instrument is that furnished by the Welsbach burner, a convenient form of lamp being shown in Fig. iii, in which the burner is inclosed in a sheet-metal chimney of suitable con- FiG. 102. — Single-wedge Saccharimeter. struction. An argand, gas, or kerosene burner may, however, be used, and in a late form of Schmidt and Haensch instrument. Fig. 103, a spe- cially constructed incandescent electric lamp is supplied. The International Commission for Uniform Methods of Sugar Analysis at its seventh session held at New York, 191 2, passed the following resolu- tion based on studies by A. H. Bryan: " Wherever white light is used in polarimetric determinations, the same must be filtered through a solution of potassium bichromate of such a concentration that the percentage con- * Handbook of Sugar Analysis, New York, 191 2. t Optical Rotation of Organic Substances, trans, by Long, Easton, 1902. t The Polariscope in the Chemical Laboratory, New York, 1905. § Handbook for Sugar Manufacturers and their Chemists, New York, 1905. II Manual of Sugar Chemistry, New York, 1905. *if Sugar Analysis, New York, 1914. 602 FOOD INSPECTION AND ANALYSIS. tent of the solution multiplied by the length of the column of solution in centimeters is equal to nine." The Single-wedge Saccharimeter. — The following description of the saccharimeter and directions for its use are from the revised regulations of the U. S. Internal Revenue Department. The tub-^ N, Fig. 102, con- tains the illuminating system of lenses and is placed next to the lamp; the polarizing prism is at O and the analyzing prism at H. The quartz wedge compensating system is contained in the portions of the tube marked FEG and is controlled by the milled head M. The tube / carries a small telescope, through which the field of the instrument is viewed, and just above is the reading-tube K, which is provided with a mirror and magnify- ing lens for reading the scale. The tube containing the sugar solution is shown in position in the trough between the two ends of the instrument. In using the instrument the lamp is placed at a distance of at least 200 mm. from the polarizing end; the observer seats himself at the opposite end in such a manner as to bring his eye in line with the tube /. The telescope is moved in or out until the proper focus is secured to give a clearly defined image, when the field of the instrument will appear as a round, luminous disk, divided into halves by a vertical line passing through its center, and darker on one half of the disk than on the other, when the com- pensating quartz wedge is displaced from the neutral position. If the observer, still looking through the telescope, will now grasp the milled head M and rotate it first one way and then the other, he will find that the appearance of the field changes, and at a certain point the dark half becomes light and the light half dark. By rotating the milled head delicately backward and forward over this point he will be able to find the exact position of the quartz wedge operated by it, in which the field is neutral, or of the same intensity of light on both halves. The three different appearances presented by the field are shown in Fig. 106, opposite page 605. One of the compensating quartz wedges is fixed and the other is movable, sliding one way or the other according as the milled head is turned, so that for different relative positions of the two wedges a different thickness of quartz is interposed in the path of the polarized ray. By tliis means the amount of the rotation which the sugar solution or other optically active substance examined exerts upon the light polarized by the prism at O may be, as it were, counteracted by varying the relative position of the wedges. SUGAR AND SACCHARINE PRODUCTS. 603 With the milled head set at the point which gives the appearance of the middle disk shown in Fig. io6, the eye of the observer is raised to the reading tube K, which is adjusted to secure a plain reading of the divisions, and the position of the scale is noted. It will be seen that the scale proper is attached to the quartz wedge, which is moved by the milled head; and attached to the other quartz wedge is a small scale called a vernier^ which is fixed, and which serves for the exact determination of the posi- tion of the movable scale with reference to it. On each side of the zera line of the vernier a space corresponding to nine divisions of the movable scale is divided into ten equal parts. By this device the fractional part of a degree indicated by the position of the zero line is ascertained in Fig. 103. — Double-wedge Soleil-Ventzke Saccharimeter, mounted on Bock Stand and provided with Incandescent Electric Lamp. tenths; it is only necessary to count from zero until a line is found which makes a continuous line with one on the movable scale. With the neutral field, as indicated above, the zero of the movable scale should correspond closely with the zero of the vernier, unless the zero point is out of adjustment. Adjusting the Instrument. — If the observer desires to secure an exact adjustment of the zero of the scale, or in any case if the latter deviates more than two-tenths of a degree, the zero lines are made to coincide by moving the milled head and securing a neutral field at this point by 604 FOOD INSPECTION AND ANALYSIS. means of the small key which comes with the instrument, and which fits a small nipple on the left-h.a.nd side of Ff the fixed quartz wedge of the compensating system. This nipple must not be confounded with a similar nipple on the rlght-h.a,nd side of the analyzing prism H, which it fits as well, but which must never be touched, as the adjustment of the instrument would be seriously disturbed by moving it. With the key on the proper nipple it is turned one way or the other until the field is neutral. Unless the deviation of the zero be greater than 0.2° it will not be necessary to use the key, but only to note the amount of the deviation, and for this purpose the observer must not be content with a single setting, but must perform the operation five or six times and take the mean of these different readings. If one or more of the readings show a deviation of more than 0.2° from the general average they should be rejected as incorrect. Between each observation the eye should be allowed a moment of rest. The Scale usually has no equal divisions on one side of the zero fol reading right-handed polarization, and 20 equal divisions on the othei side for left-handed polarization. The scale is an arbitrary one, based on the plan that a normal aqueous solution of pure cane sugar (26.048 grams made up to 100 cc.) will read exactly 100° or divisions to the right of the zero when polarized in a 200-mm. tube. The accuracy of various portions of the scale may be verified bf quartz control plates of varying thickness, usually mounted in tubes, the correct polariscopic reading of each of which plates has been accurately determined, this reading being as a rule marked on the tube. As the sugar value of such a quartz plate varies with the temperature, the temperature at which the particular reading marked thereon applies is usually specified, and in many cases a table giving its exact value at different temperatures from 10° to 35° accompanies the plate. The Double-wedge Saccharimeter is shown in Fig. 104, the arrangement of the optical parts being also shown. In this instrument the two sets of wedges employed are of oppo- site optical properties, so that extreme accuracy may be arrived at by making the readings with both, the inaccuracies of one being compen- sated for by the other. Ordinarily in using this form, one movable wedge, say the one controlled by the right-hand milled screw head, is set at zero, while the reading of the sugar solution or other substance to be polar- ized is made with the other movable wedge. The Triple-field Saccharimeter. — The latest form of saccharimeter SUGAR AND SACCHARINE PRODUCTS. 605 Fig. 104. — Triple-wedge, Triple-field Soleil-Ventzke Saccharimeter. is the triple-field instrument, the construction of the polarizer being shown in Fig. 105. In this form the analyzer is the same as in the fore- going instruments, but the polarizer consists of one large and two small Nicol prisms I, II, and III, the construction and arrangement being such that when the compensating wedges are at the neutral point, sections i, 2, and 3 of the circular field (corresponding respectively to the prisms I, II, and III) are evenly lighted, forming a circular uniformly colored field, while in any other position of I — the wedges section i is dark while 2 and 3 are light or vice versa. The accompanying diagram, Fig. 106, shows the appearance of the field of this instrument in the three positions of the quartz wedge, viz., at the neutral point and at both sides thereof. The lamp used for illumination should be separated from the polariscope on account of the influence of its Fig. 105. heat on the readings. This is best accomplished by having the lamp in a separate compartment from the polariscope, so 606 , FOOD INSPECTION AND ANALYSIS. that both are on opposite sides of a partition, an opening in which trans- mits the Hght. In any event some kind of screen should be interposed between the two. Best resuks are obtained if the room in which the observations are made is dark. Comparisons of Scales of Various Polariscopes. — Besides the Soleil- Ventzke instrument, there are various other forms of polariscope. Among the best known of these are Laurent's, Wild's, and Duboscq's, all of which are made with scales reading in circular degrees, while in some cases modified forms have scales in which, like the Soleil- Ventzke, per- centages of sugar are directly read off. Some instruments are provided with double scales reading both circular degrees and percentages of sugar, and in certain of the Duboscq instruments additional scales for percent- ages of milk sugar and diabetic sugar are provided. In the Wild, Duboscq, and Laurent instruments the source of light is the sodium flame, yielding what is termed a monochromatic light. This is produced by fused sodium cliloride passing through a Bunsen flame, various mechanical devices being employed for making the light continuous. In the Ventzke instrument, as was stated above, the ordinary light from a bright gas or oil flame is used. For convenience in conversion of readings on one instrument to their equivalents on other scales, the following factors can be used: r° Ventzke =0.3468° angular rotation Z). ° angular rotation Z) =2.8835° Ventzke. ° Ventzke =2.6048° Wild (sugar scale). ° Wild (sugar scale) =0.3840° Ventzke. ° " " " =^.1331° angular rotation Z). ° angular rotation D =7.5110° Wild (sugar scale) ° Laurent (sugar scale) =0.2167° angular rotation Z). ° angular rotation D =4.6154° Laurent (sugar scale). ° Soleil-Duboscq =0.2167° angular rotation £>. ° " " =0.2450° " " ;'. ° " " =0.620° Soleil- Ventzke. ° " " =1.619° Wild. ° Soleil-Ventzke =1.608° Soleil-Duboscq (old scale). ° " " =1.593° " " (new scale). ° Wild =0.611° " " (Wild normal weight 10). o li ^j_223° " " ( " " " 20). Normal Weights of Sugar for Different Instruments. — The follow- ing normal weights (number of grams in 100 cc. at 17.5° C.) are those on which the scales of the various instruments are based: Soleil-Ventzke, 26.048; Soleil-Duboscq 16.29 (formerly 16.19); Wild, usually, 10 or 20; Laurent, 16.29. The International Commission for Uniform Methods in Sugar Analysis has decided to use for the Ventzke scale 26 grams and make up at 20° C. to 100 metric cc, which figures are approximately equivalent to 26.048 SUGAR AND SACCHARINE PRODUCTS. 607 grams made up to loo Mohr cc. Unless otlierwise stated the term normal weight as here used refers to 26 grams. At the date of writing Browne and other prominent American sugar chemists are advocating the adoption of an international weight of 20 grams and a scale to correspond. This change, which is in the interest of sim- plicity, is endorsed also by leading French and English authorities. Specific Rotatory Power.— This is a theoretical term to express a stand- ard by which the various optically active substances may be compared, and is understood to mean the amount in angular degrees through which the plane of polarization of a ray of light of stated wave length is rotated by I gram of a given substance in aqueous solution of i cc. and forming a column i decimeter in length. The actual rotatory power of a solution varies directly with the length of the column traversed by the light, with the concentration of the solution, and with the wave length of light, hence the need of a purely theoretical basis for purposes of comparison. The specific rotatory power is usually expressed as [ajo or [a]j, the letters D or ; indicating the character of the light. Thus, D indicates the monochromatic light obtained from the sodium flame, named from the D line of Fraunhofer in the yellow portion of the spectrum, while j (from the French jaime) indicates what is known as the transition tint, the rose-purple color produced when ordinary white light passes through the polarizer and analyzer, placed with then: principal sections parallel to each other and with r plate of quartz 3.75 mm. thick interposed between them.* The specific rotatory power is determined as follows: [a]D or [a]j = -^, where a = observed angular rotation, <; = grams of the substance in 100 cc. of the solution, and / = length of the observation-tube in decimeters; or in cases where, instead of the grams per 100 cc, the percentage composition is known (expressed by ^ = grams of the substance in 100 grams of the solvent), and the specific gravity (expressed by d), then [a]r, or [a]j = looa ~pdi' * Some confusion is caused by the adoption of the characters D and j, since both would naturally seem to indicate yellow light. The so-called transition tint above defined is, how- ever, complementary to the mean yellow, or jaune moyen, and it is the complementary color and not the yellow itself that is indicated by the character j. 608 FOOD INSPECTION AND ANALYSIS. Birotation.— In polarizing solutions of all the common sugars other than sucrose the phenomenon of birotation should be taken into account, whereby a change in optical activity is shown by standing. Thus, solu- tions of dextrose, levulose, and lactose polarize much higher when freshly prepared than after long standing, requiring in some instances several hours before the lowest or normal figure is reached. Maltose, on the other hand, increases in polarization after standing in solution. By boiling the solution it may at once be brought to its correct reading. The desired result may also be accomplished by adding a few drops of ammo- nia, either treatment being resorted to before the solution is made up to the required volume. ANALYSIS OF CANE SUGAR AND ITS PRODUCTS. Qualitative Tests for Sucrose. — (a) Polariscope Test. — The substance to be tested, if not already in solution, is dissolved in water, and if the solution is not perfectly clear, is clarified by the addition of alumina cream or by subacetate of lead (page 6io) and filtered. An observation tube is filled with the clear solution and the polariscope reading noted. A measured portion of the same solution is then treated with one-tenth its volume of concentrated hydrochloric acid and is subjected to inversion (page 6ii), after which the same tube as before is filled with the inverted solution and a second reading obtained, one-tenth of the observed reading being added for the true invert polariscopic reading. If the two readings are virtually the same, sucrose is absent, but, in the presence of sucrose, the second reading will be considerably lower than the first or may even be to the left of the zero. (6) Test with Nitrate of Cobalt.^ — Prepare a 5% solution of cobaltous nitrate, and a 50% solution of potassium hydroxide. If the sugar solution to be tested contains dextrin or gums, these should be first removed by treatment with alcohol. 15 cc. of the sugar solution to be tested are mixed with 5 cc. of the cobaltous nitrate reagent, and 2 cc. of the potassium hydroxide solution are added. Sucrose produces under these conditions a permanent amethyst-blue color, while dextrose gives at first a turquoise- blue passing over into light green. In a mixture of the two sugars the color due to sucrose will predominate. According to Wiley, i part of sucrose in 9 parts of dextrose may be * Wiley, Ag. Anal., p. 189. Fig. io6. — Appearance of the Field in the Half-shade (above) and Triple-shade (below) Saccharimeter. SUGAR AND SACCHARINE PRODUCTS. 609 detected by this test. Browne * notes that other sugars give a similar coloration, hence the test is not infalHble although a useful guide. Analysis of Cane Sugar.— In the case of commercial granulated or loaf sugar the sucrose determination is usually all that is necessary to determine its purity, and the same is true, as a rule, of the powdered white sugars. A fahly complete analysis of raw or brown sugar con- sists in the determinations of moisture, sucrose, invert sugar, ash, organic non-sugars, and quotient of purity. Care should be taken that the por- tion subjected to analysis is a fair representation of the whole, and is perfectly homogeneous. Determination of Moisture. — Two to five grams of the sample are dried in a flat, tared metal dish, to constant weight in vacuo, or in a McGill oven t in a current of ah, at about 70° C, at which temperature levulose is not decomposed. For ordinary purposes drying to constant weight in a boiling-water oven is sufhciently accurate. Determination of Ash. — The residue from the moisture determination is burned slowly and cautiously over a low flame until frothing has ceased. Afterwards increase the flame and ignite to a white ash at a low red heat, preferably in a muffle furnace. In igniting saccharine substances. which contain an appreciable amount of cane sugar, the contents of the dish will swell up and froth, unless great care be taken, to such an extent as to flow over the sides of the dish, occasioning loss and inconvenience. Such frothing may be largely held in check by directing the flame at first down from above upon the pasty mass, instead of from under the dish as ordinarily, till all is reduced to a dry char, afterwards continuing the ignition from below in the usual manner. Organic Non-sugars. — These consist mainly of compounds of organic acids, together with gum, coloring matter, albuminous bodies, etc. They * Sugar Anal., p. 681. t A. McGill, Laboratory of Inland Revenue, Ottawa, Canada, has devised a forced- draft water-oven for drying at temperatures between 60° and 90° C. The oven is heated by means of ordinary gas-burners, and the temperature is controlled by introducing at the bottom of the oven a blast of air from a blower run by a small water-motor. Before dis- charging into the oven, the air-tube enters the water-chamber and is coiled a number of times in order to sufficiently warm the air before it enters the oven. The exit end of tlie air-tube is covered with a concavo-convex disk in order to distribute the blast and to pre- vent harmful currents. By regulating the burners and the flow of air, a fairly constant tem- perature can be obtained. The bottom of the oven is curved instead of flat, to prevent bumping when the water is boiling; a perforated plate serves as a false bottom. 610 FOOD INSPECTION AND ANALYSIS. are determined by difference between ioo% and the sum of the sucrose, invert sugar, moisture, and ash. Quotient of Purity. — By this term is meant the percentage of pure sugar in the dry substance. It is calculated by dividing the per cent of sucrose by the percentage of total solids and multiplying the result by loo. Determination of Sucrose by the Polariscope. — Reagents. — (a) Lead- Suhacetate Solution.* — Boil for half an hour 430 grams of normal lead acetate, 130 grams of litharge, and 1000 cc. of v^ater, allow to cool and settle. Dilute the supernatant liquid to 1.25 specific gravity with recently boiled water. Anhydrous lead subacetate, first proposed by Horne,t may be sub- stituted for the solution. {b) Alumina Cream. — Divide a cold, saturated solution of alum into two unequal portions, add to the larger a slight excess of ammonia, then by degrees the remaining portion to faint acid reaction. Process. — If the Soleil-Ventze polariscope is to be used, weigh out 26 grams of the sugar, which may conveniently be done in the German- silver, tared tray especially designed for this purpose (Fig. 107). If any Fig. 107. German-silver Sugar-tray with Tare. other instrument is employed, weigh out the standard or normal weight for that instrument (see page 606). Transfer the sugar by washing to a loo-cc. graduated sugar-flask, and if the solution is perfectly clear, as would be the case with a refined sugar, make up to the mark and shake to insure a uniform solution. If the solution is slightly turbid, or more or less opaque or dark-colored, a clarifier must be added before making up to the mark to obtain a clear solution for polarization. The kind and amount of clarifier to be used depends on the nature of the sugar solution and must be learned by experience. If the turbidity is only slight, from 5 to 10 cc. of alumina cream alone will often prove sufficient; if * U. S. P. lead subacetate, sometimes sold as Goulard's extract, may also be used. t Jour. Am. Chem. Soc, 26, 1904, p. 186. SUGAR AND SACCHARINE PRODUCTS. 611 more opaque, lo cc. of lead subacetate solution or a small amount of the dry salt may be used. For additional details as to clarification see page 644, under Molasses. After adding the clarifier, the flask is filled to the mark with water and shaken, the solution being poured upon a dry filter and the first few cubic centimeters of the filtrate rejected. A 2oo-mm. observation- tube is filled with the clear sugar solution and the polarization noted. If sucrose is the only optically active substance present, the direct reading on the polariscope will indicate its percentage. Inversion by the Clerget-Herzfeld Method. — In the presence of invert or other sugars the normal solution is subjected to inversion as follows: Free a portion of the solution from lead by treating with anhydrous Fig. 108. — A Convenient Sugar-scale. sodium carbonate, sodium sulphate or potassium oxalate, filter, place 50 cc. in a loo-cc. flask, add 25 cc. of water and little by little, while rotating the flask, 5 cc. of 38.8% hydrochloric acid. Heat in a water bath at 70° C, so that the solution in the flask reaches 67° to 69° C. in 2\ to 3 minutes. Maintain at 69° C. during 7 to 7I minutes, making a total time of heating of 10 minutes. Remove the flask, cool the contents rapidly to 20° C, and dilute to 100 cc. Polarize this solution in a 200-mm. tube provided with a lateral branch and a water jacket, passing a current of water around the tube to maintain a temperature of 20° C. The inversion may also be accomplished by allowing a mixture of 50 cc. of the clarified solution, freed from lead, and 5 cc. of the acid to stand for 24 hours at no less than 20° C. or for 10 hours at not less than 25°. The sucrose is obtained by the Clerget-Herzfeld formula based on the rotation of cane sugar before and after inversion, ^_ ioo{a-h) 142.66— // 2' 612 FOOD INSPECTION AND ANALYSIS. where 5 = per cent of sucrose, a = direct polarization, &-- invert polari- zation, and / = temperature. Note that if the direct polarization is to the right or positive, and the invert to the left or negative, then a—h would be the sum of the two polarizations. In many cases where it is almost impossible to obtain a colorless solu- tion for polarization in the 200-mm. tube, a loo-mm. tube may be employed, and the readings multiplied by 2, or half the normal weight,* viz., 13 grams of the sample may be taken and made up to 100 cc, the 200-mm. tube employed, and the readings multiplied by 2. The determination of sucrose by the Clerget-Herzfeld formula is applicable to all mixtures of the common sugars excepting those in which lactose, or milk sugar, is present. Theory of Inversion. — On page 586 a reaction is given showing that when sucrose is subjected to inversion by the action of dilute acids or of invertase or yeast it splits up into the two sugars dextrose and le\ailose, forming equal quantities of each. The dextrose is, however, dextro- rotatory and the levulose laevorotatory. Invert sugar is the term applied to the mixture of dextrose and levulose formed by the inversion of sucrose. The specific rotatory power of sucrose varies so little with the temperature as to be regarded for practical purposes as constant. At 87° a solution of invert sugar polarizes at zero. This is due to the fact that the rotatory power of levulose, unlike that of sucrose and dextrose, varies with the temperature. At from 87° to 88° the left-handed rotation of the levulose balances the right-handed rotation of the dextrose in the invert sugar, hence the zero reading. As the temperature decreases from 87°, the rotatory power of the levulose proportionally increases, till at 0° the normal invert sugar solution would polarize —42.66. On these facts the Cherget- Herzfeld formula is based, assuming that a normal solution of pure cane sugar polarizes + 100, while after inversion the reading for 0° temperature would be —42.66 and would decrease 0.5 for each degree in temperature above 0°. Thus at 20° the invert reading would be —32.66. Neutralization of the free acid after inversion is sometimes practiced to avoid the disturbing influence of mineral acid on the polarization of c?-fructose as well as of certain impurities present in molasses, juices, etc. * Wherever the term " normal weight " occurs hereafter will be meant, unless otherwise noted, the normal weight of sugar for the Soleil-Ventzke polariscope, viz., 26 grams, and by a " normal solution " will be meant 26 grams in 100 cc. of water at 20° C. Clerget's formula, as originally worked out by him, was not based on this normal weight, but on 16.35 grams. It is, however, applicable to 26 grams. SUGAR AND SACCHARINE PRODUCTS. 613 When neutralization is practiced the factor in the Clerget-Herzfeld formula should be 141. 7 instead of 142,66.* Neutralization, however, introduces another disturbing factor, namely sodium chloride, to counterbalance which Saillard f adds an equivalent amount of this salt to the solution used for direct polarization. The most rational system of defecating and inverting is that proposed by Deerr.| He employs for defecation barium hydroxide in conjunction with a acid reagent containing aluminum sulphate and sulphuric acid in such proportions that the two solutions neutralize each other forming aluminum hydroxide and barium sulphate. After direct polarization of the filtered solution inversion is carried on with another portion of the acid reagent, then an equivalent amount of barium hydroxide is added thus again precipitating all added substances. Detection of Invert Sugar. — Methyl-bhie TesL§ — This test depends on the decolorization of methyl blue by invert sugar. Twenty grams of sugar are dissolved in water and made up to 100 cc. If the solution is not clear, sufficient subacetate of lead solution is added to clarify before making up to the mark, and the solution is filtered. Add to the filtrate enough 10% sodium carbonate solution to make alkaline, and filter a second time. Take about 50 cc. of the filtrate in a casserole, add 2 drops of a 1% solu- tion of methyl blue, and boil over a free flame, noticing particularly the time the solution begins to boil. If the color disappears in one minute after boiling, there is present at least 0.01% of invert sugar. If it is not completely decolorized by 3 minutes' boiling, no invert sugar is present. Determination of Invert Sugar in Cane Sugar Products by the Polar- iscope. — While invert sugar is best determined by Fehling's solution as described elsewhere, it may be approximately estimated by the polari- scope, though less satisfactorily. On page 671 a method is given for the determination of levulose by polariscopic readings at two different tem- peratures. Since invert sugar is composed of equal parts by weight of dextrose and levulose, the percentage of levulose multiplied by 2 would give that of invert sugar. Test for Ultramarine in Sugar.[[ — A large amount of the sugar is dissolved in water and the coloring matter is allowed to settle out, wash- * Browne, Handbook of Sugar Analysis, New York, 1912, p. 271. t 8th Int. Cong. App. Chem., 27, 1912, p. 63. t Int. Sugar Jour., 17, 191 5, p. 179. § Wiechmann, Sugar Analysis, New York, 1914, p. no. ||Leffmann and Beam, Select Methods of Food Analysis, p. 126. 614 FOOD INSPECTION AND ANALYSIS. ing the residue several times by decantation. On treatment with hydro- chloric acid, the blue color is discharged if due to ultramarine. SUGAR DETERMINATION BY COPPER REDUCTION. Various convenient methods of determining sugars depend on the readiness with which certain of them, known as reducing sugars, act on copper salts, especially on the tartrate of copper, reducing it to cuproui- oxide. This reducing power is exercised in a definite degree under fixe " conditions, so that the amount of reducing sugar present may be accuratel determined. Of the common sugars, sucrose is the only one that has practically no dnect reducing action, but on undergoing inversion it is con- verted into reducing sugars, which are readily determined. Use of Fehling's Solution. — There are various well-known mixtures of copper sulphate, tartaric acid salts (usually Rochelle salts or cream of tartar), and alkalies, called after chemists who have employed them in the determination of the reducing sugars, each one possessing certain advantages, but none have become so widely adopted as Fehling's solu- tion, the use of which in one form or another is now well-nigh universal. There are a number of methods by which Fehling's solution is employed for this purpose, both volumetric and gravimetric. The former are simpler and quicker of manipulation, and thus are preferable for com- mercial work where extreme accuracy is not required. The gravimetric methods are usually considered more delicate and accurate, calling for less skill, but more time in arriving at results, and with less of the " per- sonal element " than the volumetric. Some modifications of the Fehling methpd, especially as carried out gravimetrically, differ for the various reducing sugars to be determined, and others are carried out alike, so far as manipulation is concerned, whether the particular sugar to be determined be dextrose, maltose, or lactose. While, strictly speaking, the reducing power of dextrose, levulose, and invert sugar are not identical, it is customary in commercial work to regard them as such, and no appreciable error arises in consequence except in extreme cases. Thus the term " reducing sugars " is com- monly applied indiscriminately to dextrose, levulose, and invert sugar, the same factor being used in calculating either, in mixtures wherein other reducing sugars, as lactose, maltose, etc., having widely different reducing powers are absent. SUGAR AND SACCHARINE PRODUCTS. 615 Fehling's solution is made up in two separate parts as follows: A. Fehling's Copper Solution. — 34.639 grams of carefully selected crystals of pure copper sulphate dissolved in water and diluted to exactly 500 cc. B. Fehling's Alkaline Tartrate Solution.— ij^ grams Rochelle salts and 50 grams sodium hydroxide are dissolved in water and diluted to exactly 500 cc. The Fehling solution should be standardized by dissolving 0.5 gram of pure anhydrous dextrose in water, and diluting to exactly 100 cc. Ten cubic centimeters of this dextrose solution should exactly reduce the copper in 10 cc. of the Fehlmg (5 cc. each of solutions A and B) when conducted according to the volumetric process described below. Volumetric Fehling Process. — For determining dextrose, levulose, or invert sugar, prepare a clarified, deleaded, and neutralized solution of the sugar of such a strength that an accurately weighed amount dissolved in water and made up to 100 cc. shall not contain more than 1% of the reducing sugar, as nearly as can be estimated with or without a rough preliminary titration. For the determination of lactose or maltose a i|% solution may be used. Measure accurately into a flask of about 250 cc, capacity 5 cc. Feh- ling's copper sulphate solution. A, and 5 cc. of the alkaline solution, B. Add about 40 cc. of water, mix and boil over a free flame, with copper gauze beneath the flask. While still boiling, add from a pipette or burette a measured quantity of the sugar solution, prepared as above, until the copper after three minutes' boiling is all reduced to cuprous oxide. The end-point is determined in a variety of ways. Practice will soon enable the eye to judge the near approach of the end- point by the changes in color that take place in the solution, which turns from a deep blue, first to green, then to a dull-red tint, and finally to a bright brick-red. The sugar- containing solution may be added from the burette quite rapidly until the solution reaches the dull-red tint, after which care is taken to add a little at a time, keeping account of the total amount added. If the flask be removed from the flame, and the bright, diffused light from a window viewed through the solution with the eye on a level with the surface, a thin film scarcely wider than a line will be observed just below the surface (see Fig. 109), which is blue so long as some of the copper in the solu- tion remains unreduced. When, however, all the copper has been reduced, this film ceases to be blue and becomes colorless or yellow. If the film is not at once apparent, it may often be made quite notice- ^ 616 FOOD INSPECTION AND ANALYSIS. able by simply diluting the solution in the flask with water. At the approach of the end-point the sugar-containing solution should be added a very little at a time. The exact end-point is best arrived at by filtering off a few drops of the liquid, acidifying the filtrate with acetic acid, and adding a drop of a solution of ferrocy- anide of potassium. As long as there is unreduced copper present, a precipitate or brown-red colora- tion will appear when the ferrocyanide is added. The testing is greatly facilitated by lowering a small filter into the liquid by means of forceps and removing a small portion of the clear solu- tion thus obtained with a medicine dropper (B. B. Ross) . The sugar solution toward the end should be added to the contents in the flask in small in- stallments (say half a cubic centimeter each time), boiling the liquor for at least three minutes after each addition, until no brown-red coloration is produced by adding the ferrocyanide to a little of the filtered acidified liquid. When the number of cubic centimeters of sugar solution necessary to reduce the copper has thus been determined, a second titration should be made to verify the first, running the entire amount of sugar-containing liquid found necessary in the first case into the second flask. The equivalents of lo cc. of the mixed alkaline copper solution in the above method are, in terms of the common reducing sugars, as follows: 0.05 gram of invert sugar, dextrose, or levulose; 0.0475 gram of cane sugar after inversion; 0.0807 gram of maltose; 0.067 gram of lactose. Suppose, for example, a sample of brown sugar is to be examined for invert sugar. This class of sugar has usually from 2 to 6 per cent of invert sugar. Hence, if 10 grams of the sample are dissolved in 100 cc, the resulting solution will contain not more than 1% of invert sugar. Suppose 12.9 cc. of this 10% sugar solution were found by the above process to reduce 10 cc. of Fehling's solution. 10 cc. Fehling's solution are equivalent to 0.05 gram i;ivert sugar. Fig. 109. — Flask and Con- tents used in Volumetric Fehling Determinations. Showing layer just be- neath the surface, the color of which indicates the end-point in adding the sugar-containing li- quid. SUGAR AND SACCHARINE PRODUCTS. 617 Therefore 12.9 cc. of the sugar solution contain 0.05 gram invert- sugar. 100 cc. sugar solution contain 10 grams sample, and 12.9 cc. contain 1.29 grams sample, the equivalent of 0.05 gram invert sugar. „ . 0.05X100 Hence per cent mvert sugar = = 3-9- GRAVIMETRIC Fehling PROCESSES.— In determining reducing sugars by gravimetric processes, a measured volume of the sugar solution is allowed to act upon a measured volume of hot Fehling's solution for a fixed time, thus forming cuprous oxide. This may be dried and weighed direct, but is more commonly converted either into cupric oxide by ignition, or into metallic copper by reduction with hydrogen or by electrolysis. In any case the sugar is calculated from the weight of the cuprous oxide, the cupric oxide, or the metallic copper (whichever method be used) by the employment of the proper factor, or by the use of tables compiled for the purpose. Note. — Much difference of opinion exists as to the best and most accurate Fehling gravimetric method to employ. For the determination of dextrose, the Association of Official Agricultural Chemists has given its approval to the AUihn method, wherein the cuprous oxide deposited is further reduced to metallic copper and the dextrose calculated from the copper by Allihn's table. The author for two reasons prefers the method of O'Sullivan as employed by Defren, with the use of the Defren tables, in accordance with which the reducing sugar is expressed in terms of its equivalence to cupric oxide, first because of its comparative simplicity, involving as it does less processes than the Allihn method (each additional process introducing a possible source of error), and, second, because the same method as carried out is applicable for the determination not only of dextrose, but also of maltose and lactose, Defren having worked out tables adopted for them all. Munsen and Walker* have also devised a simple method with accompanying tables, adapted, with a uniform system of procedure, to the determination of the various reducing sugars. In using the tables for dextrose, maltose, and lactose compiled by Allihn, Wein, and Soxhlet, the method employed must in each case be carried out in strict accordance to the minutest details adopted by each of the above authorities, and they are by no means uniform. * U. S. Dept. of Agric, Bur. of Chem., Bui. 107 (rev.), p. 241. 618 FOOD INSPECTION AND ANALYSIS. The Defren-O'Sullivan Method.* — Mix 15 cc. of Fehling's copper solution A (page 615), with 15 cc. of the tartrate solution, ^, in a quarter- liter Erlenmeyer flask, and add 50 cc. of distilled water. Place the flask and its contents in a boiling water bath and allow them to rerhain five minutes. Then run rapidly from a burette into the hot liquor in the flask 25 cc. of the sugar solution to be tested (which should contain not more than one-half per cent of reducing sugar). Allow the flask to remain in the boiling water bath just fifteen minutes after the addition of the sugar solution, remove, and with the aid of a vacuum filter the contents rapidly in a platinum or porcelain Gooch crucible containing a layer of prepared asbestos filler about i cm. thick, the Gooch with the asbestos having been previously ignited, cooled, and weighed. The cuprous oxide precipitate is thoroughly washed with boiling distilled water till the water ceases to be alkaline. The asbestos used should be of the long-fibered variety, and should be specially prepared as follows: Boil first with nitric acid (specific gravity 1.05 to i.io), washing out the acid with hot water, then boil with a 25% solution of sodium hydroxide, and finally wash out the alkali with hot water. Keep the asbestos in a wide-mouthed flask or bottle, and transfer it to the Gooch by shaking it up in the water and pouring it quickly into the crucible while under suction. Dry the Gooch with its contents in the oven, and finally heat to dull redness for fifteen minutes, during which the red cuprous oxide is con- verted into the black cupric oxide. If a platinum Gooch is used (and this variety is preferred by the writer), it may be heated directly over the low flame of a burner. If the Gooch is of porcelain, considerable care must be taken to avoid cracking the crucible, the heat being increased cautiously and the operation preferably conducted in a radiator or muffle. After oxidation as above, the crucible is transferred to a desiccator, cooled, and quickly weighed. From the milligrams of cupric oxide, calculate the milligrams of dextrose from the following table: * Jour. Am. Chem. Soc, 18, 1896, p. 749, and Tech. Quart., 10, 1897, p. 167. 1 SUGAR AND SACCHARINE PRODUCTS. 619 DEFREN'S TABLE FOR THE DETERMINATION OP DEXTROSE, MALTOSE, AND LACTOSE. Milligrams of Cupric Oxide. Milligrams Milligrams Milligrains Milligrams of Cupric O.xide. Milligrams Milligrams Milligrams of Dextrose. of Maltose. of Lactose. of De.xtrose. of Maltose. of Lactose. 3° 13.2 21-7 18.8 80 35-4 58-1 50-5 31 ^3-7 22.4 19-5 81 35-9 58-9 5I-I 32 14. 1 23.1 20.1 82 36-3 59-6 51-7 33 14.6 23-9 20.7 83 36.8 60.3 52-4 34 15-0 24.6 21.4 84 37-2 61. 1 53-0 35 15-4 25-3 22.0 85 37-7 61.8 53-6 36 15-9 26.1 22.6 86 38.1 62.5 54-3 37 16.3 26.8 23-3 87 38-5 63-3 54-9 38 16.8 27-5 23-9 88 39-0 64.0 55-5 39 17.2 28.3 24-5 89 39-4 64.7 56.2 40 17-6 29.0 25.2 90 39-9 65-5 56.8 41 18. 1 29.7 25-8 91 40.3 66.2 57-4 42 18.5 30-5 26.4 92 40.8 66.9 58-1 43 19.0 31.2 27.1 93 41.2 67.7 58-7 44 19.4 31-9 27-7 94 41.7 68.4 59-3 45 19.9 32-7 28.3 95 42.1 69.1 60.0 46 20.3 33-4 29.0 96 42.5 69.9 60.6 47 20.7 34-1 29.6 97 43-0 70.6 61.2 48 21.2 34-8 30.2 98 43-4 71-3 61.9 49 21.6 35-5 30.8 99 43-9 72.1 62.5 50 22.1 36.2 31-5 100 44-4 72.8 63-2 51 22.5 37-0 32.1 lOI 44-8 73-5 63.8 52 23.0 37-7 32-7 102 45-3 74-3 64-4 53 23 -4 38.4 33-3 103 45-7 75-0 65.1 54 23.8 39-2 34-0 104 46.2 75-7 65-7 55 24.2 39-9 34-6 105 46.6 76-5 66.3 56 24-7 40-5 35-2 106 47.0 77-2 67.0 57 25-1 41-3 35-9 107 47-5 77-9 67.6 58 25-5 42.1 36-5 108 48.0 78.7 68.2 59 26.0 42.8 37-1 109 48.4 79-4 68.9 60 26.4 43-5 37-8 no 48-9 80.1 69-5 61 26.9 44-3 38-4 III 49-3 80.9 70.1 62 27-3 45-0 39-0 112 49-8 81.6 70.8 63 27.8 45-7 39-7 "3 50.2 82.3 71-4 64 28.2 46-5 40.3 114 50-7 83.1 72.0 65 28.7 47-2 40.9 "5 51 -I 83.8 72-7 66 29.1 47-9 41.6 116 51.6 84-5 73-3 67 29-5 48.6 42.2 117 52.0 85-2 74.0 68 30.0 49-4 42.8 118 52-4 85-9 74-6 69 30-4 50.1 43-5 119 52-9 86.6 75-2 70 30-9 50.8 44-1 120 53-3 87.4 75-9 71 31-3 51.6 44-7 121 53-8 88.1 76.6 72 31.8 52-3 45-4 122 54-2 88.9 77.2 73 32.2 53-0 46.0 123 54.7 89.6 77-9 74 32.6 53-8 46.6 124 55-1 90-3 78-5 75 33-1 54.5 47-3 125 55-6 91. 1 79. r 76 33-5 55-2 47-9 126 56.0 91.8 79.8 77 34-0 56.0 48.5 127 56.5 92-5 80.4 78 34-4 56-7 49-2 128 56.9 93-3 81. 1 79 34-9 57-4 49-8 129 57-3 94-0 81.7 620 FOOD INSPECTION AND ANALYSIS. DEFREN'S TABLE FOR THE DETERMINATION OF DEXTROSE, MALTOSE, AND LACTOSE— {Continued). Milligrams of Cupric Oxide. Milligrams Milligrams Milligrams Milligrams of Cupric Oxide. Milligrams Milligrams > Milligrams of Dextrose. of Maltose. of Lactose. of Dextrose. of Maltose. of Lactose. 130 57-8 94-8 82.4 180 80.4 131-8 114. 6 1,31 58.2 95-5 83.0 181 80.8 132-5 115.2 132 58.7 96.2 83.6 182 81.3 133-2 115.8 ^33 59-1 97-0 84.2 183 81.8 134-0 116.5 134 59-6 97-7 84-9 184 82.2 134-7 117. 1 135 60.0 98-4 85-5 185 82.7 13--5 117. 8 136 60.5 99.2 86.1 186 83.1 136.2 118. 4 137 60.9 99.9 86.8 18/ 83-5 136.9 119. 1 138 61-3 100.7 87.4 188 84.0 137-7 "9-7 139 61.8 101.4 88.1 189 84-4 138.4 120.4 140 62.2 102. 1 88.7 190 84-9 139-I 121. 141 62.7 102.8 89-3 191 85-4 139-9 121. 7 142 63.1 103-5 90.0 192 85-9 140.6 122.3 143 63.6 104.3 90.6 193 86.3 141.4 123.0 144 64.0 105.0 91-3 194 86.8 142.1 123.6 145 64-5 105.8 91.9 195 87.2 142.8 124-3 146 64.9 106.5 92.6 196 87.7 143.6 124.9 147 65-4 107.2 93-2 197 88.1 144-3 125.6 148 6s. 8 108.0 93-9 198 88.6 145 -I 126.2 149 66.3 108.7 94-5 199 89.0 145-8 126.9 150 66.8 109.5 95-2 200 89-5 146.6 127.5 151 67-3 no. 2 95-8 201 89.9 147-3 128.2 152 67-7 III.O 96-5 202 90.4 148.1 128.8 153 68.3 III. 7 97-1 203 90.8 148.8 129-5 154 68.7 112. 4 97-8 204 91-3 149-6 130. 1 155 69.2 113. 2 98.4 205 91.7 150.3 130.8 156 69.6 113-9 99-1 206 92.2 151.1 131-5 157 70.0 114. 7 99-7 207 92.6 151.8 132.1 158 70-5 115-4 100.4 208 93-1 152-5 132.8 159 70.9 116. 1 101.0 209 93 -S 153-3 133-4 160 71-3 116. 9 101.7 210 94.0 154-I 134-1 161 71.8 117. 6 102.3 211 94-4 154.8 134-7 162 72-3 118. 4 103.0 212 94-9 IS5-6 135-4 163 72.7 119. 1 103.6 213 95-3 156-3 136.0 164 73-2 119. 9 104.3 214 95-8 157-1 136-7 165 73-6 120.6 104.9 215 96-3 157-8 137-3 166 74-1 121. 4 105.6 216 96.7 158.6 138.0 167 74-5 122. 1 106.2 217 97-2 159-3 138.6 168 74-9 122.9 106.9 218 97-6 160. 139-3 169 75-4 123.6 107-5 219 98.1 160.8 139-9 170 75-8 124.4 108.2 220 98.6 161.5 140.6 171 76-3 125. 1 108.8 211 99.0 162.3 141. 2 172 76.8 125.8 109-5 222 99-5 163.0 141. 9 173 77-3 126.6 no. I 223 99-9 163-7 142.5 174 77-7 127.3 110.8 224 100.4 164.5 143-2 175 78.2 128. 1 III. 4 225 100.9 165.3 143.8 176 78.6 128.8 112.0 226 101.3 166.0 144. 5 177 ^9.1 129.5 112.6 227 101.8 166.8 145-1 178 79-5 130-3 ^^3-3 228 102.2 167.5 145.8 179 80.0 131. "3-9 229 102.7 168.3 146.4 SUGAR AND SACCHARINE PRODUCTS. 621 DEFREN'S TABLE FOR THE DETERMINATION OF DEXTROSE, MALTOSE, AND -LACTOSE—iConcli'ded). Milligrams of Cupric Oxide. Milligrams Milligrams Milligrams Milligrams of Cupric Oxide. Milligrams Milligrams Milligrams of Dextrose. of Maltose. of Lactose. of Dextrose. of Maltose. of Lactose. 230 103. 1 169. 1 147-P 280 126.1 206.8 179.6 231 103.6 169.8 147-7 281 126.5 207.5 180.2 232 104.0 170.6 148.3 282 127.0 208.3 180.9 233 104 -5 171-3 149-0 283 127.4 209.0 181.5 234 105.0 172. 1 149.6 284 127.9 209.8 182.2 235 105.4 172.8 150-3 285 128.3 210.5 182.9 236 105.9 173-6 .150-9 286 128.8 211. 3 183.6 237 106.3 174-3 151. 6 287 129.3 212. 1 184.2 238 106.8 175-I 152.2 288 129.7 212.8 184.9 239 107.2 175-8 152-9 289 130.2 213.6 185.6 240 107.7 176.6 153-5 290 130.6 214-3 186.2 241 108. 1 177-3 154-2 291 131.1 215.1 186.9 242 108.6 178. 1 154.8 292 13I-5 215-9 187.6 243 109.0 178.8 155-5 293 132.0 216.6 188.2 244 109.5 179.6 156.1 294 132-5 217.4 188.9 245 109.9 180.3 156.8 295 133-0 218.2 189.5 246 no. 4 181. 1 157-4 296 133.4 218.9 190.2 247 no. 9 i8r.8 158.1 297 133-9 219.7 190.8 248 III. 3 182.6 158-7 298 134-3 220.4 191-5 249 III. 8 183-3 159-4 299 134-8 221.2 192.1 250 112. 3 184. 1 160.0 300 135-3 221.9 192.8 251 112. 7 184.8 160.7 301 135-7 222.7 193.4 252 113. 2 185-5 161. 3 302 136.2 223-5 194.1 253 "3-7 186.3 162.0 303 136.6 224.2 194.7 254 114. 1 187. 1 162.6 304 137-1 225.0 195.3 255 114. 6 187.8 163-3 305 137.6 225.8 196.0 256 115. 188.6 163.9 306 138.0 226.5 196.6 257 115-5 189.3 164.6 307 138-5 227.3 197-3 358 116. 190. 1 165.2 308 138.9 228.1 197.9 259 116. 4 190.8 165.9 309 139-4 228.8 198.6 260 116. 9 191. 6 166.5 310 139-9 229.6 199-3 261 "7-3 192.4 167.2 3" 140.3 230.4 199.9 262 117. 8 193 -I 167.8 312 140.8 231.1 200.6 263 118. 3 193-9 168.1 313 141.2 231.9 201.3 264 118. 7 194.6 169.5 314 141.7 232.7 202.0 265 119. 2 195-4 169.8 315 142.2 233.4 202.6 266 119. 6 196. 1 170.4 316 142.6 234.2 203-3 267 120. 1 196.9 171.1 317 143 -I 234.9 203.0 268 120.6 197.7 171.7 318 143.6 235-7 204.6 269 121. 198.4 172.4 319 144.0 236.5 205.3 270 121. 4 199.2 173-0 320 144-5 237.2 205.9 271 121. 9 199.9 173-7 272 122.4 200.7 174.4 273 122.8 201.5 I75-0 274 125.3 202.2 175-7 27s 123-7 203.0 176.3 376 124.2 203.7 177.0 277 124.6 204.5 177.6 278 125. 1 205 . 2 178.3 279 12^.6 206.0 T78.0 622 FOOD INSPECTION AND ANALYSIS. Munson and Walker Method.* — i. Preparation of Solutions and Asbestos. — Use the copper sulphate solution and alkaline tartrate solution as given on page 615. Prepare the asbestos, which should be the amphibole variety, by first digesting with i :3 hydrochloric acid for t\A o or three days. Wash free from acid, and digest for a similar period with soda solution, after which treat for a few hours with hot alkaline copper tartrate solution of the strength employed in sugar determinations. Then wash the asbestos free from alkali, finally digest with nitric acid for several hours, and after washing free from acid, shake with water for use. In preparing the Gooch crucible, load it with a film of asbestos one-fourth inch thick, wash this thoroughly with water to remove fine particles of asbestos; finally wash with alcohol and ether, dry for thirty minutes at 100° C, cool in a desiccator and weigh. It is best to dissolve the cuprous oxide with nitric acid each time after weighing, and use the same felts over and over again, as they improve with use. 2. Process. — Transfer 25 cc. each of the copper and alkaline tartrate solutions to a 400-cc. Jena or Non-sol beaker, and add 50 cc. of reducing sugar solution, or, if a smaller volume of sugar solution be used, add water to make the final volume 100 cc. Heat the beaker upon an asbestos gauze over a Bunsen burner, so regulate the flame that boiling begins in four minutes, and continue the boiling for exactly two minutes. Keep the beaker covered with a watch-glass throughout the entire time of heating. Without diluting, filter the cuprous oxide at once on an asbestos felt in a porcelain Gooch crucible, using suction. Wash the cuprous oxide thoroughly with water at a temperature of about 60° C., then with 10 cc. of alcohol, and finally with 10 cc. of ether. Dry for thirty minutes in a water oven at 100° C., cool in a desiccator and weigh as cuprous oxide. The number of milligrams of copper reduced by a given amount of reducing sugar differs when sucrose is present and when it is absent. In the tables on pages 623 to 631 the absence of sucrose is assumed, except in the two columns under invert sugar, where one for mixtures of invert sugar and sucrose (0.4 gram of total sugar in 50 cc. of solution), and one for invert sugar and sucrose when the 50 cc. of solution contains 2 grams of total sugar are given, in addition to the column for invert sugar alone. * Jour. Am. Chem. Soc, 28, 1906, p. 163; 29, 1907, p. 541; U. S. Dept. Agric, Bur. of Chem., Bui. 107 (rev.), p. 241; Circ. 82. SUGAR AND SACCHARINE PRODUCTS. 623 MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSE. [Weights in milligrams.] Invert Sugar o and Sucrose. Lactose. Maltose. 3 3 o (U •o O 'a ^ X + d X + d X + 3 s a 3 u d X i X 6 6 6 6 Si X 6 d 1 a • 10 8.9 4.0 4.5 1.6 3.8 3.9 4.0 5.9 6.2 10 II 9.8 4.5 S-o 2 . 1 4.S 4.6 4-7 6.7 7.0 II 13 10.7 4.9 5-4 2.5 5.1 5.3 5.4 7.5 7.9 12 13 ii-S 5.3 5.8 3.0 5.8 5.9 6.1 8.3 8.7 13 14 12.4 5.7 6.3 3.4 6.4 6.6 6.8 9.1 95 14 IS 13-3 6.2 6.7 3.9 7-1 7.3 7.S 9.9 10. 4 IS i6 14-2 6.6 7.2 4.3 7.8 8.0 8.2 10.6 II. 2 16 17 IS-I 7.0 7.6 4.8 8.4 8.6 8.9 II. 4 12 .0 17 i8 16 .0 7.5 8.1 5-2 9.1 9.3 9-5 12 . 2 12.9 18 19 16.9 7.9 8.5 5.7 9.7 10. 10.2 13.0 13.7 19 ao 17.8 8.3 8.9 6.1 10.4 10.7 10.9 13.8 14.6 20 31 18.7 8.7 9.4 6.6 n.o II. 3 II. 6 14.6 15.4 21 32 I9S 9.2 9.8 7.0 II. 7 12.0 12.3 15.4 16. 2 32 23 20 . 4 9.6 10.3 7.5 12.3 12.7 13.0 16.2 17.1 23 24 21.3 10. 10.7 7.9 13.0 13.4 13.7 17.0 17.9 24 as 22 . 2 10, s 1 1 . 2 8.4 13.7 14.0 14.4 17.8 18.7 25 a6 23.1 10. 9 II .6 8.8 14.3 14.7 IS. I 18.6 19.6 26 27 24 . 11-3 12.0 9.3 15.0 15.4 15.8 19.4 20 . 4 27 28 24.9 II. 8 12.5 9-7 15.6 16. I 16. s 20. 2 21.2 28 29 25. 8 12.2 12.9 10 . 2 16.3 16.7 17. 1 21.0 22 . 1 29 30 26.6 12.6 13.4 10.7 4.3 16.9 17.4 17.8 21.8 32.9 30 31 27.5 13.1 13.8 1 1 . I 4.7 17.6 18. I 18. s 22.6 23-7 31 32 28.4 13.5 14.3 II. 6 5.2 18.3 18.7 19.2 23.3 24. 6 32 33 293 13.9 14.7 12 .0 5.6 18.9 19.4 19.9 24.1 25.4 33 34 30.2 14.3 IS. 2 12. s 6.1 19.6 20. I 20.6 24.9 26. 2 34 35 311 14.8 15.6 12.9 6.5 20.2 20.8 21.3 25.7 27. 1 35 36 32.0 15-2 16. 1 13.4 7.0 20.9 21.4 22.0 26. s 27.9 36 37 32.9 15.6 16. s 13.8 7.4 21.5 22. I 22.7 27-3 28.7 37 38 33-8 16. I 16.9 14.3 7.9 22.2 22.8 23.4 28.1 29.6 38 39 34-6 16. s 17.4 14.7 8.4 22.8 23. 5 24.1 28.9 30.4 39 40 35-5 16.9 17.8 15.2 8.8 23.5 24.1 24.8 29.7 31.3 40 41 36.4 17.4 18.3 15.6 9.3 24.2 24.8 25.4 30. 5 32.1 41 42 37-3 17.8 18.7 16. 1 9.7 24.8 25. S 26. 1 31.3 32.9 42 43 38.2 18.2 19. 2 16.6 10. 2 25.5 26.2 26.8 32.1 33.8 43 44 391 18.7 19 .6 17.0 10.7 26. 1 26.8 27.5 32.9 34.6 44 4S 40.0 19. 1 20. 1 17.5 II . I 26.8 27.5 28.2 33.7 35-4 45 46 40.9 19.6 20. s 17.9 II. 6 27.4 28.2 28.9 34.4 36.3 46 47 41.7 20.0 21.0 18.4 12.0 28.1 28.9 29.6 35.2 37.1 47 48 42 .6 20. 4 21.4 18.8 12. S 28.7 29.5 30.3 36.0 37.9 48 49 43-5 20.9 21.9 19-3 12.9 29.4 30.2 31.0 36.8 38.8 49 SO 44-4 21.3 22.3 • 19.7 13.4 30.1 30.9 31.7 37-6 39.6 SO SI 45-3 21 .7 22.8 20. 2 13.9 30.7 31.5 32.4 38.4 40.4 51 S2 46. 2 22 . 2 23.2 20. 7 14.3 31.4 32.2 33.0 39.2 41.3 52 S3 47-1 22.6 23.7 21 . 1 14.8 32.1 32.9 33.7 40.0 42. I 53 54 48.0 23.0 24.1 21.6 15.2 32.7 33.6 34-4 40.8 42.9 54 55 48.9 23. 5 24.6 22 .0 15.7 33.4 34-3 35-1 41 .6 43.8 55 56 49-7 23.9 25.0 22. s 16.2 34.0 34.9 35.8 42.4 44.6 S6 57 SO. 6 24.3 25.5 22.9 16.6 34.7 35.6 36.5 43.2 45.4 57 58 51-5 24.8 25-9 23.4 17. 1 35.4 36.3 37.2 44.0 46.3 58 59 52.4 25.2 26.4 23.9 17.5 36.0 37.0 37.9 44.8 47.1 59 60 53-3 25 .6 26.8 243 18.0 36.7 37.6 38.6 45.6 48.0 60 61 62 63 54.2 26.1 27.3 24.8 18. 5 37.3 38.3 39.3 46.3 48.8 61 55-1 26. 5 27.7 25.2 18.9 38.0 39.0 40.0 47-1 49-6 62 56.0 27.0 28.2 25-7 19.4 38.6 39.7 40.7 47.9 50.5 63 64 56.8 27.4 28.6 26.2 19.8 39.3 40.3 41.4 48.7 51.3 64 624 FOOD INSPECTION AND ANALYSIS. MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, SUGAR, LACTOSE, AND MALTOSE— (Continued). [Weights in milligrams.] INVERT o 3 Invert Sugar and Sucrose. Lactose. Maltose. d 5I O 0) a' d u eo 3 tn — 1- d X + d + d X + V •0 ■>< 3 i 3 O w. S 2 S, GS, 6 d d d 3 4-> Q 0^ 6 6 !3 S3 X X 6 ?! s a 3 6S 57-7 27.8 29. 1 26.6 20.3 40.0 41.0 42.1 49.5 52.1 6S 66 S8.6 28.3 29s 27.1 20.8 40.6 41.7 42.8 50.3 S3.0 66 67 59. S 28.7 30.0 27-5 21.2 41.3 42.4 43-5 51. 1 S3. 8 67 68 60. 4 29. 2 30.4 28.0 21.7 41.9 43.1 44.2 51.9 54.6 68 69 61.3 29.6 30.9 28. 5 22 .2 42.6 43.7 44-8 52-7 S5.5 69 70 62.2 30.0 313 28.9 22 .6 43.3 44.4 45. 5 S3. 5 56.3 70 71 63.1 30.5 31.8 29.4 231 43.9 45. 1 46.2 54. 3 57. I 71 72 64.0 30.9 32.3 29.8 23-5 44.6 45.8 46.9 55.1 58.0 72 73 64.8 314 32.7 30.3 24.0 45. 2 46.4 47.6 55. 9 S8.8 73 74 6S-7 31.8 33-2 30.8 24.5 45. 9 47.1 48.3 56.7 59.6 74 7S 66.6 32.2 33.6 31-2 24.9 46.6 47.8 49.0 57. 5 60. 5 75 76 67. S 32.7 34-1 31.7 25-4 47.2 48.5 49.7 58.2 61.3 76 77 68.4 33 -^ 345 321 25.9 47.9 49.1 SO. 4 59.0 62.1 77 78 69 -3 33-6 350 32.6 26.3 48. 5 49.8 51. 1 59.8 63.0 78 79 70.2 34-0 35.4 33-1 26.8 49.2 SO. 5 51.8 60.6 63.8 79 80 71. 1 34-4 35-9 33 5 27-3 49.9 51.2 52. S 61 .4 64.6 80 81 71.9 34.9 36.3 34.0 27.7 SO. 5 SI. 9 53.2 62.2 6S.5 81 82 72.8 35-3 36.8 34-5 28.2 SI.2 52. S 53.9 63.0 66.3 82 83 73-7 35-8 37-3 34-9 28.6 SI. 8 53.2 54.6 63.8 67.1 83 84 74.6 36.2 37-7 35-4 29.1 S2.5 S3. 9 553 64.6 68.0 84 8S 75-5 36.7 38.2 35-8 29.6 S3. 1 54.6 56.0 65.4 68.8 85 86 76.4 37-1 38.6 36.3 30.0 S3. 8 55.2 S6.6 66.2 69.7 86 87 77-3 37-5 39-1 36.8 30. 5 54-5 55.9 S7.3 67 .0 70.5 87 88 78.2 38.0 39-5 37-2 310 SS. I S6.6 S8.o 67.8 71.3 88 89 79.1 38.4 40.0 37-7 31-4 55.8 57.3 58. 7 68.5 72.2 89 90 79-9 38.9 40.4 38.2 319 S6.4 58.0 59.4 69.3 73.0 90 91 80.8 39.3 40.9 38.6 32.4 57.1 58.6 60. 1 70.1 73.8 91 92 81.7 39-8 41.4 39-1 32.8 57.8 59-3 60.8 70.9 74-7 92 93 82.6 40.2 41.8 39.6 33.3 S8.4 60.0 61. S 71.7 75.5 93 94 83. S 40.6 42.3 40.0 33.8 59. I 60.7 62.2 72. 5 76.3 94 9S 84.4 41. 1 42.7 40.5 34.2 59.7 61.3 62.9 73.3 77.2 95 96 85.3 41. 5 43.2 41 .0 34-7 60.4 62.0 63.6 74.1 78.0 96 97 86.2 42 .0 43.7 41 .4 35-2 61. I 62.7 64.3 74.9 78.8 97 98 87.1 42.4 44.1 41.9 35.6 61.7 63.4 65.0 75. 7 79.7 98 99 87.9 42 .9 44.6 42.3 36.1 62.4 64.0 65.-' 76. 5 80. s 99 100 88.8 43-3 4SO 42.8 36.6 63.0 64.7 66.4 77.3 81.3 100 101 89.7 43-8 45.5 43-3 37.0 63.7 65.4 67.1 78.1 82.2 lOI 102 90.6 44.2 46.0 43.8 37. S 64.4 66.1 67.8 78.8 83.0 102 103 91. S 44.7 46.4 44.2 38.0 65.0 66.7 68. s 79.6 83.8 103 104 92.4 45-1 46.9 44.7 38.5 65.7 67.4 69.1 80.4 84.7 104 los 93-3 45-5 47.3 45-2 38.9 66.4 68.1 69.8 81.2 85.5 105 106 94.2 46 . 47-8 45-6 39.4 67.0 68.8 70.5 82.0 86.3 106 107 9.S.O 46.4 48.3 46. I 39-9 67.7 69.5 71.2 82.8 87.2 107 108 9S-9 46.9 48.7 46.6 40.3 68.3 70. I 71.9 83.6 88.0 108 109 96.8 47-3 49.2 47.0 40.8 69.0 70.8 72.6 84.4 88.8 1 09 no 97-7 47.8 49-6 47.5 41.3 69.7 71.5 73.3 85.2 89.7 no III 98.6 48.2 SO. I 48.0 41.7 70.3 72.2 74.0 86.0 90.5 III 112 99-5 48.7 SO. 6 48.4 42.2 71 .0 72.8 74.7 86.8 91.3 112 113 100. 4 49-1 5I.O 48.9 42.7 71.6 73. 5 734 87.6 92.2 113 114 101.3 49.6 51-5 49-4 43.2 72.3 74.2 76.1 88.4 93.0 114 "5 102 . 2 50.0 SI. 9 49.8 43.6 73.0 74.9 76.8 89.2 93.9 IIS 116 103.0 SO. 5 52.4 50.3 44.1 73.6 75.6 77-5 90.0 94.7 116 H7 103.9 50.9 52.9 SO. 8 44.6 74.3 76.2 78.2 90.7 95.5 117 118 104.8 51.4 53-3 51.2 45.0 75-0 76.9 78.9 91-5 96.4 118 119 105.7 SI.8 53.8 SI. 7 45. S 75.6 77.6 79.6 92.3 97.2 119 SUGAR AND SACCHARINE PRODUCTS. 625 MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSE— (Continued). [Weights in milligrams.] o Invert Sugar and Sucrose. Lactose. Maltose. 3 3 o Q a "rt ^^ d u O '3 u n! 3 C/3 2 X + X + •f V} 3 i-i =5 rt 6 ? 6 d 6 d d fl (U ij Ih 0^ rt 5? a n a Si 13 p u P. 3 0. a 0) > C 3 0^ K X 2 ffi X X Ih a 3 O Q 6 " CJ C 6 I20 106.6 52.3 54.3 52.2 46.0 76.3 78.3 80.3 93 I 98.0 120 121 107.5 52.7 54-7 52.7 46.5 76.9 79.0 81.0 93-9 98.9 121 122 108.4 53-2 55-2 S3 -I 46.9 77.6 79.6 81.7 94-7 99-7 123 123 109.3 53-6 SS-7 53.6 47.4 78.3 80.3 82.4 95-5 TOO. 5 123 124 no. I S4-I S6.i 54-1 47-9 78.9 81.0 83.1 96.3 lOI . 4 124 I2S I II .0 54-5 56.6 54-5 48.3 79-6 81.7 83.8 97 I 102 . 2 12s 126 1 1 1 .9 55-0 57-0 SS-o 48.8 80.3 82.4 84-s 97-9 103.0 126 127 112. 8 55-4 57-5 SS-S 49-3 80.9 83.0 8s. 2 98.7 103.9 127 128 II3-7 55-9 58.0 SS-9 49.8 81.6 83-7 8S.9 99-4 104.7 128 12 9 114. 6 56.3 58.4 56.4 50.2 82.2 84-4 86.6 lOO. 2 I05-S 129 130 iiS-S 56.8 58.9 56.9 SO-7 82.9 8S.1 87.3 lOI .0 106.4 130 131 116.4 57-2 59-4 57-4 51-2 83.6 85.7 88.0 IOI.8 107 . 2 131 132 117. 3 57-7 59-8 S7-8 51-7 84.2 86.4 88.7 102 .6 108.0 132 133 118. I 58.1 60.3 58-3 S2-I 84.9 87.1 89.4 103 -4 108.9 133 134 1190 S8.6 60.8 S8.8 52-6 85.5 87.8 90. 1 104.2 109-7 134 13s 119. 9 59-0 61.2 59-3 S3-I 86.2 88.5 90.8 105.0 no. 5 135 136 120.8 59-5 61.7 59-7 53-6 86.9 89- I 91.5 105.8 III .4 136 137 121 . 7 60.0 62.2 60. 2 54-0 87-S 89.8 92.1 106 .6 112 . 2 137 138 122 .6 60.4 62.6 60. 7 54-5 88.2 90. S 92.8 107.4 113 -0 138 139 123-5 60.9 63.1 61 . 2 55-0 88.9 91.2 93 5 108.2 113-9 139 140 124-4 61.3 63.6 61.6 SS-S 89. S 91.9 94-2 109.0 114-7 140 141 125.2 61.8 64.0 62.1 55-9 90. 2 92. 5 94-9 109. 8 115-5 141 142 126. 1 62.2 64. 5 62.6 56-4 90.8 93-2 95-6 110.5 1 16. 4 142 143 127.0 62.7 65-0 63.1 56-9 9I-S 93.9 96.3 III. 3 117. 2 143 144 127.9 63.1 65-4 63-5 57-4 92.2 94-6 97.0 112 . 1 118. 144 145 128.8 63-6 65-9 64.0 S7-8 92.8 95-3 97.7 112 .9 118.9 I4S 146 129.7 64.0 66.4 64-5 s8-3 93 S 95-9 98.4 113-7 119-7 146 147 130.6 64. 5 66.9 65.0 58.8 94-2 96.6 99.1 114-S 120. 5 147 148 131-5 65.0 67-3 65-4 59-3 94-8 97-3 99.8 115-3 121 .4 148 149 132.4 65-4 67.8 6s-9 59-7 95-5 98.0 100. s 116. 1 122 . 2 149 ISO 133-2 65-9 68.3 66.4 60.2 96. 1 98.7 I0I.2 116. 9 123.0 150 ISI 134-1 66.3 68.7 66.9 60.7 96.8 99.3 101.9 117-7 123-9 151 152 I3S-0 66.8 69. 2 67-3 61 .2 97.5 100. 102.6 118. 5 124-7 152 153 135-9 67.2 69-7 67.8 61.7 98.1 100.7 103.3 119-3 125-5 153 154 136.8 67.7 70.1 68.3 62.1 98.8 IOI.4 104.0 120.0 126. 4 154 ISS 137-7 68.2 70.6 68.8 62.6 99-5 102 . I 104.7 120.8 127.2 15s 156 138.6 68.6 71-1 69 . 2 63-1 100. I 102.8 105.4 121 .6 128.0 156 157 139-5 69. 1 71.6 69.7 63-6 100.8 103-4 106. I 122.4 128.9 157 158 140.3 69-5 72.0 70.2 64. 1 lOi.S 104. 1 106.8 123.2 129-7 158 IS9 141 . 2 70.0 72. S 70.7 64-S 102. 1 104.8 107. 5 124.0 130. 5 159 160 142 . 1 70.4 73-0 71.2 65.0 102.8 105.5 108.2 124.8 131-4 160 161 143-0 70.9 73-4 71.6 65-5 103-4 106.2 108.9 125.6 132.2 i6r 162 143-9 71.4 73-9 72.1 66.0 104. I 106.8 109.6 126. 4 133-0 162 163 144-8 71.8 74-4 72.6 66.5 104.8 107. 5 no. 3 127.2 133-9 163 164 145-7 72.3 74-9 73-1 66.9 105 -4 108.2 III.O 128.0 134-7 164 i6s 146.6 72.8 75-3 73-6 67.4 106. 1 108.9 III. 7 128.8 I3S-S i6s 166 147-5 73-2 75-8 74.0 67-9 106.8 109.6 112. 4 129.6 136-4 166 167 148.3 73-7 76.3 74-S 68.4 107.4 no. 3 113. 1 130.3 137-2 167 168 149.2 74-1 76.8 7S-0 68.9 108. i no. 9 1138 1311 13G-0 168 169 150.1 74.6 77.2 75-5 69 -3 108.8 III. 6 114-5 131. 9 138.9 169 170 151 -0 75-1 77-7 76.0 69.8 109.4 112. 3 IIS-2 132.7 139-7 170 171 151-9 75-5 78.2 76.4 70.3 no. I 113. llS-9 133-5 140-5 171 172 152.8 76.0 78.7 76.9 70.8 no. 8 113. 7 116. 6 134.3 141-4 17a 173 153-7 76.4 79 I 77.4 71-3 III. 4 114-3 117. 3 I3S-I 142 . 2 ^73 174 154.6 76.9 79-6 77-9 71.7 112. 1 nS.o 118. 135-9 143-0 174 626 FOOD INSPECTION AND ANALYSIS. MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSE— (Continued). [Weights in milligrams.] o Invert Sugar and Sucrose. Lactose. Maltose. 5 3 3 "(3 d d d V 3 "5 is 4-) B t5 6 + 6 X + d q + d •a 3 O f2 E 3 w W K 1 K a 3 o Q d « 6 6 u d 175 IS5-5 77-4 80.1 78.4 72.2 112. 8 IIS. 7 118. 7 136.7 143-9 175 176 1S6.3 77-8 80.6 78.8 72.7 113. 4 116. 4 119.4 137.5 144.7 176 177 IS7-2 78.3 81.0 79-3 73-2 114. 1 117. 1 120. 1 138.3 I4S-S 177 178 158. I 78.8 81.5 79-8 73-7 114. 8 117. 8 120.8 I39-I 146.4 178 179 IS9-0 79-2 82.0 80.3 74-2 IIS. 4 118. 4 121. S 139-8 147.2 179 180 IS9-9 79-7 82.5 80.8 74.6 116. 1 119. 1 122.2 140.6 148.0 180 i8i 160.8 80.1 82.9 81.3 75-1 116.7 119. 8 122 .9 I4I-4 148.9 181 182 161 . 7 80.6 83-4 81.7 75-6 117. 4 120. s 123.6 142 .2 149-7 182 183 162.6 81. 1 83.9 82.2 76.1 118. 1 121 . 2 124.3 143-0 150.5 183 184 163.4 81.5 84-4 82.; 76.6 118. 7 121. 8 125.0 143-8 151-4 184 i8s 164.3 82.0 84-9 83.2 77-1 119. 4 122. s 125-7 144.6 152.2 185 186 165.2 82.5 8S-3 83-7 77.6 120. 1 123 . 2 126.4 145-4 IS3-0 186 187 166. 1 82.9 85.8 84.2 78.0 120.7 123.9 127.1 146. 2 153-9 187 188 167 .0 83-4 86.3 84.6 78.5 121. 4 124. 6 127.8 147-0 154-7 188 189 167.9 83-9 86.8 85.1 79-0 122. 1 125. 3 128.5 147-8 155-5 189 190 168.8 84.3 87.2 85.6 79-5 122.7 125.9 129.2 148.6 156.4 190 191 169. 7 84.8 87-7 86.1 80.0 123.4 126.6 129.9 149-3 157-2 191 192 170. S 85-3 88.2 86.6 80.5 124. I 127.3 130.6 150. I 158.0 192 193 171-4 85-7 88.7 87.1 81.0 124.7 128.0 131.3 150.9 158.9 193 194 172.3 86.2 89.2 87.6 81.4 125.4 128.7 132.0 151-7 159-7 194 19s 1732 86.7 89.6 88.0 81.9 126. 1 129.4 132.7 152.5 160.5 195 196 174. I 87.1 90 . 1 88.5 82.4 126. 7 130.0 133.4 153-3 161 . 4 196 197 175.0 87.6 90.6 89.0 82.9 127.4 130.7 134-1 154-1 162 . 2 197 198 175-9 88.1 91. 1 89 -5 83-4 128. I 131.4 134-8 154.9 163 .0 198 199 176.8 88.5 91.6 90.0 83 -9 128.7 132. I I35S 155-7 163.9 199 200 177-7 89.0 92 .0 90.5 84-4 129.4 132.8 136.2 156.5 164.7 200 201 178. 5 89.5 92.5 91 .0 84.8 130.0 133. 5 136.9 IS7-3 165.5 201 202 179-4 89.9 93-0 91.4 85-3 130.7 134- I 137.6 158. I 166. 4 202 203 180.3 90.4 93-5 91.9 85-8 131. 4 134-8 138.3 158.8 167 . 2 203 204 181. 2 90.9 94.0 92.4 86.3 132.0 I3S-S 139.0 159-6 168.0 204 20s 182. 1 91.4 94-5 92.9 86.8 132.7 136.2 139.7 160.4 168.9 205 206 183.0 91.8 94-9 93-4 87.3 133.4 136.9 140.4 161 . 2 169.7 206 207 183.9 92-3 95-4 93-9 87.8 1340 137.6 141. I 162 .0 170.5 207 208 184.8 92.8 95-9 94-4 88.3 134-7 138.3 141. 8 162.8 171.4 208 209 185.6 93-2 96.4 94-9 88.8 13s -4 138.9 142. 5 163.6 172.2 209 210 186.5 93-7 96.9 95-4 89.2 136.0 139.6 143.2 164.4 1730 210 211 187.4 94.2 97-4 95-8 89.7 136.7 140.3 143.9 165.2 173-8 211 ZI2 188.3 94.6 97-8 96.3 90. 2 137-4 141 . 144.6 166.0 174-7 212 213 189.2 95-1 98.3 96.8 90.7 138.0 I4I-7 1453 166.8 175-5 213 214 190. 1 95-6 98.8 97-3 91.2 138.7 142.4 146.0 167-5 176.4 214 21S 191 .0 96 . 1 99.3 97-8 91.7 139-4 143 146.7 168.3 177.2 215 216 191 .9 96.5 99-8 98.3 92 . 2 140.0 143-7 147.4 169. 1 178.0 216 217 192.8 970 100.3 98.8 92.7 140.7 144.4 148.1 169.9 178.9 217 218 193-6 97-5 100.8 99-3 93-2 14I-4 145. I 148.8 170.7 179-7 218 219 194-S 98.0 lOI .2 99-8 93-7 142.0 145.8 149.5 I7I-5 180.5 219 220 195-4 98.4 lOI . 7 100 . 3 94-2 142.7 146. 5 150.2 172.3 181.4 220 221 196.3 98.9 102 . 2 100.8 94-7 143.4 147.2 150.9 173-I 182.2 221 222 197.2 99-4 102 . 7 lOI . 2 95-1 144.0 147.8 15I-6 173-9 183.0 222 223 198. I 99-9 103.2 loi . 7 95-6 144.7 148. S 152.3 174-7 183.9 223 224 199.0 100.3 103-7 102 . 2 96. I 145.4 149.2 153. 175-5 184-7 224 225 199 9 100.8 104. 2 102 . 7 96.6 146.0 149.9 153.7 176.2 185. 5 22s 226 200. 7 loi .3 104.6 103.2 97-1 146.7 150.6 IS4-4 177.0 186.4 226 227 201 .6 101.8 105. I 103.7 97.6 147.4 151.3 iSS-i 177-8 187.2 227 228 202 . 5 102 . 2 105 . 6 104 . 2 98.1 148.0 152.0 ISS.8 178.6 188.0 218 329 203.4 102 . 7 106. 1 104.7 98.6 148.7 152.6 156.5 179-4 188.8 229 SUGAR AND SACCHARINE PRODUCTS. 627 MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSE— (Continued). [Weights in milligrams.] o Invert Sugar and Sucrose Lactose. Maltose. q 3 3 o d (U H __ d d V 13 o 3 i d + X + •0 3 u ta 0! B "1 6 6 d d 3 01 , h '^^ rt M fj 5! a *! 3 a a > 3 £ 3 ffi w m X ffi a 3 o Q 103 . 2 d « CJ 6 CJ u ■ 230 204.3 106.6 105.2 99-1 149.4 IS3.3 157.2 180.2 189.7 230 231 20s . 2 103-7 107 . 1 ioS-7 99-6 150.0 154.0 157.9 181. 190.5 231 232 206. 1 104. 1 107 .6 106. 2 100. 1 150.7 154.7 158.6 181. 8 191. 3 232 233 207 .0 104.6 108. I 106. 7 100. 6 151.4 155.4 159.3 182.6 192 . 2 233 234 207.9 los- J 108.6 107 . 2 lOI . 1 152.0 156. 1 160.0 183.4 193-0 234 235 208.7 105 .6 109. 1 107.7 loi .6 152.7 156.7 160.7 184.2 193-8 235 236 209. 6 106 .0 109.5 108.2 102 . 1 153.4 157.4 161 .4 184.9 194-7 236 237 210.5 106.5 I lO.O 108.7 102 .6 154.0 158.1 162. 1 185.7 195-5 237 238 21 1 . 4 107 .0 iio.s 109. 2 103. 1 154.7 158.8 162.8 186.5 196.3 238 239 212.3 I07-S I II .0 109.6 103-5 155.4 159-S 163. 5 187.3 197.2 239 240 213.2 108.0 III. 5 1 10 . I 104.0 156. 1 160.2 164.3 188. 1 198.0 240 241 214. 1 108.4 112 .0 1 10.6 104.5 156.7 160.9 165.0 188.9 1 98. 8 241 242 21 >; .0 108.9 112. 5 III . I 105.0 157.4 161. 5 165.7 189.7 199.7 242 243 215.8 109.4 113. III . 6 105-5 158. 1 162.2 166.4 190.5 200. 5 243 244 216.7 109.9 113. S 112 . 1 106.0 158.7 162.9 167 . 1 191.3 201.3 244 24s 217.6 no. 4 114. 1 12 . 6 106. 5 159.4 163.6 167.8 192. 1 202 . 2 245 246 218. 5 no. 8 114. 5 113. 1 107 .0 160. 1 164.3 168. 5 192.9 203.0 246 247 219.4 III. 3 115.0 113-6 107.5 160.7 165.0 169.2 193-6 203.8 247 248 220.3 III. 8 ilS-4 114. 1 108.0 161 .4 165-7 169.9 19.4.4 204.7 248 249 221.2 112. 3 iiS-9 114. 6 108. 5 162. 1 166.3 170.6 195-2 205.5 249 250 222.1 112. 8 116. 4 115.1 109.0 162.7 167.0 171-3 196.0 206.3 250 251 223 .0 113. 2 116. 9 115. 6 109.5 163.4 167-7 172.0 196.8 207 . 2 251 252 223.8 113-7 117. 4 116 . 1 IIO.O 164. 1 168.4 172.7 197.6 208.0 252 2S3 224.7 114. 2 117. 9 116. 6 110.5 164.7 169- 1 173-4 198.4 208.8 253 2S4 225.6 114. 7 118. 4 117. 1 1 1 1 .0 165.4 169-8 174-1 199.2 209.7 254 25s 226. 5 115-2 118. 9 117 .6 III. 5 166. 1 170.5 174-8 200.0 210.5 255 256 227.4 liS-7 119-4 118. 1 112.0 166.8 171.1 175-5 200. 8 211.3 256 257 228.3 116. 1 119. 9 118. 6 112. 5 167.4 171.8 176.2 201 .6 212.2 257 2S8 229.2 116. 6 120. 4 119. 1 113-0 168. 1 172.5 176.9 202.3 213.0 258 259 230.1 117. 1 120.9 119. 6 113-5 168.8 173.2 177.6 203.1 213.8 259 260 231 .0 117 . 6 121. 4 120. 1 114.0 169.4 173-9 178.3 203.9 214.7 260 261 231.8 118. 1 121 . 9 120.6 114.5 170. 1 174-6 179.0 204.7 215.5 261 262 232.7 118. 6 122 .4 121 . 1 115-0 170.8 175-3 179.8 205.5 216.3 262 263 2336 119. 122.9 121 .6 115-S 171.4 176.0 180. 5 206.3 217.2 263 264 234-S 119-S 123-4 122 . 1 116. 172. 1 176.6 181. 2 207 . 1 218.0 264 265 235-4 120 .0 123-9 122.6 116.5 172.8 177-3 181. 9 207.9 '218.8 26s 266 236.3 120. 5 124.4 123. 1 117.0 173. 5 178.0 182.6 208.7 219.7 266 267 237.2 121 .0 124.9 123.6 117-5 174. I 178.7 183.3 209.5 220.5 267 268 238.1 121 . 5 125-4 124. 1 118. 174-8 179-4 184.0 210.3 221.3 268 269 238.9 122 .0 125-9 124.6 118.5 175.5 180.1 184.7 211 .0 222 . 1 269 270 239.8 122 . 5 126.4 125. 1 119.0 176. 1 180.8 185.4 211. 8 223.0 270 271 240.7 122.9 126.9 125.6 119. 5 176.8 181. 5 186. I 212.6 223.8 271 272 241 .6 123-4 127.4 126.2 120.0 177. 5 182.1 186.8 213.4 224 .6 272 273 242.5 123-9 127.9 126. 7 120.6 178. I 182.8 187.5 214.2 225.5 273 274 243-4 124.4 128.4 127.2 121 . 1 178.8 183. 5 188.2 215.0 226.3 274 275 244-3 124.9 128.9 127.7 121 .6 179.5 184.2 188.9 215.8 227.1 27S 276 245.2 125.4 129.4 128.2 122 . 1 180.2 184.9 189.6 2^6.6 228.0 276 277 2,46. I 125-9 129.9 128.7 122.6 180.8 185.6 190.3 217.4 228.8 277 278 246.9 126.4 130.4 129.2 123. 1 181. 5 186.3 191 .0 218.2 229.6 278 279 247-8 126.9 130.9 129.7 123.6 182.2 187.0 191.7 218.9 230-5 279 280 248.7 127.3 131-4 130.2 124.1 182.8 187-7 192.4 219.7 231-3 280 281 249.6 127.8 131-9 130.7 124.6 183. 5 188.3 193.1 220.5 232-1 281 282 250. S 128.3 1-3 2-4 131 .2 125.1 184.2 189.0 193.9 221 .3 233-0 282 283 251-4 128.8 132-9 131-7 125.6 184.8 189.7 194.6 222.1 233-8 283 284 252-3 129.3 133-4 132.2 126. 1 185.5 190.4 195-3 222 .9 234.6 284 628 FOOD INSPECTION AND ANALYSIS. MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MAL,TOSE— (Continued). [Weights in millign-ams.] o Invert Sugar and Sucrose. Lactose. Maltose. 3 3 o V "(3 ^^ d d Q> •a O 'a u u a 00 6 + 6 + + 6 •a 3 o V u 1-1 0^ 6 rt 5P u » Si 8 a t-i a O 0, a i Q > E 3 1 6 6 u 0. a 285 253-2 129.8 133-9 132.7 126.6 186.2 191. 1 196.0 223.7 235-5 28s 286 254-0 130.3 134-4 133-2 127. 1 186.9 191. 8 196.7 224.5 236.3 286 287 254-9 130.8 134-9 133-7 127 .6 187. s 192. S 197-4 225.3 237.1 287 288 2SS-8 131-3 135-4 134-3 128.1 188.2 193-2 198. I 226. 1 238.0 288 389 256.7 131-8 135-9 134-8 128.6 188.9 193.8 198.8 226.9 238.8 289 ago 257-6 132.3 136.4 I3S-3 129.2 189. s 194. S 199.5 227.6 239.6 290 291 258. 5 132.7 136-9 135-8 129-7 190.2 195-2 200. 2 228.4 240.5 291 292 259-4 133-2 137-4 136-3 130.2 190.9 195-9 200.9 229. 2 241.3 292 293 260.3 133-7 137-9 136.8 130.7 I9IS 196. 6 201.6 230.0 242.1 293 294 261 .2 134-2 138.4 137-3 131-2 192.2 197.3 202.3 230.8 242.9 294 295 262 .0 134-7 138.9 137-8 131-7 192.9 198.0 203.0 231 .6 243-8 29s 296 262 .9 135-2 139-4 138.3 132.2 193.6 198.7 203.7 232.4 244-6 296 297 263.8 135-7 140.0 138.8 132.7 194-2 199.3 204.4 233-2 245-4 297 298 264.7 136-2 140.5 139-4 133-2 194-9 200.0 205. I 234.0 246.3 298 299 265.6 136-7 141 .0 139-9 133-7 195-6 200.7 205 . 8 234-8 247-1 299 300 266.5 137-2 141.5 140.4 134-2 196.2 201.4 206.6 235-5 247.9 300 301 267.4 137-7 142 .0 140.9 134-8 196.9 202. I 207.3 236.3 248.8 301 302 268.3 138-2 142.5 141.4 135-3 197.6 202.8 208.0 2371 249.6 302 303 269. 1 138-7 143-0 141.9 135-8 198.3 203.5 208.7 237-9 250.4 303 304 270.0 139-2 143-5 142.4 136.3 198.9 204.2 209.4 238.7 251.3 304 30s 270.9 139-7 144-0 142.9 136.8 199.6 204.9 210. 1 239-S 252.1 30s 306 271.8 140. 2 144-5 143-4 137-3 200.3 205.5 210.8 240.3 252.9 306 307 272.7 140-7 I45-0 144.0 137-8 201.0 206.2 211. 5 241 . 1 253-8 307 308 273.6 141 . 2 145-S 144. 5 138-3 201.6 206.9 212.2 241.9 254.6 308 309 274-5 14I-7 146. 1 145-0 138-8 202.3 207.6 212.9 242.7 255-4 309 310 275-4 142 . 2 146.6 1455 139-4 203.0 208.3 2x3.7 243-5 256.3 310 311 276-3 142.7 147-I 146.0 139-9 203.6 209.0 214.4 244.2 257.1 311 312 277.1 143.2 147-6 146. 5 140.4 204.3 209.7 215.1 245.0 2579 312 313 278.0 143-7 148. 1 147.0 140.9 205.0 210.4 215. 8 245-8 258.8 313 314 278.9 144-2 148.6 147-6 141-4 20s. 7 211.1 216.5 246.6 259.6 314 31S 279-8 144.7 149.1 148. 1 141.9 206.3 211. 8 217.2 247-4 260. 4 315 316 280.7 145-2 149.6 148.6 142.4 207.0 212. 5 217.9 248.2 261 .2 316 317 281.6 145-7 150. 1 149. 1 143-0 207.7 213. I 2x8.6 249.0 262 . 1 317 318 282.5 146.2 ISO. 7 149-6 143 -5 ao8.4 213.8 219.3 249.8 262 . 9 318 319 283.4 146.7 151-2 150-1 144.0 309.0 214. S 220.0 250.6 263.7 319 320 284.2 147.2 151-7 150.7 144-S 209.7 215.2 220.7 251.3 264.6 320 321 285.1 147-7 152-2 151 -2 145.0 210.4 215.9 221.4 252.1 265.4 321 322 286.0 148.2 152-7 151-7 145-5 aii.o 216.6 222.2 252.9 266. 2 322 323 286.9 148.7 153-2 152.2 146-0 211. 7 217.3 222.9 253.7 267 . 1 323 324 287.8 149.2 153-7 152.7 146-6 312.4 218.0 223.6 254-5 267.9 324 32s 288.7 149.7 154-3 153-2 147-1 213. 1 218.7 224.3 255-3 268.7 32s 326 289.6 150. 2 154-8 153-8 147-6 213.7 219.4 225.0 256. 1 269.6 326 327 290. 5 150.7 155-3 154-3 148. 1 214.4 220. I 225.7 256.9 270.4 327 328 291.4 151-2 iSS-8 154-8 148.6 21S.1 220. 7 226.4 257-7 271.2 328 329 292 .2 iSi-7 156-3 iSS-3 I49-I 21S.8 221.4 227.1 258.5 272.1 329 330 293-1 152.2 156.8 155-8 I t».7 216.4 222. I 227.8 259-3 272.9 330 331 294.0 152-7 IS7-3 156.4 150.2 217. 1 222.8 228. 5 260.0 273-7 331 332 294.9 153-2 157-9 156.9 150.7 217.8 223. S 229.2 260.8 274.6 332 333 295.8 153-7 158.4 157-4 151. 2 218.4 224. 2 230.0 261 .6 275.4 333 334 296.7 154-2 158-9 157-9 151-7 219. 1 224.9 230.7 262 . 4 276.2 334 335 297-6 154-7 159-4 158.4 152.3 219.8 225.6 231.4 263.2 277-0 335 336 298. 5 ISS-2 159-9 1590 152-8 220.5 226.3 22.1 264.0 277-9 336 337 299-3 155-8 160.5 1 59 5 153-3 221 . 1 227. 232.8 264.8 278.7 337 338 300.2 156.3 161 .0 160 .0 153-8 221.8 227.7 233.5 265.6 279.5 338 339 301. 1 156-8 161. 5 160.5 154.3 222. 5 228.3 234-2 266.4 280.4 339 SUGAR AND SACCHARINE PRODUCTS. 629 MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSFr— {Continued). [Weights in milligrams.] 340 341 342 343 344 34S 346 347 348 349 35° 351 352 353 354 355 356 357 358 359 360 361 362 363 364 36s 366 367 368 369 370 371 372 373 374 37S 376 377 378 379 380 381 382 383 384 38s 386 387 388 389 390 391 392 393 394 302.0 302.9 303-8 304.7 305-6 306. s 3073 308.2 309.1 310.0 310.9 3II-8 312.7 313-6 314-4 31S-3 316.2 317-1 318.0 318.9 319-8 320.7 321.6 322.4 323-3 324-2 325-1 326.0 326.9 327-8 328.7 3295 330.4 331-3 332-2 333-1 3340 334-9 33S-8 336-7 337-5 338.4 339-3 340.2 34I-I 342.0 342.9 343-8 344-6 345-5 346.4 347-3 348.2 349.1 3SO.O Invert Sugar and Sucrose. Lactose. 57-3 57-8 s8-3 S8.8 59-3 59-8 60.3 60.8 61 . 4 61 .9 62 .4 62 .9 63-4 63-9 64.4 64-9 65-4 66.0 66.5 67 .0 67-5 68.0 68.5 69.0 69.6 70. 1 70.6 71. 1 71.6 72 . 1 72.7 73-2 73-7 74-2 74-7 75-3 75-8 76.3 76.8 77-3 77-9 78.4 78.9 79-4 80.0 80. 5 81.0 81. S 82.0 82.6 83.1 83-6 84.1 84-7 8S-2 62 .0 62. s 63-1 63-6 64. 1 64.6 6s-i 65-7 66.2 66.7 67 . 2 67.7 68.3 68.8 69-3 69.8 70.4 70.9 71.4 71.9 72.5 73.0 73.5 74.0 74.6 75. 1 75.6 76. 1 76.7 77.2 77.7 78.3 78.8 79.3 79.8 80.4 80.9 81.4 82.0 82. s 83.0 83.6 84.1 84.6 85.2 85.7 86.2 86.8 87.3 87.8 88.9 90.0 90. 5 O 3 61 .0 61.6 62 . 1 62.6 63.1 63.7 64. 2 64.7 65 . 2 65.7 66.3 66.8 67.3 67-8 68.4 68.9 69-4 70.0 70. 5 71 .0 71-5 72 . 1 72 .6 73-1 73-7 74-2 74-7 75-2 75-8 76.3 76.8 77-4 77.9 78.4 79.0 79.5 80.0 80.6 81. 1 81.6 82.1 82.7 83.2 83.8 84.3 84.8 85.4 85.9 86.4 87-0 87-5 88.0 88.6 89.1 6 rt 54.8 55.4 55-9 56.4 56.9 57-5 S8.o 58-5 59-0 59-5 60. 1 60.6 61. 1 61.6 62 .2 62 .7 63-2 63-7 64-3 64-8 65-3 6s-8 66.4 66.9 67-4 67-9 68.5 69.0 69 -5 70.0 70.6 71. 1 71 .6 72 .2 72.7 73-2 73.7 74.3 74.8 75-3 78. 5 79.1 79.6 80.1 80.6 81.3 81.7 82.3 82.8 83.3 Maltose. 223.2 223.8 224. 5 225.2 225.9 226. S 227.2 227.9 228. 5 229. 2 229.9 230.6 231.2 231.9 232.6 233.3 233.9 234.6 235. 3 236.0 236.7 237.3 238.0 238.7 239.4 240.0 240.7 241.4 242. I 242.7 243.4 244.1 244.8 245.4 246. I 246.8 247.5 249. 5 250.2 250.8 251. 5 252.2 252.9 253. 254 254 25s 256.3 256.9 257.6 258.3 259.0 3S9.6 229.0 229. 7 230.4 231. 1 231.8 232. 5 233.2 233.9 234.6 235. 3 23s. 9 236.6 237.3 238.0 238.7 239-4 240. I 240. 8 241 S 242. 2 242.9 243.6 244.3 245.0 245.7 246. 4 247.0 247.7 248.4 249. I 249.8 250.5 251 . 2 251.9 252.6 253.3 254.0 254. 7 255.4 256. I 256.8 257. 5 258. I 258.8 259.5 260. 2 260 . 9 261 . 6 262 .3 263.0 263.7 264.4 265. 1 265-8 266.5 234-9 235.6 236.3 237.0 237.8 238. S 239.2 239.9 240.6 241.3 242.0 242.7 243.4 244.1 244.8 245.6 246.3 247.0 247.7 248.4 249.1 249.8 250.5 251.2 252.0 252.7 253.4 254.1 254.8 255. S 256.2 256.9 257.7 •258.4 259.1 259.8 260. 5 261 .2 261 .9 262.6 263.4 264. 1 264.8 265.5 266.2 266.9 267.6 268.3 269.0 269.8 270.5 271 . 2 271.9 272.6 373.3 267 . 1 267.9 268.7 369.5 270.3 271 . 1 271 .9 272 . 7 273. 5 274.3 275-0 275-8 276.6 277-4 278.2 279-0 279.8 280.6 281.4 282 .2 282 .9 283.7 284-5 285.3 286.1 286.9 287.7 288.5 289.3 290.0 290.8 291 .6 292.4 293.2 294.0 294.8 295.6 296. 4 297.2 297.9 298.7 299.5 300.3 301 .1 301 .9 302.7 3*3. 5 304.2 305.0 30s. 8 306.6 307.4 308.2 3090 309.8 281.2 282 .0 282 .9 283.7 284-5 285.4 286.2 287 .0 287.9 288.7 289-5 290.4 291 . 2 292 .0 292 .8 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 293 7 355 294 5 3S6 295 3 357 296 2 3S8 297 359 297 8 360 298 7 361 299 5 362 300 3 363 301 2 364 302 365 302 8 366 301 6 367 104 5 368 305 3 369 306 I 370 307 371 .107 8 372 308 6 373 309 5 374 310 3 375 311 I 376 .^12 377 312 8 378 313 6 379 314 5 380 ^15 3 381 316 I 383 316 9 383 317 8 384 318 6 38s 319 4 386 320 3 387 321 I 388 321 9 389 322 8 390 323 6 391 324 4 392 325 2 393 326 I 394 630 FOOD INSPECTION AND ANALYSIS. MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSE— (Continued). [Weights in milligrams.] Q Invert Sugar and Sucrose. Lactose. Maltose. 3 3 o 0" V H ^^ d d « •0 ^ X ffi w •a •a O (A 3 ^ 00 3 to 2 V-' .i + + .; -f s h J? rt 6 S, d 6 d d d 3 s 3 0. 0. i u > 13 2^ 0^ X s a 3 o Q HH d " 6 u u 395 350.9 185.7 191 .0 190.2 183.9 260.3 267.2 274.0 310.6 326.9 39S 396 351.8 186.2 191. 6 190.7 184.4 261 .0 267.9 274.7 311-4 327.7 396 397 352.6 186.8 192. 1 191. 3 184.9 261 .7 268.6 275.5 312.1 328.6 397 398 353-5 187.3 192.7 191.8 185.5 262.3 269.3 276. 2 312.9 3294 398 399 354-4 187.8 193-2 192.3 186.0 263.0 269.9 276.9 313-7 330.2 399 400 335-3 188.4 193-7 192.9 186. 5 263.7 270.6 277.6 314-s 331-1 400 401 356-2 188.9 194-3 193-4 187. 1 264.4 271.3 278.3 31S-3 331-9 401 402 3S7-I 189.4 194-8 194.0 187.6 265.0 272.0 279.0 316. 1 332.7 403 403 358-0 189.9 195-4 194-S 188.1 265.7 272.7 279.7 316.9 333-6 403 404 358-9 190. 5 195-9 I9S-0 188.7 266.4 273.4 280.4 317-7 334-4 404 40 s 359-7 191.0 196.4 195-6 189.2 267. 1 274. 1 281. 1 318. 5 335-2 40s 406 360.6 191. 5 197.0 196. 1 189.8 267.8 274-8 281.9 319.2 336.0 406 -.07 361.5 192 . 1 197.5 196.7 190.3 268.4 275-5 282.6 320.0 336.9 407 408 362.4 192 .6 198.1 197.2 190.8 269. 1 276. 2 283.3 320.8 337-7 408 409 363-3 193 -I 198.6 197-7 191. 4 269.8 276.9 284.0 321.6 338.5 409 410 364-2 193-7 199.1 198-3 191. 9 270. 5 277.6 284.7 322.4 339-4 410 411 365-1 194.2 199.7 198-8 192.5 271.2 278.3 285.4 323-2 340.2 411 412 366.0 194-7 200. 2 199.4 193.0 271.8 279.0 286.2 324-0 341-0 412 413 366.9 195-2 200.8 199.9 193.5 272. 5 279.7 286.9 324.8 341-9 413 414 367-7 195-8 201.3 200.5 194.1 273.2 280. 4 287.6 325-6 342.7 414 41S 36^.6 196.3 201.8 201 .0 194.6 273.9 281. I 288.3 326.3 343-5 41s 416 369. 5 196.8 202 .4 201 .6 195.2 274-6 281.8 289.0 327.1 344-4 416 417 370.4 197-4 202 .9 202 . 1 195.7 275.2 282. s 289.7 327-9 345-2 417 418 371-3 197.9 203.5 202 .6 196 . 2 275.9 283.2 290.4 328.7 346.0 418 419 372.2 198.4 204.0 203.2 196.8 276.6 283.9 291 .2 329-S 346.8 419 (30 373-1 199.0 204.6 203.7 197-3 277.3 284.6 291.9 330.3 347-7 420 421 3740 199.5 205. I 204.3 197.9 277.9 285.3 292.6 331-1 348.5 421 422 374-8 200. I 205.7 204.8 198.4 278.6 286.0 293.3 331-9 349-3 42a 423 375-7 200.6 206. 2 205.4 198.9 279.3 286.7 294.0 332.7 3SO-2 423 424 376-6 201 . I 206. 7 205.9 199-5 280.0 287.4 294.7 333-4 3S1-0 424 42s 377-5 201 . 7 207.3 206.5 200.0 280.7 288. I 295-4 334-2 3SI-8 42s 426 378.4 202 . 2 207.8 207 .0 200 . 6 281.3 288.8 296. 2 33S-0 352-7 426 427 379-3 202 .8 208.4 207 .6 201 . I 282.0 289.4 296.9 335-8 353-5 427 428 380.2 203.3 208.9 208.1 201.7 282.7 290. I 297.6 336.6 354-3 428 429 381. I 203.8 209.5 208.7 202 . 2 283.4 290. 8 298.3 337-4 355-1 429 430 382.0 204.4 210.0 209 . 2 202 . 7 284.1 291.5 299.0 338-2 356.0 430 431 382.8 204.9 210.6 209. 8 203.3 284.7 202 . 2 299.7 339-0 356.8 431 432 383-7 205.5 211.1 210.3 203.8 285.4 292.9 300. s 339-7 357-6 43a 433 384-6 206.0 211.7 210.9 204.4 286.1 293.6 301.2 340.5 3.S8.5 433 434 385-5 206. s 212.2 211.4 204.9 286.8 294.3 301.9 341-3 359-3 434 435 386.4 207 . 1 212.8 212.0 205-5 287.5 295.0 302.6 342.1 360.1 43S 436 387-3 207 .6 213.3 212.5 206.0 288. I 295. 7 303.3 342.9 361 .0 436 437 388.2 208. 2 213.9 213. I 206 . 6 288.8 296.4 304.0 343-7 361.8 437 438 389-1 208.7 214.4 213 .6 207 . 1 289. S 297. I 304.7 344-5 362.6 438 439 390-0 209.2 215.0 214.2 207.7 290.2 297.8 305. 5 345-3 363-4 439 440 390.8 209.8 2 15 5 214.7 208.2 290.9 298 . S 306.3 346.1 364-3 440 441 391.7 210.3 216. 1 215-3 208.8 291. s 299.2 306.9 346.8 365. I 441 442 392.6 210.9 216.6 215.8 209.3 302.2 299.9 .^07.6 347-6 365-9 442 443 393-5 2H . 4 217.2 216.4 209.9 392.9 300.6 308.3 348.4 366.8 443 444 394.4 212.0 217.8 216.9 210.4 293.6 301.3 309.0 349-2 567-6 444 445 395-3 212. S 218.3 217.5 211.0 294.2 302.0 309-7 350-0 368.4 445 446 396.2 213.1 218.9 218.0 2 1 1 . 5 294-9 302.7 310. s 350.8 3693 446 447 397-1 213.6 219.4 218.6 212 . 1 295.6 303.4 311.2 3SI-6 370.1 447 448 397-9 214 I 220 .0 2 19. I 212.6 296.3 304.1 311. 9 352-4 370.9 448 449 398.8 214.7 220.5 219.7 213.2 397.0 304.8 312. <5 353-2 371-7 449 SUGAR AND SACCHARINE PRODUCTS, 631 MUNSON AND WALKER'S TABLE FOR CALCULATING DEXTROSE, INVERT SUGAR, LACTOSE, AND MALTOSE— {Continued). [Weights in milligrams.] q Invert Sugar and Sucrose. Lactose. Maltose. s 3 o Q 9) "rt _ d d a ■d O S si M 3 C4 + + + 13 (0 3 u <5 rt B S 6 d 6 d d 3 O ^ Ui 3 S <^ a ;:! a fi s< a 3 0. 0. 1) V > u 3 0^ X ffi ffi X ffi u a 3 o Q 6 r. u (J 6 6 45° 399-7 215-2 221 . I 220 . 2 213.7 297-6 305 -s 313.3 353-9 372.6 450 451 400 . 6 215-8 221 .6 220.8 214.3 298.3 306.2 314-0 354-7 373-4 451 452 401.5 216.3 222.2 221.4 214.8 299.0 306.9 314-7 355-5 374-2 452 453 402.4 216.9 222 .8 221 .9 215.4 299.7 307-6 315-5 356.3 375.1 453 454 403 -3 217.4 223.3 222 . 5 215. 9 300.4 308.3 316.2 357- I 375.9 454 455 404.2 218.0 223.9 223.0 216.5 301. 1 309-0 316.9 357-9 376.7 455 456 405-1 218. 5 224.4 223.6 217.0 301-7 309-7 317.6 358.7 377.6 456 457 405-9 219. 1 225.0 224. 1 217.6 302.4 310.4 318.3 359-5 378.4 457 458 406.8 219.6 225. 5 224.7 218. I 303-1 311- 1 3190 360.3 379-2 458 459 407.7 220 . 2 226. 1 225.3 218.7 303-8 311-8 319-8 361 .0 380.0 459 460 408.6 220. 7 226.7 225.8 219.2 304. s 312. s 320. 5 361.8 380.9 460 461 409.5 221.3 227.2 226.4 219.8 30s. I 313-2 321 .2 362.6 381.7 461 462 410.4 221.8 227.8 226 . Q '>20.3 305-8 313-9 321.9 363-4 382.5 462 463 411 -3 222 . 4 228.3 227.5 220 9 306.5 314-6 322.6 364-2 383-4 463 464 4T2 . 2 222 .9 228.9 228.1 221.4 307.2 315-3 323-4 365.0 384-2 464 46s 413-0 223-5 229.5 228.6 222 .0 307-9 316.0 324-1 365.8 385-0 465 466 413-9 224.0 230.0 229.2 222.5 308.6 316.7 324-8 366.6 385-9 •466 467 414-8 224.6 230.6 229.7 223.1 309-2 317-4 325.5 367-3 386.7 467 468 415-7 225.1 231.2 230-3 223.7 309-9 318. 1 326.2 368.1 387-5 468 469 416.6 225.7 231.7 230.9 224.2 310.6 318.8 326.9 368.9 388.3 469 470 417-5 226.2 232.3 231.4 224.8 3II-3 319-5 327-7 369-7 389-2 470 471 418.4 226.8 232.8 232 .0 225.3 312.0 320.2 328.4 370.5 390.0 471 472 419-3 227.4 233-4 232.5 225.9 312.6 320.9 329.1 371 -3 390.8 472 473 420. 2 227.9 234.0 233-1 226.4 313-3 321 .6 329.8 372- I 391-7 473 474 421 .0 228. 5 234-5 233-7 227 .0 314-0 322.3 330. S 372.9 392.5 474 475 421 .9 229.0 235-1 234-2 227 .6 314-7 323 -0 331 3 373-7 393-3 47S 476 422.8 229.6 235-7 234.8 228.1 3IS-4 323.7 332.0 374-4 394-2 476 477 423-7 230.1 236.2 235.4 228.7 316. 1 324.4 332.7 375-2 395-0 477 478 424.6 230.7 236.8 235-9 229. 2 316.7 325.1 333.4 376.0 395-8 47» 479 425-5 231-3 237-4 236.5 229.8 317.4 325.8 334-1 376.8 396.6 479 480 426.4 231.8 237-9 237-1 230.3 318. 1 326. S 334-8 377-6 397-5 480 481 427-3 232.4 238-5 237-6 230.9 318.8 327.2 335-6 378-4 398.3 481 482 428.1 232.9 239-1 238.2 231-S 3I9-S 3279 336.3 379-2 399- I 482 483 429-0 233-5 239.6 238.8 232-0 320. 1 328.6 337-0 380.0 400 . 483 484 429.9 234.1 240. 2 239-3 232 -6 320.8 329-3 337.7 380.7 400. 8 484 48s 430.8 234.6 240 .8 239-9 233-3 321.5 330.0 338-4 381. 5 401 .6 48s 486 431-7 235.2 241.4 240.5 233-7 322.2 30.7 339-1 382.3 402.4 486 487 432.6 235.7 241 .9 241 .0 234-3 322.9 331-4 339-9 383-1 403-3 487 488 433-5 266.3 242. 5 241.6 234.8 323-6 332.1 340.6 383.9 404.1 488 489 434-4 236.9 243.1 242.2 235.4 324-2 332.8 341-3 384.7 404.9 489 490 435-3 237-4 243-6 242-7 236.0 324 9 333.5 342.0 385.5 405.8 490 632 FOOD INSPECTION AND ANALYSIS. Allihn's Method for the Determmation of Dextrose.* — The solutions used are those described on page 615, except that 125 grams of potassium hydroxide are used in place of 50 grams of sodium hydroxide in preparing the alkaline tartrate solution. Place 30 cc. of Fehling's copper solution, 30 cc. of the alkaline tartrate solution, and 60 cc. of water in a beaker and heat to boiling. Add 25 cc. of the sugar solution, which must be so prepared as not to contain more than 1% dextrose, and boil over the flame for two minutes. Filter immediately without diluting through a Gooch crucible containing a layer of asbestos fiber, prepared as described on page 618, and wash thoroughly with hot water, using reduced pressure. Transfer the asbestos fiber and the adhering cuprous oxide by means of a glass rod to a beaker and rinse the crucible with about 30 cc. of a boiling mixture of dilute sulphuric and nitric acids containing 65 cc. of sulphuric acid (specific gravity 1.84) and 50 cc. of nitric acid (specific gravity 1.42) per liter. Heat and agitate till the solution is complete, then filter into a scrupulously clean, tared platinum dish of loo-cc. capacity, taking care to wash out all the copper solution from the filter into the dish. Deposit the copper electrolytically in the platinum dish and weigh. Determine the dextrose from Allihn's table, pages 633-634. Or, the metallic copper may be calculated by means of the factor 0.7989 from the cupric oxide obtained as in Defren's method (page 618) and Allihn's table used. Or, the cuprous oxide as directly obtained by either Allihn's or Defren's method may be washed with alcohol and ether, dried for twenty minutes at 100° C, and weighed, its equivalent in dextrose being ascertained from Allihn's table. Browne's Correction Formula,'^ for use when the Allihn method is carried out on samples containing a considerable amount of sucrose, is as follows : C= £>+4o' in which C = correction in milligrams to be deducted from dextrose found, »S = milligrams of sucrose, and D = milligrams of dextrose. He found that the reducing action of sucrose is proportional (i) to the concentration of the sucrose and (2) to the amount of unreduced copper. In the volumetric methods and in the gravimetric methods when the amount * Jour. prak. Chem., 22, 1880, p. 46. t Jour. Amer. Chem. Soc, 1906, p. 451. SUGAR AND SACCHARINE PRODUCTS. 633 ALLIHN'S TABLE FOR THE DETERMINATION OF DEXTROSE Milli- MilU- Mim- Milli- Milli- MilH- MilU- Mim- MilU- MilH- Milli- MilU- grams grams grams grams grams grams grams grams grams grams grams grams of of Cu- of of of Cu- of of of Cu- of of of Cu- of Cop- prous Dex- Cop- prous Dex- Cop- prous Dex- Cop- prous Dex- per. Oxide. trose. per. Oxide. trose. per. Oxide. trose. per. Oxide. trose. II 12.4 6.6 76 85.6 38.8 141 158.7 71.8 206 231-9 105.8 12 13-5 7.1 77 86.7 39.3 142 159-9 72.3 207 233-0 106.3 13 14.6 7.6 78 87.8 39.8 143 161 .0 72.9 208 234-2 106.8 14 iS-8 8. I 79 88.9 40.3 144 162. I 73-4 209 235-3 107.4 15 16.9 8.6 80 90. 1 40.8 145 163.2 73.9 2IO 236.4 107.9 i6 18.0 9.0 81 91.2 41.3 146 164.4 74-4 211 237-6 108.4 17 ig.i 9-5 82 92.3 41.8 147 165.5 74-9 21 2 238.7 109.0 i8 20.3 10. 83 93-4 42.3 148 166.6 75-5 213 239-8 I09-S 19 21.4 lO-S 84 94-6 42.8 149 167.7 76.0 214 240.9 IIO.O 20 22. s II .0 85 95.7 43.4 150 168.9 76.5 215 242. 1 110.6 31 23.6 ii-S 86 96.8 43-9 151 170.0 77-0 216 243.2 III . I 32 24.8 12.0 87 97-9 44-4 152 171. I 77-5 217 244-3 III .6 23 25-9 12.5 88 99 I 44-9 153 172-3 78.1 218 245.4 112. 1 24 27 .0 13.0 89 100. 2 45.4 154 173-4 78.6 219 246. 6 112. 7 2S 28.1 13. s 90 loi . 3 45-9 155 174-5 79.1 220 247-7 ii3-a 26 29 -3 14.0 91 102.4 46.4 156 175.6 79-6 221 248.7 113.7 27 30.4 14-5 92 103 . 6 46.9 157 176.8 80.1 222 249-9 II4-3 38 31-5 15.0 93 104.7 47-4 158 177.9 80.7 223 251.0 114. 8 29 32-7 15-5 94 105.8 47.9 159 179.0 81.2 224 252.4 115-3 30 33-8 16.0 95 107 . 48.4 160 180. I 81.7 225 253-3 115.9 31 34-9 16.5 96 108. 1 48.9 161 181. 3 82.2 226 254.4 1 16.4 32 36.0 17.0 97 109. 2 49-4 162 182.4 82.7 227 255-6 116.9 33 37-2 17-5 98 no. 3 49-9 163 183-5 83-3 228 256.7 117.4 34 38.3 18.0 99 iii.S SO. 4 164 184.6 83-8 229 257-8 118. 35 39-4 18. s 100 112 . 6 50.9 1 65 185.8 84-3 230 258.9 118. s 36 40. 5 18.9 lOI 113-7 51-4 166 186.9 84.8 231 260. I 119.0 37 41.7 19.4 102 114. 8 51-9 167 188.0 8S-3 232 261 . 2 119.6 38 42.8 19.9 103 1 16 . 52-4 168 189. I 85-9 233 262.3 120. 1 39 43-9 20. 4 104 117.1 52.9 169 190.3 86.4 234 263.4 120.7 40 45.0 20. 9 105 118. 2 53-5 170 191-4 86.9 23s 264 6 121 . 2 41 46. 2 21.4 106 119-3 54-0 171 192.5 87.4 236 265.7 121.7 42 47-3 21 .9 107 120. S 54-5 172 193.6 87.9 237 266.8 122.3 43 48.4 22.4 108 1 21 . 6 55-0 173 194.8 88.5 238 268.0 122.8 44 49-5 22.9 109 122.7 55.5 174 195.9 89.0 239 269. 1 123.4 45 5° -7 23.4 no 123.8 56.0 175 197.0 89. 5 240 270. 2 123-9 46 SI. 8 239 III 125.0 56. 5 176 198. I 90.0 241 271.3 124.4 47 52.9 24.4 I 12 126. 1 57-0 177 199-3 90.5 242 272. 5 125.0 48 54-0 24.9 113 127.2 57-5 178 200.4 91. 1 243 273-6 125.5 49 55-2 25-4 114 128.3 58.0 179 201 . 5 91 .6 244 274-7 126.0 5° 56.3 25-9 IIS 129.6 58.6 180 202.6 92.1 245 275.8 126.6 SI S7-4 26.4 116 130.6 59-1 181 203.8 92.6 246 277.0 127 . 1 52 58.5 26.9 117 131-7 59-6 182 204.9 93.1 247 278.1 127 . 6 53 59-7 27.4 118 132.8 60. 1 183 206.0 93-7 248 279.2 128. 1 54 60.8 27.9 119 134-0 60.6 184 207 . 1 94-2 249 280.3 128.7 55 61 . 9 28.4 120 13S-I 61. 1 185 208.3 94-7 250 281.5 129? 2 56 63.0 28.8 121 136. 2 61.6 186 209.4 95-2 251 282.6 129-7 57 64.2 29 -3 122 137-4 62.1 187 210.5 95-7 252 283.7 130.3 58 65.3 29.8 123 138-5 62.6 188 211.7 96-3 253 284.8 130.8 59 66.4 30.3 124 139-6 63-1 189 212.8 96.8 254 286.0 131-4 60 67.6 30.8 125 140.7 63.7 190 2139 97.3 255 287.1 131-9 61 68.7 31.3 126 141-9 64. 2 191 215.0 97.8 256 288.2 132.4 62 69.8 31.8 127 143.0 64.7 192 216.2 98.4 257 289.3 133-0 63 70.9 32.3 128 144-1 65.2 193 217-3 98.9 258 290.5 133.5 64 72.1 32.8 129 145-2 65-7 194 218.4 99-4 259 291 . 6 134-1 65 73-2 33-3 130 146-4 66.2 195 219-5 100. 260 292.7 134-6 66 74-3 33-8 131 147 -5 66.7 196 220. 7 100. 5 261 293.8 I35-I 67 75-4 34-3 132 148.6 67 . 2 197 221.8 loi .0 262 295.0 135-7 68 76.6 34-8 133 149.7 67.7 198 222 . 9 101 . 5 263 296. 1 136.2 69 77-7 35-3 134 150.9 68.2 199 224.0 102.0 264 297.2 136.8 70 78.8 35-8 135 152.0 68.8 200 225.2 102 . 6 265 298.3 137-3 71 79-9 36.3 136 1S3-I 69.3 201 226.3 103.1 266 299-5 137-8 72 81. I 36.8 137 154-2 6g.8 202 227.4 103-7 267 300. 6 138.4 73 82.2 37-3 138 iSS-4 70.3 203 228.5 104. 2 268 301.7 138-9 74 83.3 37.8 139 156-5 70.8 204 229.7 104.7 269 3^2.8 139-5 75 84.4 38.3 140 IS7-6 71.3 20S 230.8 105.3 270 304.0 140.0 634 FOOD INSPECTION AND ANALYSIS. ALLIHN'S TABLE FOR THE DETERMINATION OF DEXTROSE— (Continued). MilU- MilH- Milli- MilH- Milli- Milli- Milli- MilU- Milli- MilU- Milli- Milli- grams grams grams grams grams grams grams grams grams grams grams grams of of Cu- of of of Cu- of of of Cu- of of of Cu- of Cop- prous Dex- Cop- prous Dex- Cop- prous Dex- Cop- prous Dex- per. Oxide. trose. per. O.Kide. trose. per. Oxide. trose. per. Oxide. trose. 271 30s I 140.6 321 361.4 168. 1 371 417-7 196.3 421 474.0 225.1 272 306. 2 141 . 1 322 362. 5 168.6 372 418.8 196.8 422 475-6 225.7 273 307.3 141.7 323 363-7 169. 2 373 420. 197-4 423 476.2 226. 3 274 308. 5 142. 2 324 364-8 169.7 374 421 . 1 198.0 424 477-4 226.9 27s 309-6 142.8 325 365-9 170.3 375 422 . 2 198.6 425 478.5 227.5 276 3IO-7 143-3 326 367.0 170.9 376 4233 199-1 426 479-6 228.0 277 3II-9 143-9 327 368.2 171-4 377 424-5 199-7 427 480.7 228.6 278 313-0 144.4 328 369-3 172.0 378 425-6 200.3 428 481.9 229. 2 279 314-1 145-0 329 370-4 172.5 379 426.7 200.8 429 483.0 229.8 280 315-2 145-5 330 371-5 173-1 380 427.8 201 .4 430 484.1 230.4 281 316.4 146. I 331 372.7 173-7 381 429.0 202 .0 431 485-3 231.0 282 3I7-S 146. 6 332 373-8 174-2 382 430.1 202. s 432 486.4 231.6 283 318.6 147.2 333 374-9 174-8 383 431.2 203.1 433 487-5 232. 2 284 319-7 147-7 334 376-0 175-3 384 432.3 203.7 434 488.6 232.8 28s 320-9 148.3 335 377-2 175-9 385 433.5 204.3 435 489-7 233-4 286 322.0 148.8 336 378.3 176-5 386 434-6 204. 8 436 490-9 233-9 287 323-1 149-4 337 379-4 177-0 387 435-7 20s -4 437 492.0 234-5 288 324.2 149-9 338 380.5 177-6 388 436.8 206. 438 493-1 235-1 289 325-4 150.5 339 381-7 178. I 389 438.0 206.5 439 494-3 235-7 290 326. S 151 -0 340 382.8 178.7 390 439-1 207 . 1 440 495-4 236.3 291 327.4 151.6 341 383-9 179-3 391 440.2 207.7 441 496-5 236.9 292 328.7 152.1 342 385.0 179-8 392 441-3 208.3 442 497-6 237-5 293 329.9 152.7 343 386.2 180. 4 393 442.4 208.8 443 498-8 238.1 294 331.0 153.2 344 387.3 180 .9 394 443-6 209.4 444 499-9 238.7 29s 332.1 153-8 345 388.4 181. 5 395 444-7 210. 445 501 .0 239-3 296 333-3 154-3 346 389.6 182. 1 396 445-9 210.6 446 502 . I 239.8 297 334-4 154-9 347 390.7 182.6 397 447.0 21 1 . 2 447 503-2 240.4 298 335-5 155-4 348 391.8 183-2 398 448.1 211. 7 448 S04-4 241 . 299 336-6 156.0 349 392.9 183-7 399 449. 2 212.3 449 505-5 241 . 6 300 337-8 156-., 350 394.0 184-3 400 450.3 212.9 4SO 506.6 242.2 301 338-9 157-1 351 395.2 184.9 401 451-5 213-5 451 507-8 242.8 302 340.0 157-6 352 396.3 185-4 402 452.6 214. I 452 508.9 243-4 303 341. 1 158.2 353 397-4 186.0 403 453-7 214.6 453 510.0 244.0 304 342.3 158-7 354 398.6 186.6 404 454-8 215.2 454 511-I 244-6 30s 343.4 159-3 355 399-7 187.2 40s 456.0 215.8 455 512. 3 245-2 306 344-5 159.8 356 400. 8 187-7 406 457-1 216.4 456 513-4 245-7 Moy 345-6 160. 4 357 401.9 188.3 407 458-2 217.0 457 514-S 246.3 31-8 346.8 160.9 358 403 . 1 188.9 408 459-4 217-5 458 515-6 246.9 309 347.9 161.5 359 404.2 189.4 409 460 . 5 218. I 459 516.8 247-5 310 349.0 162.0 360 405-3 190.0 410 461.6 218.7 460 517-9 248.1 311 350.1 162.6 361 406. 4 190. 6 411 462.7 219.3 461 519-0 248.7 312 351.3 163. I 362 407.6 191 . 1 412 463.8 219.9 462 520. I 249-3 313 352.4 163-7 363 408.7 191-7 413 465-0 220 . 4 463 521.3 249-9 314 353-5 164. 2 364 409.8 192.3 414 466. 1 221.0 . 3IS 354.6 164.8 365 410.9 192.9 415 467.2 221 . 6 316 355. 8 165-3 366 412. 1 193-4 416 468.4 222. 2 317 356.9 165.9 367 413-2 194.0 417 469-5 222.8 318 358.0 166. 4 368 414-3 194.6 418 470.6 223.3 339 359-1 167 .0 369 415-4 195. 1 419 471.8 223.9 320 360.3 167-5 370 416.6 195-7 420 472.9 224. 5 of reducing sugars is sufficient to remove nearly all the copper from the solution, the error due to sucrose is but slight. Electrolytic Apparatus. — The author has devised the apparatus shown in Fig. no for the electrolytic deposition of copper in sugar analysis and for other work of like nature. A, Fig. no, is a hard-rubber plate 50 cm. long and 25 cm. wide provided with four insulated metal binding posts, B, each carrying at the top a thumb screw by which a coiled platinum wire SUGAR AND SACCHARAINE PRODUCTS. 635 Fig. iio. — Four Pan Electrolytic Apparatus, shown (above) with Glass-covered Top Partially Removed, and (below) in Diagram. 636 FOOD INSPECTION AND ANALYSIS. electrode, C, may be attached. In front of each post is a copper plate about 4 cm. square covered with thin platinum foil, P, which is bent around the edges of the copper plate and so held in place, the copper plate being screwed to the rubber from beneath. On the square platinum- covered plate is set the platinum evaporating-dish which holds the solu- tion from which the copper is to be deposited, the inside of the dish form- ing the cathode, while the electrode C, dipping below the surface of the solution, forms the anode. In front of each platinum-covered plate is a switch, S, and at either end of the hard-rubber plate is a binding post, R, for connection with the electric current. The wiring, which is on the under side of the rubber plate, is best illustrated by the diagram in Fig. no. Four determinations may be carried on simultaneously in four plat- inum dishes, if desired, the wiring and the switches being so arranged that beginning at one end of the plate either the first dish or the first two or three may be thrown in or out of circuit at will without inter- rupting the current through the remaining dishes. A cover with wooden sides and glass top fits closely over the whole apparatus as a protec- tion from dust, but may be easily lifted off to manipulate the dishes when desked. The sides of the cover are perforated to permit the escape of the gas formed during the electrolysis. The ordinary street current is used when available, and the strength of the current may be varied within wide limits by means of a number of 1 6 or 32 candle-power lamps, K, coupled in multiple, and a rheostat, L, consisting of a vertical glass tube sealed at the bottom, containing a column of dilute acid, the resistance being changed by varying the length of the acid column contained between the two platinum terminals immersed therein, one of which is movable. A gravity battery of four cells may be employed if the laboratory is not equipped with electric lights. In using this apparatus for determining copper, as in sugar work the plating process should go on till all the copper is deposited, requiring several hours or over night with a current strength of about 0.25 ampere. Before stopping the process, the absence of copper in the solution should be proved by removing a few drops with a pipette, adding first ammonia, then acetic acid, and testing with ferrocyanide of potassium. If no brown coloration is produced, all the copper has been plated out. Throw the dish out of circuit by means of the switch, pour out the acid solution quickly before it has a chance to dissolve any of the copper, wash the dish first with water and then with alcohol, dry, and weigh. SUGAR AND SACCHARINE PRODUCTS. 637 The copper may be removed from the platinum dish by strong nitric acid. The Ross Apparatus^ consists of a funnel tube provided with a stop cock and a spiral of platinum wire one end of which passes through and is fused into the glass at the constriction. In using the apparatus form an asbestos mat in the constriction with the aid of suction, reduce the cuprous oxide by a suitable method, and filter and wash through the asbestos mat in the same manner as on a Gooch crucible. Close the stop cock, add dilute nitric acid (4 : 100) suflScient to nearly fill the tube, introduce a plati- num cylinder to serve as the cathode, and use the spiral as the anode. Employ a current yielding not more than i cc. of electrolytic gas per minute. When the copper is all deposited draw ofif the liquid, wash the platinum cylinder, dry, and weigh. Determination of Invert Sugar in the Presence of Cane Sugar. — Meissl and Hiller Method.^ — Defecate 40 grams of the sample dissolved in 100 cc. of water in a 200-cc. graduated flask with a slight excess of normal lead acetate, make up to the mark, shake, filter, delead with dry sodium carbonate or sulphate and again filter. Place 5 cc. of alkaline copper solution in each of five test-tubes or small beakers, add i, 2, 3, 4, and 5 cc. of the sugar solution to form a series, heat each to boiling, boil 2 minutes, and filter. The solution which gives the highest shade of blue (not colorless) contains the proper proportion of sugars for the actual deter- mination. Pipette 20 times the volume used in the preliminary test into a loo-cc. graduated flask, make up to the mark and shake. Prepare 50 cc. of alkaline copper solution by mixing 25 cc. of each of the two solutions (page 615), heat to boiling, add 50 cc. of the sugar solution, heat again to boiling and boil for exactly 2 minutes. Filter and weigh as metallic copper, cuprous oxide, or cupric oxide and calculate the results using the following formulas and table as simplified by Rice : { ,^ 100 Cu 88.82 CW2O 70.80 CuO looP I-=ioo-S, r = 0.02 YF, in which S and / = approximate per cents of sucrose and invert sugar in sugar solids, P = polarization of sample, Cu, CU2O, and CmO = weights * B. B. Ross, 8th Int. Cong. App. Chem., 8, 191 2, p. 75. t Zeits. Ver. deutsch. Zuker-Ind., 14, 1889, p. 715. X Personal communication. 638 FOOD INSPECTION AND ANALYSIS. of copper, cuprous oxide, and cupric oxide found, TF = weight of sample in ICO cc, i^ = factor found in following table, and /' = true per cent of invert sugar in the sample. MEISSL AND HILLER TABLE OF FACTORS FOR INVERT SUGAR DETERMINATION. Factors for Weights of Cu, CuiO, and CuO in Milligrams. Cu Cu Cu Cu Cu Cu Cu 400 350 300 250 200 150 100 S : I CU2O CuiO CU2O CuzO Cu'iO Cm20 CmO 450 394 338 281 225 169 113 CuO CuO CuO CuO CuO CuO CuO 500 437 375 312 250 187 125 o : loo 564 55-4 54-5 53.8 53-2 530 530 lo : 90 56.3 55 3 54 4 53 8 53 2 52.9 529 20 : 80 56.2 55 2 54 3 53 7 53 2 52.7 52.7 30 : 70 56.1 55 I 54 2 53 7 53 2 52.6 52.6 40 : 60 55-9 55 54 I 53 6 53 I 52.5 52.4 5° : 50 55-7 54 9 54 53 5 53 I 52.3 52.2 60 : 40 55-6 54 7 53 8 53 2 52 8 52.1 51-9 70:30 55-5 54 5 53 5 52 9 52 5 519 51.6 80: 20 55-4 54 3 53 3 52 7 52 2 51-7 513 90 : 10 54-6 53 6 53 I 52 6 52 I 51-6 52.2 91 : 9 54-1 53 6 52 6 52 I 51 6 512 50.7 92 : 8 53-6 53 I 52 I 51 6 51 2 50.7 50-3 93 : 7 53.6 53 I 52 I 51 2 50 7 50.3 49.8 94 : 6 531 52 6 51 6 50 7 50 3 49-8 48.9 95 ' 5 52.6 52 I 51 2 50 3 49 4 48.9 48.5 96:4 52.1 51 2 50 7 49 8 48 9 47.7 46.9 97 : 3 50-7 50 3 49 8 48 9 47 7 46.2 45-1 98 : 2 49.9 48 9 48 5 47 3 45 8 43-3 40.0 99 : I 47-7 47 3 46 5 45 I 43 3 41.2 38.1 Rice's Expanded Meissl and Hiller Table * given on pages 639 to 641 greatly facilitates the calculation of invert sugar as it gives percentages corresponding to different weights of copper, cuprous oxide, and cupric oxide, different amounts of the sample, and different polarizations. Instead of the amounts directed by Meissl and Hiller use for the preliminary tests 0.25, 0.50, 1.25, 2.50, and 5 cc. These amounts multiplied by 20 represent I, 2, 5, 10, and 20 grams of the sample per 100 cc. Rice states, however, that he makes no preliminary tests; if the quantity used is too much he 8th Int. Cong. App. Chem., 8, 191 2, p. 47. SUGAR AND SACCHARINE PRODUCTS. 639 RICE'S EXPANDED MEISSL AND HILLER TABLE GIVING PERCENTAGES OF INVERT SUGAR. Wt. of Sample in loo cc. Polarization. Wt. Obtained as Cu CuaO CuO 0.0999 0.II2S|0. 1250 O.IOI90.11471OI275 0.10390.1170I0.1300 0. 1059 O.1192 0.1325 0.10700.12150.1350 0.10990.12370.137s 0.III9 0.1260 0.1400 0.11380.12820.1425 O.I158 0.1305 0.1450 0.11780.13270,1475 O.I198 0.1350 0.1500 I Gram. 0. 1462 0.148s 0.1507 0.1530 0.1525 0.1550 0.1575 o. 1600 o. 1625 1650 0.167s o. 1700 0.ISS2I0.I725 0.157s O.IS97 0.12180.1372 0.12380. 1395 0.12580.1417 0.1278 0.1440 0.1298 0.1318 0.1338 0.1358 0.1378 0.1398 0.1418 o.i438'o. 1620 0.1458 0.1642 0.147810. 1665 0.1498 0.1687 0.15180.1710 0.1538 0.1732 0.15580.1755 0.15780. 1777 0.15980.1800 0.1618 0.1822 0.1638 0.1845 0.165810. 1867 0.1678 o.i" 2 Grams. O.1718 0.1738 0.1758 0.1778 0.1798 0.1817 0.1837 0.1912 0.1935 0.1957 0.1980 . 2002 o. 2025 2047 2070 1750 O.I77S 1800 1825 0.1850 0.1875 0.1900 1925 1950 1975 2000 2025! 2050 2075 .2100 .2125 .2150 .2175 . 2200 .2225 .2250 0.2275 o . 2300 10.28 10.48 10.69 10.89 II. 10 11.3^ 11.52 "•73 11.94 12.15 12.36 12.57 12.78 12.99 13.21 13-42 13-64 13-85 14.07 14.28 14-50 14.72 U-93 15-15 15-37 15-59 15-81 16.03 16.25 16.47 16.69 16.91 17-13 17-35 T7-S7 17.79 18.01 18.23 18.45 18.67 19. II 19-34 xo. 26 10.46 10.67 10.87 11.08 11.29 11.50 II. 71 11.92 12.13 12.34 12.55 12.76 12.97 13-19 13-40 13.62 13-831 14 05 14. 26 14.48 14.69 14.91 15.12 15-34 15-56 15-78 16.00 16.22 16.44 16.66 16.88 17.10 17.32 17-54 17.76 17.98 18.20 18.42 18.64 I 19.08 19.30 5 Grams. 85° S-I3 5-24 5-34 5-44 5-54 5-65 5 -76 5- 5-96 6.07 6.18 6.28 6.38 6.49 6.60 6.70 6.81 6.92 7-03 7.13 7.24 7-35 7.46 7-56 7-67 7-78 7-89 7-99 8.10 8.21 8.32 8.43 8.54 8.65 8.76 8.87 9.09 9.20 9 31 9-42 9-53 9.64 5-12 5-23 5-33 5-43 5 -S3 5-63 5-74 5-84 5-95 6.05 6.16 6.26 6.36 6.47 6.58 6.68 6.79 6.90 7.01 7. II 7.22 7.33 7-44 7-54 7-65 7.76 7-87 7-97 8.08 8.19 8.30 8.40 8.51 8.62 8.73 8.83 8.94 905 9.16 9.26 9-37 9-48 9-59 10 Grams. 20 Grams 85° 1. 661 1.708 1-755 1.802 I . 1.896 1.942 1.989 2.036 2.082 2.128 2-175 2.221 2 .267 2-3^3 2-359 2-405 2.451 2-4971 2.543 2.589 2-635 2.680 2.726 2.772 2.817 2.862 2.907 2-952 2.997 3.042 3-087 3-132 3-177 3-221 3.266 3-310 3-354 3-398 3-433 3-488 3-532 3-576 1 .600 1.696 1-744 1.792 1-839 1.886 1-933 1 .980 2.027 2.074 2. 121 2.168 2.215 2.262 . 2 . 309 2-356 2.403 2.449 2.543 2.589 2.63s 2.682 2.728 2.774 2.820 2.867 2.913 2.959 3-005 3-051 3-097 3-143 3.188 3-234 3.280 3-325 3 370 3-416 3-461 3-506 3-551 0.76 0.78 0.80 0.82 0.84 85° 0.90 0.92 0.94 0.96 1 .00 1 .02 I -OS 1 .07 1 .09 I . II I -13 1-15 1. 17 1. 19 1 .22 1 . 24 1 .27 1 . 29 1-31 1-33 1-35 1-37 1 .40 1.42 1.44 1.46 1-49 I-51 1-53 I-S5 i-S8 1 .60 1 .62 1.64 1.67 0.76 0.78 0.80 0.82 0.84 0.90 0.92 0.94 0.96 0.98 1. 00 1 .02 1 .04 1 .06 1. 10 1. 12 1. 14 1. 16 1. 18 1 .21 1-23 1.25 1.27 1.30 1.32 1-34 1.36 1.38 1.40 1.42 1.44 1-47 1-49 I-51 1-53 1.56 1.58 1.60 1.62 1.6s 0.72 0.73 0.75 0.76 •0.77 0.78 0.79 640 FOOD INSPECTION AND ANALYSIS. RICE'S EXPANDED MEISSL AND HILLER TABLE GIVING PERCENTAGES OF INVERT SUGAR— Continued. Wt. of Sample in loo cc. I Gram. 2 Grams. 5 Grams. ID Grams. 20 Grams. Polarization. 30° 35° 20° 30° 85° 95° bS° 95° 85° 95° Wt. Obtained as 19.56 Cu CU2O CuO 0.1857c 3.2092 ( 3.2325 19.52 9-75 9.70 3.621 3-597 1.69 1.67 0.80 0.187710. 2II5'( 3-2350 19.78 19-74 9.86 9.81 3.666 3.642 I. 71 1.69 0.8I 0. 1897 0.2137 3-2375 20.00 19.96 9-97 9-92 3.710 3.687 1-73 1.72 0.82 0.81 0. 1917 0.2160 3.2400 20.23 20.19 10.08 10.03 3-754 3-732 1.76 1-75 0.83 0.83 01937 3.2182 3.2425 20.45 20.41 10.19 10.14 3-799 3-777 1.78 1-77 0.84 0.84 0-1957 3.2205 3.2450 20.67 20.63 10.30 10.25 3 844 3.822 1.80 1-79 0.85 0.85 0.1977 3.2227 3-2475 20.89 20.85 10.41 10.36 3.888 3-867 1.83 1.81 0.86 0.86 0. 1997 0.2250] 0.2500 21.12 21.08 10.52 10.47 2.932 3.912 1.86 1.84 0.88 0.87 0.2017 0.2272 0-2525 21-34 21.30 10.63 10.58 3.977 3-957 1.88 1.86 0.89 0.88 0.2037 0.2295 0.2550 21.56 21.52 10.74 10.69 4.. 02 2 4.002 1.90 1.88 0.90 0.89 0.2057 0.2317 ^■2S75 21.78 21.74 10.85 10.80 4.066 4.047 1.92 1.90 0.91 0.90 0.2077 0.2340 0.2600 22.00 21 .96 10.96 10.91 4.110 4.092 1-95 I 93 0.92 0.91 0. 2097 0.2362 0.2625 22.22 22.18 II .07 11.02 4.155 4.137 1-97 1-95 0.93 0.92 0.2117 0.2385 0.2650 22.44 22.40 II. 18 II. 13 4. 200 4.182 1-99 1-97 0.94 0-93 0.2137 0.2407 0.2675 22.66 22.62 11.29 11.24 4.244 4-227 2.02 1.99 0.95 0.94 0.2157 0.2430 0.2700 22.89 22.85 II .40 11-35 4.288 4.271 2.05 2.02 0.97 0.96 0.2177 0-2452 0.2725 23.11 23.07 II. 51 11.46 4-333 4-316 2.07 2.04 0.98 0.97 0.2197 0-2475 0.2750 23 -33 23-29 11.62 11-57 4-378 4-361 2.09 2.06 0.99 0.98 0.2217 0.2497 0.2775 23-55 23-51 "•73 11.68 4-422 4-405 2. II 2.08 1.00 0.99 0.2237 0.2520 0.2800 23.78 23 -74 11.84 11.79 4.466 4-449 2.14 2.12 1. 01 1.00 0.2257 0.2542 0.2825 24.00 23.96 11-95 11.90 4-511 4-494 2.16 2.14 1.02 I.Ol 0.2277 0.2565 0.2850 .24.22 24.18 12.06 12.01 4-556 4-538 2.18 2.16 1.03 1.02 0.2297 0.2587 0.2875 24.44 24.40 12.17 12.12 4.600 4-582 2.20 2.18 1.04 1.03 0.2317 0.2610 0. 2900 24.67 24.63 12.28 12.23 4.644 4.626 2.23 2.21 1.06 1-05 0-2337 0.2633 0.2925 24.89 24-85 12.39 12.34 4.689 4-671 2.25 2.23 1.07 1.06 0-2357 0-2655 0.2950 25.11 25-07 12.50 12.45 4.734 4.716 2.27 2.25 1.08 1.07 0.2377 0.2677 0.2975 25-33 25-29 12.61 12.56 4-779 4.761 2.29 2.27 1.09 1.08 0.2397 0.2700 . 3000 25 56 25-52 12.73 12.67 4-823 4.805 2.32 2.30 1. 10 1.09 0.2417 0.2722 0.3025 25-78 25-74 12.84 12.78 4.868 4.850 2-34 2.32 1. 11 l.IO 0.2437 0-2745 0.3050 26.00 25.96 12.95 12.89 4-913 4-895 2.36 2.34 1.12 1. 11 0-2457 0.2767 0.3075 26.22 26.18 13.06 13.00 4-958 4.940 2.39 2-37 I -13 1.12 0.2477 0.2790 0.3100 26.45 26.41 13.18 13-11 5-003 4 985 2.42 2.40 I-I5 1.14 0.2497 0.2812 0.3125 26.67 26.63 13.29 13.22 5 049 5.031 2.44 2.42 1.16 I-I5 0.2517 0.2835 0.3150 26.90 26.85 13-40 ^3-33 5-095 5.076 2.46 2.44 1. 17 1.16 02537 0.2857 3175 27.12 27.07 13-51 13.44 5-141 5.121 2.48 2.46 1.18 1.17 0.2556 0.2880 . 3 200 27-35 27.30 13-63 13.56 5-186 5-166 2.51 2-49 1.19 I. 18 0.2576 0.2902 0.3225 27-57 27-52 13-74 13.67 4-232 5-212 2-53 2-51 1 .20 I. 19 0.2596 0.2925 0.3250 27.80 27-75 13-85 13.78 5-278 5-258 2-55 2-53 1.21 I .20 0.2616 0.2947 0.3275 28.02 27.97 13.96 13.89 5-324 5 303 2-57 2-55 1.22 I . 21 0.2636 0.2970 0.3300 28.25 28.20 14.08 14.01 5.371 5 348 2.60 2.58 1.24 1.23 0.2656 0. 2992 0.3325 28.47 28.42 14.19 14.12 5.418 5-394 2.62 2.60 1.25 1.24 0.2676 0.3015 0.3350 28.70 28.65 14-30 14.23 5.465 5 440 2.64 2.62 1.26 1.25 0.2696 0.3037 3375 28.93 28.87 14.42 14.35 5-512 5.486 2.66 2.64 1.27 1.26 SUGAR AND SACCHARINE PRODUCTS. 641 RICE'S EXPANDED MEISSL AND HILLER TABLE GIVING PERCENTAGES OF INVERT SUGAR— CoMc/M(/e(/. Wt. of Sample in loo cc. I Gram. 2 Grams. 5 Grams. 10 Grams. 20 Grams. Polarization. 30° 35° 20° 30° 85° 95° 95° 8s° 85° 95° Wt. Obtained as Cu CujO CuO 0.2716 . 3060 0.3400 29.16 29. 10 14 -54 14.47 5 558 5-532 2.69 2.67 1.28 1.27 0.2736 0.3082 0.3425 29 39 29 32 14 65 14. 59 I .605 5 578 2 71 2 69 1.29 1.28 0.2756 0.3105 0.3450 29 62 29 55 14 76 14 70 5.652 5.624 2 73 2 71 1.30 1.29 0.2776 0.3127 0.3475 29 85 29 77 14 88 14 81 5.699 5.671 2 75 2 73 131 1.30 0.2796 0.3150 0.3500 30 08 30 00 15 00 14 93 5.746 5. 718 2 78 2 76 1-33 1.32 0.2816 0.3172 0.3525 30 31 20 23 15 II IS 04 5.793 5.765 2 80 2 78 1.34 I 33 0.2836 0.3195 0.3550 30 54 30 46 15 22 IS 15 5.840 5.812 2 82 2 80 1.35 1.34 0.2856 0.3217 0.3575 30 77 30 69 15 34 IS 27 5.888 5.859 2 84 2 82 1.36 1-35 0.2876 0.3240 0.3600 31 00 30 93 15 46 IS 39 5. 936 5.906 2 87 2 85 1-37 1.36 0.28960.3262 0.3625 31 23 31 16 15 57 15 50 5 983 5. 953 2 89 2 87 1.38 I 37 0.2916 0.3285 0.3650 31 46 31 40 15 69 15 61 6.031 6.000 2 91 2 88 1.39 1.38 0.2936 0.33070.3675 31 69 31 63 15 81 15 73 6.079 6.048 2 93 2 91 1.40 1-39 0.2956 0. 3330,0. 3700 31 93 31 87 15 93 15 85 6.127 6.096 2 96 2 94 1.42 1. 41 0.2976 0.33520.3725 32 16 32 10 16 04 15 96 6.174 6.144 2 98 2 96 1-43 1.42 0.2996 o.3375j0.375o 32 40 32 34 16 16 16 08 6.222 6.192 3 00 2 98 1-44 1.43 0.3016 0.33970.3775 32 63 32 67 16 28 16 20 6.270 6.240 3 03 3 00 1-45 1.44 0.3036 0.3420,0.3800 32 87 32 81 16 40 16 32 6.318 6.288 3 06 3 03 1.46 1.45 0.3056 0.34420.3825 33 10 33 04 16 52 16 44 6.366 6.337 3 08 3 05 1-47 1.47 0.3076 0.3465,0.3850 33 34 33 28 16 64 16 56 6.414 6.386 3 10 3 07 1.48 1.48 0.3096 0.3487 0.387s 33 58 33 52 16 76 16 68 6.462 6.434 3 12 3 09 1-49 1.49 O.3116 0.3510 . 3900 33 82 33 76 16 88 16 80 6.510 6.482 3 15 3 12 i-Si i-So 0.3136 0.3532 0.3925 34 06 34 00 17 00 16 92 6.558 6.531 3 17 3 14 1.52 I 51 0.3156 0.3555 0.3950 34 30 34 24 17 12 17 04 6.608 6.580 3 19 3 16 1.53 1.52 0.3176 0.3577 0.397s 34 54 34 48 17 24 17 16 6.654 6.629 3 21 3 18 1.54 1.53 0.3196 0.3600 . 4000 34 78 34 72 17 36 17 28 6.703 6.678 3 24 3 21 1.5s 1.54 0.3216 0.3622 0.4025 35 02 34 96 17 48 17 40 6.751 6.727 3 26 3 23 1.56 1-55 0.3236 0.3645 0.4050 35 26 35 20 17 60 17 52 6.799 6.776 3 28 3 26 1.57 1.56 0.3256 0.3667 0.4075 35 50 35 44 17 72 17 64 6.848 6.82s 3 30 3 27 1.58 1.57 0.3275 0.3890 0.4100 35 75 35 68 17 84 17 76 6.897 6.875 3 33 3 30 1.60 1.59 0.3295 0.3712 0.4125 35 99 35 92 17 96 17 88 6.945 6.924 3 35 3 32 1.61 1.60 0.3315 0.3735 0.4150 36 24 36 16 18 08 18 00 6.993 6.973 3 37 3 34 1.62 1.60 0.3335 0.3757 0.4175 36 48 36 40 18 20 18 12 7.042 7.023 3 39 3 36 1.63 1.62 0.33550.37800 4200 36 73 36 65 18 33 18 25 7.091 7.073 3 42 3 39 1.64 1.63 0.3375 o.38o2|0.4225 36 97 36 89 18 45 18 37 7-139 7.122 3 44 3 41 1.65 1.64 0.3395 0.38250.4250 37 22 37 13 18 57 18 49 7.188 7.172 3 46 3 43 1.66 1.6s 0.3415 0.38470 4275 37 47 37 37 18 69 18 61 7 237 7.222 3 48 3 45 1.67 1.66 0.3435 0.38700.4300 37 .72 37 62 18 82 18 ■74 7.286 7.272 3 51 3 48 1.69 1.68 0.345s 0.38920 4325 37 .96 37 86 18 94 18 .86 7.334 7.321 3 ■53 3 50 1.70 1.69 0.3475 0.39150 4350 38 .21 38 10 19 06 18 .99 7.383 7.371 3 ■55 3 52 1.71 1.70 0.3495 0.3937 0.4375 38 .46 38 44 19 .19 19 .12 7432 7.421 3 58 355 1.72 1. 71 642 FOOD INSPECTION AND ANALYSIS. starts with another portion of half the dilution. Full details of the process as now conducted follow : * " Weigh out a quantity which from the direct polarization seems proper, always estimating low. Dissolve and make up to mark and if not clear pour onto a filter paper in which has been placed a level teaspoonful of dry kieselguhr. Pour back until the filtrate comes clear. Place 50 cc. of the solution and 50 cc. of mixed alkaline copper solution in a 350-cc. Grifhn beaker and cover with clock glass. Heat on a piece of sheet asbestos, with a hole 5 cm. in diameter below which is a wire gauze, so as to reach boiling in 4 minutes or under 5 minutes. Boil exactly 2 minutes, then pour in 100 cc. of cold water. Remove from the flame immediately, filter through an ignited weighed porcelain Gooch crucible containing a layer of asbestos 3 mm. thick, previously treated for days with strong hydrochloric acid and alkaline copper solution. Heat ^ hour at dull redness, cool, and weigh as CuO." Determination of Sucrose by Fehling's Solution.t — If a polariscope is not available, cane sugar can be determined as follows: First determine the percentage of invert sugar present in the sample by one of the Fehling methods already described. Then dissolve i gram of the sugar in about 100 cc. of water in a 500-cc. graduated flask, add 3 cc. of concentrated hydrochloric acid and invert by heating in water to 68° and cooling in the regular manner. Neutralize with sodium hydroxide or sodium carbonate, and make up to the mark with water. Determine the per cent of total reducing sugar as invert sugar either by the volumetric or gravimetric Fehling process. Subtract the invert sugar found present in the sugar by d'rect determination from the total found present after inversion, and the remainder is the invert sugar due to cane sugar. This figure multi- plied by 0.95 gives the percentage of cane sugar. For the determination of sucrose by the gravimetric Fehling process on the inverted sample, multiply the cupric oxide (CuO) by the factor 0.4307, or the copper (Cu) by the factor 0.5394. ANALYSIS OF MOLASSES AND SYRUPS. First insure a perfectly homogeneous sample by stirring with a rod to evenly distribute any separated sugar. * Personal communication. t Tucker, Manual of Sugar Analysis, p. 182. 1 SUGAR AND SACCHARINE PRODUCTS. 643 Determination of Total Solids. — (i) Asbestos Method. — Weigh 20 grams into a ico-cc. graduated flask, dissolve in water, and make up to the mark. Insure a uniform solution by shaking. Measure 10 cc. of this solution into a tared platinum dish containing about 5 grams of freshly ignited, finely divided asbestos fiber, and dry to constant v^eight at 70° in vacuo, or in a McGill oven (see page 609). (2) Sand Method. — Place a stirring rod in a flat-bottom metal dish, add ignited quartz sand sufficient to bring the total weight up to an even number of grams using not less than 12 to 15 grams, and weigh. Add 2 to 4 grams of the material, dilute with water, and mix thoroughly. Dry on a water bath with stirring and finally in a water oven until the loss is insignificant. (3) By Calculation from Refractive Index. — Determine the refractive index by means of the Abb^ refractometer (page 94), and calculate the total solids, using Geerlig's tables (p. 645). This method is more accurate and convenient than the specific gravity method and employs a smaller quantity of material. The investigations of Stolle * and of Tolman and Smith f have shown that sucrose, maltose, dextrose, levulose and lactose all have practically the same refractive index. Dextrin has a somewhat' higher refractive index, nevertheless the solids of commercial glucose do not give a reading appreciably higher than the sugars named. A. H. Bryan J has compared this method with the method of drying at 70° in vacuo, with the following results : Number of Difference compared with Samples. the Gravimetric Method. Maple syrup 13 -1.3410+0.72 Cane table syrup 10 —o. 79 to +0 . 62 Cane molasses 17 — i . 53 to +0 . 59 Beet molasses 15 —1.83 to —0.07 Honey 24 —2.52 to +0.91 Glucose 2 — o . 27 to +0 . 27 (4) By Calculation from Specific Gravity. — Weigh 25 grams of the sample into a loo-cc. graduated flask, dissolve in water, and make up * Zeits. deutsch. Zucker-Ind., 1901, pp. 335, 469. t Jour. Am. Chem. Soc, 28, 1906, p. 1476. t Ibid., 30, 1908, p. 1443. 644 FOOD INSPECTION AND ANALYSIS. 20° to the mark. Determine the specific gravity, at —5 C, of the diluted solution by means of a pycnometer or accurate hydrometer. Ascertain from the table on pages 647 and 648 the percentage by weight of solids (sugar) corresponding to the specific gravity of the diluted solution, and calculate the total solids in the original sample by the following formula: in which S' is the total solids in original sample, D is the specific gravity of the diluted solution, and S is the per cent of solids in the diluted solution. The solids may also be obtained directly by means of the saccha- rometer, also known as the Brix spindle. This instrument is a hydrometer graduated so as the show the per cent of sugar when the temperature of the liquid is 20° C. If the specific gravity or saccharometer reading is taken at any other temperature than 20° C. the necessary correction may be found in the table on page 649. Determination of Ash. — Weigh from 5 to 10 grams of the sample into a tared platinum dish, evaporate to dryness on the water-bath, and proceed as directed for ash of sugar (page 609). Polarization and Determination of Sucrose. — Molasses and golden syrup require the application of clarifying reagents before a suflficiently clear solution can be obtained for reading on the polariscope. Even then it is not possible nor is it necessary to get a water-white solution, so that in this class of products greater accuracy can usually be attained by polarizing in a loo-mm. tube (half the standard length) and multiplying the reading by 2. In some cases it may be found necessary to use an even shorter tube. When the sample contains a considerable amount of glucose the use of the shorter tube is absolutely necessary since otherwise the range of the scale would not permit of a reading. The clarifier best adapted as a rule for molasses and golden syrup is lead subacetate either in the form of a solution as described on page 610, or, as first proposed by Home,* in the form of the anyhdrous salt. * Jour. Am. Chem. Soc, 26, 1904, p. 186. SUGAR AND SACCHARINE PRODUCTS. 645 GEERLIGS'S TABLE FOR DRY SUBSTANCE IN SUGAR-HOUSE PRODUCTS BY THE ABBE REFRACTOMETER, AT 28° C* Per Per Refrac- Cent Decimals to be Added for Re frac- Cent Decimals to be Added for tive Dry Fractional Readings, t tive Dry Fractional Readings t Index. Sub- stance. 1 In dex. Sub- stance. 1-3335 I 0.0001 = 0.05 0.0010=0.75 I 4083 45 0.0004 = 0.2 0.0015 = 0.75 3349 2 0.0002 = 0.1 0.0011 = 0.8 I 4104 46 0.0005 = 0.25 0.0016 = 0.8 3364 3 0.0003 = 0.2 0.0012 = 0.8 I 4124 47 0.0006 = 0.3 0.0017 = 0.85 3379 4 0.0004 = 0.25 0.0013 = 0.85 I 4145 48 0.0007 = 0.35 0.0018 = 0.9 3394 5 0.0005 = 0.3 0.0014 = 0.9 I 4166 49 0.0008 = 0.4 0.0019=0.95 3409 6 . 0006 = 0.4 0.0015=1.0 I 4186 50 0.0009 = 0.45 0.0020= I.O 3424 7 0.0007 = 0.5 4207 51 0.0010 = 0.5 0.0021 = 1.0 3439 8 0.0008 = 0.6 4228 52 0.0011 = 0.55 3454 9 0.0009 = 0.7 4219 53 3469 ID 4270 54 3484 II 0.0001 = 0.05 4292 55 0.0001 = 0.05 0.0013=0.55 3500 12 0.0002 = 0.1 4314 56 0.0002 = 0.1 0.0014=0.6 3516 13 0.0003 = 0.2 4337 57 0.0003 = 0.1 0.0015 = 0.65 3530 14 0.0004 = 0.25 4359 58 0.0004=0.15 0.0016=0.7 3546 15 0.0005 = 0.3 4382 59 0.0005 = 0.2 0.0017 = 0.75 3562 16 0.0006=0.4 4405 60 0.0006 = 0.25 0.0018 = 0,8 3578 17 0.0007 = 0.45 4428 61 0.0007 = 0.3 0.0019=0.85 3594 18 0.0008=0.5 4451 62 0.0008 = 0.35 0.0020 = 0.9 3611 19 0.0009=0.6 4474 63 0.0009 = 0.4 0.0021 =0.9 3627 20 0.0010=0.65 4497 64 0.0010=0.45 0.0022 = 0.95 3644 21 0.0011=0.7 4520 65 0.0011 = 0.5 0.0023= i-o 3661 22 0.0012 = 0.75 4543 66 0.0012 = 0.5 0.0024=1.0 3678 23 0.0013 = 0.8 4567 67 3695 24 0014=0.85 4591 68 3712 25 0.0015 = 0.9 4615 69 3729 26 0.0016 = 0.95 4639 70 4663 71 4687 72 1-3746 27 0.0001 = 0.05 0.0012 = 0.6 3764 3782 28 0.0002 = 0.1 0.0003 = 0.15 n no T "2 = 6 c - 29 0.0014 = 0.7 I 4711 73 0.0001 = 0.0 0.0015=0.55 3800 30 0.0004=0.2 0.0015 = 0.75 I 4736 74 0.0002 = 0.05 0.0016 = 0.6 3818 31 0.0005 = 0.25 0.0016 = 0.8 I 4761 75 0.0003 = 0.1 0.0017 = 0.65 3836 32 . 0006 = 0.3 0.0017 = 0.85 I 4786 76 0.0004=0.15 0.0018 = 0.65 3854 33 0.0007 = 0.35 0.0018 = 0.9 I 4811 77 0.0005 = 0.2 0.0019=0.7 3872 34 0.0008 = 0.45 0.0019=0.95 I 4836 78 0.0006 = 0.2 0.0020 = 0. 7J 3890 35 0.0009 = 0.4 0.0020=1.0 I 4862 79 0.0007 = 0.25 0.0021 = 0.8 3909 36 0.0010=0.5 0.0021 = 1.0 I 4888 80 . 0008 = 0.3 0.0022 = 0.8 3928 37 0.0011 = 0.55 4914 81 0.0009=0.35 0.0023 = 0.85 3947 38 4940 82 0.0010 = 0.35 0.0024 = 0.9 3966 39 4966 83 0.0011 = 0.4 0.0025 = 0.9 3984 40 4992 84 0.0012 = 0.45 0.0026 = 0.95 4003 41 5019 85 0.0013 = 0.5 0.0027 = 1.0 5046 86 87 0014 = 0.5 0.0028=1.0 5073 1.4023 42 0.0001 = 0.05 0.0012 = 0.6 I 5100 88 1.4043 43 0.0002 = 0.1 0.0013 = 0.65 I 5127 89 1.4063 44 0.0003 = 0.15 0.0014=0.7 I 5155 90 * Intern. Sugar Jour., lo, pp. 69-70. t Find in the table the refractive index which is next lower than the reading actually mada and note the corresponding whole number for the per cent of dry substance. Subtract the refractive index obtained from the table from the observed reading; the decimal corresponding to this difference, as given in the column so marked, is added to the whole per cent of dry substance as first obtained. 646 FOOD INSPECTION AND ANALYSIS. TEMPERATURE CORRECTIONS FOR USE WITH GEERLIGS'S TABLE. Tempera- Dry Substance. ture of the Prisms in 1 5 10 1 li^ 1 20 25 1 30 1 40 1 50 1 60 1 70 80 j 90 °C. Subtract — 20 0-53 0.54 0-5S 0.56 0-57 0.58 0.60 0.62 0.64 0.62 0.61 0.60 0.58 21 .46 ■47 .48 -49 -50 •51 .52 -54 -56 -54 -53 -52 -50 22 .40 .41 -42 -42 -43 .44 -45 -47 .48 -47 .45 -45 -44 23 -33 -33 -34 -35 •3<> -37 -38 -39 .40 -39 -38 -38 -38 24 .26 .20 .27 .28 .28 .29 -30 -31 •32 •31 •31 -30 ■30 ^s .20 .20 .21 .21 .22 .22 •23 •23 -24 •23 -23 -23 .22 26 .12 .12 -13 -14 -14 -15 -15 .16 .16 .16 ■ 15 ■IS .14 27 .07 .07 .07 .07 .07 .07 .08 .08 .08 .08 .08 .08 .07 Add— 29 0.07 0.07 0.07 0.07 0.07 0.07 0.08 0.08 0.08 0.08 0.08 0.08 0.07 30 .12 .12 -13 .14 .14 .14 -15 -15 .16 .15 .16 -15 ■14 31 .20 .20 .21 .21 .22 .22 •23 ■23 -24 .23 ■23 -23 .22 32 .26 .2b .27 .28 .28 •29 -30 -31 -32 -31 ■31 -30 -30 33 •33 ■33 -34 -35 -3b •37 -38 -39 .40 ■39 .38 ■38 ■38 34 .40 -41 -42 .42 -43 • 44 -45 ■47 ■ 48 ■47 .4b -45 -44 35 .40 -47 .48 -49 -50 -51 -52 -=^4 .r6 .■^4 .5^ .t;2 ■ ,^0 The Process. — The normal weight, 26 grams, of the molasses or s}Tup is dissolved in water in a loo-cc. flask, and in the case of molasses and "golden," or "drip" syrup, sufficient subacetate of lead solution is added ^.o precipitate the coloring matter. From 5 to 10 cc. of the clarifier usually suffice. The flask is then filled to the mark with water and the contents shaken thoroughly and filtered. If on account of air bubbles it is difficult to make up to the mark, the bubbles may usually be dis- pelled by a drop of ether. With maple syrup no clarifier is, as a rule, necessary, though sometimes alumina cream is helpful. With a very dark-colored molasses 20 to 30 cc. of lead subacetate are required for clarification and in extreme cases (though rarely with the grades of molasses used as food) it is necessary, after the ordinary filtration, to pass through from 5 to 6 grams of powdered, dried bone charcoal.* An excess of subacetate of lead should be avoided on account of the possibility of the filtrate becoming turbid through the formation of lead carbonate by exposure to the air. A drop of acetic acid will nearly always clear the solution, if the turbidity is due to carbonate. If cloudiness in the filtrate persists, weigh out a fresh portion of the sample, dilute, and add first the lead subacetate solution, and afterwards enough of a strong solution of sodium sulphate or common salt to precipitate the excess of lead; then fill to the mark and filter. Polarize, and conduct the inver- sion as directed on p. 610, using, however, a loo-mm. tube, and multi- * The treatment with bone char should be used only as a last resort, as, on account of slight absorption of sugar, observed readings are from 0.4° to to 0.5° too low. SUGAR AND SACCHARINE PRODUCTS. 647 DENSITY OF SOLUTIONS OF CANE SUGAR AT C* si Tenths of Per Cent. (S I 2 3 4 5 6 7 8 9 0.9982 0. 9986 0.9990 0.9994 0. 9998 I . 0002 1 .0006 I .OOIO I -0013 I .0017 I I .0021 I .0025 I .0029 I 0033 I .0037 1 .0041 1 0045 I .0048 1 .0052 I .0056 2 I .0060 I .0064 1 .0068 I .0072 I .0076 1 .0080 1 .0084 1.0088 1 .0091 1.0095 3 I .0099 I .0103 I .0107 1 .01 1 1 I . 01 1 5 I .01 19 1. 0123 I .0127 I 0131 I-013S 4 I. 0139 I. 0143 I-0147 1.0151 I-OI5S 1 .0159 I .0163 I .0167 1 .01 71 1.017s 5 I. 0179 1-0183 I .0187 I .0191 I .0195 I. 0199 I .0203 I .0207 1 .021 1 I -0215 6 I .0219 I .0223 I .0227 1 -0231 1.0235 I .0239 1 .0243 1 .0247 1.0251 I -0255 7 I.02S9 I .0263 I .0267 1 .0271 1 .0276 1.0279 I .0283 1.0287 1 .0291 1 -0295 8 I .0299 1-0303 I .0308 I .0312 I .0316 I .0320 1-0324 1.0328 1-0332 1 -0336 9 I .0340 1-0344 1 0349 I 0353 I-03S7 I .0361 1-0365 1.0369 1-0373 1-0377 lO I. 0381 1.0386 I .0390 I 0394 1.0398 I .0402 1 .0406 I .0410 1.041S I. 0419 1 1 1.0423 I .0427 1 .0431 I 0435 1 .0440 I .0444 I .0448 I .0452 I .0456 I .0460 12 I .0465 I .0469 1 .0473 I .0477 1 .0481 I .0486 I .0490 1.0494 I .0498 I .0502 13 1.0507 1.0511 I .0515 1 .0519 1 -0524 1-0528 1-0532 1-0536 I .0540 I-OS45 14 I -0549 I-0553 I 0558 I .0562 1 .0566 1.0570 1-0575 I-OS79 1.0583 1-0587 IS 1.0592 I .0596 I .0600 1 . 0605 1 .0609 1-0613 I .0617 I .0622 I .0626 I .0630 i6 1.063s I .0639 I .0643 I .0648 I .0652 I .0656 I .0661 I .0665 1 .0669 1.0674 17 1.0678 I .0682 I .0687 I .0691 I -0695 I .0700 I .0704 I .0708 1 -0713 1. 0717 i8 I .0721 I .0726 I .0730 1 -073s I-0739 1 -0743 I .0748 I .8752 1 -0757 I .0761 19 1.0765 1.0770 I .0774 I .0779 1.0783 1.0787 I .0792 1.0796 I .0801 1 .0805 20 I .0810 I .0814 I .0818 1.0823 I .0827 1.0832 1.0836 1 .0841 1-0845 I .0850 21 I .0854 I .0859 1 .0863 I .0868 1 .0872 1.0877 1.0881 1.0885 I .0890 I .0894 22 I .0899 I .0904 I .0908 I -0913 I .0917 I .0922 1 .0926 I. 0931 I -093s I .0940 23 1.0944 1.0949 I 0953 1 -0958 I .0962 I .0967 1 -0971 I .0976 1.0981 1.098s 24 I .0990 1.0994 I .0999 I . 1003 I . 1008 I .1013 I . 101 7 I . 1022 1 . 1026 I .1031 25 I. 1036 I . 1040 1.1045 1 .1049 I. 1054 I. 1059 I - 1063 1.1068 1 . 1072 1. 1077 26 I . 1082 I. 1086 I . 1091 I . 1096 I . 1 100 I . iios I . II 10 I . 1 1 14 1 . 1 119 I . 1124 27 I .1128 1.1133 1 . 1138 I . 1142 I. 1147 1.1152 1.1156 1 . 1161 1 . 1166 I . 1170 28 I.II7S I . 1 1 80 1-1185 I. II 89 1.1194 I 1199 1. 1 203 I .1208 1 . 1213 1.1218 29 I . 1222 I . 1227 I . 1232 1.1237 I . 1241 I . 1246 1 .1251 I .1256 I . 1260 I . 1265 3° I . 1270 I.I27S 1 .1279 I .1284 I .1289 I .1294 I. 1299 I -1303 1.1308 I-1313 31 1. 131** 1-1323 1 -1327 I -1332 1-1337 I .1342 1-1347 1-1351 II3S6 1.1361 32 1. 1366 1-1371 1.1376 I. 1380 I. 1385 1.1390 1.139s I . 1400 I .1405 I . 1410 33 1.1415 1.1419 I .1424 I .1429 I-1434 I -1439 I .1444 I. 1449 1.1454 I-I4S9 34 I. 1463 I . 1468 1-1473 I. 1478 I -1483 1.1488 I. 1493 1.1498 I -1503 I. 1508 3S 1.1513 1.1518 I -1523 1.1528 I-1S33 I-1538 1.1542 I-IS47 1-1552 1. 1557 36 I. 1562 1.1567 1.1572 1-1577 1.1582 I. 1587 I .1592 I -1597 I . 1602 I . 1607 37 I . 1612 I . 161 7 I . 1622 1 . 1627 I -1632 1.1637 I. 1643 1.1648 11653 1.1658 38 I. 1663 1.1668 I .1673 1. 1678 I. 1683 I. 1688 I .1693 1 .1698 1-1703 1.1708 39 1-1713 1.1718 I .1724 I. 1729 1-1734 1-1739 1-1744 I-1749 1-1754 I.I7S9 40 I. 1764 I .1770 1-1775 I .1780 I. 1785 1. 1 790 I-I79S 1 . 1800 1. 1 806 I.i8n 41 1.1816 I .1821 I .1826 1.1831 I. 183 7 1.1842 I-1847 1.1852 1-1857 1.1863 42 I. 1868 I. 1873 1.1878 I. 1883 1.1889 1.1894 I . 1899 I .1904 1 . 1909 1 -191S 43 I . 1920 1-1925 1.1930 I .1936 I -1941 I. 1947 I-I9SI I -1957 I . 1962 I. 1967 44 1. 1972 1.1978 I. 1983 I. 1988 I. 1994 I 1999 I . 2004 I . 2009 I .2015 I . 2020 45 1.2025 I . 2031 I .2036 I .2041 1.2047 I .2052 I.20S7 I .2063 1.2068 I .2073 46 1.2079 I . 2084 I . 2089 1.2095 I . 2100 1 • 2105 1.2111 1.2116 1.2122 I .2127 47 I. 2132 I. 2138 I .2143 I .2149 1.2154 1-2159 I .2165 1 . 2170 I .2176 I .2181 48 1. 2 1 86 I . 2192 I .2197 I .2203 I .2208 I . 2214 1.2219 1 .2224 I .2230 1.2235 49 I .2241 I . 2246 I .2252 1.2257 I .2263 1.2268 I .2274 1 .2279 I .2285 I . 2290 50 1 . 2296 I. 2301 1.2307 1. 2312 1.2318 1-2323 I .2329 1-2334 I .2340 1-2345 * According to Dr. F. Plato (Kaiserlichen Normal-Eichungs-Kommission, Wiss. Abh., 2, 1900, page 153). This table (carried out to the 6th place of decimals) is given by the U. S. Bureau of Stan- dards. (Circ. 44, pp. 137-139) as the basis for standardizing hydrometers, indicating per cent of sugar at 20°, known as saccharometers or Brix spindles. The table is also useful in calculating the per cent of sugar from the specific gravity as determined by the pycnometer. Temperature corrections are given on page 649. 648 FOOD INSPECTION AND ANALYSIS. DENSITY OF SOLUTIONS OF CANE SUGAR AT -3- C— Continued 4 Tenths of Per Cent. ft I 2 3 4 5 6 7 8 9 50 1 . 2296 I .2301 1.2307 I .2312 I. 2318 1.2323 1.2329 1-2334 1-2340 I-234S SI 1-2351 1.2356 I .2362 1.2367 1.2373 1.2379 1-2384 1.2390 1-2395 I .2401 52 I . 2406 r . 2412 I . 2418 I .2423 I .2429 1.2434 I . 2440 I . 2446 1.2451 1.2457 53 I . 2462 1.2468 1.2474 1.2479 1-2485 I .2490 I . 2496 I . 2502 1.2507 1.2513 54 1-2519 1.2524 1-2530 1.2536 I. 2541 1.2547 I-2SS3 1.2558 1.2564 1.2570 55 1-2575 I. 2581 1.2587 I .2592 1.2598 I . 2604 I . 2610 I .2615 I . 2621 I . 2627 56 I . 2632 1.2638 I . 2644 I .2650 1.2655 I .2661 I .2667 1.2673 1.2678 1.2684 57 I . 2690 I .2696 I . 2701 1.2707 I .2713 1.2719 1.272s 1-2730 I -2736 1.2742 58 1.2748 1-2754 I-27S9 1.276s I. 2771 1.2777 1.2783 1.2788 1.2794 I . 2800 59 1.2806 I . 2812 I. 2818 1.2823 I .2829 1.2835 I. 2841 1.2847 1.2853 I .2859 60 1.286s 1.2870 1.2876 1.2882 1.2888 I .2894 I . 2900 I . 2906 I . 2912 I .2918 61 I . 2924 I . 2929 1.2935 1.2941 1.2947 1.2953 I -2959 1.2965 1-2971 I -2977 62 I .2983 I .2989 1.2995 I .3001 I .3007 I. 3013 I. 3019 1.302s 1-3031 1-3037 63 1-3043 1-3049 1.3055 I .3061 1-3067 1.3073 1-3079 1.308s I-3091 I -3097 64 1-3103 I. 3109 1.3115 I .3121 I-3127 1-3133 I. 3139 I. 3145 1. 3151 1-3157 65 I-3163 1. 3169 1.317s I. 3182 I. 3188 I. 3194 1.3200 I .3206 I .3212 1.3218 66 I .3224 I -323* 1.3236 1-3243 1.3249 1-3255 I .3261 I .3267 1.3273 1-3279 67 1.3286 I .3292 1.3298 1-3304 I. 3310 1-3316 1.3322 1.3329 1.3335 I -3341 68 1-3347 I-33S3 1.3360 1-3366 1-3372 1-3378 1.3384 1. 3391 1.3397 I -3403 69 1.3409 I. 3416 1.3422 1.3428 1.3434 1.3440 1.3447 1.3453 1. 3459 1.346s 70 1.3472 1-3478 1.3484 1-3491 1.3497 1.3503 1-3509 1.3516 1.3522 1-3528 71 1.3535 I. 3541 1.3547 1.3553 1.3560 1.3566 1-3572 1.3579 1-3585 1-3591 72 1.3598 I .3604 I .3610 I. 3617 1-3623 1.3630 1.3636 I .3642 I -3649 1-3655 73 I .3661 1.3668 1-3674 I. 3681 1.3687 1.3693 1.3700 1.3706 1-3713 1-3719 74 1.3725 1.3732 1-3738 1-3745 1-3751 I -3757 1.3764 1.3770 1.3777 1.3783 75 1-3790 1-3796 1.3803 I .3809 I. 3816 1.3822 1.3829 1-3835 1.3841 1.3848 76 1.3854 I. 3861 1.3867 1-3874 1.3880 1.3887 1-3893 I -3900 1.3907 1-3913 77 1.3920 1.3926 1.3933 1-3939 I -3946 I-39S2 I -3959 1.3965 1.3972 1-3978 78 1.398s 1.3992 I ■405» 1.3998 I .4005 I . 401 1 I .4018 1.4025 1. 403 1 1 .4038 I . 4044 79 1.4051 I .4064 I. 4071 I .4077 I .4084 I .4091 1.4097 I .4104 I .4111 80 1.4117 I. 4124 I .4130 1-4137 I -4144 1-4150 I. 4157 I .4164 I. 4170 I-4177 81 I. 4184 I .4190 I. 4197 I .4204 I . 4210 I .4217 1.4224 . I. 4231 1.4237 1.4244 82 1.4251 I -4257 I . 4264 1-4271 I .4278 I . 4284 I .4291 I .4298 I .4305 I -4311 83 1. 43 1 8 1-4325 1.4332 1.4338 I -4345 1-4352 1.4359 1.4365 1-4372 I -4379 84 1.4386 1.4393 1-4399 I .4406 I. 4413 I .4420 I .4427 1.4433 I -4440 1 -4447 8S 1-4454 I . 4461 1 .4468 1.4474 I .4481 I .4488 I. 4495 1.4502 1-4509 1-4515 86 1-4522 I -4529 1-4536 1.4543 1.4550 I .4557 1.4564 1.4570 1-4577 I .4584 87 I. 4591 I .4598 I .4605 I .4612 I . 4619 I .4626 1.4633 I .4640 I . 4646 1-4653 88 I . 4660 I .4667 I -4674 I. 4681 1.4688 1.4695 1.4702 1.4709 I. 4716 1-4723 89 1.4730 1-473 7 1.4744 1.4751 1.4758 1.476s 1.4772 1-4779 1.4786 1-4793 90 I .4800 I . 4807 I . 4814 I .4821 1.4828 1.483s I .4842 1.4849 1.4856 1-4863 91 I .4870 1.4877 1.4884 I .4891 1.4898 I .4905 I .4912 1.4919 I .4926 1-4934 92 I. 4941 1.4948 I -4955 I .4962 1.4969 I .4976 1 -4983 1.4990 I .4997 I .5004 93 I. 5012 1.5019 I .5026 I 5033 I . 5040 I-S047 1-5054 I .5061 1 .5069 I -5076 94 I • 5083 1.5090 I -5097 I .5104 1.5112 I .5119 I .5126 1.S133 I .5140 I-5147 95 I -SI 55 I .5162 I. 5169 1.5176 I-S183 I-5191 1.5198 I-520S I .52x2 1-5219 96 1-5227 1.5234 1-5241 1.5248 I-52S5 1-5263 1-5270 1-5277 1-5284 1-5292 97 I -5299 1.5306 I -53 1 3 1.5321 1-5328 i-53?5 1-5342 1-5350 5-5357 I -5364 98 1-5372 1-5379 1.5386 1.5393 I .5401 I -5408 I-5415 1-5423 1-5430 1-5437 99 I -5445 I-54S2 I-S459 1.5467 1-5474 I. 5481 1-5489 1-5496 1-5503 i-SSii 100 I . 5 5 1 8 SUGAR AND SACCHARINE PRODUCTS. 649 TEMPERATURE CORRECTIONS TO SACCHAROMETER READINGS (STANDARD AT 20° C.).* Observed Per Cent of Sugar. Tempera- ture in Degrees Centigrade. 5 10 15 20 25 30 35 40 45 50 55 60 70 Subtract from Observed Per Cent. o 0.30 0.49 0.6s 0.77 0.89 0.99 1.08 1. 16 1.24 1. 31 1-37 1. 41 1.44 1.49 5 0.36 0.47 0.56 0.65 0.73 o.8d 0.86 0.91 0.97 1. 01 I. OS 1.08 1 . 10 1. 14 lo II 12 13 14 0.32 0.31 0.29 0.26 0.24 0.38 0.35 0.32 0. 29 0.26 0.43 0.40 0.36 0.32 0.29 0.48 0.44 0.40 0.35 0.31 0.52 0.48 0.43 0.38 0.34 0.57 0.51 0.46 0.41 0.36 0.60 0.55 0.50 0.44 0.38 0.64 0.58 0.52 0.46 0.40 0.67 0.60 0.54 0.48 0.41 0.70 0.63 0.56 0.49 0.42 0.72 0.65 0.58 0.51 0.44 0.74 0.66 0.59 0.52 0.45 0.75 0.68 0.60 0.53 0.46 0.77 0.70 0.62 O.S5 0.47 IS l6 17 l8 19 0.20 0.17 0.13 0.09 0.05 0.22 0.18 0.14 0. 10 0.05 0.24 0.20 0.15 0. ID 0.05 0.26 0.22 0. 16 O.II 0.06 0.28 0.23 0.18 0.12 0.06 0.30 0.25 0. 19 0.13 0.06 0.32 0.26 0.20 0.13 0.07 0.33 0.27 0. 20 0.14 0.07 0.34 0.28 0.21 0. 14 0.07 0.36 0.28 0, 21 0.14 0.07 0.36 0.29 0.22 O.IS 0.08 0.37 0.30 0.23 0.15 0.08 0.38 ;.3i 0.23 0.15 0.08 0.39 0.32 0. 24 0.16 0.08 17.5 O.II 0. 12 0. 12 0. 14 o.is 0. 16 0.16 0.17 0.17 0.18 0.18 0.19 0.19 0. 20 15 36 (6o° F.) 0.18 0.20 0.22 0.24 0.26 0.28 0.29 0.30 0.30 0.32 0.33 0.33 0.34 0.34 A dd to Obser ved P er Cei it. 21 22 23 24 25 0.04 0. 10 "0.16 0. 21 0.27 0.05 0. 10 0. 16 0.22 0.28 0.06 0. II 0.17 0.23 0.30 0.06 0.12 0.17 0.24 0.31 0.06 0. 12 0. 19 0.26 0.32 0.07 0.13 0. 20 0.27 0.34 0.07 0.14 0.21 0.28 0.35 0.07 0.14 0.21 0.29 0.36 0.07 O.IS 0. 22 0.30 0.38 0.08 O.IS 0.23 0.31 0.38 0.08 0.16 0. 24 5.32 0.39 0.08 0. 16 0. 24 0.32 0.39 0.08 0.16 0.24 0.32 0.40 .0.09 0.16 0.24 0.32 0.39 26 27 28 29 30 0.33 0.40 0.46 O.S4 0.61 0.34 0.41 0.47 0.5s 0.62 0.36 0.41 0.49 0.56 0.63 0.37 0.44 0.51 0.59 0.66 0.40 0.46 O.S4 0.61 0.68 0.40 0.48 0.56 0.63 0.71 0.42 o.so 0.58 0.66 0.73 0.44 O.S2 0.60 0.68 0.76 0.46 0.54 0.61 0.70 0.78 0.47 0.54 0.62 0.70 0.78 0.47 0.55 0.63 0.71 0.79 0.48 0.56 0.64 0.72 0.80 0.48 0.56 0.64 0.72 0.80 0.48 0.56 0.64 0.72 0.81 35 0.99 1. 01 1.02 1.06 1. 10 1. 13 1. 16 I. 18 1.20 1. 21 1.22 1.22 1.23 1.22 40 1.42 1. 45 1.47 I. 51 1.54 1.57 1.60 1.62 1.64 1.65 1.65 1.65 1.66 1.65 45 1. 91 1.94 1.96 2.00 2.03 2.05 2.07 2.09 2.10 2. 10 2. 10 2.10 2.10 2.08 50 2.46 2.48 2.50 2.53 2.56 2.57 2.58 2.59 2.59 2.58 2.58 2.57 2.56 2.52 55 3 -OS 3.07 3.09 3.12 3.12 3.12 3.12 3. II 3.10 3.08 3.07 3.05 3.03 2.97 60 3 69 3-72 3-73 3.73 3.72 3.70 3.67 3.65 3.62 3.60 3.57 3.54 3.50 3.43 6S 70 75 80 4.4 S-i 6.1 7-1 4.4 5.1 6.0 7.0 4.4 5.1 6.0 7.0 4.4 5.0 5.9 6.9 4.4 5.0 5.8 6.8 4.4 5.0 5.8 6.7 4.3 4.9 5.7 6.6 4.2 4.8 5.6 6.4 4.2 4.8 5-5 6.3 4.1 4.7 5-4 6.2 4.1 4.7 5.4 6.1 4.0 4.6 5-3 6.0 4.0 4.6 5.2 5.9 3.9 4.4 5.0 5.6 * U. S. Dept. of Commerce and Labor, Bur. of Standards, Circular 44, 1913, p. 129. This table is calculated using the data on thermal expansion of sugar solutions by Plato (Wiss. Abh. der Kaiser- lichen Normal-Eichungs-Kommission, 2, 1900, p. 140), assuming the instrument to be of Jena i6''^ glass. The table should be used with caution and only for approximate results when the tempera- ture differs much from the standard temperature or from the temperature of the surrounding air. 650 FOOD INSPECTION AND ANALYSIS. plying the reading by 2, both direct and invert. Use the Clerget-Herzfeld formula for calculation of the sucrose. For medium- or light-colored grades of molasses, which yield but a small precipitate with lead subacetate, the above method of simple polarization, both direct and invert, gives results sufficiently accurate for ordinary work. For dark-colored, or "black-strap" molasses, or wherever extreme accuracy is required, the solution should be first made up to the mark and then clarified by the addition of a slight excess of anhydrous lead subacetate (p. 610), as proposed by Home, or else the double dilution method of Wiley should be em- ployed. Both methods make due allowance for the volume of the pre- cipitate. Double Dilution Method.^ — Take half the normal weight of the sample md make up the solution to 100 cc, using the appropriate clarifier. Take the normal weight of the sample and make up a second solution with the clarifier to 100 cc. Filter and obtain direct polariscopic readings of both solutions. Invert each in the usual manner and obtain the invert reading of the two. The true direct polarization of the sample is the product of the two direct readings divided by their difference. The true invert polariza- tion is the product of the two invert readings divided by their dif- ference. Determination of Raffinose in Beet Sugar Molasses. — For the deter- mination of sucrose and raffinose when present in the same solution, use the following formulas of Creydt as modified by Browne t to correspond with the Clerget-Herzfeld method of inversion: 0.5124^-6 •^ 0.839 ' and a-5 or 0.3266a -l-& R= 1-554 where 5= per cent of sucrose, 7? = per cent of raffinose, a = direct reading, and 6 = reading after inversion. * Wiley and Ehvell, Analyst, i8q6, 21, p. 184. t Handbook of Sugar Analysis, New York, 191 2, p. 283. SUGAR AND SACCHARINE PRODUCTS. 651 Davoll * recommends for purposes of clarification of tlie molasses the ase of powdered zinc after inversion of the molasses sample according to Clerget's method. He adds i gram of the zinc to the sample after in- version while at the temperature of 69° C, allowing it to act for three to fov.r minutes at that temperature, after which he cools and filters, with the production of an almost colorless solution. Determination of Reducing Sugar. — {Estimated as Dextrose.) — Dilute 5 grams of molasses or syrup with water in a loo-cc. graduated flask, using 2 to 5 cc. normal lead acetate. Make up to 100 cc, filter, take an aliquot part of the filtrate (25 to 50 cc.) and make this up to 100 cc, the amount taken being such that, when diluted, the solution will contain not more than J% of dextrose. Since lead acetate has been used to clarify, add to the aliquot part taken and before dilution, enough sodium sulphate to precipitate the excess of lead, then filter and make up to the 100 cc. mark. Determine the reducing sugar in this solution by either volumetric or gravimetric Fehling processes. U. S. Standard Molasses is molasses containing not more than 25% of water, nor more than 5% of ash. Adulteration of Molasses and Syrups. — A common adulterant of all these products is commercial glucose. From its water-white color and inert sweetness, no less than from its cheapness, it forms an admirable adulterant for dark-colored or low-grade molasses and syrups, counter- acting to a great extent by its smoothness the strong and often disagree- able taste of the inferior products with which it is mixed. Thus a grade of molasses too cheap to be ordinarily used for food purposes can be made to assume the appearance, and to some extent the taste, of the higher-priced and light-colored grades, by admixture with commercial, glucose. Tin salts are also used to improve the color of low-grade or dark molasses, and bleaching agents, such as sulphurous acid, are frequently employed. Copper is sometimes found, due to utensils or vessels used in processes of manufacture. Lead may occur in maple syrup, due to the leaden plugs or spigots through which the sap is sometimes drawn from the trees. Detection and Determination of Commercial Glucose.f — From the direct polarization of a normal solution of molasses or syrup the presence * Jour. Am. Chem. Soc, 25 (1903), p. 1019. t Leach, ibid., p. 982. 652 FOOD INSPECTION AND ANALYSI§. or absence of commercial glucose can usually be established. The direct polarization of a normal solution of pure molasses should not be much in excess of 50° on the Soleil-Ventzke scale, while a pure, dark-colored molas- ses should polarize well under 40°. Golden syrup and maple syrup read higher than molasses, and a normal solution of pure maple syrup may have a direct polarization as high as 65°, being more often than not above 60°. An excessively high direct polarization is at once an indication of the presence of commercial glucose, while an invert reading at ordinary room temperature to the right of the zero-point is an almost positive proof of its presence in either of the above products. The optically active constituents of commercial glucose, viz., dextrin, maltose, and dextrose, are present in such varying amounts, that it is impossible to determine accurately the exact amount of this adulterant in complex saccharine products which themselves contain components common to glucose. Its approximate amount can, however, be very satisfactorily estimated in molasses and syrups by the use of the follow- ing formula: 175 ' where G = per cent of commercial glucose, a = direct polarization, and 5= per cent of cane sugar previously obtained from the Clerget-Herzfeld formula. A large amount of invert sugar present affects the accuracy of this formula. It is especially applicable to maple syrup, wherein the per cent of invert sugar is small, but may be applied also to molasses and golden syrup, wherein the amount of invert sugar is not so large but that results may be obtained as close as it could be expected from an empirical formula.! In saccharine products containing considerable invert sugar the invert reading at 87° C. obtained as directed on page 671, is divided by * Leach, U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 48. t This formula is based on the assumption that 42° Be. mixing glucose, the grade specially made and used for admixture with molasses, syrups, and honey, has a maximum polarization of 175° V. It was adopted as a result of investigations made some years ago by the author, but subsequently it appeared that 42° Be. mixing glucose polarizes lower than formerly. Thus a sample recently examined by the author polarized at 162.4° V. Pending further investigations it seems best for the present to retain the old formula, for, while it undoubtedly gives low results, especially with higher admixtures of glucose, it approximates the truth more closely than would be expected, perhaps because it tends to compensate for the error due to substances in genuine molasses and honey that polarize to the right after inversion. Furthermore, it has been adopted by the A. O. A. C. To avoid misunderstanding, express results in terms of glucose polarizing at that factor. SUGAR AND SACCHARINE PRODUCTS. 653 the appropriate factor (163) to obtain the percentage of commercial glucose. While theoretically pure molasses and syrups would be expected to show no rotation when polarized at 87° C. after inversion, as a matter of fact most samples exhibit a decidedly right-handed reading at that temperature. Occasionally a zero reading is noted, and in rare instances a slight left-handed rotation occurs under the above conditions, Dextro-rotation is undoubtedly caused by some form of decomposition or fermentation. It may be due to a preponderance of dextrose in the reducing sugars, since levulose is more easily decomposed than dextrose, or it may be caused by the decomposition products formed when the raw juice is being defecated with lime, or again it might result from a special fermentation forming dextran. The following table shows results by A. H. Bryan* of polarization of samples of Louisiana molasses and syrup of known purity, showing especially the invert readings at 87° C: POLARIZATION OF LOUISIANA MOLASSES AND SYRUP. MOLASSES. SYRUP. Direct Polariza- tion at 20° C. Corrected Invert Polarization — Dry Substance. Direct Polariza- tion at 20° C. Corrected Invert Polari zation — Dry Substance. At 20° C. At 87° C. At 20° C. At 87° C. ° V. 40.8 24.6 26.0 42.4 52-4 55-6 39-6 39-6 ° V. — 20.24 — 20.9 -18.26 -16.94 -16.28 -13-59 — 18.04 -17.82 — 17.16 — 17.60 -17.27 -16.94 — 1 7 . 60 -19.8 -25.08 — 16.72 -14.74 -15-4 ° V. + 2.2 + 2.2 + 3-52 + 2.42 + 2.20 + 4.18 + 2. 20 + 2.20 + 2.64 + 2.42 + 3-52 + 3.96 + 3-52 0.00 + I.IO + 3-96 + I.IO + 2.20 Per Cent. 80.8 76.8 76.8 78.2 69.1 69.6 80.8 79.0 72.0 73-8 76.1 74.0 76.1 78.1 87-5 84.1 75-0 78.0 ° v. 48.4 54-0 50.2 50-4 61.8 ° V. -17.6 -18.7 — 12. 1 -14-3 -16.5 ° V. + 1.98 + 3-3° + 6.i6t + 1.76 + 2.20 Per Cent. 74-3 68.3 Average. Maximui Minimur + 2.65 + 6.16 0.00 44.0 42.0 n n. 42.4 41.6 52-4 26.6 50.8 22.6 41.6 45-6 * A. O. A. C. Proc, 1908, U. S. Dept. of ■\ Sample ropy and badly fermented. jric, Bur. of Chem., Bui. 122, p. 182. 1 654 FOOD INSPECTION AND ANALYSIS. TYPICAL ANALYSES OF MOLASSES AND SYRUPS ADULTERATED WITH COMMERCIAL GLUCOSE. Polarization. § O Of? <-> o aj C u 3fi p bcQ "S ii-"i U (a) Molasses W " (c) " (a) Golden drip syrup (6) " " (c) " ''a) Maple syrup (b) " " (0 " " 62 98 109 73 109 143 76 77 87 + 36.3 + 71-9 + 90 + 39-8 + 87.6 + 136.0 + 7.6 + 24 + 30.6 18° 18° 17° 18° 17° 18.4° 18.6° 19° 22.4° 19 19.9 14-5 25 16.9 5-6 51 40.1 42.5 30-03 27.62 33-11 31.61 33-44 38-17 10.55 16. QO 24.6 45 -o 54-4 27.7 52.8 78.5 14.4 21.6 25.4 29.36 27.98 22.02 23.67 24.48 21.52 31-91 23-44 28.80 3-83 3-53 2.67 3-94 2-51 1. 00 0.65 1.08 Determination of Dextrin. — According to Beckman's method a weighed amount of the honey or molasses is diluted with an equal volume of water and from ten to twelve times its volume of methyl alcohol is added. The precipitated dextrin is collected in a tared filter and thor- oughly washed with methyl alcohol, after which it is dried and weighed. Reduction of Saccharine Products to an Ash for Mineral Analysis. — If a considerable quantity of molasses, syrup, or other saccharine sub- stance is to be burnt to an ash, it is both tedious and annoying to ignite directly, by reason of the excessive swelling and frothing of such substances during ignition. Small quantities of molasses, syrup, or honey may with care be reduced to an ash by the method described on page 609. If a readily controlled electric current is available, it may be utilized as follows : * Mix 100 grams cf molasses, syrup, or other saccharine solution, which should be evaporated to syrupy consistency if not already such, with about 35 grams of concentrated sulphuric acid in a large porcelain evaporating-dish. An electric current is then passed through it while stirring, by placing one platinum electrode in the bottom of the dish near one side and attaching the other to the lower end of the glass rod, with which the contents are stirred. Begin with a current of about I ampere and gradually increase to 4.f In from ten to fifteen minutes * Leach, 32d An. Rept. Mass. State Board of Health (1900), p. 653. Reprint, p. 37. This method is preferred to the ordinary method of heating with sulphuric acid, especially in case of molasses, because, if properly manipulated, it so quietly comes into the form of a very finely divided char or powder, especially adapted for subsequent quick ignition. f Modified from method of Budde and Schou for determining nitrogen electrolyticall/. Ztschr. anal. Chem., 38 (1899), p. 345. SUGAR AND SACCHARINE PRODUCTS. 655 the mass is reduced to a fine, dry char, which may then be readily burnt to a white ash in the original dish over a free flame or in a muffle. Or, ICO grams of the molasses or syrupy solution to be ashed may be first evaporated to dryness and afterward mixed with from lo to 20 cc. of concentrated sulphuric acid in a porcelain evaporating-dish, or if the substance to be ashed be a dr}^ sugar or confectioneiy, 20 grams are mixed with the above amount of acid. Heat is gently applied by means of the gas flame till the swelling and frothing have ceased, which usually requires only a few minutes. The final ignition is then accomplished in the usual manner, nitric acid being added if necessary to completely destroy the organic matter. Determination of Tin in Molasses. — Fuse the ash from a weighed portion of the sample with sodium hydroxide in a silver crucible, dis- soh'e in water, and acidulate with hydrochloric acid; filter and precipi- tate the tin from this solution with hydrogen sulphide; wash the pre- cipitate on a filter and dissolve it in an excess of ammonium sulphide. Filter this solution into a tared platinum dish, and deposit the tin directly in the dish by electrolysis, using a current of 0.05 ampere and the appa- ratus described on page 634. Distinction between Invert Sugar, Maltose, and Lactose.* — All these sugars reduce Fehling's solution. Dextrose and Icvulose (invert sugar) when boiled with Barfoed's copper acetate solution (14 grams crystal- lized copper acetate and 5 cc. acetic acid in 200 cc. water) will form a precipitate of cuprous oxide, while neither maltose nor lactose will do this. The solution, which has thus been tested for invert sugar and found to be free, or the filtrate from the cuprous oxide precipitate, is treated with an excess of basic lead acetate, filtered, and to the filtrate is added an excess of sodium sulphate solution to precipitate the lead. The solution 13 again filtered and treated with copper sulphate solution, if not already blue. It is then made alkaline with sodium hydroxide and heated to boiling. A red precipitate of cuprous oxide at this stage indicates either lactose or maltose or both. A solution of the sugar, made strongly ammoniacal, is then mixed with alkaline bismuth solution f and the container is set in a water- bath at 60° C. Maltose soon reduces the bismuth, but lactose does not. To test for lactose, add strong nitric acid to the solid sugar residue * Bartley and Mayer, Merck's Report, 12 (1903), p. 100. t This reagent is prepared as follows: Bismuth subnitrate, 2 grams; Rochelle salt, i grams; sodium hydroxide, 8 grams; dissolved in 100 cc. of water by the aid of heat. 656 FOOD INSPECTION AND ANALYSIS. and warm gently till red fumes come off. Then set the container in hot water and cool gradually. Crystals of mucic acid appear after a time if any appreciable amount of lactose be present. Determitiation of Lactose or Maltose. — Either sugar, if in solution free from other reducing sugars, may be determined by the volumetric Fehling method (page 615) or by the Defren method, using the table on page 619. For the determination of maltose in commercial glucose, see page 661. Estimation of Cane Sugar and Dextrose in Mixtures. — Obtain true direct and invert readings of a normal solution of the mixture. Deter- mine the per cent of sucrose by Clerget-Herzfeld formula. This figure represents the right-handed rotation due to a sucrose. Subtracting this from the direct polarization, the difference represents the right-handed rotation due to dextrose. The specific rotatory power of sucrose is 66.5 and that of dextrose 52.76. Calling d the percentage of dextrose and R' the right-handed rota- tion due to dextrose as above obtained, if the Soleil-Ventzke scale is used. 66.5:52.76 = c?:i?', whence 66.57?' d= 52.76* ANALYSIS OF MAPLE PRODUCTS. Preparation of Sample. — S3rrups are analyzed in the condition they are placed on the market, rejecting any sediment which may have settled out. Jones has noted that if maple sugar is analyzed in its commercial form the results would include mineral matter and other insoluble constituents which might invite a considerable admixture of ordinary sugar. It is therefore important to carry out the analysis on a syrup prepared according to Bryan * as follows : Dissolve 100 grams of the sugar in at least 200 cc. of water and boil down to 65% of solids. If the solution is cloudy, filter after the liquid has been boiled down to about ^0% of solids, then complete the concentration. Allow to stand at 20° C. for two days and decant from the sediment. Determination of Moisture. — This is accomplished by direct drying with sand, or by calculation from the specific gravity, or, preferably from the refractive index. See molasses methods, page 643. * A. W. Bryan, U. S. Dept. of Agric, Bur. of Chem., Circ. 40, p. 6. SUGAR AND SACCHARINE PRODUCTS. 657 Determination of Ash. — Burn 5 grams in a platinum dish by the usual method, observing the precautions given for molasses, page 644. Soluble and Insoluble Ash* — To the platinum dish containing the ash add 40 cc. of hot water and boil gently for two minutes. Filter through a small ashless filter, and wash with hot water until the filtrate amounts to ICO cc. Return the filter to the dish used for ashing, burn at a low red heat, cool and weigh, thus obtaining the insoluble ash. The soluble ash is obtained by difference, subtracting the weight of insoluble from that of total ash. Alkalinity of Soluble Ash."^ — Allow the filtrate from the above deter- mination to cool, then titrate with tenth-normal hydrochloric acid, using methyl orange as an indicator. Alkalinity of Insoluble Ash.* — Add excess of tenth-normal hydrochloric acid (usually 10 cc.) to the ignited insoluble ash in the platinum dish, boil gently, cool and titrate with tenth-normal sodium hydroxide, using methyl orange as an indicator. Express the alkalinity in each case as the number of cubic centimeters of tenth-normal acid on the ash of i gram of sample. Determination of Sucrose. — Calculate by Clerget-Herzfeld formula (page 610). Use 5 cc. of alumina cream but no lead subacetate except when necessary and then but i cc. Determination of Reducing Sugar. — Follow Defren-O' Sullivan or Munson and Walker method (pages 618 and 622). Determination of Malic Acid Value. — Leach and Lythgoe Method, f modified by Cowles.X — The modified method differs from the original chiefly in that no ammonia is added and calcium acetate is substituted for calcium chloride ; it gives slightly higher results. Weigh 6.7 grams of the sample in a sugar dish, transfer to a 200-cc. beaker with 5 cc. of water, add 2 cc. of a 10% calcium acetate solution, and shake. Stir in 100 cc. of 95 per cent alcohol and warm the solution until the precipitate settles, leaving the supernatant liquid clear. Filter off the precipitate and wash with 75 cc, of 85% alcohol, dry the filter paper, and ignite in a platinum dish. Add 10 cc. of tenth-normal hydrochloric acid and warm gently until all the lime dissolves. Cool and titrate back with tenth-normal sodium hydroxide, using methyl orange as an indicator. One-tenth of the number of cubic centimeters of tenth-normal acid is the * A. H. Bryan, U. S. Dept. ofAgric, Bur. of Chem., Circ. 40, p. 6. t Jour. Amer. Chem. Soc, 26, 1904, pp. 380, 1536. t Ibid., 30, 1908, p. 1285; U. S. Dept. of Agr., Bui. 466, 1917, p. 11, 658 FOOD INSPECTION AND ANALYSIS. malic acid value. Run a blank determination with each set of deter- minations, using the same amount of reagents, and subtract the result obtained from the malic acid number. Determination of Lead Number. — Winton Method* — Weigh 25 gi-ams of the material (or 26 grams if a portion of the filtrate is to be used for polarization) and transfer by means of boiled water into a loo-cc. flask. Add 25 cc. of standard lead subacetate solution, fill to the mark, shake, allow to stand at least three hours and filter through a dry filter. From the clear filtrate, pipette off 10 cc, dilute to 50 cc, add a moderate excess of sulphuric acid, and 100 cc. of 95% alcohol. Let stand over night, filter on a Gooch crucible, wash with 95% alcohol, dry at a moderate heat, ignite at low redness for three minutes, taking care to avoid the re- ducing cone of the flame, cool, and weigh. Calculate the amount of lead in the precipitate, using the factor 0.6831, subtract this from the amount of lead in 2.5 cc. of the standard solution, multiply the remainder by 100, and divide by 2.5, thus obtaining the lead number. The standard lead subacetate is prepared by diluting one part of the ordinary solution (page 610) with four volumes of water, filtering if not clear. It is standardized by a blank determination conducted as above described, but acidifying with a few drops of acetic acid before making up to volume, as recommended by A. H. Bryan. The solution deposits a slight precipitate on standing, but this does not usually appre- ciably affect its strength. The range in lead number of maple products calculated to the dry basis is given on pages 593 and 594; Snell and Scott have shown, how- e\'er, that the range in the case of syrups is narrower when the compari- son is made on the wet basis. Adding of cane sugar reduces the lead number to a greater degree than the percentage of admixture thus rendering the fact more apparent, Ross Modification. '\ — This process yields higher results than the original methods (see page 594). The number of mixtures of maple and cane syrups (or sugars) is proportional to the admixture. Transfer 25 grams of the syrup to a loo-cc flask, using about 25 cc. of freshly boiled water, add 10 cc. of potassium sulphate solution (7 grams per liter), then 25 cc. of lead subacetate solution of the strength employed in the foregoing method. Make up to the mark with boiled water and proceed as in the Winton method. * Jour. Am. Chem. Soc, 28, 1Q06, p. 1204. t U. S. Dept. of Agric, Bur. of Chem., Circ. 53, SUGAR AND SACCHARINE PRODUCTS. 659 Run the blank in exactly the same way, substituting 25 grams of pure cane sugar syrup (66 grams of sucrose dissolved in 34 grams of water) for the maple syrup. McGill or Canadian Method."^ — To 5 grams of the dry sugar, or its equivalent in syrup, dissolved in water and made up to 20 cc, add 2 cc. of lead subacetate solution, mix and allow to stand for two hours. Filter on a Gooch crucible, or sugar tube packed with asbestos, wash 4 to 5 times with hot water, dry, and weigh. Multiply the weight by 20 to obtain the lead number. In genuine maple syrups McGill found a range of 1.37 to 6.56 for 456 samples (using 5 grams of syrup), Snell and Scott a range of 1.74 to 7.50 for 126 samples (using 5 grams of dry matter). Snell, MacFarlane, and Von Zoeren Volumetric Method.'\ — Dilute the syrups with water, boil until the temperature reaches 219° F, and filter through cotton wool. After cooling, dilute to cc. to 100 cc. with distilled water, and measure 60 cc. of the diluted solution into a loo-cc. beaker. Measure the electrical resistance using a dip electrode as described for the Snell method of determining electrical resistance (page 661). Maintaining the temperature constant, add i cc. of lead acetate solution (a filtered solution of Home's lead subacetate sp.gr. 1.033) ^^m a burette, stir well, and again measure the electrical resistance. Continue the addi- tion in this manner, i cc. at a time, until 10 cc. have been added. Plot the resistances found against the quantities of subacetate solution used. If the syrup is genuine the results of the plot will be two intersecting straight lines. In 70 genuine maple syrups examined by the originators of the method the intersections fell between 4.8 and 6.6 cc. Pure maple sugars converted into syrups give practically the same values as pure syrups. | Determination of Volume of Lead Precipitate. § — Hortvet Method. — The apparatus consists of (i) a tube, 15.3 cm. in length, made up of a wide cylindrical portion 3 cm, in diameter, narrowed at the top to a neck 2 cm. in diameter, and at the bottom to a stem graduated in tenths to 5 cc. and (2) a holder, made of pine or white wood, of a size adapted to carry the tube in the shield of the centrifuge. The holders and tubes should be arranged in balanced pairs in the centrifuge. * Lab. Ind. Rev. Dept., Ottowa, Bui. 228, 1911, p. $. t Jour. Ind. Eng. Chem., 8, 1916, p. 241. X Ibid., 8, 1916, p. 421. § Jour. Am. Chem. Soc, 26, 1904, p. 1532. 1 660 FOOD INSPECTION AND ANALYSIS, f Introduce 5 cc. of syrup or 5 grams of sugar into the tube. Add 10 cc. of water, and dissolve completely. Next add 10 drops of alumina cream, and 1.5 of lead subacetate. Shake thoroughly, and allow to stand from forty-five to sixty minutes. Place the tube in its holder in the centrifuge shield, and run six minutes. If, after the end of this time, any material adheres to the sides of the wide part of the tube, loosen with a small wire or by giving the tube a slight twist, then run the tube six additional minutes, and finally read the volume of the precipitate in the stem, estimating to o.oi cc. Run a blank with the above reagents in water, subtracting the blank reading from that of the precipitate. In the case of syrup, reduce to the 5-gram basis by dividing by the specific gravity of the sample. If the sugar content of the sample is known, the specific gravity can be calculated from the table on page 648. For pure maple syrup 1.33 is very nearly correct. The centrifuge used by Hortvet had a radius of 18.5 cm. and was run at a speed of 1600 revolutions per minute. The corresponding velocity in cm. per second (v) and revolutions per minute (R) for any given centri- fuge with a radius of r cm. may be calculated by the following formula): v=\/^2o,ooor, R = 6ov/2irr. Results by Hortvet on pure maple syrups vary from 1.2 cc. to about 2.5 cc, and on pure maple sugars from 1.8 to 4 cc. Commercial brands of adulterated syrups and sugars give such pre- cipitates as 0.00 cc, 0.02 cc, 0.05 cc, and 0.08 cc Hortvet regards with suspicion a syrup testing lower than 1.2 cc, and when the result is below I cc, the sample is positively condemned as being mixed with refined cane sugar. In the case of sugar, a somewhat higher minimum figure is adopted than with syrup. In view of the fact that the speed has much to do with the volume of the precipitate, the analyst should make a series of similar experiments with his own centrifuge, and work out his own standards. Results may be better compared with each other, if calculated on the water-free basis. In case of doubt, and in fact in all cases at first, it would be well to make confirmatory tests, such as determining the ash and reducing sugar. Sy's Lead Method.* — In a 25-cc. graduated cylinder introduce 5 cc. of syrup, or 5 grams of sugar which is afterwards dissolved in a little * Jour. Am. Chem. Soc, 30, 1908, p. 1430. SUGAR AND SACCHARINE PRODUCTS. 661 water. Add water to the 15 cc. mark and 2 cc. of lead subacetate solution. Shake thoroughly and allow the mixture to stand twenty hours. Then read the volume of the precipitate, which for pure maple products should be at least 3 cc. and is usually over 5 cc. Determination of Electrical Conductivity Value. — Snell Method.'^ — Measure out into a small beaker (or directly into the conductivity cell) 20 cc. of the syrup, allowing thorough draining. Using the same graduate, add two successive portions of water, each equal in volume to the syrup taken. Mix thoroughly, pour into conductivity cell, bring to 25° C, and make the measurement. Divide the constant of the cell by the observed number of ohms and multiply the result by 100,000. Genuine syrups examined by Snell and co-worker have given values of 96 to 230. The essential features of the apparatus are: 1. A low voltage electrical current operating an induction coil. 2. A conductivity cell of a form suitable for liquids of low conductivity, and with electrodes not easily displaced.! 3. A Wheatstone bridge with telephone. 4. A device for exact regulation of temperature. ANALYSIS OF COMMERCIAL GLUCOSE. Wiley X has worked out a method for calculating the percentage of dextrin, maltose, and dextrose present in commercial glucose, based on the specific rotatory power of these substances and on the reducing power of maltose and dextrose. To apply this method, the operator, if he has a polariscope reading in sugar scale degrees, must ascertain the equivalent readings in angular degrees from the table on page 606, and calculate the specific rotatory power in each case from the formula («)o=-^, page 607. Thus, if he possesses a Schmidt and Haensch instrument, he should multiply the true reading, as obtained on that instrument, with a normal solution of the given sugar or mixture, by the factor 0.3468, to convert the reading into circular degrees from which to figure the specific rotatory power as above. * Jour. Ind. Eng. Chem., 5, 19 13, p. 740. t Van Zoeren, Jour. Amer. Chem. Soc, 38, 1916, p. 652. % Chem. News, 46, p. 175; Agric. Anal., 3, pp. 288-290. 662 FOOD INSPECTION AND ANALYSIS. The specific rotatory power of dextrin is fixed at 193, that of maltose at 138, and that of dextrose at 53. Then if P = total polarization of the mixture in terms of specific rotatory power, c?==per cent dextrose, m = per cent maltose, and c?' = per cent dextrin, P-53(/ + i38w + i93(i'. . (i) The value of P is obtained from observation and calculation as above described on a known solution of the sample, say 10 grams in ico cc. The reducing sugars, maltose and dextrose, are then removed, prefer- ably by oxidation with cyanide of mercury, as follows :* Prepare the reagent by dissolving 120 grams mercuric cyanide and 120 grams sodium hydroxide in water, mixing the two solutions, and making up to 1000 cc. Remove any precipitate that may gather by filtration. Make a solution of 10 grams of the glucose sample in 100 cc. and take 10 cc. of this solution in a 50-cc. graduated flask. Add sufiicient mercuric cyanide solution to have an excess of reagent after the oxidation (from 20 to 25 cc), and boil for three minutes under a hood with a good draft. Cool and neutralize the alkali with concentrated hydrochloric acid, adding the latter till the brown color is discharged. By this method the optical activity of the maltose and dextrose is discharged, while that of the dextrin remains unaffected. From the polariscope reading cal- culate as above the specific rotatory power of the dextrin (P'), Then P'=^92>d' (2) The reducing power on Fehling's solution of dextrose is to that cf maltose as 100 is to 62. Whence, if i? = reducing sugar (reckoned as dextrose) we have R = d+o.62m (3) Subtracting equation (2) from equation (i) we have P-P' = 53^ + i38m (4) Multiplying equation (3) by 53 and subtracting from equation (4), P-P' = 53^ + i38m, 53^ = 53^+32-86w, P-P^ -53^= 105-14^ (5) * Wiley, Agric. Anal., p. 290. 1 SUGAR AND SACCHARINE PRODUCTS. 663 Therefore w= T^^TT, — ' (^) 105.14 /^ d = R— 0.62m, (7) d' =— (8) 193 Determination of Dextrin in Commercial Glucose. — One volume of the sample is well shaken with about 10 volumes of 90% alcohol, and the precipitated dextrin is separated by filtration through a tared filter, washed thoroughly with strong alcohol, dried at 100°, and weighed. Qualitative Tests for Commercial Glucose. — Several confirmatory chemical tests may be employed for commercial glucose, aside from the optical test with the polariscope. Thus a precipitate of dextrin by treatment of the sample with an excess of strong alcohol, in the absence of mineral salts insoluble in alcohol, is strongly indicative of commercial glucose. An excess of sodium chloride in the ash also points strongly to the presence of glucose. Determination of Ash. — Formerly, when sulphuric acid was used for conversion of the starch, the ash consisted largely of calcium sulphate, but at present when hydrochloric acid is almost exclusively used the mineral matter is almost entirely common salt, formed by the neutralization of the acid. Determine ash by burning in a platinum dish at dull redness as in the case of other saccharine products. Qualitative or quantitative tests may be made for chloride, in the latter case calculating the equivalent amount of sodium chloride. If the amount of sodium chloride found does not equal the total ash, sulphates may be looked for. Determination of Sulphurous Acid. — At the present time glucose usually is free from an appreciable amount of sulphurous acid which formerly was extensively employed for bleaching. It may be determined by distillation, oxidation to sulphuric acid, and precipitation with barium chloride as described on page 313. Detection of Arsenic. — Since the Manchester epidemic of arsenical poisoning, due to the consumption of beer prepared from glucose con- taminated through the sulphuric acid with this poison, it is highly important that both the acid used for conversion and the glucose be frequently tested for this contamination. 664 FOOD INSPECTION AND ANALYSIS. The tests may be made on 2 to 5 grams of the materials without charring or destruction of the organic matter, by the Marsh test or the Sanger- Black-Gutzeit test as described under general methods on pages 63 to 66. The English limit of one and one-half parts per million calculated as metallic arsenic should not be exceeded. HONEY. Composition and Occurrence. — Honey is the saccharine product deposited by bees {Apis mellijica and A. dorsata) in the cells of honey- comb, which the insect forms out of wax secreted by its body. Honey has its source chiefly in the nectares of flowers, from which the bees abstract it, also in the juices of ripe fruits and the exudations of leaves (honeydew). While in the honey-sac of the bee, the sucrose, which forms the chief constituent of the fruit juice or nectar, becomes for the most part inverted, forming, in the honey, dextrose and levulose. The evaporation to a syrupy consistency is effected in the hive by exposure to a current of air, produced by fanning of the wings of the bees. The flavor of honey varies considerably, according to its source. Besides water and the sugars named honey contains dextrin and small amounts of protein, mineral matter (including phosphates), and organic acids. Pollen is usually present, also as a rule a small quantity of wax. Fincke * states real honey may or may not contain formic acid. European Honey. — Neufeld f gives the following limits for pure honey : Water 8.30 to 33.59% Protein 0.03 to 2.67% Invert sugar 49 . 59 to 93 . 96% Sucrose o . 10 to 10 . 12% Dextrin 0.99 to 9.70% Formic acid 0.03 to 0.21% Ash 0.02 to 0.68% Canadian Honey.— A large number of samples of genuine honey analyzed in 1897 for the Department of Inland Revenue, Canada (Bui, 47), showed the following variations: * Zeits. Unters. Nahr. Genussm., 23, 1912, p. 255. t Der Nahrungsmittelchemiker als Sachverstandiger, Berlin, 1907, p. 275. SUGAR AND SACCHARINE PRODUCTS. 665 Direct polarization — 2.4 to — 19 Invert " -10.2 " -28 Sucrose (by Clerget) 0.5 " 7. 64% Invert sugar 60.37 " 78.8% Water 12 '* t,t,% Ash 0.03 " 0.50% American Honey. — Browne* has examined 97 samples of American and Hawaiian honey, representing the product made from the nectar of numerous flowers as well as honeydew. Maxima and minima of polarizations and analyses of some of the more important kinds, and of all the levorotatory and the dextrorotatory samples are given in the table on page 666. As regards the chemical characteristics of honey from different flowers, Browne states that alfalfa honey usually has less dextrin and undetermined matter — the so-called ' impurities " — and more sucrose than the other varieties, although the low amount of impurities is, to some extent, char- acteristic of the honey of the whole family (leguminosa?) . The compositae yield honey with about the average amount of organic non-sugars; the rosaceae yield a product low in dextrin, but high in undetermined m tter. Buckwheat and other polygonaceous honeys contain almost no sucrose, but give tests for tannins. Basswood honey is relatively high in dextrin, and that from poplar, oak, hickory and other trees, all of which contain considerable quantities of honeydew, are rich in both dextrin and ash. Pronounced tannin reactions are obtained in honey gathered from the flowers or plants of the sumac, hop and others rich in tannin. Tupelo, mangrove and sage honeys are distinguished by their high levulose content. Browne found the average per cent of water in honey from the arid states of Arizona, Nevada, Utah, and Colorado was 15.60, and from the humid states of Minnesota, Wisconsin, Illinois, Missouri and Iowa was 18.88. Hawaiian Honey. — This is characterized by its high ash and the presence of decided amounts of chlorides in the ash. Van Dinef states that the floral honey of Hawaii is largely from the blossoms of the algarroba {Prosopis juliferd), while the honeydew honey, which, together with mixtures of honeydew and floral honey forms about two-thirds of the * U. S. Dept. of Agric, Bur. of Chem., Bui. no (1908 flbid., p. 52. 666 FOOD INSPECTION AND ANALYSIS. ^ •DIUIJOJ SB ppV 33-1^ 6? w O d d •pauiiu -ja^apuj-)^ 4 d \0 r^ •& \0 rf •uu:(X3Q •qsv ■asojong •jBgng IjaAuj U9JBA\ ^ w" d d >* 00 CO "OoiS ■Oo°2^ + + + + M 00 + + M-00 vO \0 ro 4 -i CO CO ++ +++ ++ ++ ro O + I O CO CO ro \0 i-i I I I II II I I I + I I + + + I •Ooig ^ O 00 00 o o >0 LOCO Tt-00 00 ci c^ ++ ++ ++ ++ ++ +++ ++ + + + + :>ub;suo3 O 0^ 00 ^ ro O 00 l^) "0 II III I I CO f^ 4 d I I o°^ 5« ajBipauiuij lo O CO o to ft. 3 ni 2 |5§ is s g| I s-^,|i si i s .s s ^.e s r^i s S .s £ c^ OH ffi O p p ^ 3 -3 i5.g S g.6 S § js:s2^:s SUGAR AND SACCHARINE PRODUCTS. 667 product of the Hawaiian Islands, comes largely from the exudations of the sugar-cane leaf-hopper {Perkinsiella saccharicida) , and the sugar- cane aphis {Aphis sacchari). Honeydew honey is dextrorotatory, and for this reason has often been condemned as adulterated. It has a strong molasses-like odor, and often a very dark color. Bakers prefer it to algarroba honey, because of its baking and boiling properties. The variation in the composition of Hawaiian honey is shown in the table on page 666, compiled from Browne's data. Cuban, Mexican, and Haitian Honey. — The following table contains analyses of :i^T, Cuban, 23 Mexican, and 16 Haitian honeys by A. H. Bryan.* One of the samples gave a faint color with Browne's test, but not sufficient to confuse the sample with honey containing an appreciable amount of commercial invert sugar. Fiehe's test gave faint reactions in five samples. Direct polarization: Immediate at 20° C Constant at 20° C Constant at 87° C , Invert polarization: At 20° C At87°C Water per cent Invert sugar " Sucrose " Ash *' Dextrin " Undetermined " Free acid as formic ... " Cuban. — 6 . 1 to — 20. o — 8. 6 to— 21. 1 -{- 6.oto-|-i7.o — 8.9 to -23.4 + 4.5 to-l-is.4 16.05 to 27.00 68.09 to 77.56 00 00 to 2 99 0.07 to 0.39 o. 29 to 3 96 1.23 to 8.07 O. GO to 0.43 Mexican. — 7.2 to— 22. 9 — 8 . 5 tcf — 24 . 2 + 3.2 to -I-15.7 — 9.3 to —26. 1 + 2.9 to-Hi3.4 19.43 to 24.40 69.27 to 75.04 o . 00 to 3.98 o. 13 to 0.58 0.52 to 3.48 1.35 to 6.30 0.07 to 0.35 Haitian. — II .3 to —19.6 — 12.5 to —20.7 -I- 4.3 to -j-io.7 -13.3 to-22.7 -t- 3.5 to-Hio.i 18.60 to 22.05 69.15 1076.73 o. 00 to 2 . 44 0.06 to 0.45 o. 26 to 1.65 o . 66 to 5 . 46 0.03 to o. 28 Dextrorotatory Honey. — The U. S. standards define honey as leevo- rotatory, thus excluding the larger part of the Hawaiian product, and also unimportant kinds of honey made from certain trees. Pure floral honey with no admixture of honeydew is seldom if ever dextrorotory. The following are the results obtained by Browne in the examination of dextrorotatory honeys: * U. S. Dept. of Agric. Bur. of Ciiem., Bui. 154, 1912. 668 FOOD INSPECTION AND ANALYSIS. Ph Hawaiian. l3 S o fe tn Direct polarization at 20° C*. . . Invert polarization at 20° C. . . . Invert polarization at 87° C. . . . Water ; per cent Invert sugar " Sucrose " Ash " Dextrin " Undertermined " Free acid as formic .... " Reducing sugar as dextrose, per cent + 17.0 + 15.0 + 35-0 16.44 71.69 0.61 0.29 6.02 4-95 0.05 + 3-6 - 2.5 + 20.9 17.02 65.80 3.10 C.76 10.19 3-13 0.19 63.04 + 7.8 + 3-4 + 26.6 16.05 65.89 2.76 0.78 12.95 1-57 63.12 + 11. o + 5.2 + 28.6 13-56 65.87 4-31 0.79 10.49 4- 0.08 63.11 + 17.8 + 13-5 + 34-8 15.46 64.84 5-27 1.29 10.01 0.15 62.12 + 3 + I + 23 16 67 2 64.96 + 5-3 + 1.9 + 23.4 17.80 66.85 2.41 0.80 8.62 3r52 0.13 64.04 * Constant. Adulteration of Honey. — The most common adulterant is commercial invert sugar. Cane sugar and glucose were formerly used. Gelatin is also said to be used. It appears to be a fact that bees may be made to feed upon cane syrup or commercial glucose, if these materials are placed in proximity to their hives, so that in some instances the adulterant may be supplied through the medium of the bee. Sophisticated honey is often put up in tumblers or jars containing pieces of honeycomb^ so that presence of the comb is by no means proof of its purity. Comb-honey, sold in the frame as sealed by the bees, is never adulterated, except when the bees are fed upon glucose or cane sugar. Cane Sugar. — The following are typical analyses of honey adulterated with cane sugar: A. B. c. Direct polarization. .. . +34.7 +12 +1.2 Invert " ....—24 —17.6 —21.5 Temperature 14° 15° i9-5° Sucrose (Clerget) 43.16% 21.8% 17.07% Invert sugar 42.48% 60.03% 67.2% Water 42-42% 21.15% i5-56% Ash .11% 0.06-% A strong right-handed polarization before inversion, coupled with a left-handed invert reading at 20°, is evidence of adulteration with cane sugar, or a product containing cane sugar. SUGAR AND SACCHARINE PRODUCTS. 669 Honey stored by bees fed on cane sugar is also characterized by its right-handed polarization. Although the bee inverts the larger part of the cane sugar in its body, this inversion is never as complete as in the case of nectar honey. Glucose. — The following are typical analyses of honey adulterated with commercial glucose: A.* B. C. Direct polarization. . +147 +66.9 +101. 5 Invert " .. +135.2 +61.9 + 99.0 Temperature 18° 20° 22° Sucrose (Clerget).... 8.83% 3.76% 0.0% Invert sugar 46.18% 74-66% 49.87% Water i5-i9% 21.40% 23.7%, Ash 0.03% Care should be taken not to confuse honeydew honey with honey adulterated with glucose. Browne gives the following means of distinction : (i) the difference in invert polarization between 20 and 87°, corrected to 77% invert sugar, (2) Beckman's iodine test (page 673), and (3) the Konig and Karsch test (page 674). He also finds the quantity and char- acter of the ash, the acidity, and microscopic examination of value. The following analyses of mixtures of commercial glucose and honey were made by A. H. Bryan. f Mixture. Constant Invert Polarization — Polariza- Invert Sugar Calculated Glucose. 100 — Direct Polariza- tion Differ- After Invert Invert Polariza- (Correct- ed Polar- Glucose Honey. tion at 20° c. At 20° C. At87°C. ence (87°- 20°). Inver- sion. Inver- sion. tion at 87°- 1.63. (20°C.-h 17.5)- ization Differ- ence X 193. 100-7- 26.7) % % °V. °V. °V. °v. % % % % % 100 + 153-8 + 153-34 + 144-32 30.02 30-45 88.5 88.5 50 50 + 67.0 + 65.67 + 73-81 8.14 53.67 54. 5^ 45-3 43-1 56.9 20 80 + 15-4 + 13-42 + 33-00 19.58 69.00 70-35 20.2 16.0 19.2 10 90 - 2.4 - 4.84 + 18.59 23-43 74.42 74. li II. 4 6.6 8.8 5 95 - II-5 - 14-31 + 11.66 25-96 75-74 77.8c 7-2 1.6 3-8 3 97 - 14.2 - 16.94 + 9-13 26.07 76.62 78.01 5-6 0.29 3-7 2 98 — 16.0 - 18.70 + 8.14 26.84 76.64 78-34 5-0 0.00 1.2 I 99 - 18.2 — 20 . 90 + 6.93 27.83 77.20 78.87 4.2 0.00 0.0 100 — 19.5 — 22.11 + 5-94 28.05 77.68 78-9: 3-2 0.00 0.0 * Both commercial glucose and added cane sugar. t A. O. A. C. Proc, 1908, U. S. Dept. of Agric, Bur. of Chem., Bui. 122, p. 181. 670 FOOD INSPECTION AND ANALYSIS. Commercial Invert Sugar is the most difficult of detection of all the adulterants. Herzfeld's process* for the manufacture of invert sugar syrups consists in boiling for thirty to forty-five minutes i kilogram of refined sugar in 300 cc. of water with i.i gram of tartaric acid. Browne f gives the following analysis of the product made by this process: Direct polarization at 20° — 6.2 Constant polarization at 20°. — 9.5 Invert polarization at 20° —16.9 Invert polarization at 87° + 4.8 Water 16.32% Invert sugar 73 -3^% Sucrose 4 - 3^% Ash 0.00% . Dextrin 4-86% 100 .00% Acids as formic 0.06% This adulterant is best detected by Browne's and Fiehe's tests (page 674). Ley's test t has value as a confirmatory test, but should be used with caution, as American honeys do not react like the European. Gelatin is indicated if a precipitate occurs- in the^ diluted sample with a solution of tannic acid. ANALYSIS OF HONEY. Preparation of Sample. — In the case of strained honey, stir with a rod, till any separated sugars are evenly distributed throughout the mass, or, if the honey has become solidified wholly or in part by crystallization, use a gentle heat on a closed water-bath to restore to it fluid form. In the case of comb honey, cut with a knife across the top of the comb if sealed, and separate completely from the comb by straining through a 40-mesh sieve. Determination cf Moisture. §— Weigh 2 grams into a flat- bottom metal dish 2j inches in diameter, which, together with 10 to 15 gram.s 1 * Zeits. ver. d. Zucker-Ind., 31, p. 1988. t Loc. cit., p. 64. X Pharm. Zeits., 47, 1902, p. 603. § Browne, U. S. Dept. of Agric, Bur. of Chem., Bui. no, p. 18. SUGAR AND SACCHARINE PRODUCTS.. 671 of fine quartz sand and a short stirring rod, has been previously tared, add 5 to lo cc. of water, stir until the whole has been thoroughly incor- porated, and dry to constant weight at 65 to 70° C. in a vacuum oven. Honeys of high purity usually dry in twelve hours, while those of the honey- dew class, rich in dextrin and gum, require thirty-six hours, or longer. Determination of Ash. — See page 644. Polarization. — Direct and Invert at 20° C. — Proceed as directed under molasses (page 644), except that only alumina cream is used as a clarifier. To destroy birotation add a drop or two of ammonia before making up to the mark.* Invert at 87° C. — Invert a half normal portion in the usual manner in a loo-cc. flask, cool, add a few drops of phenolphthalein and enough sodium hydroxide to neutralize; discharge the pink color with a few drops of dilute hydrochloric acid, add from 5 to 10 cc. of alumina cream, make up to the mark and filter. Polarize in a 200-mm. tube at 87°, and multiply reading by 2. Polarization at the temperature of 87° can most readily be effected by the use of a water-jacketed tube, as shown in Fig. iii. An all-metal tube, the interior of which is heavily gold-plated to avoid corrosion by acid, is preferable to one in which the inner tube is glass with a metal jacket, as in the latter leaky joints are liable to occur, due to uneven expansion. A tubulure is provided in the outer tube for a thermometer, so that the exact temperature may be noted. A tank of boiling water placed on a shelf above the polariscope is connected by rubber tubing with the jacketed tube as it rests in the polariscope, as shown in Fig. iii. Determination of Reducing Sugars. — Determine by Allihn's method (page 632) in an aliquot of 25 cc. of a solution obtained by making 10 cc. of the solution prepared for polarization up to 250 cc. If desired the sugar may be determined by the volumetric Fehling process (page 615). The reducing sugars may be calculated as dextrose as obtained from Allihn's table, or as levulose by multiplying the dextrose by 1.044. Determination of Levulose. — Wilefs Method.-f — This may be calcu- lated approximately by the following formula : 100(1.0315^ —a) 100(1.0315/! —a) (2.3919)26 62.19 ' * Fruhling, Zeits. offentl. Chemie, 4, 1898, p. 410. t Principles and Practice of Agricultural Analysis, 1897, III, p. 267. Browne, loc. cit, p. 17. 672 FOOD INSPECTION AND ANALYSIS. in which / = levulose, a = the direct polarization at 20° of a solution of the normal quantity of honey made up to 100 cc. at 20°, and A = the direct polarization of the same solution at 87° C, 2.3919 = the variation in polarization of i gram of levulose in 100 cc. of solution between 20 and 87° C, and 1.0315 = the factor for converting the volume of the solution at 20° into that at 87° C. Determination of Dextrose.* — Multiply the percentage of levulose as obtained in the preceding section by 0.915, thus obtaining the equivalent dextrose, and subtract this from the per cent of reducing sugars expressed as dextrose. Determination of Sucrose. — Owing to the inaccuracies of Clerget's method as applied to honey, Browne recommends the following : Neutralize the free acid of 10 cc. of the solution used for invert polarization with sodium carbonate, make up to 250 cc. and determine the reducing sugars by Allihn's method. Subtract from the invert sugar thus obtained the invert sugar found before inversion, and multiply the difference by 0.95. Determination of Dextrin. — Browne's Method.^ — Weigh 8 grams of honey directly into a loo-cc. flask, add 4 cc. of water, and finally with continued agitation sufficient absolute alcohol to fill to the mark. Shake thoroughly and allow to stand twenty-four hours, or until the dextrin is deposited on the bottom and sides of the flask and the liquid is perfectly clear. Decant on a filter and wash the precipitate in the flask with 10 cc. of cold 95% alcohol, pouring the liquid finally on the filter. Dissolve the precipitate in the flask and on the filter in a little boiling, distilled water, collecting the solution in a tared platinum dish. E\aporate the liquid, and dry to constant weight at 100° C. If the alcohol precipitate is considerable, it should be dried at 70° C. in vacuo. After weighing, dissolve in water and make up to a definite volume according to the weight as follows : Residue, grams. 0-0.5 0.5-1.0 i. 0-1.5 i-5~2.o 2.0-2.5 2.5-3.0 Volume, cc. . . . 50 too 150 200 250 300 Filter, determine invert sugar and sucrose in aliquots by copper reduction before and after inversion, and subtract the sum of these sugars from the total alcohol precipitate. * Browne, loc. cit., p. 17. Jour. Am. Chem. Soc, 28, 1906, p. 446. SUGAR AND SACCHARINE PRODUCTS. 673 Determination of Acids. — Dissoh'e lo grams of the honey in water and titrate with tenth-normal sodium hydroxide, using phenolphthalein as indicator. Express result as formic acid. Beckman's Test for Glucose.*— Treat a mixture of equal parts of honey and water with a solution of iodine in potassium iodide. If glucose is present, a red or violet color (due to erythro- or amylo-dextrin) appears, the shade and intensity depending on the nature and amount of the glucose present. Determination of Commercial Glucose in Honey. — Except for rough work, the method described on page 651 for calculating the per cent of commercial glucose from the sucrose and from the direct polarization is not recommended for use with honey and other products wherein the invert sugar is so large as to considerably affect its accuracy. In this case, it is best after inversion to polarize the sample at 87° C, the temperature at which the reading due to invert sugar would theoretically be o. At this temperature, any considerable right-handed polarization can be accounted as due to commercial glucose. (See page 671.) As in the case of molasses, the writer advocates assuming 175° as the direct polarization of the glucose used, this being about the maximum reading for a normal solution of 42°- Be. glucose. Lythgoe has shown that in polarizing at high temperatures samples of saccharine products containing commercial glucose, certain precautions have to be observed not necessary when cane or invert sugar are the only sugars present. Thus, a normal solution of glucose, when polarized at 87° C, has a lower reading than in the cold, the difference being doubtless due partly at least to the expansion of the liquid. Again, on subjecting a normal solution of glucose to inversion with acid, as in Clerget's process, and heating to 87° C, it will be found impossible to get a constant reading, but the reading will drop rapidly, due to a partial hydrolysis of the maltose or dextrin. In honey and other preparations containing much invert sugar and commercial glucose, it is best to proceed as follows: Divide the polariza- tion at 87° by i63°t and multiply the result by 100 for the percentage of commercial glucose in terms of glucose polarizing at 175°. It should be * Zeits. Anal. Chem., 35, 1896, p. 267. fThe true polarization at 87° C. of a normal solution of glucose subjected to inversion and neutralization as above (but without the use of the clarifier), will be about 93% that of the direct polarization of the sample in the cold. Hence 175X0.93 = 162.7. 674 FOOD INSPECTION AND ANALYSIS. borne in mind that the results by even this method are only approximate, as genuine honey is more or less dextrorotatory at 87° C. The foilowincr formula is used by European chemists: G = -^, in 1.93 which G=the per cent of commercial glucose, and & = the polarization after inversion at 20° C. Browne's Test for Commercial Invert Sugar.* — Reagent. — This should be freshly prepared each time before using. Shake 5 cc. of c. p. anilin with 5 cc. of water, and add sufficient glacial acetic acid (2 cc.) to just clear the emulsion. Process. — Treat 5 cc. of a i : i solution of the honey in a test-tube with I to 2 cc. of the anilin reagent, allowing the latter to flow down the walls of the tube so as to form a layer upon the honey solution. If, when the tube is gently agitated, a red ring forms beneath the anilin solution, this color becoming gradually imparted to the whole layer, artificial invert sugar is present. This reaction is due to furfural formed during the l^^^h temperature employed in the commercial processes of inversion. Boiling genuine honey also causes the formation of furfural, but this treat- ment impairs the flavor and is probably never practiced, Fiehe's Test for Commercial Invert Sugar Modified by Bryan. f — Place 10 cc. of a 50% solution of the sample in a test tube, add 5 cc. of ether, shake vigorously, allow to stand until the ether is clear, then transfer 2 cc. to a small test-tube and add a large drop of a solution of i gram of resorcin in 100 cc. of hydrochloric acid and shake. A cherry-red color indicates commercial invert sugar while a faint orange to rose color, disappearing after a short time, may be due to heating of the honey. Ley's Ammoniacal Silver Nitrate Test % is not so reliable as the two preceding tests. Distinction of Honeydew and Glucose Honeys. — Method of Kdnig and Karsch.^ — Dissolve 40 grams of honey in a cylinder in water, and make up to 40 cc. Transfer 20 cc. of the homogeneous solution to a 250-cc. flask and fill to mark with absolute alcohol with slow addition and constant shaking, and then allow to stand two or three days, with occasional agitation. At the end of this time all the dextrin has settled out. After shaking the solution, filter and evaporate ico cc. of the filtrate until free * U. S. Dept. of Agric, Bur. of Chem., Bui. no, p. 68. t Zeits. angew. Chem., 21, i8q8, p. 2315; Bur. of Chem., Bui. 154, p. 15. JPharm. Ztg., 1902, p. 603; Zeits. angew. Chem., 1907, p. 993. § Zeits. anal. Chem., 34, 1895, p. i. U. S. Dept. of Agric, Bur. of Chem., Bui. no, p. 63. SUGAR AND SACCHARINE PRODUCTS. 675 from alcohol. To the liquid residue add a little subacetate of lead and sodium sulphate, make up to 20 cc. with water, and polarize the filtered solution. Dextrorotatory natural honeys show by this method a laevo- rotation; honeys adulterated with dextrose of glucose to the extent of 25% or more, a dextrorotation. In case the honey contains a large amount of sucrose, the solution should be inverted with hydrochloric acid before polarizing. BEESWAX.— The purity of beeswax is best established by determming its melting-point, its specific gravity, its saponification equivalent, and its refractometric reading. The melting-point of pure wax is about 64° C, while that of paraffin, its chief adulterant, is from 52 to 55° C. Its saponification equivalent should be from 87.8 to 107, while that of paraffin is o. Method of Determining Specific Gravity of Beeswax."^— V\d.ce a weighed rod of the wax, about i to 1.5 cm. long by 0.5 cm. diameter, in an accurately marked 50 cc. flask, and run in water from a burette till the water level reaches the mark. 50 cc. minus the burette reading represent the vol- ume occupied by the wax. The rod should be made to lie flat on the bottom of the flask, so that the incoming water will force its end against the sides and prevent the end from rising above the mark. The weight of the rod, divided by its volume gives its specific gravity. The specific gravity of various mixtures of wax of 0.969 specific gravity and paraffin of 0.871 are given in the following table, prepared by Wagner, so that from the specific gravity of the mixture the percentage of paraffin can be calculated : Wax (Percentage). Paraffin (Percentage). Specific Gravity. Wax (Percentage). Paraffin (Percentage). Specific Gravity. 25 50 100 75 50 .871 -893 .920 75 80 100 25 20 .942 .948 .969 The Refractometer Reading is most useful in establishing the purity of wax. Observations with this instrument are best made at 65° and great care should be taken in the case of the Zeiss butyro-refractometer not to exceed this temperature, or injury to the instrument may result. The Abbe refractometer may be used with perfect safety and, when available, is to be preferred for the examination of beeswax. Many * Gawalowski, Chem. CentrbL, 1890, p. 502. 676 FOOD INSPECTION AND ANALYSIS. food laboratories are, however, not equipped with the Abbe, but nearly all find the butyro-refractometer indispensable. The latter instrument was primarily designed for such substances as butter and lard, so that the manufacturers did not intend it to be subjected to as high a temperature as 65°. _ They have, however, assured the author that if care be taken Fig. III. — Apparatus for Polarizing at High Temperatures. to bring the temperature very slowly and gradually to the required degree 65°, and to avoid also sudden cooling, the cement that secures the prisms in place will not be appreciably affected; otherwise cracking or loosening of the cement would be liable to occur after a time. At 65° C. pure beeswax should have a reading on the butyro-refrac- tometer of 30 to 31.5,* while that of paraffin is from 11 to 14.5.! * wz>, 1.4452 to 1.4463. t«z>, 1.4310 to 1.4335- SUGAR AND SACCHARINE PRODUCTS. 677 CONFECTIONERY. The composition of confectionery is more complex than that of the saccharine products hitherto consideredo As a rule, cane sugar, or one of its products, as molasses, forms the basis of most of the confections. Commercial glucose is also a common ingredient, while a large variety of such materials as eggs, butter, chocolate, various flavoring extracts, spices, nuts, and fruits, enter into the composition of confectionery. U. S. Standard Candy is candy containing no terra alba, barytes, talc, chrome, yellow, or other mineral substances or poisonous colors or flavors, or other ingredients injurious to health. Adulteration. — Of late the adulteration of confectionery has been held largely in check by the National Confectioners' Association of the United States, which has fixed high standards of purity, and has been very zealous in restricting the use of harmful adulterants. Commercial glucose is not regarded as an adulterant of confectionery by the above-named association and by but few food authorities. On the contrary, any ingredient, other than color, that has no food value, may logically be considered as an adulterant. Under this head are included such substances as paraffin, as well as make-weight mineral matters, such as terra alba, talc, or calcium sulphate. B, H. Smith * has called attention to the presence of arsenic in shellac used to coat certain kinds of confectionery. Colors in Confectionery. — A very wide range of colors is necessarily employed in the manufacture of confectionery, and the almost endless variety of coal-tar dyes now available lend themselves most readily to the confectioner's needs. Elsewhere, under " colors," lists of injurious and non-injurious dyes are given as compiled by the National Confec- tioners' Association, though it is not always readily apparent how the lines are drawn. The tinctorial power of these dyes is so high that the actual amount of substance contained in a thin coating of the color on the outside of the candy is exceedingly small, so that it is doubtful whether serious cases of injury have ever arisen from their use. This was not the case formerly when such poisonous mineral pigments as chromate of lead were frequently used. * U. S. Dept. of Agric, Bur. of Chem., Circ. 91, 1912. 678 FOOD INSPECTION AND ANALYSIS ANALYSIS OF CONFECTIONERY. The following methods are largely those submitted by the author as provisional methods of the A. O. A. C.:* (i) Products of Practically Uniform Composition Throughout. — (a) Lozenges and Other Pulverizable Products. — Grind in a mortar or mill to a fine powder. For total solids, weigh from 2 to 5 grams of the powdered sample in a tared platinum dish, and dry in a McGill oven to constant weight. For Ash, ignite the residue from total solids in the original dish, observing the precautions given under sugar (page 609), and molasses (page 644). (b) Semi-plastic, Syrupy, or Pasty Products. — Weigh 50 grams of the sample into a 50-cc. graduated flask, mix thoroughly or dissolve, if soluble in water, and fill to the mark. Be sure that the solution is uniform, or, if insoluble material is present, that it is evenly mixed by shaking before taking aliquot parts for the various determinations. For total solids and ash, measure 25 cc. of the above solution or mixture into a tared platinum dish, and proceed as directed under (a). (2) Confectionery in Layers or Sections of Different Composition. — When it is desired to examine the different portions separately, they should be separated mechanically with a knife, when possible, and treated as directed under (i). (3) Sugar-coated Fruit, Nuts, etc. — In case of a saccharine coating inclosing fruit, nuts, or any less readily soluble material, dissolve or wash off the exterior coating in water, which may, if desired, be evaporated to dryness for weighing, and proceed as in (i). (4) Candied or Sugared Fruits. — Proceed as in the examination of fruits (Chapter XXI). Detection of Mineral Adulterant.— As in the case of molasses, a considerable quantity, say 100 grams, should be reduced to an ash for examination for mineral adulterants, such as talc, calcium sulphate, and iron oxide, which are detected by regular qualitative tests. Detection of Lead Chromate. — Fuse the ash in a porcelain crucible with a mixture of sodium carbonate and potassium chlorate, boil the fused residue with water, neutralize with acetic acid, filter, and treat the filtrate with barium chloride or lead acetate solution. A yellow pre- * U. S. Dept. of Agric; Bur. of Chem., Bui. 65, p. 44. SUGAR AND SACCHARINE PRODUCTS. 679 cipitate indicates a chromate. Treat the insoluble part of the fusion with nitric acid, and test for lead in the usual manner. If a drop of ammonium sulphide be applied to a piece of confectionery colored with lead chromate, it will produce a black coloration. Determination of Ether Extract. — The ether extract includes the fat derived from chocolate, eggs, or butter, as well as any paraffin present. Measure 25 cc. of the 2o7o solution (i) (b) (page 678) into a very thin, readily frangible glass evapora ting-shell {Hoffmeister's Schakhen), con- taining 5 to 7 grams of freshly ignited asbestos fiber; or, if impossible to thus obtain a uniform sample, weigh out 5 grams of the mixed, finely divided sample into a dish, and wash with water into the asbestos in the evaporating-shell, using, if necessary, a small portion of the asbestos fiber on a stirring-rod to transfer the last traces of the sample from dish to shell. Dry to constant weight at 100°, after which cool, wrap loosely in smooth paper, and crush into rather small fragments between the fingers, carefully transferring the pieces with the aid of a camel's-hair brush to an extraction-tube, or to a Schleicher and Schull cartridge for fat extraction. Extract with anhydrous ether or with petroleum ether in a continuous extraction apparatus for at least twenty-five hours. Trans- fer the solution to a tared flask, evaporate the ether, dry in an o\'en at 100° C. to constant weight, and weigh. More recently the association adopted the Rose-Gottlieb method for butter scotch. Determination of Paraffin. — Add to the ether extract in the flask, as above obtained, 10 cc. of 95% alcohol, and 2 cc. of i : i sodium hydroxide solution, connect the flask with a reflux condenser, and heat for an hour on the water-bath or until saponification is complete. Remove the con- denser, and allow the flask to remain on the bath till the alcohol is evapo- rated off, and a dry residue is left. Treat the residue with about 40 cc. of water, and heat on the bath, with frequent shaking, till everything soluble is in solution. Wash into a separatory funnel, cool, and extract with four successive portions of petroleum ether, which are collected in a tared flask or capsule. Remove the petroleum ether by evaporation, and dry in the oven to constant weight. It should be noted that any phytosterol or cholsterol present in the fat would come down with the paraffin, but the amount would be so insignificant that, except in the most exacting work, it may be disregarded. The character of the final residue should, however, be confirmed by determining its melting-point and specific gravity, and by subjecting it 680 FOOD INSPECTION AND ANALYSIS. to examination in the butyro-refractometer. The melting-point of par- alTm is about 54.5° C. ; its specific gravity at 15.5° C. is from 0.868 to 0.915, and on the butyro-refractometer the reading at 65° C. is from 11 to I4-5- Determination of Starch. — Measure gradually 25 cc. of a 20% aqueous solution or uniform mixture of the sample into a hardened filter or Gooch crucible, or transfer by washing 5 grams of the finely powdered substance to the filter or Gooch, and allow the residue on the filter to become air- dried. Extract with five successive portions of 10 cc. of ether, then wash with 150 cc. of 10% alcohol, and finally with 20 cc. of strong alcohol. Transfer the residue to a large flask and boil gently for four hours with 200 cc. of water and 20 cc. of hydrochloric acid (specific gravity 1.125), the flask being provided with a reflux condenser. Cool, neutralize with sodium hydroxide, add 5 cc. of alumina cream, and make up the volume to 250 cc. with water. Filter and determine the dextrose in an aliquot part of the filtrate by any of the various Fehling methods. The weight of the dextrose multiplied by 0.9 gives the weight of the starch. Polarization of Confectionery. — As a clarifier use either alumina cream or subacetate of lead, according to the nature and capacity of the sample. Ordinarily alumina cream is best, but in dark-colored samples, or those in which molasses has been used, it is sometimes necessary to employ the subacetate. When starch is absent, and the sample is practi- cally soluble, polarize and invert in the usual manner (page 610). Where considerable starch or insoluble matter is present, use the double-dilution method of Wiley and Ewell (page 650), thus making due allowance for the volume of the precipitate. Ca}2e sugar, invert sugar, and dextrin, are determined as directed for honey. Commercial glucose is roughly determined by polarizing the sample at 87° C., as in the case of honey (page 671). Confectionery is made in such a wide variety of forms, and these differ in consistency to such an extent that commercial glucose of all available degrees of density can be utilized to advantage in one product or another. In this respect confectionery is unlike honey and molasses, wherein a fairly uniform grade of commercial glucose is necessarily used for mixing, this grade being naturally selected with reference to its similarity in density to the molasses. On this account the glucose factor used for honey and molasses (175) may in some varieties of confectionery be too high. SUGAR AND SACCHARINE PRODUCTS. 681 Determination of Alcohol in Syrups Used in Confectionery. — (Brandy- drops.) — Open each drop by cutting off a section with a sharp knife, and collect in a beaker the syrup of from 15 to 25 of the drops, which will usually yield from 30 to 50 grams of syrup. Strain the syrup into a tared beaker through a perforated porcelain filter-plate in a funnel to separate from particles of the inclosing shell, and ascertain the weight of the syrup. Wash into a distilling-flask, dilute with half its volume of water, and distil off into a tared receiving-flask a volume equal to the original volume of syrup taken. Ascertain the weight of the distillate and its specific gravity by means of a pycnometer. Multiply the per- centage by weight of alcohol corresponding to the specific gravity, as found in the tables on page 690 et seq., by the weight of the distillate, and divide this by the weight of syrup taken. The result is the per cent by weight of alcohol in the syrup. Detection of Colors. — It is sometimes necessary to macerate a con- siderable mass of the material to remove the color, which is, however, in the majority of cases readily soluble. The insoluble colors are nearly all mineral pigments to be looked for in the ash, as in the case of chromate of lead (page 678). Frequently the coloring matter is confined to a thin outer layer, which is readily washed off. The solution of the dyestuff is examined as directed under colors. Detection of Arsenic. — Arsenic may be present through impure glu- cose, shellac, or coloring-matter. If the color is confined to an exterior coating, this should be washed ofT and examined. If distributed through the mass, a solution of the whole should be taken. Examine for arsenic by the Gutzeit or Marsh method, as directed on pages 63 to 66. CHAPTER XV. ALCOHOLIC BEVERAGES. Alcoholic Fennentation. — In a broad sense all alcoholic liquors are saccharine products, in that they are essentially the result of the fermen- tation of sugars. In the case of fruits, the sugars already exist as such in their juices, which, when expressed, almost immediately begin to undergo spontaneously the process of alcoholic fermentation, through the agency of the enzyme zymase of the wild yeasts introduced with the skins of the fruit or from the air. The reaction is as follow^s: (l) C6Hi206=2C2H60 + 2C02. Dextrose or Alcohol Carbon Levulose dioxide While the foregoing reaction applies to the dextrose and levulose of invert sugar, which sugar usually predominates in fruit juices, being formed by the inversion of sucrose, the reaction with sucrose itself, which is not directly fermentable, involves a preliminary inversion through the agency of the enzyme invertase present in yeast, thus: (2) Ci2H220n+H20=C6Hi206+C6Hi206. Sucrose Dextrose Levulose In the case of grains the process is more complex, involving hydroliza- tion of the starch into maltose through the action of the diastase of malt and the further hydrolization of the maltose, which, like sucrose, is not directly fermentable, into dextrose by means of an enzyme of yeast known as maltase or maltoglucase. These reactions may be expressed as fol- lows: (3) 2C6Hio05 + H20=Ci2H220ii Starch Maltose (4) Ci2H220n +H20= 2C6H12O6 Maltose Dextrose 682 ALCOHOLIC BEVERAGES. 683 The above reaction, No. i, illustraUng the sphtting up of grape sugar into alcohol and carbon dioxide, does not represent the practical yield of alcohol under ordinary condi.ions that occur in vinous fermentation, for, as a matter of fact, instead of 51.11 parts of alcohol and 48.89 parts carbon dioxide, which would theoretically result as above from the fer- mentation of 100 par.s of dextrose, only about 95% of the theoretical yield can be obtained, so that in practice it is possible to form but about 48.5% alcohol and 46.5% carbon dioxide. The balance, amounting to some 5%, consists chiefly of glycerin, succinic acid, and traces of various compounds, including some of the higher-boiling alcohols (propyl, butyl, and amyl) and their ethers, which form the fusel oil of the dis- tilled liquors. Vinous fermentation takes place most readily in slightly acid liquids, at a temperature ranging from 25° to 30° C. It is convenient to divide alcoholic beverages into two main groups, first the fermented and second the distilled liquors. The fermented liquors naturally subdivide themselves into (a) the products of the direct spontaneous fermentation of saccharine fruit juices, such, for example, as those of the apple and the grape, to form cider and wine respectively, and (b) the mal ed and brewed liquors,, such as beer and ale, produced by the conversion of the starch of grain into sugar, and the final alcoholic fermentation of the latter. The distilled liquors include such products as whiskey, brandy, rum, and gin, wherein alcoholic infusions prepared by previous fermentation in various ways are further subjected to distillation. Alcoholic Liquors and State (or Municipal) Control. — The mere adulteration of liquors does not constitute the only feature which brings them within the scope of the public analyst's work and renders them especially amenable to stringent laws. Indeed, it is often a far more important ques ion for the analyst to decide by his results whether or not the samples submitted to him, by pohce seizure or otherwise, are sold in violation of the regulations in force in his particular locaHty govern- ing the liquor traffic. A common regulation in no-license localities fixes the maximum per cent of alcohol which shall decide whether or not a liquor is legally a temperance drink, and can be sold as such wilh impuni.y. From ils low content in alcohol, an analyst's findings regarding a certain sample may exonerate the dealer suspected of violating this law, while yet by the very reason of its being low in alcohol the same sample would be placed 684: FOOD INSPECTION AND ANALYSIS. in the adulterated list as regards non-conformance to a standard of purity. While the raising of revenue is one purpose for the existence of these laws bearing on liquor license, an equally important object sought to be gained is doubtless the repression of intemperance. Toxic Effects. — A popular impression seems to exist that the toxic effects of an adulterated liquor are far worse from a temperance stand- point than those of a sample of good standard quality, and it is a common experience of the public analyst to have submitted to him by well-mean- ing temperance advocates samples which are alleged to have caused the worst forms of intoxication, and are thus suspected of being impure. As a matter of fact the chief adulterants of liquors are water, sugar, and, in the case of beer, various bitter principles and vegetable extractives, none of which are on record as being in themselves actively toxic* Alcohol is the one ingredient of liquor which, more than any other, produce^ a marked physiological effect. Many liquors, especially those of the distilled variety classed as adulterated, are so considered by reason of their low alcoholic content through watering or otherwise, hence this commonest form of adulteration, far from being detrimental in itself, is actually helpful to the temperance cause. Details of Liquor Inspection. — The same precautions should be carefully observed by officers making seizures of liquors for analysis, as by food inspectors, regarding safe delivery of the samples to the analyst. The following instructions are circulated by the State Board of Health of Massachusetts, which has in charge the inspection of liquors, concerning the taking of samples in that state and the transmission to the analyst: DIRECTIONS FOR TAKING SAMPLES FOR ANALYSES. The officer making a seizure, or taking samples of beer, should note at the time of such seizure the general appearance of the liquor, — as to whether it is clear or cloudy, whether it is still or has a strong head. If the liquor is in bottles, take at least one pint bottle; if in barrels, draw a pint bottle from each. Request the owner to seal each sample taken. If the bottles have cork stoppers, cut the stoppers off level with the top of the bottle and cover with w^ax; if with patent stoppers, a little wax placed upon the wire at the point where it lays against the neck of the bottle is sufficient. If the owner refuses to seal it, then the officer * The writer refers to substances intentionally added, and not to accidental impurities, such as arsenic, etc., that are occasionally found. ALCOHOLIC BEVERAGES. 685 should seal it in his presence, caUing his attention to the fact. Before leaving the premises, place upon the bottle a label or tag, with the date, the name of the owner, and the name of the officer upon it, and also the name of the town or city. Then place in a box, with the certificate required by law, and forward without delay to the analyst. FORM OF LABEL. , Town , Date of seizure 19 Owner Kind of liquor Brewer Accompanying each sample is a certificate like the following, the first part of which is filled out and figned by the officer, while the second part, containing the data of analysis, is filled out and signed by the analyst and returned by him to the officer. Such a certificate is nearly always accepted as evidence in court without the personal appearance of the analyst. ss 19 , To the State Board of Heahh: I send herewith a sample of taken from liquors seized by me 19 . Ascertain the percentage of alcohol it contains, by volume, at sixty degrees Fahrenheit, and return to me a certificate herewith upon the annexed form. Seized from Officer. COMMONWEALTH OF MASSACHUSETTS. No Office of the State Board of Health. Boston, 19 . This is to certify that the received by me with the above statement contains per cent of alcohol, by volume, at sixty degrees Fahrenheit. ^°'^ Received : 19 . Analysis made 19 . [seal.] Analyst State Board of Heahh, FOOD INSPECTION AND ANALYSIS. A convenient method for recording analyses is by the employment of numbered library cards, which bear the same number as the certificates and are kept by the analyst. The following is a convenient form: No Analyzed County Wt. flask and ale City or town Wt. flask Ofiicer Wt. ale Defendant Sp. gr. ale. (60°) Address Per cent aleohol Kind of liquor Reported Seized Received How delivered Sealed Condition Kind of bottle Registered METHODS OF ANALYSIS COMMON TO ALL LIQUORS. Specific Gravity. — This should be taken at 15.6° or calculated to that temperature. The most convenient mode of procedure is to bring the temperature of the sample somewhat below that point by allowing the flask containing it to stand in cold water, and to have everything in readiness to make the determination when 15.6° temperature has been reached, either by the hydrometer spindle in a glass cylinder, by the Westphal balance, or by the pycnometer. The latter is by far the most accurate, especially if it is of the form which is fitted with a thermometer- stopper. Detection of Alcohol. — It is rarely necessary to make a qualitative test for alcohol in liquors, since it is almost invariably present even in many of the so-called temperance drinks, at least in small amount. Indeed in many localities a beverage is legally a temperance drink that contains not more than 1% alcohol by volume. The Iodoform Test. — Alcohol, when present in aqueous solution to the extent of o.i% or more, may be detected by the iodoform test. The solution is warmed in a test-tube with a few drops of a strong solution of iodine in potassium iodide, after which enough sodium hydroxide solution is added to nearly decolorize. On standing for some time a yellow precipitate of iodoform will appear if alcohol be present, or at once if there is a considerable amount, and the characteristic odor of iodoform will be rendered apparent, "even when the precipitate is so slight as to be almost imperceptible. This iodoform precipitate is crystalline, showing under the microscope as star-shaped groups or hexagonal tablets. ALCOHOLIC BEVERAGES. 687 It should not be forgotten thai other substances than alcohol give the reaction, as lactic acid, acetone, and various aldehydes and ketones. Pure methyl or amyl alcohol or acetic acid do not thus react. Bcrthelot recommends benzoyl chloride as a reagent for detecting alcohol. By warming a mixture of a few drops of benzoyl chloride with the solution to be tested, and adding a little sodium hydroxide, ethyl benzoate is formed, recognizable by its distinctive odor. This reaction is delicate to o.i% alcohol. The presence of other alcohols than ethyl produces ethers of characteristic odor. Hardy's Test jor Alcohol consists in shaking the aqueous solution with some powdered guaiacum resin, filtering, and adding to the filtrate a little hydrocyanic acid and a drop of dilute copper sulphate sohition. A blue coloration considerably deeper than that due to the copper salt is indicalive of alcohol. Methyl Alcohol in spirits is tested for as described on pp. 781-784. Determination of Alcohol. — In the case of carbonated liquids it is necessary to first expel the free carbon dioxide, which is readily accom- plished by pouring the liquor back and forth from one beaker to another, from time to time removing the excess of froth from the top of the vessel by the aid of the hand. Or, the sample may be shaken vigorously in a large separatory funnel, and the still liquor drawn off from below the froth, repeating the operation several times if necessary. In either case the mechanical treatment should be continued till the liquor is com- paratively quiet and free from foam. (i) By Distillation. — This is by far the most accurate method of determining alcohol, and should be carried out in all cases where any legal controversy is apt to be involved. Into a flask of 250 to 400 cc. capacity introduce a convenient quantity of the liquor, which should be accurately weighed or measured, according to whether the percentage by weight or measure is desired. The following are suitable quantities* Distilled liquors, 25 grams or cc; cordials, 25 to 50 grams or cc; wineSj ciders, and malt liquors, 100 grams or cc. In the case of wines or ciders which have undergone acetic fermentation, add o.i to 0.2 gram of precipitated calcium carbonate or neutralize with standard alkali. Dilute the liquid to 150 cc. and distil into a loo-cc flask. Nearly all alcoholic liquors, if comparatively free from carbon dioxide, will boil without undue frothing or foaming. New wine will occasionally give trouble in this regard, but foaming may usually be prevented in this 688 FOOD INSPECTION AND ANALYSIS. case by the addition of tannic acid. In case of wine, cider, and beer all the alcohol will have passed over in the first 75 cc. of the distillate, or three-fourths the original measured volume, but with distilled liquors high in alcohol the process had better be continued till nearly 100 cc. or the original volume taken have passed over. If the condenser is of glass, one can observe when all the alcohol has been distilled over, for the reason that the mixed alcohol and water vapors in the upper portion of the con- denser present a striated or wavy appearance, readily apparent so long as the alcohol is passing over, while after all the alcohol has been distilled, the condenser-tube appears perfectly clear. The distillation is thus continued for some time after this striated appearance has ceased. The distillate in the receiving glass is finally made up to the mark or to the original volume of the liquor taken. Strictly speaking, the measure- ments before and after distillation should be made at 15.6° C, but, except- ing in case of distilled liquors, no appreciable error results from making both measurements at the same or room temperature. Another precau- tion formerly thought necessary was to have the delivery-tube from the condenser pass below the level of a little water in the receiving-flask from the start, but equally accurate results have been obtained by simply allowing the end of the condenser-tube to enter the narrow-necked flask. Fig. 112 shows a bank of six stills of the kind used in the author's laboratory for alcohol determination in liquors. In each still the verti- cal glass worm-condenser, the round-bottomed distilling-flask, and the lamp, are supported by rings held by a single upright rod. The receiving flask is readily connected wi.h the condenser by means of a single bent tube provided with a rubber stopper. The cold-water pipe supplying the condensers is shown at the top, and the gas-supply pipe at the bottom. The distillate, made up to 100 cc, is thoroughly shaken and its specific gravity taken at exactly 15.6° in a pycnometer, or by the Westphal balance. From the specific gravity the corresponding percentage of alcohol by weight or volume,- or the grams per 100 cc. in the distillate, is ascertained by reference to the accompanying tables. To obtain percentage of alcohol by weight in the sample, multiply the per cent by weight in the distillate by the weight of the distillate, and divide by the weight of the sample taken; to obtain per cent by volume, multiply the per cent by volume in the distillate by 100, and divide by the volume of the sample used. (2) From the Specific Gravity of the Sample. — In the case of dis- tilled liquors having very little residue, an approximation to the true ALCOHOLIC BEVERAGES. 689 percentage of alcohol may be obtained by using the alcohol table in con- nection with the specific gravity of the liquor itself. The accuracy of this method depends largely on the freedom from residue, being absolutely correct for mixtures of alcohol and water only. (3) By Eva poral ion. —Determine the specific gravity of the sample, evaporate a measured portion of the liquor (50 or 100 cc.) in a porcelain FiG. 112. — Bank of Stills for Alcohol Determination. dish over the water-bath to one-fourth its bulk, make up to its original volume with distilled water, and determine the specific gravity of this second or dealcoholized portion. Add i to the original specific gravity, and from this subtract the second specific gravity. The difference is the specific gravity corresponding to the alcohol in the liquor, the per cent of which is found from the table. Example. — Suppose the specific gravity of the original sample to be 0.9900 while that of the dealcoholized sample is 1.0009. Then 1.9900 — 1.0009 = 0.9891. .'. Per Cent by volum.e of alcohol = 8.io. 690 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF ALCOHOL. (According to Hehner.) Spec. Absolute Alcohol. Spec. Absolute Alcohol. Spec. Absolute Alcohol. 1 ' Grav. at 15.6° C. Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Pel Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams by by Vol- per bv by Vol- per by by Vol- per Weight ume. Wei>jht ume. TOO cc. Weight ume. 100 cc. I .0000 0.00 0.00 0.00 0.9999 0.05 0.07 0.05 0-9959 2-33 2-93 2.32 0.9919 4.69 5-86 4-65 8 O.II 0.13 O.II 8 2-39 3 .00 2.38 8 4-75 5-94 4.71 7 0.16 0.20 0.16 7 2-44 3 .07 2.43 7 4.81 6.02 4-77 6 0.21 0.26 0.21 6 2.50 3 -14 2-49 6 4.87 6.10 4-83 5 0.26 0-33 0.26 5 2.56 3 21 2-55 5 4-94 6.17 4.90 4 0.32 0.40 0.32 4 2.61 3 28 2.60 4 5.00 6.24 4-95 3 0-37 0.46 0-37 3 2.67 3 •35 2.65 3 5.06 6.32 5.01 2 0.42 0-53 0.42 2 2.72 3 42 2.70 2 5-12 6.40 5-07 I 0.47 0.60 0.47 I 2.78 3 49 2.76 I 5-19 6.48 5-14 0.53 0.66 0.53 2-83 3 55 2.81 5-25 6.55 5.20 0.9989 0.58 0.73 0.58 0.9949 2.89 3 62 2.87 0.9909 5-31 6.63 5.26 8 0.63 0.79 0.63 8 2.94 3 69 2.92 8 5-37 6.71 5-32 7 0.68 0.86 0.68 7 3.00 3 .76 2.98 7 5-44 6.78 5-39 6 0.74 0-93 0.74 6 3.06 3 .83 3-04 6 5-50 6.86 5-45 5 0.79 0.99 0.79 S 3.12 3 90 3.10 5 5-56 6-94 5-51 4 0.84 1.06 0.84 4 3.18 3 98 3.16 4 5.62 7.01 5-57 3 0.89 I-I3 0.89 3 3-24 4 05 3-22 3 5-69 7.09 5-64 2 0-95 1. 19 0-95 2 3-29 4 12 3-27 2 5-75 7.17 5-70 I 1. 00 1.26 1. 00 I 3-35 4 20 3-33 I 5.81 7-25 5-76 1.06 1-34 1.06 3-41 4 27 3-39 5-87 7-32 5-81 0.9979 1. 12 1.42 I. 12 0.9939 3-47 4 34 3-45 0.9899 5-94 7.40 5-88 8 1. 19 1-49 I. 19 8 3-53 4 42 3-51 8 6.00 7.48 5-94 7 1.25 1-57 I-2S 7 3-59 4 49 3-57 7 6.07 7-57 6.01 6 1-31 1-65 I-3I 6 3-65 4 56 3-^3 6 6.14 7.66 6.07 5 1-37 1-73 1-37 5 3-71 4 63 3-69 5 6.21 7-74 6.14 4 1-44 1. 81 1-44 4 3-76 4 71 3-74 4 6.28 7-83 6.21 3 1-50 1.88 1-50 3 3.82 4' 78 3-80 3 6.36 7.92 6.29 2 1.56 1.96 i.s6 2 3.88 4 85 3-85 2 6.43 8.01 6.36 I 1.62 2.04 1. 61 I 3-94 4 93 3-91 I 6.50 8.10 6.43 1.69 2.12 1.68 4.00 5 00 3-97 6.57 8.18 6.50 0.9969 1-75 2.20 1-74 0.9929 4.06 5 08 4-03 0.9889 6.64 8.27 6-57 8 1. 81 2.27 1.80 8 4.12 5 16 4.09 8 6.71 8.36 6.63 7 1.87 2-35 1.86 7 4.19 5 24 4.16 7 6.78 8-45 6.70 6 1-94 2-43 1-93 6 4-25 5 32 4.22 6 6.86 8.54 6.78 5 2.00 2-51 1-99 5 4-31 5 39 4.28 5 6-93 8.63 6.85 4 2.06 2.58 2-05 4 4-37 5 47 4-34 4 7.00 8.72 6.92 3 2. II 2.62 2.10 3 4-44 5 55 4.40 3 7.07 8.80 6-99 2 2.17 2.72 2.16 2 4-50 5- 63 4.46 2 7-13 8.88 7-05 I 2.22 2.79 2.21 I 4.56 5- 71 4-52 I 7 20 8.96 7.12 2.28 2.86 2.27 4.62 5- 78 4-58 7.27 9.04 7.19 ALCOHOLIC BEVERAGES. 691 SPECIFIC GRAVITY AND PERCENTAGE OF A'LCOHO'L— {Continued). Absolute Alcohol. _ r* . _ . Absolute Alcohol. Absolute Alcohol. Spec. Spec. , Spec. , , Grav. at 15.6° C. Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams Grav. at Per Cent Per Cent Grama by by Vol- - per by by Vol- per 15-6° C. by by Vol- per Weight ume. 100 cc. Weight ume. 100 cc. Weight ume. 100 cc. 0.9879 7-33 9-13 7.24 0.9829 10.92 13-52 10-73 0.9779 14.91 18.36 14-58 8 7-40 9.21 7-31 8 11.00 13.62 10.81 8 15.00 18.48 14.66 7 7-47 9.29 7-37 7 11.08 13-71 10.89 7 15-08 18.58 14-74 6 7-53 9-37 7-43 6 II. 15 13.81 10.95 6 15-17 18.68 14-83 5 7.60 9-45 7-50 5 11.23 13.90 11.03 5 15-25 18.78 14.90 4 7.67 9-54 7-57 4 II. 31 13.99 II-II 4 15-33 18.88 14-98 3 7-73 9.62 7-63 3 11.38 14.09 II. 18 3 15-42 18.98 15-07 2 7.80 9-70 7.70 2 11.46 14.18 11.26 2 15-50 19.08 15-14 I 7.87 9-78 7-77 I 11-54 14.27 11-33 I 15-58 19.18 15.21 7-93 9.86 7-83 11.62 14-37 II. 41 15-67 19.28 15-30 0.9869 8.00 9-95 7.89 0.9819 11.69 14.46 11.48 0.9769 15-75 19-39 IS -38 8 8.07 10.03 7.96 8 11.77 14-56 11.56 8 15-83 19.49 15-46 7 8.14 10.12 8.04 7 11.85 14.65 11.64 7 15-92 19-59 15.54 6 8.21 10.21 8.10 6 11.92 14-74 11.70 6 16.0c 19.68 15.62 5 8.29 10.30 8.17 5 12.00 14.84 11.78 5 16.08 19-78 15-70 4 8.36 10.38 8.24 4 12.08 14-93 11.85 4 16.15 19.87 15-76 3 8.43 10.47 8.31 3 12.15 15.02 11.92 3 16.23 19.96 15-84 2 8.50 10.56 8.38 2 12.23 15.12 12.00 2 16.^1 20.06 15-90 I 8-57 10.65 8.45 I 12.31 15.21 12.08 I 16-38 20.15 15-99 0' 8.64 10.73 8.52 12.38 15-30 12.14 16.46 20.24 16.06 0.9859 8.71 10.82 8.s8 0.9809 12.46 15.40 12.22 0.9759 16.54 20.33 16.13 8 8.79 10.91 8.66 8 12.54 15-49 12.30 8 16.62 20.43 16.21 7 8.86 11.00 8-73 7 12.62 15-58 12.37 7 16.69 20.52 16.28 6 8.93 11.08 8.80 6 12.69 15.68 12.44 6 16-77 20.61 16.3s 5 9-00 II. 17 8.87 5 12.77 15-77 12.51 5 16.85 20.71 16-43 4 9.07 11.26 8-93 4 12.85 15.86 12-59 4 16.92 20.80 16.50 3 9.14 11-35 9.00 3 12.92 15.96 12.66 3 17 . 00 20.89 16.57 2 9.21 11.44 9.07 2 13.00 16.05 12.74 2 17.08 20.99 16.65 I 9.29 11.52 9.14 I 13.08 16.15 12.81 1 17.17 21.09 16.74 9-36 II. 61 9.22 13-15 16.24 12.89 17-25 21.19 16. 8i 0.9849 9-43 11.70 9.29 0.9799 13-23 16.33 12.96 0.9749 17-33 21.29 16.89 8 9-50 1 1 . 79 9-35 8 13-31 16.43 13-03 8 17.42 21.39 16.97 7 9-57 11.87 9.42 7 13-38 16.52 13.10 7 17-50 21.49 17.05 6 9.64 11.96 9-49 6 13-46 16.61 13.18 6 17-58 21-59 17--I3 S 9.71 12.05 9-56 5 13-54 16.70 13.26 5 17.67 21.69 17.20 4 9-79 12.13 9.64 4 13.62 16.80 ^3-33 4 17-75 21.79 17.29 3 9.86 12.22 9.71 3 13.69 16.89 13-40 3 17-83 21.89 17 37 2 9-93 12.31 9-77 2 13-77 16.98 13-48 2 17-92 21.99 17.46 I 10.00 12.40 9.84 I 13-85 17.08 13-56 I 18.00 22.09 17-54 10.03 12.49 9.92 13-92 17.17 13-63 18.08 22.18 17.61 0.9839 10.15 12.58 9-99 0.9789 14.00 17.26 13-71 0.9739 18.15 22.27 17.68 8,10.23 12.68 10.06 8 14.09 17-37 13-79 8 18.23 22.36 17.76 7,10-31 12.77 10.13 / 14.18 17-48 13.88 7 18.31 22.46 17.82 610.38 12.87 10.20 6 14.27 17-59 13.96 6 18.38 22-55 17.90 S 10.46 12.96 10.28 5 14.36 17.70 14.04 5 18.46 22.64 17-97 4 10-54 13-05 10.36 4 14-45 17.81 14-13 4 18. =^4 22.73 18.05 3 10.62 13-15 10.44 3 14-55 17.92 14-23 3 18.62 22.82 18.13 2 10.69 13-24 10.51 2 14.64 18.03 14.32 2 18.69 22.92 18.19 1 10.77 13-34 10.59 I 14-73 18.14 14-39 I 18.77 23.01 18.27 10.85 1 13-43 10.67 14.82 1 18.25 14-48 18.85 21.10 18. M 692 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF ALCOHOL— (Con/iwwei). Spec. Absolute Alcohol. Spec. Absolute Alcohol. Absolute Ale ohol. , Spec. Grav. at 15.6° C. Per Cent Per Cent Grams Grav. at Per Cent Per Cent Grams Grav. at Per Cent Per Cent Grama by by Vol- per 15.6° C. by by Vol- per 15.6° C. by by Vol- per Weight ume. 100 CO, Weight ume. 100 cc. Weight ume. 100 cc. 0.9729 18.92 23.19 18.41 0.9679 22.92 27-95 22.18 0.9629 26.60 32.27 25.61 8 19.00 23.18 18.48 8 23.00 28. 04 22.26 8 26.67 32-34 25-67 7 19.08 23-38 18.56 7 23.08 28.13 22-33 7 26.73 32.42 25-73 6 19.17 23.48 18.65 6 23-15 28.22 22.40 6 26.80 32-50 25-79 5 19-25 23-58 18.73 5 23-23 28. 31 22.47 5 26.87 32-58 25-85 4 19-33 23.68 18.80 4 23-31 28.41 22.54 4 26.93 32-65 25-91 3 19.42 23-78 18.88 3 23.38I 28.50 22.61 3 27.00 32-73 25-98 2 19-5C 23.88 18.9s 2 23.46 28.59 22.69 2 27-07 32.81 26.04 I 19-58 23.98 19-03 I 23-54 28.68 22.76 I 27.14 32-90 26.10 19.67 24.08 19.12 23.62 28.77 22.83 27-21 32.98 26.17 0.9719 19-75 24.18 19.19 0.9669 23.69 28.86 22.90 0.9619 27.29 33-06 26.25 8 19.83 24.28 19.27 8 23-77 28.95 22-97 8 27.36 33-15 26.31 7 19.92 24.38 19.36 7 23-85 29.04 23-05 7 27-43 33-23 26.37 6 20.00 24.48 19-44 6 23-92 29-13 23.11 6 27-50 33-3^ 26.43 5 20.08 24-58 19-51 5 24.00 29.22 23-19 5 27-57 33-39 26.51 4 20.17 24.68 19-59 4 24.08 29-31 23-27 4 27.64 33-48 26.57 3 20.25 24-78 19.66 3 24-15 29.40 23-33 3 27.71 33-56 26.64 2 20.33 24.88 19-74 2 24-23 29.49 23-40 2 27-79 33-64 26.71 I 20.42 24.98 19.83 I 24-31 29-58 23-48 I 27.86 33-73 26.78 20.50 25-07 19.90 24-38 29.67 23-55 27-93 33.81 26.84 0.9709 20.58 25-17 19.98 0.9659 24.46 29.76 23.62 0.9609 28.00 33-89 26.90 8 20.67 25-27 20.07 8 24-54 29.86 23.70 8 28.06 33-97 26.96 7 20.75 25-37 20.14 7 24.62 29-95 23-77 7 28.12 34-04 27.01 6 20.83 25-47 20.22 6 24-69 30.04 23.84 6 28.19 34-11 27.07 5 20.92 25-57 20.30 5 24-77 30-13 23-91 5 28.25 34-18 27-13 4 21.00 25-67 20.33 4 24-85 30.22 23-99 4 28.31 34-25 27.18 3 21.08 25-76 20.46 3 24.92 30-31 24-05 3 28.37 34-33 27.24 2 21.15 25.86 20.52 2 25.00 30.40 24.12 2 28.44 34-40 27-31 I 21.23 25-95 20.59 1 25-07 30.48 24.19 I 28.50 34-47 27.36 21.31 26.04 20.67 25.14 30.57 24.26 28.56 34-54 27.42 0.9699 21.38 26.13 20.73 0.9649 25.21 30.65 24-32 0-9599 28.62 34-61 27-47 8 21.46 26.22 20.81 8 25.29 30-73 24-39 8 28.69 34-69 27-53 7 21.54 26.31 20.89 7 25-36 30-82 24-46 7 28.75 34-76 27-59 ■ 6 21.62 26.40 20.96 6 25-43 30.90 24-53 6 28.81 34-83 27-64 5 21.69 26.49 21.03 5 25-50 30.98 24-59 5 28.87 34-90 27.70 4 21.77 26.58 21. II 4 25-57 31-07 24.66 4 28.94 34-97 27-76 3 21.85 26.67 21.18 3 25-64 S'^-^S 24.72 3 29.00 35-05 27.82 2 21.92 26.77 21.25 2 25-71 31-23 24.79 2 29-07 35-12 27.89 1 22.00 26.86 21-33 I 25-79 31-32 24-86 1 29-13 35-20 27-95 22.08 26.95 21.40 25.86 31-40 24-93 29.20 35-28 28.00 0.9689 22.15 27.04 21.47 0.9639 25-93 31-48 24-99 0.9589 29.27 35-35 28.07 8 22.23 27-13 21-54 8 26.00 31-57 25.06 8 29-33 35-43 28.12 7 22.31 27.22 21.61 7 26.07 31-65 25.12 7 29.40 35-51 28.18 6 22.38 27-31 21.68 6 26.13 31.72 25.18 6 29-47 35-58 28.24 5 22.46 27.40 21 .76 5 26.20 31.80 25-23 5 29-53 35-66 28.30 4 22.54 27-49 21.83 4 26.27 31.88 25-30 4 29.60 35-74 28.36 3 22.62 27-59 21.90 3 26-33 31.96 25-36 3 29.67 35-81 28. 4i 2 22.69 27.68 21.96 2 26.40 32-03 25-43 2 29-73 35-89 28. 4? I 22.77 27.77 22.01 I 26.47 32.11 25-49 I 29.80 35-97 28.54 22.85 27.86 22.12 26.53 32.19 25-55 c 29.87 36.04 28.61 ALCOHOLIC BEVERAGES. 693 SPECIFIC GRAVITY AND PERCENTAGE OF ALCOKO'L— (Continued). Absc lute Alcohol. Absolute Alcohol. Absolute Alcohol. Spec. Spec. Spec. Grav. at Per Per Grams Grav. at Per Per Grams Grav. at Per Per Grams 15.6° c. Cent by Cent by Vol- per 100 cc. 15.6° C. Cent by Cent by Vol- per 100 CC. 15.6° C. Cent by Cent by Vol- per 100 CC. Weight ume. Weight ume. Weight ume. 0.9579 29-93 36.12 28.67 0-9529 32-94 39-54 31-38 0.9479 35-55 42-45 33-70 8 30.00 36.20 28.73 8 33-00 39.61 31-43 8 35-60 42.51 33-75 7 30.06 36.26 28.78 7 33-06 39.68 31-48 7 35-65 42.56 33-79 6 30.11 36.32 28.82 6 33-12 39-74 31-53 6 35-70 42.62 33-83 5 30-17 36-39 28.88 5 33-18 39.81 31-59 5 35-75 42.67 33-88 4 30.22 36-45 28.92 4 33-24 39-87 31-63 4 35-80 42-73 33-92 3 30.28 36-51 28.98 3 33-29 39-94 31.69 3 35-85 42-78 33-97 2 30-33 36-57 29.03 2 33-35 40.01 31-74 2 35-90 42.84 34-01 I 30-39 36.64 29.08 1 33-41 40.07 31.80 I 35-95 42-89 34-05 30.44 36.70 29.13 33-47 40.14 31.86 36-00 42-95 34-09 0.9569 30-50 36.76 29.18 0.9519 33-53 40.20 31-91 0.9469 36.06 43-01 34-14 8 30-56 36-83 29-23 8 33-59 40.27 31.96 8 36.11 43-07 34-09 7 30.61 36.89 29-27 7 33-65 40.34 32-01 7 36-17 43-13 34-24 6 30.67 36-95 29-33 6 33-71 40.40 32-07 6 36-22 43-19 34.28 5 30-72 37.02 29.38 5 33-76 40.47 32.12 5 36.28 43-26 34-34 4 30.78 37.08 29-43 4 33-82 40-53 32-17 4 36-33 43-32 34-38 3 30.83 37.14 29.48 3 33-88 40.60 32.22 3 36-39 43-38 34-44 2 30.89 37.20 29-53 2 33-94 40.67 32-27 2 36.44 43-44 34-48 I 30.94 37-27 29-58 I 34.00 40.74 32-32 I 36.50 43-50 34-54 31.00 37-34 29.63 34-05 40.79 32-37 36.56 43-56 34-58 0.9559 31.06 37.41 29.69 0.9509 34-10 .40.84 32.41 0.9459 36.61 43-63 34-63 8 31.12 37-48 29-74 8 34-14 40.90 32-45 8 36.67 43-69 34-69 7 31-19 37-55 29.81 7 34-19 40-95 32-49 7 36.72 43-75 34-73 6 31-25 37.62 29.86 6 34-24 41.00 32-54 6 36-78 43-81 34-79 5 3^-3^ 37-69 29.91 5 34-29 41-05 32-59 5 36-83 43-87 34-83 4 31-37 37-76 29.97 4 34-33 41. II 32.63 4 36.89 43-93 34.88 3 31.44 37-83 30-03 3 34.38 41.16 32.67 3 36.94 44.00 34-92 2 31-50 37-90 30.09 2 34.43 41.21 32-71 2 37-00 44.06 34-96 I 31-56 37-97 30.14 I 34.48 41.26 32-75 I 37-06 44.12 35-02 31.62 38.04 30.20 34-52 41-32 32-79 37-" 44.18 35-07 0.9349 31.69 38.11 30.26 0.9499 34-57 41-37 3^-ft 0.9449 37-17 44-24 35-12 8 31-75 38.18 30-31 8 34.62 41.42 32.88 8 37-22 44-30 35-10 7 31.81 38-25 30-36 7 34-67 41-48 32-92 7 37-28 44-36 35-21 6 31-87 38-33 30.42 6 34-71 41-53 32-96 t 37-33 44-43 35 -2<' 5 31-94 38.40 30-48 5 34-76 41-58 33-00 5 37-39 44-49 35-31 4 32.00 38.47 30-53 4 34-81 41.63 33-04 4 37-44 44-55 35-35 3 32.06 38-53 30-59 3 34.86 41.69 33-09 3 37-50 44.61 35-41 2 32.12 38.60 30.64 2 34-90 41.74 33-'^3 2 37-56 44.67 35-46 I 32.19 38.68 30-71 I 34-95 41.79 33-17 I 37.61 44-73 35-51 32-25 38.75 30-77 35-00 41.84 33-21 c 37-67 44-79 35-56 C.9S39 32-31 38.82 30.81 0.9489 35-05 41.90 32.26 0.9439 37-73 44-86 35-60 8 32-37 38.89 30.87 8 35-10 41.95 33-30 8 37-78 44-92 35-65 7 32-44 38.96 30.93 7 35-15 42.01 33-34 7 37-83 44-98 35-70 6 32-50 39-04 30-99 6 35-20 42.06 33-39 6 37-89 45-04 35-75 5 32-56 39-11 31-05 5 35-25 42.12 33-43 5 37-49 45-10 35-80 4 32.62 39.18 31.10 4 35-30 42.17 33-48 4 38.00 45.16 35-85 3 32.69 39-25 31-15 3 35-35 42.23 33-53 3 38-06 45-22 35-90 2 32-75 39-32 31.20 2 35-40 42.29 33-57 2 38.11 45.28 35-95 1 32.81 39-40 31.26 I 35-45 42.34 33-61 I 38-17 45»34 36-00 32.87 39-47 31-32 35-50 42.40 33-65 38.22 45-41 36.04 694 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF A-LCOKOL— (Continued). Absolute Alcohol. Spec. Absc lute Alcohol. Absolute Alcohol. Spec. Spec. Grav. at Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams Grav. at 15.6° C. Per Cent Per Cent Grams 15.6° C. by by Vol- per by by Vol- per by by Vel- per Weight ume. 100 cc. Weight ume. 100 cc. Weight um e._ 100 cc. 0.9429 38.28 45-47 36-08 0-9379 40-85 48.26 38.31 0.9329 43-29 50-87 40.38 8 38-33 45-53 36-13 8 40.90 48.32 38.35 8, 43-33 50.92 40.42 7 38.39 45-59 36-18 7 40.95 48..37' 38.39 7! 43-39 50-97 40.46 6 38-44 45-65 36-23 6 41.00 48-43 38.44 6 43 43 51.02 40.50 5 38.50 45-71 36.28 5 41-05 48.48 38.48 5 43-48 51-07 40.54 4 38.56 45-77 36-33 4 41.10 48-54 38-52 4 43-52 51.12 40.58 3 38.61 45-83 36.38 3 41-15 48.59 38-58 3 43-57 51-17 40.62 2 38.67 45-89 36-43 2 41.20 48.64 38.62 2 43-62 51.22 40.66 I 38.72 45-95 36.48 I 41-25 48.70 38.66 I 43-67 51-27 40.70 38.78 46.02 36.53 41-30 48-75 38.70 43-71 51-32 40.74 0.9419 38.83 46.08 36.57 0.9369 41.35 48.80 38.74 0.9319 43.76 51-38 40.78 8 38.89 46.14 36. 62 8 41.40 48.86 38.78 8 43.81 51-43 40.81 7 38-94 46.20 36-67 7 41.45 48.91 ^8.82 7 43.86 51.48 40.85 6 39.00 46.26 36.72 6 41.50 48.97; 38.87 6| 43-90 51-53 40.89 5 39-05 46.32 36-76 5 41-55 49-02^ 38.91 5 43-95 51-58 40.93 4 39.10 46-37 36.80 4 41.60 49.07, 38.95 4 44.00 51-63 40.97 3 39.15 46.42 36-85 3 41-65 49.13 38-99 3 44-05 51.68 41.01 2 39.20 46.48 36.89 2 41.70 49.18 39-04 2 44-09 51-72 41.05 1 39-25 46.53 36-94 I 41-75 49-23 39.08 I 44.14 51-77 41.09 39-30 46.59 36.98 41.80 49.29 39-13 44.18 51.82 41 13 9409 39-35 46.64 37.02 0.9359 41.85 49-34 39-17 0.9309 44-23 51-87 41.17 8 39-40 46.70 37-07 8 41.90 49 40 39.21 8 44-27 5I-9J 41-20 7 39.45 46.75 37-11 7 41-95 49-45 39-25 7 44-32 51.96 41.24 6 39-50 46.80 37-15 6 42.00 49 50 39-30 6 44-36 52.01 41.28 5 39-55 46.86 37-19 5 42-05 49-55 39-34 5 44.41 52.06 41-31 4 39.60 46.91 37-23 4 42.10 49.61 39-38 4 44-46 52.10 41-35 3 39-65 46.97 .37-27 3 42.14 49.66 39-42 3 44-50 52-15 41.49 2 39-70 47.02 37-32 2 42-19 49-71 39-46 2 44.55 52-20 41.43 I 39-75 47.08 37-36 I 42.24 49-76 39-50 I 44-59 52-25 41.47 39.80 47-13 37-41 42.29 49.81 39-54 •44.64 52-29 41.51 0.9399 39-85 47.18 37-45 0.9349 42.33 49.86 39-58 0.9290 44.68 52-34 41.55 8 39-90 47-24 37-49 8 42.38 49-91 39-62 8 44-73 52-39 41.59 7 39-95 47.29 37-53 7 42.43 49-96 39.66 7 44.77 52-44 41.63 6 40.00 47-35 37-58 6 42.48 50.01 39-70 6 44.82 52.48 41.67 5 40.05 47.40 37.62 5 42.52 50-06 39.74 5 44.86 52-53 41.70 4 40.10 47-45 37-67 4 42-57 50.11 39-78 4 44.91 52-58 41-74 3 40.15 47-51 37-71 3 42.62 50.16 39.82 3 44.96 52-63 41-77 2 40.20 47-56 37-75 2 42.67 50.21 39-86 2 45.00 52. 68 41.81 I 40.25 47.62 37.80 I 42.71 50.26 39-90 I 45-05 52.72 41-85 40.30 47-67 37-84 42.76 50.31 39-94 45-09 52-77 41.89 0.9380 40.35 47.72 37-88 0-9339 42.81 50.37 39.98 0.9289 45-14 52-82 41-93 8 40.40 47.78 37-92 8 42.86 50.42 40.02 8 45-18 52.87 41.97 7 40.45 47-83 37-96 7 42.90 50-47 40.06 7 45-23 52.91 42.00 6 40-50 47.89 38.00 6 42.95 50-52 40.10 6 45-27 52-96 42.04 5 40.55 47-94 38-05 5 43.00 50-57 40.14 5 45-32 53-01 42.08 4 40.60 47-99 38.09 4 43-05 50.62 40. 18 4 45-36 53-06 42.12 3 40.65 48.05 38.13 3 43.10 50.67 40.22 3 45-41 53-10 42.16 2 40.70 48.10 38-18 2 43-13 50.72 40.26 2 45-46 53-15 42.19 I 40.75 48.16 38.22 I 43-19 50.77 40.30 I 45-50 S3-20 42.23 40.80 48.21 38.27 43-24 50.82 40.34 45-55 53-24 42.27 ALCOHOLIC BEVERAGES. 695 SPECIFIC GRAVITY AND PERCENTAGE OF ALCOHOL— (Con/inwcd). Absolute Alcohol. c^.. Absolute Alcohol. Absolute Alcohol. Spec. - Grav. Per Per bpec. Grav. at 15.6° C. Per Per Grav. at Per Per at Cent Cent Cent Cent 15.6° C. Cent Cent IS. 6" C. by by Vol- by by Vol- by by Vol- Weight. ume. Weight. ume. Weight. ume. 0.9279 45-59 53-29 0.9229 47-86 55-65 0.9179 1 50-13 57-97 8 45-64 53-34 8 47.91 55-69 8 50-17 58.01 7 45.68 53-39 7 47.96 55-74 7 50.22 58.06 6 45-73 53-43 6 48.00 55-79 6 50-26 58.10 5 45-77 53-48 5 48.05 55-83 5 50-30 58-14 4 45.82 53-53 4 48.09 55-88 4 50-35 58.19 3 45.86 53-58 3 48.14 55-93 3 50-39 58-23 2 45-91 53-62 2 48.18 55-97 2 50-43 58.28 I 45-96 53-67 I 48.23 56.02 I 50-48 58.32 46.00 53-72 48.27 56-07 50.52 5S-36 0.9269 46.05 53-77 0.9219 48.32 56.11 0.9169 50-57 58-41 8 46.09 53-81 8 48.36 56.16 8 50.61 58-45 7 46.14 53-86 7 48.41 56.21 7 50-65 58-50 6 46.18 53-91 6 48.46 56.25 6 50.70 58-54 5 46.23 53-yS 5 48.50 56-30 S 50-74 58-58 4 46.27 54-00 4 48.55 56-35 4 50-78 58-63 3 46.32 54-05 3 48-59 56-40 3 50-S3 58.67 2 46.36 54.10 2 48.64 56-44 2 50-87 58-72 1 46.41 54-14 I 48.68 56-49 I 50.91 58-76 46.46 54-19 48.73 56-54 50.96 58-80 «-9259 46.50 54-24 0.9200 48.77 56-58 0.9159 51.00 58-85 8 46.55 54-29 8 48.82 56-63 8 51.04 58.89 7 46.59 54-33 7 48.86 56.68 7 51.08 58-93 6 46.64 54-38 6 48.91 56.72 6 51-13 58-97 5 46.68 54-43 5 48. 96 56.77 5 51-17 59-01 4 46.73 54-47 4 49.00 56-82 4 51.21 59-05 3 46.77 54-52 3 49-04 56.86 3 51-25 59.09 2 46.82 54-57 2 49.08 56.90 2 51-29 59-14 I 46.86 54-62 I 49.12 56-94 I 51-33 59-18 46.91 54.66 49.16 56.98 51-38 59.22 0.9249 46.96 54-71 0.9199 49-20 57-02 1 0.9149 51-42 59.26 8 47.00 54-76 Proof 8 49-24 57-06 8 51.46 59-30 7 47-05 54.80 7 49-29 57-10 7 51-50 59-34 6 47-09 54-85 6 49-34 57-15 6 51-54 59-39 5 47-14 54-90 S 49-39 57.20 5 51-58 59-43 4 47-18 54-95 4 49-44 57-25 4 51-63 59-47 3 47-23 54-99 3 49-49 57-30 3 51-67 59-51 2 47.27 55-04 2 49-54 57-35 2 51-71 59-55 I 47-32 55-09 I 49-59 57.40 I 51-75 59-59 47-36 55-13 49-64 57-45 51-79 59-63 0.9239 47-41 55-18 0.9189 49-68 57-49 0.9139 SI -83 59.68 8 47-46 55-23 8 49-73 57-54 8 51.88 59-72 7 47-50 55-27 7 49-77 57-59 7 51.92 59-76 6 47-55 55-32 6 49.82 57-64 6 51.96 59.80 5 47-50 55-37 5 49.86 57-69 5 52.00 59.84 4 47.64 55-41 4 49-91 57-74 4 52-05 59.89 3 47-68 55-46 3 49-95 .57-79 3 52.09 59-93 2 47-73 55-51 2 50.00 57-84 2 52.14 59.98 I 47-77 55-55 I 50.04 57-88 I 52. iS 60.02 47-82 55-60 50.09 58.92 52-23 60.07 696 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF ALCOHOL— (CoM/m«e(f). Spec. Grav. at 15.6° C. Absolute Alcohol. Spec. Grav. at 15-6° C. Absolute Alcohol. Absolute AlcohoL Per Cent by Per Cent by Vol- Per Cent by Per Cent by Vol- Spec. Grav. at 15.6° C. Per Cent by Per Cent by Vol- Weight. ume. Weight. ume. Weight. ume. 0.9*129 52.27 60.12 0.9079 54-52 62.36 0.9029 56.82 64.63 8 52-32 60.16 8 54-57 62.41 8 56.86 64.67 7 52.36 60.21 7 54.62 62.45 7 56.91 64.71 6 52-41 60.25 6 54-67 62.50 6 56.95 64.76 S 52-45 60.30 5 54-71 62.55 5 57.00 64.80 4 52-50 60.34 4 54-76 62.60 4 57-04 64-85 3 52-55 60.39 3 54-81 62.65 3 57-08 64.89 2 52-59 60.44 2 54.86 62.69 2 57-13 64-93 1 52-64 60.47 I 54-90 62.74 I 57-17 64.97 52-68 60.52 54-95 62.79 57-21 65.01 0.9119 52-73 60.56 0.9069 55-00 62.84 0.9019 57-25 65-05 8 52-77 60.61 8 55-05 62.88 8 57-29 65-09 7 52.82 60.65 7 55-09 62.93 7 57-33 65-13 6 52-86 60.70 6 55-14 62.97 6 57-38 65-17 5 52-91 60.74 5 55-18 63.02 5 57-42 65.21 4 52-95 60.79 4 55-23 63-06 4 57-46 65-25 3 53-00 60.85 3 55-27 63.11 3 57-50 65.29 2 53-04 60.89 2 55-32 63-15 2 57-54 65-33 I 53-09 60.93 I 55-36 63.20 I 57-58 65.37 53-13 60.97 55-41 63-24 57-63 65.41 0.9109 53-17 61.02 0.9059 55-45 63.28 0.9009 57-67 65-45 8 53-22 61.06 8 55-50 63-33 8 57-71 65-49 7 53-26 61.10 7 55-55 63-37 7 57-75 65-53 6 53-30 61.15 6 55-59 63-42 6 57-79 65-57 5 53-35 61.19 5 55-64 63-46 5 57-83 65-61 4 53-39 61.23 4 55-68 63-51 4 57-88 65-65 3 53-43 61.28 3 55-73 63-55 3 57-92 65-69 2 53-48 61.32 2 55-77 63.60 2 57-96 65-73 I 53-52 61-36 I 55-82 63.64 I c;8.oo 65-77 53-57 61.40 55-86 63-69 58-05 65.81 0.9099 53-61 61.45 0.9049 55-91 63-73 0.8999 58-09 65-85 8 53-65 61.49 8 55-95 63-78 8 58.14 65.90 . 7 53-70 61-53 7 56.00 63.82 7 58.18 65-94 6 53-74 61-58 6 56.05 63-87 6 58-23 65 .99 5 53-78 61.62 5 56.09 63.91 5 58.27 66.03 4 53-83 61.66 4 56.14 63-96 4 58.32 66.07 3 53-87 61.71 3 56.18 64.00 3 58.36 66.12 2 53-91 61-75 2 56.23 64.05 2 58.41 66.16 I 53-96 61.79 I 56.27 64.09 I 58-45 66.21 54.00 61.84 56-32 64.14 58-50 66.25 0.9089 54-05 61.88 0.9039 56.36 64.18 0.8989 58-55 66.29 8 54-10 61-93 8 56.41 64.22 8 58-59 66.34 7 54.14 61.98 7 56-45 64.27 7 58.64 66.38 6 54-19 62.03 6 56-30 64.31 6 S8.68 66.43 5 54-24 62.07 5 56.55 64-36 5 58.73 66.47 4 54 - 29 62.12 4 56.59 64.40 4 58.77 66.51 3 54-33 62.17 3 56.64 64-45 3 58.82 66. s6 2 54-38 62.22 2 56.68 64-49 2 58.86 66.60 I 54-43 62.26 I 56-73 64-54 I 58.91 66.65 54-48 62.31 56-77 64.58 58.95 66.69 ALCOHOLIC BEVERAGES. 697 SPECIFIC GRAVITY AND PERCENTAGE OF ALCOUO'L— (.Continued). Spec. Grar. at Absolute Alcohol. Spec. Grav. at Absolute Alcohol. Spec. Grav. at Absolute Alcohol. Per Per Per Per Per Per 15.6° C. Cent Cent 15.6° C. Cent Cent 15.6° C. Cent Cent by by Vol- by by Vol- by by Vol- Weight. ume. Weight. ume. Weight. ume. 0.8979 59.00 66.74 0.8929 61.13 68.76 0.8879 63-30 70.81 8 59-04 66.78 8 61.17 68 .80 8 63-35 70.85 7 59-09 66.82 7 61.21 68 -83 7 63-39 70.89 6 59-13 66.86 6 61.25 68 87 6 63-43 7o»93 5 59-17 66.90 5 61.29 68 91 5 63-48 70.97 4 59.22 66.94 4 61-33 68 95 4 63-52 71.01 3 59.26 66.99 3 61.38 68 99 3 63-57 71-05 2 59-30 67.03 2 61.42 69 03 2 63.61 71.09 I 59-35 67.07 I 61.46 69 07 I 63-65 71-13 59-39 67.11 61.50 69 II 63.70 71.17 0.8969 59-43 67-15 0.8919 61.54 69 15 0.8869 63-74 71.22 8 59-48 6>.i9 8 61.58 69 19 8 63-78 71.26 7 59-52 67.24 7 61.63 69 22 7 63-83 71-30 6 59-57 67.28 6 61.67 69 26 6 63.87 71-34 5 59-61 67.32 5 61.71 69 30 5 63.91 71-38 4 59-65 67-36 4 61-75 69 34 4 63-96 71.42 3 59-70 67.40 3 61.79 69 38 3 64.00 71.46 2 59-74 67.44 2 61.83 69 42 2 64.04 71-50 I 59-78 .67.49 I 61.88 69 46 I 64.09 71-54 59-83 67-53 61.92 69 50 64.13 71-58 0.8959 59-87 67-57 0.8909 61.96 69 54 0.8859 64.17 71.62 8 59-91 67.61 8 62.00 69 58 8 64.22 71.66 7 59-96 67.65 7 62.05 69 62 7 64.26 71.70 6 60.00 67.69 6 62.09 69 66 6 64.30 71-74 5 60.04 67-73 5 62.14 69 71 5 64-35 71.78 4 60.08 67.77 4 62.18 69 75 4 64-39 71.82 3 60.13 67.81 3 62.23 69 79 3 64-43 71.86 2 60.17 67.85 2 62.27 69 84 2 64.48 71.90 I 60.21 67.89 I 62.32 69 88 I 64.52 71-94 60.26 67-93 62.36 69 92 64-57 71.98 0.8940 60.29 67.97 0.8899 62.41 69 96 0.8849 64.61 72.02 8 60.33 68.01 8 62.45 70 01 8 64.65 72.06 7 60.38 68.05 7 62.50 70 05 7 64-70 72.10 6 60.42 68.09 1 6 62.55 70 09 6 64.74 72.14 5 60.46 68.13 5 62.59 70 14 5 64.78 72.18 4 60.50 68.17 4 62.64 70 18 4 64.83 72.22 3 60.54 68.21 3 62.68 70 22 3 64.87 72.26 2 60.58 68.25 2 62.73 70 27 2 64.91 72.30 I 60.63 68 29 I 62.77 70 31 I 64.96 72-34 60.67 68.33 62.82 70 35 65.00 72.38 0.8939 60.71 68.36 0.8889 62.86 70 40 0.8839 65.04 72.42 8 60.76 68.40 8 62.91 70 44 8 65.08 72.46 7 60.79 68.44 7 62.95 70 48 7 65-13 72.50 6 60.83 68.48 6 63.00 70 52 6 65-17 72-54 5 60.88 68.52 5 63.04 70 57 5 65.21 72.58 4 60.92 68.56 4 63-09 70 61 4 65-25 72.61 3 60.96 68.60 3 63-13 70 65 3 65.29 72.65 2 61.00 68.64 2 63-17 70 69 2 65-33 72.69 I 61.04 68.68 I 63.22 70 73 I 65-38 72-73 61.08 68.72 63.26 70. 77 65-42 72.77 698 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF Al.COUO'L— (Continued). Absolute Alcohol. Absolute Alcohol. Spec. Absolute Alcohol. Spec. Spec. Grav. Per Per Grav. Per Per Grav. Per Per at 15.6° C. Cent Cent at 15.6° C. Cent Cent at 15.6° C. Cent Cent by by Vol- by by Vol- by by Vol- Weight. ume. Weight. •ume. Weight. ume. 0.8829 65.46 72.80 0.8779 67-58 74-74 0.8729 69.67 76.61 8 65-50 72.84 8 67.63 74-78 8 69.71 76-65 7 65-54 72.88 7 67.67 74.82 7 69-75 76.68 6 65-58 72.92 6 67.71 74.86 6 69.79 76.72 5 65-63 72.96 5 67-75 74.89 5 69.83 76.76 4 65-67 72.99 4 67-79 74.93 4 69.88 76.80 3 65-71 73-03 3 67.83 74-97 3 69.92 76.83 2 65-75 73-07 2 67.88 75-OI 2 69.96 76.87 I 65-79 73-11 I 67.92 75-04 I 70.00 76.91 65-83 73-15 67.96 75-08 70.04 76.94 0.8819 65.88 73-19 0.8769 68.00 75-12 0.8719 70.08 76.98 8 65.92 73.22 8 68.04 75-16 8 70.12 77.01 7 65-96 73.26 7 68.08 75-19 7 70 16 77-05 6 66.00 73 30 6 68.13 75-23 6 70.20 77.08 5 66.04 73-34 5 68.17 75-27 5 70.24 77.12 4 66.09 73-38 4 68.21 75-30 4 70.28 77-15 3 66.13 73-42 3 68.25 75-34 3 70.32 77.19 2 66.17 73-46 2 68.29 75-38 2 70.36 77.22 . I 66.22 73-50 I 68.33 75-42 I 70.40 77-25 66.26 73-54 68.38 75-45 70.44 77-29 0.8809 66.30 73-57 0.8759 68.42 75-49 0.8709 70.48 77-32 8 66.35 73-61 8 68.46 75-53 8 70.52 77-36 7 66.39 73-65 7 68.50 75-57 7 70.56 77-39 6 66.43 73-69 6 68.54 75-60 6 70.60 77-43 5 66.48 73-73 5 68.58 75-64 5 70-64 77-46 4 66.52 73-77 4 68.63 75-68 4 70.68 77-50 3 66.57 73-81 3 68.67 75-72 3 70.72 77-53 2 66.61 73-85 2 68.71 75-75 2 70.76 77-57 I 66.65 73-89 I 68.75 75-79 I 70.80 77.60 66.70 73-93 68.79 75-83 70.84 77-64 0.8799 66.74 73-97 0.8749 68.83 75-87 0.8699 70.88 77.67 8 66.78 74.01 8 68.88 75-90 8 70.92 77.71 7 66.83 74-05 7 68.92 75-94 7 70.96 77-74 6 66.87 74.09 6 68.96 75-98 6 71.00 77-78 5 66.91 74-13 5 69.00 76.01 5 71.04 77-82 4 66.96 74-17 4 69.04 76-05 4 71.08 77-85 3 67.00 74.22 3 69.08 76.09 3 7^-'^3 77.89 2 67.04 74-25 2 69.13 76-13 2 71.17 77-93 I 67.08 74-29 I 69.17 76.16 I 71.21 77.96 67-13 74-33 69.21 76.20 71-25 78.00 0.8789 67.17 74-37 0.8739 69-25 76.24 0.8689 71.29 78.04 8 67.21 74.40 8 69.29 76.27 8 71-33 78-07 7 67-25 74-44 7 69-33 76-31 7 71-38 78.11 6. 67.29 74-48 6 69.38 76.35 6 71.42 78.14 5 67-33 74-52 5 69.42 76.39 5 71.46 78.18 4 67-38 74-55 4 69.46 76.42 4 71-50 78.22 3 67.42 74-59 3 69.50 76.46 3 71-54 78.25 2 67.46 74-63 2 69-54 76-50 2 71-58 78.29 I 67.50 74-67 I 69-58 76.53 I 71-63 78.33 67-54 74-70 69.63 76-57 71.67 78.36 ALCOHOLIC BEVERAGES. 699 SPECIFIC GRAVITY AND PERCENTAGE OF Al.COUOL—{Conlinued). Absolute Alcohol. Absolute Alcohol. Absolute Alcohol. Spec. Grav. of Spec. Grav. at Spec. Grav. at Per Per Per Per Per Per Cent Cent 15.6° C. Cent Cent 15.6° C. Cent Cent by by Vol- by by Vol- by by Vol- Weight. ume. Weight. time. Weight. uine. 0.8679 71.71 78.40 0.8629 73-83 80.26 0.8579 76.08 82.23 8 71-75 78-44 8 73-88 80.30 8 76.13 82.26 7 71.79 78-47 7 73-92 80.33 7 76.17 82.30 6 71-83 78-51 6 73-96 80.37 6 76.21 82.33 5 71.88 78-55 5 74.00 80.40 5 76-25 82.37 4 71.92 78.58 4 74-05 80.44 4 76.29 82.40 3 71.96 78.62 3 74-09 80.48 3 76-33 82.44 2 72.00 78.66 2 74.14 80.52 2 76.38 82.47 I 72.04 78.70 I 74.18 80.56 I 76.42 82.51 72.09 78-73 74-23 80.60 76.46 82.54 0.8669 72-13 78.77 0.8619 74.27 80.64 0.8569 76.50 82.58 8 72.17 78.81 8 74-32 80.68 8 76-54 82.61 7 72.22 78.85 7 74-36 80.72 7 76.58 82.65 6 72.26 78.89 6 74.41 80.76 6 76-63 82.69 5 72.30 78.93 5 74-45 80.80 5 76.67 82.72 4 72-35 78.96 4 74-50 80.84 4 76.71 82.76 3 72-39 79.00 3 74-55 80.88 3 76-75 82.79 2 72.43 79.04 2 74-59 80.92 2 76-79 82.83 I 72.48 79.08 I 74.64 80.96 I 76.83 82.86 72.52 79.12 74.68 81.00 76.88 82.90 0.8659 72-57 79.16 0.8609 74-73 81.04 0-8559 76.92 82.93 8 72.61 79.19 8 74-77 81.08 8 76.96 82.97 7 72.65 79-23 7 74.82 81.12 7 77.00 83.00 6 72.70 79.27 6 74.86 8r.i6 6 77.04 83.04 5 72.74 79-31 5 74-91 81.20 5 77.08 83-07 4 72.78 79-35 4 74-95 81.24 4 77-13 83.11 3 72.83 79-39 3 75.00 81.28 3 77.17 83.14 2 72.87 79.42 2 75-05 81.32 2 77.21 83.18 I 72.91 79.46 I 75-09 81.36 I 77-25 83.21 72.96 79-50 ; 75-14 81.40 77.29 83-25 0.8649 73.00 79-54 0.8599 75-18 81.44 0.8549 77-33 83.28 8 73-04 79-57 8 75-23 81.48 8 77-38 83-32 7 73.08 79-61 7 75-27 81.52 7 77-42 83.36 6 73-13 79-65 ! 6 75-33 81.56 6 77.46 83-39 5 73-17 79.68 5 75-36 81.60 5 77-50 83-43 4 73-21 79.72 4 75-41 81.64 4 77-54 83.46 3 73-25 79-75 3 75-45 81.68 3 77-58 83-50 2 73-29 79-79 2 75-50 81.72 2 77-63 83-53 I 73-33 79-83 I 75-55 81.76 I 77-67 83-57 73-38 79.86 75-59 81.80 77.71 83.60 0,8639 73-42 79-90 0.8589 75-64 81.84 0-8539 77-75 83.64 8 73-46 79-94 8 75-68 81.88 8 77-79 83-67 7 73-50 79-97 7 75-73 81.92 7 77-83 83-71 6 73-54 80.01 6 75-77 81.96 6 77.88 83-74 5 73-58 80.04 5 75-82 82.00 5 77-92 83.78 4 73-63 80.08 4 75-86 82.04 4 77-96 83.81 3 73-67 80.12 3 75-91 82.08 3 78.00 83-85 2 73-71 80-15 2 75-95 82.12 2 78.04 83.88 I 73-75 80.19 I 76.00 82.16 I 78.08 83.91 73-79 80.22 76.04 82.19 78.12 83-94 700 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF ALCOB.O'L— (Continued). Spec. Grav. at iS.6°C. Absolute Alcohol. Per Cent by Weight. 0.8529 78. 8 78. 7 78. 6 78. 5 78. 4 78. 3 78. 2 78. I 78. 78. 0.8519 78. 8 78. 7 78. 6 78. 5 78. 4 78. 3 78. 2 78. I 78. 78. 0.8509 78. 8 79- 7 79- 6 79- 5 79- 4 79- 3 79- 2 79- I 79- 79- 0,8499 79- 8 79- 7 79- 6 79- 5 79- 4 79- 3 79- 2 79- I 79- 79- 0.8489 79- 8 79- 7 79- 6 79- 5 79- 4 79- 3 80. 2 80. I 80. 80. Per Cent, by Vol- ume. 83.98 84.01 84.04 84.08 84.11 84.14 84.18 84.21 84.24 84.27 84.31 84-34 84-37 84.41 84.44 84.47 84.51 84-54 84-57 84.60 84.64 84.67 84.70 84-74 84.77 84.80 84.83 84.87 84.90 84-93 84.97 85.00 85-03 85.06 85.10 85-13 85.16 85.19 85-23 85.26 85.29 85-33 85-36 85-39 85-42 85.46 85-49 85-53 85-56 85-59 Spec. Grav. at 15.6° C. 0.8479 8 7 6 5 4 3 0.8469 8 7 6 5 4 3 0.8459 8 7 6 5 4 3 .8449 8 7 6 5 4 3 0.8439 8 7 6 5 4 3 Absolute Alcohol. Per Cent by Weight. Per Cent by Vol- ume. 15 Spec. Grav. at :S.6°C. 0.8429 8 7 6 5 4 3 0.0419 8 7 6 5 4 3 0.8409 8 7 6 5 4 3 0.8399 8 7 6 5 4 3 0.8: Absolute Alcohol. Per Cent by Weight. 82.19 82.23 82.27 82.31 82.35 82.38 82.42 82.46 82.50 82.54 82.58 82.62 82.65 82.69 82.73 82.77 82-81 82.85 82.88 82.92 82.96 83.00 83.04 83.08 83.12 83-iS 83.19 83-23 83-27 83-31 83-35 83-38 S3. 42 83.46 83-50 83-54 83-58 83.62 83-65 83.69 83-73 83-77 83-81 83-85 83.88 83.92 83.96 84.00 84.04 84-08 Per Cent by Vol- ume. 88 ALCOHOLIC BEVERAGES. 701 SPECIFIC GRAVITY AND PERCENTAGE OF Al.COHO'L— (Continued). Spec. Grav. at Absolute Alcohol. Spec. Grav. at Absolute Alcohol. Spec. Grav. at Absolute Alcohol. Per Per Per Per Per Per 15.6° C. Cent Cent 15.6° C. Cent Cent iS.6°C. Cent Cent. by by Vol- by by Vol- by by Vol- Weight. ume. "Weight. ume. Weight. ume. 0.8379 84.12 88.79 0.8329 86.08 90.32 0.8279 88.00 91.78 8 84.16 88.83 8 86.12 90-35 8 88.04 91.81 7 84.20 88.86 7 86-15 90.38 7 88.08 91.84 6 84.24 88-89 6 86-19 90.40 6 88.12 91.87 5 84.28 88.92 5 86.23 90-43 5 88.16 91.90 4 84.32 88.95 4 86.27 90.46 4 88.20 91-93 3 84-36 88.98 3 86.31 90.49 3 88.24 91.96 2 84.40 89.01 2 86.35 90.52 2 88.28 91.99 I 84.44 89.05 I 86.38 90-55 I 88.32 92-02 84.48 89.08 86.42 90-58 88.36 92.05 0.8369 84-52 89.11 0.8319 86.46 90-61 0.8269 88.40 92.08 8 84-56 89.14 8 86.50 90-64 8 88.44 92.12 7 84.60 89-17 7 86.54 90.67 7 88.48 92-15 6 84.64 89.20 6 86.58 90-70 1 6 88.52 92.18 5 84.68 89.24 5 86.62 90-73 5 88-56 92-21 4 84.72 89.27 4 86.65 90.76 4 88.60 92.24 3 84.76 89.30 3 86.69 90.79 3 88.64 92.27 2 84.80 89-33 2 86.73 90.82 2 88.68 92-30 I 84.84 89.36 I 86.77 90.85 I 88.72 92-33 84.88 89-39 86.81 90.88 88.76 92.36 0.8359 84.92 89.42 0.8309 86.85 90.90 0.8259 88-80 92-39 8 84.96 89-46 8 86.88 90-93 8 88.84 92.42 7 85.00 89.49 7 86.92 90.96 7 88.88 92-45 6 85.04 89 52 6 86.96 90-99 6 88.92 92.48 5 85.08 89-55 5 87.00 91.02 5 88.96 92-51 4 85.12 89.58 4 87.04 91-05 4 89.00 92-54 3 85-15 89.61 3 87.08 91.08 3 89.04 92.57 2 85.19 89-64 2 87.12 91. II 2 89.08 92.60 I 85-23 89-67 I 87-15 91.14 I 89.12 92-63 85-27 89.70 87.19 91.17 89.16 92.66 0.8349 85-31 89.72 0.8299 87-23 91.20 0.8249 89.19 92-68 8 85-35 89-75 8 87-27 91-23 8 89-23 92.71 7 85-38 89.78 7 87-31 91-25 7 89.27 92.74 6 85.42 89.81 6 87-35 91.28 6 89.31 92.77 5 85.46 89.84 5 87-38 91-31 5 89-35 92.80 4 85-50 89.87 4 87-42 91-34 4 89.38 92-83 3 85-54 89.90 3 87.46 91-37 3 89.42 92.86 2 85-58 89-93 2 87.50 91.40 2 89.46 92.89 I 85.62 89.96 I 87-54 91-43 I 89-50 92.91 85-65 89-99 87-58 91.46 89-54 92.94 0-8339 85.69 90.02 0.8289 87.62 91.49 0.8239 89-58 92.97 8 85-73 90.05 8 87.65 91-52 8 89.62 93.00 7 85-77 90.08 7 87.69 91-55 7 89.65 93-03 6 85.81 90.11 6 87-73 91-57 6 89.69 93.06 5 85-85 90.14 5 87.77 91.60 5 89-73 93-09 4 85.88 90-17 4 87.81 91.63 4 89-77 93-11 3 85.92 90.20 3 87.85 91 -66 3 89.81 93-14 2 85.96 90.23 2 87.88 91.69 2 89.85 93-17 I 86.00 90.26 I 87.92 91.72 I 89.88 93-20 86.04 90.29 87.96 91-75 89.92 93-23 702 FOOD INSPECTION AND ANALYSIS. SPECIFIC GRAVITY AND PERCENTAGE OF AJ.COnO'L— (Continued). Absolute Alcohol. Absolute Alcohol. Absolute Alcohol. Spec. Spec. Spec. Grav. at teft°C Per Per Grav. at Per Per Grav. at Per Per Cent Cent 15.6° C. Cent Cent 15.6° C. Cent Cent 15. u \^. by by Vol- by by Vol- by by Vol- Weight. ume. Weight. ume. Weight. ume. 0.8229 89.96 93.26 0.8179 91-75 94-53 0.8129 93-59 95-84 8 90.00 93-29 8 91.79 94-56 8 93-63 95-87 7 90.04 93-31 7 91.82 94-59 7 93-67 95-90 6 90.07 93-34 6 91.86 94.61 6 93-70 95-92 5 90.11 93-36 5 91.89 94.64 5 93-74 95-95 4 90.14 93-39 4 91-93 94.66 4 93-78 95-97 3 90.18 93-41 3 91.96 94.69 3 93-81 96.00 2 90.21 93-44 2 92.00 94.71 2 93-85 96.03 I 90.25 93-47 I 92.04 94-74 I 93-89 96.05 90.29 93-49 92.07 94.76 93-92 96.08 0.8210 90.32 93-52 0.8169 92.11 94.79 0.8119 93-96 96.11 8 90.36 93-74 8 92-15 94.82 8 94.00 96.13 7 90-39 93-57 7 92.18 94.84 7 94-03 96.16 6 90-43 93-59 6 92.22 94.87 6 94-07 96.18 5 90.46 93.62 5 92.26 94.90 5 94.10 96.20 4 90.50 93-64 4 92.30 94.92 4 94.14 96.22 3 90-54 93-67 3 92-33 94-95 3 94.17 96.25 2 90-57 93-70 2 92-37 94.98 2 94.21 96.27 I 90.61 93-72 I 92.41 95-00 I 94-24 96.29 90.64 93-75 92.44 95-03 94.28 96.32 0.8209 90.68 93-77 0.8159 92.48 95.06 0.8109 94-31 96-34 8 90.71 93.80 8 92-52 95-08 8 94-34 96.36 7 90-75 93.82 7 92.55 95-11 7 94.38 96-39 6 90.79 93-85 6 92-59 95-13 6 94.41 96.41 S 90.82 93-87 5 92.63 95.16 5 94-45 96-43 4 9c. 86 93-9° 4 92.67 95-19 4 94.48 96.46 3 90.89 93-93 3 92.70 95-21 3 94-52 96.48 2 90-93 93-95 2 92.74 95-24 2 94-55 96.50 I 90.96 93-98 I 92.78 95-27 I 94-59 96-53 91.00 94.00 92.81 95-29 94.62 96-55 0.8199 91.04 94-03 0.8149 92.85 95-32 . 8099 94-65 96-57 8 91.07 94-05 8 92.89 95-35 8 94-69 96.60 7 91.11 94.08 7 92.92 95-37 7 94-73 96.62 6 91.14 94.10 6 92.96 95-40 6 94-76 96.64 5 91.18 94-13 5 93.00 95-42 5 94.80 96-67 4 91.21 94-15 4 93-04 95-45 4 94-83 96.69 3 91-25 94.18 3 93-07 95-48 3 94.86 96.71 2 91.29 94.21 2 93-11 95-50 2 94.90 96-74 I 91.32 94-23 I 93-15 95-53 I 94-93 96.76 91.36 94-26 93.18 95-55 94-97 96.78 0.8189 91-39 94-28 0.8139 93.22 95-58 0.8089 95-00 96-80 8 91-43 94-31 8 93.26 95.61 8 95-04 96.83 7 91.46 94-33 7 93-30 95-63 7 95-07 96.85 6 91.50 94-36 6 93-33 95.66 6 95- " 96.88 5 91-54 94-38 5 93-37 95-69 5 95-14 96.90 4 91-57 94.41 4 93-41 95-71 4 95.18 96-93 3 91.61 94-43 3 93-44 95-74 3 95-21 96-95 2 91.64 94-46 2 93-48 95-76 2 95-25 96.98 I 91.68 94-48 I 93-52 95-79 I 95-29 97.00 91.71 94-51 93-55 95.82 95-32 97.02 ALCOHOLIC BEVERAGES. 703 SPECIFIC GRAVITY AND PERCENTAGE OF Al.COUO'L— (Continued). Spec. Absolute Alcohol. Absolute Alcohol. Absolute Alcohol. Spec. Spec. Orav Per Per Grav. Per Per Grav. Per Per at iS-6°C. Cent bv i Cent i by Vol- at IS.6°C. Cent by Cent by Vol- at 15.6° C. Cent by Cent by Vol- Weight. 1 ume. Weight. ume. Weight. ume. 0.8079 95-36 ' 97-05 0.8029 97-07 98.18 0.7979 98.69 99.18 "^ 95-39 97-07 8 97.10 98.20 8 98.72 99.20 7 95-43 97.10 7 97-13 98.22 7 98.75 99.22 6 95-46 1 97-12 6 97.16 98.24 6 98.78 99-24 5 95-50 : 97-15 5 97.20 98.27 5 98.81 99.26 4 95-54 t 97-17 4 97-23 98.29 4 98.84 99.27 3 95-57 97.20 3 97.26 98.31 3 98.87 99-29 2 95-61 1 97.22 2 97-30 98.33 2 98.91 99-31 I 95-64 1 97-24 I 97-33 98-35 I 98.94 99-33 95.68 97.27 97-37 98-37 98.97 99-35 0.8069 95-71 97-29 0.8019 97.40 98-39 0.7969 99.00 99-37 8 95-75 97-32 8 97-43 98.42 8 99-03 99-39 7 95-79 97-34 7 97.46 98-44 7 99.06 99.41 6 95-82 97-37 6 97-50 98.46 6 9Q.IO 99-43 5 95-86 97-39 5 97-53 98.48 5 99-13 99-45 4 95-89 97.41 4 97-57 98.50 4 99.16 99-47 3 95-93 97-44 3 97.60 98.52 3 99.19 99-49 2 95-96 97.46 2 97-63 98-54 2 99-23 99-51 I 96.00 97-49 I 97.66 98-56 I 99.26 99-53 96.03 97-51 97-70 98-59 99.29 99-55 0.8059 96.07 97-53 0.8009 • 97-73 98.61 0-7959 99-32 99-57 8 96.10 97-55 8 97-76 98.63 8 ' 99.36 99-59 7 96.13 97-57 7 97.80 98.65 7 99-39 99.61 6 96.16 97.60 6 97-83 98.67 6 99-42 99-63 S 96.20 97.62 5 97-87 98.69 5 99-45 99-65 4 96.23 97.64 4 97.90 98.71 4 99.48 99-67 3 96.26 97.66 3 97-93 98.74 3 99-52 99-69 2 96.30 97.68 2 97-96 98.76 2 99-55 99.71 I 96.33 97.70 I 98.00 98.78 I 99-58 99-73 96-37 97-73 98.03 98.80 99.61 99-75 0.8049 96.40 97-75 0.7999 98.06 98.82 0.7949 99-65 99-77 8 96-43 97-77 8 98.09 98.83 8 99.68 99.80 7 96.46 97-79 7 98.12 98-85 7 99.71 99.82 6 96.50 97.81 6 98.16 98.87 6 99-74 99-84 5 96-53 97-83 5 98.19 98.89 5 99-78 99.86 4 96-57 97.86 4 98.22 98.91 4 99.81 99.88 3 96.60 97.88 3 98.25 98.93 3 99-84 99-90 2 96-63 97.90 2 98.28 98.94 2 99.87 99-92 1 96.66 97-92 I 98.31 98.96 1 99.90 99-94 96.70 97-94 98-34 98.98 99-94 99-96 0.8039 96-73 97.96 0.7989 98-37 99.00 0.7939 99-97 99-98 8 96.76 97.98 8 98.41 99.02 7 96.80 98.01 7 98-44 99.04 Abs. Ale. 6 96-83 98.03 6 98-47 99.05 0.7938 100.00 100.00 S 96.87 98-05 5 98.50 99.07 4 96.90 98.07 4 98-53 99.09 3 96-93 98.09 3 98.56 99-11 2 96.96 98.11 2 98-59 99-13 I 97.00 98.14 I 98.62 99-15 97-03 98.16 98.66 99.16 704 FOOD INSPECTION AND ANALYSIS. (4) Determination of Alcohol hy the Ebullioscope or Vaporimeter is based on the variation in boiling-point of mixtures of alcohol and water, in accordance with the amount of alcohol present. There are various forms of this instrument, one of the simplest and most convenient being that of Salleron, Fig. 113, the apparatus being known in France as an o-^-o -^91- 3-18 20 Fig. 113. — Salleron's Ebullioscope and Scale for Calculation of Results. ebulliometer. This consists of a jacketed metallic reservoir, healed by a lamp placed beneath, and fitted with a return-flow condenser at the top and with a delicate thermometer graduated in tenths of a degree. As the boiling-point of water varies with the atmospheric pressure, it is necessary to determine the actual boiling-point corresponding with the barometric conditions each time a series of determinations are made. ALCOHOLIC BEVERAGES. 705 This is done by boiling a measured portion of distilled water in the reser- voir, and carefully noting the temperature when it becomes constant. The reservoir is then rinsed out with a little of the liquor to be tested, after which a measured amount of this liquor is boiled in the reservoir and the temperature again noted. A sliding scale (Fig. 113) accompanies the instrument, having three graduated parts as shown. The central movable portion is graduated in degrees and tenths of a degree centi- grade, the part at the left has the per cent of alcohol corresponding to the temperature in the case of simple mixtures of alcohol and water, while the part at the right is used for reading the per cent in the case of wine, cider, beer, etc., which have a considerable residue. The movable scale bearing the degrees of temperature is first set with the actual tem- perature of boiling water (as ascertained) opposite the o mark on the stationary scale. Suppose the temperature of boiling water has been found to be 100.1°. The scale is in this case set as shown in Fig. 113. Suppose also the temperature of boiling of the wine to be tested is found to be 89.3°. From the right-hand scale the corresponding per cent of alcohol is found to be 17.2. When the liquor to be tested contains more than 25% of alcohol, it is necessary to dilute with a measured amount of distilled water and calculate the per cent from the dilution. When once the boiling-point of water has been determined for a given barometric pressure, it is unnecessary to change the position of the slid- ing scale during a series of alcohol determinations unless that pressure changes. Expression of Results. — Some confusion is caused by the three ways of expressing results of the alcohol determination, whether as per cent by weight, per cent by volume, or grams per 100 cc. The particular mode adopted should depend upon the nature of the case and upon the prevail- ing custom. In laboratory analyses, unless otherwise qualified, the simple expression of "per cent" usually implies per cent by weight, and for the reason that this conforms with other determinations, the adoption of the weight-percentage plan is perhaps most natural to the chemist on the grounds of uniformity. In enforcing the laws regulating the liquor traffic, the custom leans to volume percentage, and many of the laws are based on the ' ' volume of alcohol at 60° F." (see page 685). In recent years many European analysts have adopted the custom of expressing results of analyses of wines and other liquors in grams per 706 FOOD INSPECTION AND ANALYSIS. loo cc. and, in order to have a common basis of comparison between the composition of American and of European wines, this manner of expression has to some extent been adopted in the United States. Proofs pirit in the United States is an alcoholic liquor containing 50% of absolute alcohol by volume at 15.6° C. A common method of express- ing alcohol is in "degree proof" or simply " proof," which in the United States is twice the per cent of alcohol by volume. Ihus, 91.3 proof or degree proof is the same as 45.65% alcohol by volume. English Proof-spirit differs from that in the United States in that it contains 49.24% by weight, or 57.06% by volume of absolute alcohol at 15.6° C. Strength is expressed in degrees over or under proof. Thus liquor 20° under proof has 80 parts by volume of proof-spirit and 20 parts of water at 15.6° C, while 20° over-proof means that 100 volumes of the liquor have to be diluted to 120 volumes with water to yield proof-spirit. To calculate the per cent by volume of English proof-spirit from the per cent of alcohol by volume, divide the latter by 0.5706, or multiply it by I-7525- Direct Determination of Extract. — In liquors having a high sugar content, the extract or total solids cannot be determined accurately by evaporation at the temperature of boiling water, owing to the dehydra- tion of the reducing sugars at temperatures exceeding 75°. When extreme accuracy is required, such liquors should be dried in vacuo at 75°, or in a McGill oven (page 609). In the case of dry wines having an extract content of less than 3% evaporate 50 cc. in a flat-bottom platinum dish 85 mm. in diameter to a syrup on the water bath and dry for two and one-half hours at the tem- perature of boiling water. Sweet wines with an extract of from 3 to 6% are treated in the same manner, using, however, only 25 cc. With sweet wines containing over 6% of extract calculate from the specific gravity of the dealcoholized liquor (page 726). With distilled liquors having low residues accurate results are obtain- able by direct evaporation at 100° (page 777). Determination of Ash. — The residue from the determination of the extract is incinerated to a white ash in the original dish at a low red heat, either over a Bunsen flame or in a muffle. The dish is finally cooled in a desiccator and weighed. Preservatives and Artificial Sweeteners in liquors are identified as described in Chapters XVIII and XIX. ALCOHOLIC BEVERAGES. 707 FERMENTED LIQUORS. . The fermented juices of many varieties of fruits and berries furnish beverages more or less popular in various localities, especially for home consumption, though, with the exception of the products of the apple and the grape, few of them are found on the market. The following table shows the average percentage of sugar and free acid in the expressed juice or must of fruits, according to Fresenius, arranged in the order of their sugar content: Per Cent Sugar. Per Cent Free Acid as Malic. Peaches 1-99 2.13 2.80 4-18 4.84 S-32 6.89 7-3° 7-56 8.00 8-43 9.14 10.00 10.44 15-30 16.15 0.85 1.29 1.72 0.67 1.80 1.42 1-57 2-43 1.08 1.63 0.09 0.82 2.02 1.52 0.88 0.80 Apricots Plums Green gages . . , Raspberries Blackberries Currants German prunes Gooseberries Pears Apples Mulberries Sour cherries Grapes CIDER. Cider is the expressed juice of the apple. When fresh and before fermentation has set in, it is known as sweet cider, but it does not long remain in this condition, developing after a good fermentation from 3 to 6 per cent of alcohol by volume. The predominating yeast under the influence of which the fermenta- tion of cider takes place is Saccharomyces apiculatus, found in consider- able quantity on the outside of the apples as well as in the soil in which the trees grow. Process of Manufacture. — The best cider is made from ripe fruit, taking care to avoid the green and the rotten apples, both of which impair the quality of the product. After gathering, the apples are best allowed tc Stand in piles. until perfectly ripe, being kept under cover. If exposed to the weather, certain of the yeast organisms found on the skins of the apples that are useful in promoting subsequent fermentation would b€ 708 FOOD INSPECTION AND ANALYSIS. washed off. As a rule the apples commonly used by farmers for cider- making are those that are unsalable or unfit for other purposes, being chiefly windfalls or bruised and imperfect fruit. The apples aie usually first crushed in a mill to a coarse pulp, which is afterward subjected to pressure in a suitable press and the juice thus extracted. In this country but little attention is paid to the after processes, the juice being usually transferred directly to barrels, which are not always particularly clean, and allowed to ferment spontaneously in a convenient place, subject to changes in temperature. There is little wonder that cider so made will keep but a short time and quickly goes over into vinegar, unless sahcylic acid or other antiseptic is added. In France more care is taken to regulate the temperature of fermen- tation, to insure absolute cleanness of all receptacles, and to separate out contaminating impurities. A preliminary fermentation is usually given to the juice in open vats, during which the yeast spores are developed, while impurities separate out both by rising to the surface and by settling to the bottom, care being taken to avoid the develop- ment of acetic fermentation. At the proper time the juice is "racked off" or drawn from the clear portion between the top and bottom, trans- ferred to scrupulously clean barrels, and allowed to undergo a second fermentation at a lower temperature than before. Sometimes the "racking off" is repeated, and the juice is further clarified by "fining" or treating with isinglass, which carries down certain albuminous substances. Cider thus made is capable of keeping a very long time. In England cider is sometimes "fined" by treatment with milk, one quart of the latter being added to eighteen gallons of cider. The apple pomace, left as a residue, is generally steeped in water and repressed. The juice from the second pressing is occasionally added to the first for cider manufacture, but more often is concentrated and made into apple jelly, or used as a fortifier for vinegar to make up deficiency in solids. Composition of Cider. — The following tables, due to Browne,* show the chemical composition of the freshly expressed juice of several American varieties of apple, as well as that of a few fermented samples of cider of known purity. * Penn. Dept. of Agric, Bui. 58. ALCOHOLIC BEVERAGES. 709 APPLE JUICES. aO CS BO Pli •a 0) . .S " ■g (U < (1) a •a g ^0. 0-37 0.28 0.77 0.65 0.27 0.44 0.24 I. II 0.31 1.22 0.26 0.87 0.28 1.07 0.28 0.66 0.24 0.49 0.26 0.22 g 0) a> 5 - . oi Red astrachan . . . . Early harvest Yellow transparent Early strawberry. . Sweet bough Baldwin, green. ... ' ' ripe Ben Davis Bellflower Tulpahocken Unknown 1-05317 1.05522 1.05020 1.04949 1.04979 1.04882 1.07362 1.05389 1.06270 1.05727 I. 05901 11.78 13.29 ir.71 II. 81 11.87 II .36 16.82 12.77 14.90 13-94 13.75 6.87 3- 7-49 8.03 3- 2. 5-47 7.61 6 96 4- 3- I. 7-97 7- 7. II 9.06 9.68 3- 4- 3- 10.52 2. .50,10 .46 10.14 15 .69 •59 .02 .96 13-38 12.79 12.83 .14 .90 .86 .78 .10 .24 .67 .46 -58 .26 .44 23.72 24.32 19.24 39-40 36.16 49.00 39.20 48.20 44.18 FERMENTED CIDER (MIXED APPLES). Rotation, Specific Gravity. Solids. Invert Sugar. Malic Acid. Acetic Acid. Alcohol. Pectin. Ash. 400-mm. Tube, Ventzke Scale. Degrees to the Left. A... i.9q805 1-94 0.19 0.21 0.2/1 6.85 0.03 0.25 2.30 B... C... I. 00122 1.00525 2.71 3.26 0.19 0.89 0.24 0.30 0.42 0.48 5-13 4.67 0.03 0.05 0.32 0.29 2-49 5.28 D. . E... I. 0007 I I. 00512 1-93 2.71 0.34 0.24 0.27 0.29 0.21 1.96 4-95 4.26 0.05 0.06 0.23 0.36 2.00 1.76 The following are summaries of the results of a large number of analyses of European apple juices made by Truelle, the quantities being expressed in grams per liter: Specific gravity Inveri mgar Sucrose Total fermentable sugars (as dextrose) Tannin Pectin and albuminous substances. . . . Acidity (sulphuric acid) Mean. Minimum. Maximum. 1.0760 1-0573 1. 1 100 135-85 108.38 181. 81 25.01 5-58 71.7 162.18 119.22 231-57 2.90 0.26 8.07 12 23 2.14 0.69 7.41 710 FOOD INSPECTION AND ANALYSIS. In the municipal laboratory of Paris, Sangle Ferriere has analyzed eleven samples of known-purity cider with the following results: Sugar per Acidity as Liter. H2SO4. >> c .Q a ^ a c £2g efore [n ver- sion. fter Inver- sion. u •S3 ,0 Q cw a m <; Pu <; < H Ph Mean I. 0159 3-9 52.67 21.31 21.62 -4°.26 3.26 2.^6 5-27 2-55 Maximum I. 0410 6.2 114.00 59-40 60.80 -11°. 20 4-32 3-68 6.59 2.94 Minimum. . . I. 0012 I.I 22.62 Trace Trace 2.48 2. 04 4.20 1-47 Six samples of bottled "sweet" cider purchased in Massachusetts were analyzed in the Food and Drug Laboratory of the Board of Health with the following results: Per Cent Alcohol by Weight. Per Cent Acid as Malic. Per Cent Extract. Maximum Minimum Average.. 8.00 3-55 5-71 0.72 0.48 C.58 7.82 2.42 4.19 Browne gives the following as the composition of the mixed ash of several varieties of apple: Ingredient. Per- cent- age. Ingredient. Per- cent- age. Potash (K2O) Soda (NaP) Lime (CaO) Magnesia (MgO) Oxide of iron (FcoOg) Oxide of aluminum (AI2O3) Chlorine (CI) Silica (SiOj) Sulphuric acid (SO3) Phosphoric acid (P2O5) Carbonic acid (COj) Deduct oxygen equivalent to CI. . Total 55-94 0.31 4-43 3-78 O.Q5 0.80 0-39 0.40 2.66 8.64 21.60 99.90 .09 99. Si Potassium carbonate (KoCOg)... Potassium phosphate (K3PO4). .. Sodium chloride (NaCl) Calcium sulphate (CaSO^) Calcium oxide (CaO) Magnesium phosphate (MgjPjO^) Magnesium oxide (MgO) Ferric oxide (FeoOj") Aluminum oxide (AlgO^) Silica (SiOg) Total 6.85 14-5S 0.60 4-52 2.57 6.97 0.59 o-gS 0.80 0.40 99.80 ALCOHOLIC BEVERAGES. 711 Burcker * gives the following composition of the ash of cider: Per Cent. Silica o . 94 Phosphoric acid 12 .68 Lime 2.77 Magnesia 2 .05 Oxides of iron and manganese o- 94 Potash 53.74 Soda 1 . 10 Carbonic acid 25 . 78 100.00 Adulteration of Cider. — ^The Committee on Standards of the A. O. A. C. have submitted for adoption the following standards for cider: Alcohol not more than 8%, extract not less than 1.8% determined by evaporation in an open vessel at ordinary atmospheric pressure and at the tempera- ture of boiling water; ash not less than 0.2%. Entirely factitious cider made from other than apple stock is rarely found, though the product as sold is frequently of inferior quality and adulterated. The chief adulterants are water and sugar, and the use of antiseptics is common, especially of salicylic and sulphurous acids, sodium benzoate, and occasionally beta-naphthol. Sodium carbonate is sometimes added to cider to neutralize the acid and thus prevent acetic fermentation. An abnormally high ash (say in excess of 0.35%) would point toward the presence of added alkali. Watering is apparent when the content of alcohol, solids, and ash of the suspected sample are found to be considerably below the corre- sponding constants of pure cider. x\ccording to Sangle Ferriere, the following are the minimum figures for these constants in a pure cider, so that a sample may safely be pronounced as watered if they all run distinctly below: Alcohol 3% by volume Extract 1.8% Ash 0.17% Besides these determinations, it is useful also to determine the fixed and volatile acids. Caramel is to be looked for, especially in watered samples. Other * Les Falsifications des Substances Alimentaires, p. 176. 712 FOOD INSPECTION AND ANALYSIS. adulterants alleged to be of frequent occurrence in French cider, but not commonly found in this country are commercial glucose, tartaric acid (to increase the acidity of a watered product), and coal-tar colors. Absence or deficiency of malates is conclusive evidence of fraud, indicating the admixture of notable quantities of the juice of the second pressing of pomace. Sugar is rendered apparent by the right-handed polarization of the sample, pure cider always polarizing well to the left. If after inversion of a dextro-rotary cider the polarization is still to the right, commercial glucose is indicated; if the reading after inversion is to the left, cane sugar has undoubtedly been added. Frequently the analyst has only to determine the alcohol, especially in cases of seizure, to ascertain whether or not there has been violation of the liquor laws. PERRY OR PEAR CIDER. This is a common French product, but is rarely if ever found on sale in this country, though sometimes made for home consumption. In composition and in method of manufacture it much resembles apple cider. It is also subject to the same forms of adulteration. The following table summarizes a number of analyses made by Truelle on pear juice, or must, amounts being expressed in parts per thousand : Specific gravity Invert sugar Sucrose Total fermentable sugars (as dextrose) Tannin Pectin and albuminous substances — Acidity (as sulphuric acid) Mean. I . 0845 145.64 36-74 184.14 1.78 13.08 1-47 Maximum. 1.0675 108. ID 16. 6() 143-78 1. 01 3 0.76 Minimum. 1.0980 200 61.41 220 ^.20 18 2.40 The following analysis of champagne perry is taken from the Lancet of October i, 1892: Alcohol by weight 1.45 Alcohol by volume i . 80 Solids II .00 Ash 0.35 ALCOHOLIC BEVERAGES. 713 WINE. Wine in its broadest sense is the fermented expressed juice of any fruit, though the term, unless otherwise restricted, is generally understood to apply to the juice of the grape. The organism present in grape juice that plays the chief part in its alcoholic fermentation is the Saccharomyces ellipsoideus, a yeast which exists on the skins of the grape. Process of Manufacture. — The grapes, which should be fully ripe, are picked and sometimes sorted, according to the care that is taken in grading the product. They are also sometimes freed from the stems, which contain considerable tannic acid, and which when crushed with the grapes impart a certain astringency to the final product. The grapes are crushed either by machinery or by the bare feet, and the juice is pressed out from the pulp in various ways, by screw or hydraulic press, or by the centrifugal process. A certain amount of juice runs off from the preliminary crushing known as the first run, and makes the choicest wine. The product from the pressure constitutes the second run, after which the pomace, by steep- ing in water and repressing, is made to yield an inferior juice used in making piquette. Red wines are made from dark grapes by fermenting the pulp, before pressing, with the skins, which by this treatment yield up their rich color (cenocyanin) to the juice. ■ Besides the color, the skins contain also tannin. White wine is made from the pressed pulp, freed from the skins at once, or from the pulp of white grapes. The unfermented must constitutes from 60 to 80 per cent of the weight of the grape. Fermentation progresses most rapidly at a temperature between 25° and 30° C, but wine having a much finer boucj[uet is produced by slower fermentation, hence the must is allowed to ferment in open vats or tubs in cool cellars, at a temperature of from 5° to 20° till it settles out com- paratively clear, special care being taken to avoid development of acetic fermentation. At the end of the first or active fermentation, the wine is drawn off and allowed to undergo a second or slow fermentation in casks, during which most of the lees or crude argols, composed of potas- sium bitartrate, settle out, being insoluble in alcohol, and the characteristic bouquet or flavor of the wine is developed. Occasionally during this process the wine is racked or drawn off. Undesirable fermentations and vegetable fungus growth, which are liable to occur at this time, are avoided by using especially clean casks, 714 FOOD INSPECTION AND ANALYSIS. which are frequently " sulphured " (or burnt out with sulphur) before being used. The wine is often clarified, by treatment with gelatin, which mechanically removes many impurities by precipitation, or is subjected to pasteurization before finally being bottled or stored in casks. Classification of Wines. — Natural wines are those which are exclusively the product of the simple juice, fermented under the best conditions, either till the sugar has been used up, or till the protein is exhausted, or until the yeast growth has been checked by the strength of the alcohol developed. When the alcohol reaches i8% by volume (in extreme cases 20%) fermen- tation due to yeast ceases. Examples of natural wines are hock and claret. Fortified wines are those to which alcohol has been added. As the addition is commonly made before the fermentation is complete, such wines are usually sweet. Examples of fortified wines are madeira, sherry and port. Still wines are those in which there is but little carbon dioxide remain- ing, so that they do not effervesce. Sparkling wines are more or less heavily charged with carbon dioxide, either naturally, as in the case of champagne, wherein the gas is formed by after fermentation of added sugar in the corked bottle, or artificially, by carbonating. Wines are also classified according to color. Red wines include clarets, chianti and red burgundies, while white wines are those of a yellowish color such as the Rhenish and Moselle wines and the sauternes. " Dry " wines are those in which the sugar has been exhausted by fermentation, while sweet wines possess a considerable amount of unfer- mented sugar which remains after the yeast ceases to grow because of the exhaustion of the protein or else the formation or addition of an excess of alcohol. Sweet wines are often reinforced by the addition of sugar. Dealcoholized wine is prepared by distilling off the esters at a low temperature and then the alcohol at a higher temperature, returning the esters to the residue and charging the whole with carbon dioxide and adding a little sugar and in some cases tartaric acid. The product contains a negligible amount of alcohol. Varieties of Wine. — Champagne according to French law is the sparkling wine made in the old province of Champagne, although similar wines of other provinces and countries are often incorrectly designated by that name. It is prepared from selected white wine clarified with gelatine, bottled with the addition of cane-sugar and tightly corked. The bottles are placed on their sides and fermentation is allowed to pro- ceed, thus charging the wine with carbon dioxide. The bottles are then ALCOHOLIC BEVERAGES. 715 gradually inverted until the sediment gathers above the cork, which by care- ful manipulation is quickly removed so as to throw out the sediment. A small amount of a lic^ueur prepared from sugar, wine and brandy is then added, after which the cork is replaced and secured. Champagne con- tains from 8 to io% of alcohol and varying amounts of sugar as indicated by the designation sec (dry), extra sec and brut (natural). Sauternes are sweetish white French wines containing 8 to 14% of alcohol by volume and varying amounts of sugar up to 2.5%. Chateau Yquem is a well-known sauterne. Rhine Wines (Hocks) and Moselle Wines are prized because of their delicate mildly tart flavor. They contain little sugar and from 7 to 13% of alcohol. Johannisberger, Steinberger, Hochheimer, Liebfraumilch, Niersteiner and Rudesheimer are well-known hocks, and Zeltinger and Berncasteler Doctor are examples of moselles. Claret is the common designation for French red wines produced in the neighborhood of Bordeaux, It is somewhat acid and astringent, contains 7 to 13% by volume of alcohol and very Httle sugar, St. Julien, Pontet Canet, Lafitte, and St. Estephe are well-known examples. Burgundies are somewhat heavier wines than the clarets and are both red and white, still and sparkling. The best are produced in the Cote d'Or of the old province of Burgundy, Chianti is an Italian wine similar in flavor to the burgundies. It is commonly sold in wicker-covered flasks. Red and white natural wines are also produced in other European countries as well as in the United States. Sherry is a deep-amber-colored sweet Spanish wine high in alcohol (18-24% by vol.) and consequently fortified. It is commonly plas- tered. Port is a sweet Portuguese wine, fortified with brandy, containing from 15 to 24% of alcohol by volume. It may be either red or white. Its name is a corruption of Oporto, Madeira is a rich wine, much improved by age, containing from 18 to 20% by vol. of alcohol and a marked quantity of sugar. It is named from the island producing it, Tokay Wines are choice medicinal Hungarian wines high in alcohol and very sweet. The Constituents of Wine may be classified as volatile organic, non- volatile organic, and mineral. The volatile organic constituents, aside from ethyl alcohol, consist of higher alcohols, notably amyl alcohol, which 716 FOOD INSPECTION AND ANALYSIS. go to form the fusel oil of brandy, traces of methyl alcohol, volatile acids, chiefly acetic acid which is present to some extent in carefully prepared wines and in large amount in wines which have undergone acetic fer- mentation, also minute quantities of proprionic, butyric, and higher acids of the series, as well as very small quantities of various ethers, acetaldehyde, furfural, acetal, and other substances influencing the bou- quet. The principal non-volatile organic substances are sugars and related substances, organic acids, glycerol, nitrogenous substances including traces of nitrates, and coloring matter {cenocyanin of red wines and quercetin of red wine and white and red pomace wines). The principal saccharine substance is invert sugar. Pentoses (chiefly arabinose), methylpentoses (chiefly rhamnose), inosite, and mannite occur in small amounts, the last named found only in unsound wines. The fixed acids derived from the fruit are (i) tartaric acid, the most abundant, existing as the free acid and as acid salts, (2) malic acid, next to tartaric in abundance, exists largely as the free acid which in the fresh juice exceeds the free tartaric acid but is largely destroyed during fer- mentation, and (3) citric acid, occurring only in small amounts. Traces of salicylic acid and probably of oxalic acid are also present in grape juice and wine. Tannic acid (tannin), the astringent principle of wines, notably the red varieties, may also be grouped with the acids derived from the fruit. The fixed acids formed during fermentation are lactic and succinic. The acidity as determined by titration does not represent accurately the sourness to the taste. This is shown by the hydrogen ion concentration. The ash constituents of chief diagnostic importance are phosphoric acid (reduced by dilution), potassium sulphate (increased by plastering), and sodium chlorate (increased by use of salt as a clarifier and preservative). Manganese is a normal constituent of wines. Traces of boric acid occur in normal wines. Arsenic and copper, derived from spraying solutions, are present in only infinitesimal quantities. Composition of Wines. — Averages of analyses of typical European wines as compiled by Konig are given in the table on page 717. A summary of analyses of California wines compiled by Bigelow appear in page 718. Standards. — The U. S. Standards follow : Wine is the product made by the normal alcoholic fermentation of the juice of sound, ripe grapes, and the usual cellar treatment, and contains not less than 7 nor more than 16 per cent of alcohol, by volume, and, in 100 cc. (20° C.) ; not more than 0.1 gram of sodium chloride nor more than 0.2 gram of potassium ALCOHOLIC BEVERAGES. ■717 COD) t^OO spixo 00 NO -ip uoqjB3 d d (=os) ■* o OO CM NO M -* PPV O O O OOOOOO OO w O O O o ounqding O O O OOOOOO OO O O O O o COM) 0\ O O O 00 ro tOOO "IINtNOINOO OOio-iOoC M ro to ^ vC •U33oj;iN O O O Q 6 6 6 6 o d O d o ^ ■ w t^ lOO •pioV lO -* t^ M • M Ot oim% O O o o O O -JBX saJJ O O o o O O t^ 0\ M O ■ '^ ^ On . •81EJ1 vo lO r^ fO CO t-» • t^ o -JB;iq 'OO'^'^imO'NloC vO CN) vo r^ to ^ IT) CS IN M (N C H(NMO»C^MC^Oir rj- O) (N M C5 IH M a •qsy I u o O O O O c OOOOOOOOC o O O O O rO O "+ lO C h OiO- ^ ^ ^NO NO NO NO IBIOX O O O O O OOOOOOOOC o o o c o c o (N :^ M (N o M M 0\ lOO r^ 0 0\ ID M \0 c^ O o) Tt- M -*00 t^ OnoO :~~ On c^ c< O M N (N M C cow Ov-*ioO '^•^C s O M '^ w C •o •loqoDjv 00 Ov O OvOC t^oo t-- t^oO t^vO O>0C NO NO -* M C O On tH M M M M 00 00 O M ■<: cor^OOMS coco On too CM -^ 0\ On O O C O^O^O^OO^O^O^O^C N On O On CO t^ -AB jQ ogpadg O O O O O OnOnO^O^O^O^O^O^O \ On O On O O OnO O O O O O OOOOOOOOC O M O M M O M •pazX ^o m f^OO f^oo t^vO O^ 0\ <^ vomO to lO CO M t^ ■* t^ CO ^X OOvOMMCSMrt OC oi H H( ir> tr -[til ly jaquin^ M H M CO C^ 2; :^ < tn (J 03 14 CO < >.>> & ^-v ^■S :?; cd 3 cS c;i 4I| >< rt e and Saar and Main. Rhine.. . . • 6 ^ u ^ o S S RED DR UX (Cla Italv. . . Q W H a. '5 ■ Si '. 3 : SWEET Sherry) al (Port a 13 s o CJ OO 03 cS o pq o 2 s UK 2 > o a f-i o c O C _tn re 03 c Q .3 X) > O H 1 < 1/) c a 718 FOOD INSPECTION AND ANALYSIS. •qsy SuuoiOQ puB iltUUBJ, ■sppiojj •g^Bqding •jBSng Supnpa^ •UOIIBZUB^OJ <5 00 O t^ MCO O^'T) MO MOoO OO voco I^O uoio M On OO 00 M O rCcO r^OO lOO roO rOO Oi-i ^O M ro 00 rO l_l Tf o ■* t^ ro -t LO NO O ON O J^vO ■o -t CO lO M Lr- w M M w O^ 0\ NO On NO NO too lO O On O ON 00 m (N) NO NO •* M O M ^O O + r II I I E° •loBj^xa •spioy M On OO O CO 00 00 NO 00 ro PO O 00 M OO M CO O NO ON CI CO NO M r'^ lO t^NO LO o 0) ^ NO CO ^ ^ NO ^ ^ " r^ n On M 00 t^ NO I^ NO On O M no CO <50 CI NO t^ LO M O 00 On LO t^ r*) 1-- rO NO 01 t^ ■^ t^ 01 [0t[O0[B 00 CO «^C0 ^ T)- r^ M CO lO H 00 0) £ o •uiaaoXfQ •loqoDtv O i^ MM r^ CO O NO NO ^ CO P) On CO Aq joqcoiv O ON 00 o O CO 00 r-~ ogiosdg o 01 H r- -f NO M On On On On ON On On On 00 0) 00 00 On 00 On On O On O On •ssfdureg JO J9qxun]sj ^ i3 s s i^^ «^ 3 6 S - '^ cS a, >^ § Ji 2 5 O ALCOHOLIC BEVERAGES. 719 sulphate; and for red wine not more than 0.14 gram, and for white wine not more than 0.12 gram of volatile acids produced by fermentation and calculated as acetic acid. Red wine is wine containing the red coloring matter of the skins of grape. White wine is wine made from white grapes or the expressed fresh juice of other grapes. Dry wine is wine in which the fermentation of the sugars is practically- complete, and which contains, in 100 cc. (20° C), less than i gram of sugars, and for dry red wine not less than 0.16 gram of grape ash and not less than 1.6 grams of sugar- free grape solids, and for dry white wine not less than 0.13 gram of grape ash and not less than 1.4 grams of sugar- free grape solids. Fortlfiel dry wine is dry wine to which brandy has been added, but which conforms in all other particulars to the standard of dry wine. Sweet wine is wine in which the alcoholic fermentation has been arrested, and which contains, in 100 cc. (20° C), not less than I gram of sugars, and for sweet red wine not less than 0.16 gram of grape ash, and for sweet white wine not less than 0.13 gram of grape ash. Fortified sweet wine is sw^eet wine to which wine spirits have been added. By act of Congress, " sweet wine " used for making fortified sweet wine and " wine spirits " used for such fortification are defined as follows (sec. 43, Act. of October i, 1890, 26 Stat. 567, as amended by section 68, Act of August 27, 1894, 28 Stat. 509, and further amended by Act of Congress, approved June 7, 1906) : " That the wine spirits mentioned in section 42 of this act is the product resulting from the distillation of fermented grape juice to which water may have been added, prior to, during, or after fermentation, for the sole purpose of facilitating the fermentation, and economical distillation thereof, and shall be held to include the products from grapes or their residues, com- monly known as grape brandy; and the pure sweet wine, which may be fortified free of tax, as provided in said section, is fermented grape juice only, and shall contain no other substance whatever introduced before, at the time of, or after fermentation, except as herein expressly provided; and such sweet wine shall contain not less than 4 per cent of saccharine matter, which saccharine strength may be determined by testing with Balling's saccharometer or must scale, such sweet wine, after the evaporation of the spirits contained therein, and restoring the sample tested to original volume by addition of water: Provided, That the addition of pure boiled or condensed grape must, or pure crystallized 720 FOOD INSPECTION AND ANALYSIS. cane or beet sugar, or pure anhydrous sugar to the pure grape juice aforesaid, or the fermented product of such grape juice prior to the fortiiication provided by this act, for the sole purpose of perfecting sweet wine according to commercial standard, or the addition of water in such quantities only as may be necessary in the mechanical operation of grape conveyors, crushers, and pipes leading to fermenting tanks, shall not be excluded by the definition of pure sweet wine aforesaid: Provided, however, That the cane or beet sugar, or pure anhydrous sugar, or water, so used shall not in either case be in excess of io% of the weight of the wine to be fortified under this act: And provided further, That the addition of water herein authorized shall be under such regula- tions and limitations as the Commissioner of Internal Revenue, with the approval of the Secretary of the Treasury, may from time to time prescribe; but in no case shall such wines to which water has been added be eligible for fortification under the provisions of this act where the same, after fermentation and before fortification, have an alcoholic strength of less than 5% of their volume." Sparkling wine is wine in which the after part of the fermentation is completed in the bottle, the sediment being disgorged and its place supplied by wine or sugar liquor, and which contains in 100 cc. (20° C), not less than 0.12 gram of grape ash. Modified wine, ameliorated wine, corrected wine, is the product made by the alcoholic fermentation, with the usual cellar treatment, of a mixture of the juice of sound, ripe grapes with sugai (sucrose), or a syrup containing not less than 65% of sugar (sucrose), and in quantity not more than enough to raise the alcoholic strength after fermentation, to 11% by volume. Raisin wine is the product made by the alcoholic fermentation of an infusion of dried or evaporated grapes, or of a mixture of such infusion, or of raisins with grape juice. Adulteration of Wine. — Beverages purporting to be wine are sometimes found on sale that are entirely spurious, in that they con- tain little if any fermented grape juice. Brannt gives recipes for the manufacture of sucii artificial products employing the following ingredients : apple juice, sugar syrup, rectified spirits, crushed raisins, cream of tartar, bilberry, elderberry, and black currant juice, acetic ether, elderberry flowers, and oil of bitter almonds. After fermentation the imitation wines are clarified with isinglass. ALCOHOLIC BEVERAGES. 721 If the imitation is largely cider the tartaric acid will be low and the ash will give a potash instead of sodium flame. Wines are most frequently adulterated by " plastering," by the addi- tion of excessive amounts of sugar or glucose, by watering, by fraudulent fortification with alcohol, by the admixture of raisin wine or imitation wine made from pomace, by the addition of glycerin, by flavoring with ethers, saccharin, etc., by artificial coloring, by the addition of preserva- tives, and by the addition of citric or tartaric acid. Plastering. — By this term is understood the addition of gypsum or plaster of Paris to the must before fermentation, a practice in vogue in parts of France, Italy, and Spain. The reaction which takes place with the potas- sium bitartrate present in the wine is, according to Chancel, as follows : 2KHC4H4O6 + CaS04 = CaC4H406 + H2C4H4O6 + K2SO4. Potassium Calcium Calcium Tartaric Potassium bitartrate sulphate tartrate acid sulphate Various advantages are said to result from this practice. The wine is clarified by the precipitation of the calcium tartrate, which mechan- ically carries down with it many impurities, the color of the wine is improved, since the solubility of the coloring principle present in the skins is incr'^ased, the fermentation is rendered more rapid and complete, and the keeping qualities are enhanced. Plastering of dry wines is per- mitted both by German and French law, provided not more than 2 grams of potassium sulphate per liter remains in the wine. Larger amounts are allowed in sweet wines (sherry, etc.). According to Blarez the limit for new natural wine is 0.6 gram and for old, i.o gram. Deplastering by means of chloride or tartrate of barium or strontium is also practiced. Addition of Cane Sugar. — During some seasons the must is deficient in sugar but contains an excess of acid. To bring the yield of alcohol up to normal the addition of sucrose is permitted in France and of sucrose, invert sugar and commercially pure dextrose in Germany. This practice is known as " chaptahzing." The addition of pure calcium carbonate to correct the acidity is also permitted. The use of commercial glucose in wine is not regarded with favor, since it contains more or less unfermentable matter, and introduces dextrin and various mineral salts into the wine. Invert sugar is the only sugar that should be present in natural wine. In normal fermentation the dextrose is more quickly destroyed 722 FOOD INSPECTION AND ANALYSIS. than the levulose, hence the polarization of pure wine is always left- handed unless all the sugar has been fermented, in which case the reading should be zero. Bigelow found in his investigation of California wines that seventy- five samples of red types polarized from —0.5 to —2.1, upward of eighty of white types from — o.i to —3.5 (excepting four, evidently abnormal, showing o to +1) and thirteen of the port type from —14.7 to —27.1. A sharp, right-handed polarization would indicate the presence of either commercial glucose, dextrose or cane sugar. After inversion, if the reading is still right-handed, glucose or dextrose is apparent, while if inversion changes the reading from right to left, cane sugar has undoubt- edly been added. By application of Clerget's formula the amount of cane sugar can be estimated. The Watering of Wine. — Gall introduced a system of correcting must for an excess of acid as well as a deficiency of sweetness by adding water together with sugar. The German wine law of 1901 permitted "gallizing" if not more than 259^ of water was added and the wine did not contain less of the other ingredients than the average of natural wines of the same class. The following minimum limits in grams per ico cc. were adopted for gallized white and red wines: total extract, white 1.6, red 1.7; total extract minus fixed acids, white i.i, red 13; total extract less total acids, white i.o, red 1.2; ash., white 0.13, red 0.16. The law of 1909 permits only 2oC^' of added water and requires that the modified must conform to the natural product of grapes of the same kind and region during good years. In France watering in any degree is not permitted. Gauticr ' a large number of analyses of unwatered wines found that the sum ot tlie per cent by volume of alcohol and the total acidity expressed in grants of sulphuric acid per liter varied within very narrow limits, rarely being below 13 or above 17. In applying this rule to plastered or soured wines the following preliminary corrections should be made: (i) if the potassium sulphate exceeds i gram per liter (plastered wine) multiply the excess by 0.2 and deduct from the total acids; (2) if the volatile acids exceed i (soured wine) multiply the excess by o.i and add the product to the alcohol, also add I to the fixed acids to obtain the total acids. This rules according to Pratolongo * applies not only to all natural Italian wines but also to other wines. * Staz. sper. agr. ital., 50, 1917, p. 315. ALCOHOLIC BEVERAGES. 723 Halphen * adds 0.70 to the fixed acid (expressed in grams of sulphuric acid per liter) and divides by the percentage of alcohol by volume. This ratio is highest in wines containing the lowest percentages of alcohol, as shown by the curves in Halphen's chart (Plate XLI). If the percentage of alcohol corresponding to the ratio found in a given sample is consider- erably greater than that obtained in the actual analysis, watering is indi- cated. Issoglio t concluded that this ratio is applicable to Italian wines, but Scurti and Rolando J found that 25% of water would escape detection, while Pratolongo, on the other hand, found that it would exclude one- fifth of the natural wines. Roos § lays stress on the ratio of the sum of the fixed acid and per- centage of alcohol by volume (C) to the quotient obtained by dividing the percentage of alcohol by volume by the percentage of extract (B). This ratio (-g j should not be less than 3.2 (or in extreme cases 3.0) for red wines or less than 2.4 for white wines. Blarez 1 1 employs a more complicated scheme of distinguishing natural from watered wines. Ash ^ regards California red and white wines as suspicious when they contain less than 2.3 and 1.6% of sugar- free solids and at the same time less than 16 and 15% of alcohol plus acids respectively. The same author concludes that a large amount of free tartaric acid in proportion to potassium bitartrate coupled with low sugar-free solids indicates acidi- fication with citric or tartaric acid as well as dilution. The presence of nitrates in wines has been regarded as evidence of watering, but Tillman,** and also Paris and Marsaglia,tt find this test valueless, as nitrates occur in natural wines. The Fortification of Wine. — The addition of alcohol to sweet wine such as sherry and port is recognized as an essential step in the process of manufacture, and in Germany the use of 1% by vol. in dry wines is also * Ann. chim. anal., 12, 1907, pp. 129, 196. t Ind. chim., 14, p. 23. t Ann. chim. appl., 8, 191 7, p. 47. § Ann. fals. 4, 1911, p. 361. II Vin et Spirituex, etc., Paris, 1908. 1 8th Int. Cong. App. Chem., 18, 191 2, p. 17. **Zeits. Unters, Nahr. Genussm., 22, 1911, p. 201. tt Staz. sperim. agrar. ital., 11, 1098, p. 123. 724 FOOD INSPECTION AND ANALYSIS. allowed. When, however, alcohol is added to imitation or stretched wines such an addition is distinctly an adulteration. A committee appointed in France to devise means of detecting added alcohol established the rule that the grams of alcohol per loo cc. divided by the grams of extract should not exceed 4.5 for red wines or 6.5 for white wines. In the case of plastered wines, or wines having added sugar, it is necessary to deduct from the total extract the weight of the reducing sugar and of the potassium sulphate (less i gram for each of these substances), the reduced extract thus obtained being used in calcula- ing the ratio. In Germany the glycerol-alcohol ratio expressed in grams per 100 cc. is also used in detecting added alcohol, the accepted limits being 7 : 100 and 14 : 100. Both limits, however, should be extended, as German wines often have a ratio as high as 6 : 100 and American wines still higher, and 19 : 100 is on record for genuine European wines. "Pomace Wine." — This term is applied to imitation wines prepared from the marc of grapes with the addition of sugar, water, and often tartaric or citric acid. It is not strictly a wine, and that term according to U. S. rulings is regarded as a misbranding even if modified by the word pomace. The product although not lacking in alcohol is naturally deficient in other characteristic constituents of true wine except, perchance, these are reinforced by skillful sophistication. EofE * has made exhaustive analyses of pomace wines from which he concludes that its presence in wine is usually indicated if the results per 100 cc. are below the following : Nitrogen 10 mg. (below 5 mg. almost cer- tain proof), total tartaric acid 20 eg. (unfortified wine 10 eg.), fixed tartaric acid 50 eg., non-sugar extract 1.5 grams for white and 2.0 grams for red wines, and pentosans 50 mg. for white and 100 mg. for red wines. Pomace wine is also indicated if the ash exceeds 20 eg. (white dry wines), if the alkalinity of the water soluble ash is below 8 cc. N/io hydrochloric acid per 100 cc, or if the amount of phosphoric acid in the ash is below 10%. Natural wines seldom contain over 5 mg. of chlorine in 100 cc; if it exceeds 10 mg. the presence of ammonium chloride or corn sugar solu- tion may be suspected. Piquette is prepared in France from second pressings obtained after soaking the marc in water. It is in a sense a diluted wine. * Jour. Ind. Eng. Chem., 8, 1916, p. 723. I ALCOHOLIC BEVERAGES. 725 Raisin Wine is defined on page 720. Its detection by chemical analysis is often more difficult than by organoleptic test. The Addition of Glycerol to increase the extract, known as scheeliz- ing, is indicated by a high glycerol-alcohol ratio. The German com- mission on wine statistics decided that the presence of over 0.5 gram of glycerol per 100 cc, is proof of addition of this substance provided: (i) the extract minus fixed acids is more than two-thirds glycerol or (2) with a glycerol-alcohol ratio of more than 10 : 100 the total extract is less than 1.8 grams per 100 cc. or the total extract minus the glycerol is less than i gram. The Coloring of Wine involves the use of both vegetable and coal- tar dyes and is considered on pages 736-737. The Addition of Preservatives other than sulphur compounds is pro- hibited in most countries and the amount of sulphur dioxide is limited. Sauternes are commonly sulphured. Hexamethylenetetraamine (urotropin) is used for concealing the pres- ence of sulphur dioxide used as a preservative. On distillation with acid the wine thus treated yields a distillate containing formaldehyde. Alum is sometimes employed to clarify and to improve the color and keeping qualities of wine. French and German laws prohibit its use. Common Salt also serves as a clarifier and preservative. While normal wines contain only traces of chlorine, under certain conditions the quantity is considerable, hence the following rather generous limits expressed in grams per 100 cc: Germany 0.05, France o.io, Spain 0.20. Fruit Wines other than Grape. — Wines mostly of domestic manufac- ture are sometimes made from small fruits, such as raspberries, straw- berries, blackberries, gooseberries, elderberries, and currants, as well as from cherries, plums, and apricots. Wines made from most of these fruirs readily undergo acetic fermentation unless antiseptics are added, or unless extreme care is taken in their manufacture and keeping. Most of the sour fruits require a liberal admixture of sugar to produce an accept- able wine. The following analysis of currant wine is due to Fresenius : Alcohol 10.01% Free acid o-79% Sugar 11-94% Water 77 . 26% 726 FOOD INSPECTION AND ANALYSIS. METHODS OF ANALYSIS OF WINE AND CIDER. For determination of specific gravity, alcohol, extract (by direct method), and ash, see pages 686-706. Calculation of the Extract in Wine. — Attention has already been called to the difficulty in accurately determining the extract of sweet wines gravimetrically by evaporation. An approximate determination of the extract may be obtained by calculation from the specific gravity of the dealcoholized liquor, or one may use for this purpose the tables compiled by Windisch, and based on experiments made on drying wine in vacuo at 75° C. In wines high in sugar, with more than 6% of extract, this method is far more accurate than drying at 100°, and is to be recommended. Evaporate a measured portion of the wine on the water-bath to one- fourth its volume, and dilute with water to exactly the volume measured. Determine the specific gravity of this dealcoholized liquid at 15.6°, and from the table on pages 727-729 ascertain the extract corresponding. Determination of Total Acidity.— Carbonated beverages are first freed from carbon dioxide by agitation as described on page 687, after which 25 cc. of the sample are heated just to the boiling-point and titrated with tenth-normal sodium hydroxide, using in the case of white wine neutral litmus solution as an indicator. With red wine delicate litmus paper should be used. Total acidity is usually expressed, in the case of cider as malic, and of wine as tartaric acid. Each cubic centimeter of tenth-normal alkali corresponds to 0.0067 gram malic, or 0.0075 gram tartaric acid. Some chemists express total acidity in terms of sulphuric acid, each cubic centimeter of tenth-normal alkali being equivalent to 0.0049 gram of sulphuric acid. Volatile Acids in all liquors are usually expressed as acetic, although traces of propionic and other volatile acids may be present. 50 cc. of the cider or wine and a little tannic acid are transferred to a distilling- flask, Fig. 115, the stopper of which is provided with two tubes, one of which connects with the condenser, while the other, arranged to reach nearly to the bottom of the distilling-flask, communicates with a second flask which contains about 300 cc. of water. The contents of both flasks are brought to boiling, after which the flame under the distilling flask is lowered, and steam from the water-flask is passed through the wine till about 200 cc. of distillate have collected in the receiving-flask. Titrate this with tenth-normal sodium hydroxide, using phenolphthalein as an indicator. Each cubic centimeter of tenth-normal alkali is equiv- alent to 0.006 gram acetic acid. ALCOHOLIC BEVERAGES. 727 EXTRACT IN WINE. [According to Windisch.] Specific Gravity. Ex- Specific Ex- Specific Ex- Specific Ex- Specific Ex- Specific Ex- tract. Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. I . oooo .00 I .0065 1.68 I .0130 3-36 1.0195 5.04 I .0260 1 6.72 1-0325 8.40 1 .0001 0.03 I .0066 1.70 1.0131 3.38 I .0196 5.06 I .0261 6.75 1.0326 8.43 I . 0002 o.c; I .0067 1.73 r .0132 3-41 I .0197 5 09 I .0262 6.77 1.0327 8.46 1 .0003 0.08 I . 0068 1.76 I. 0133 3.43 I .0198 5-II I .0263 6.80 1.0328 8.48 I .0004 0. 10 I .0069 1.78 I. 0134 3.46 I .0199 S-14 1 .0264 6.82 1.0329 8.51 I .0005 0.13 1 .0070 1. 81 I. 0135 3.49 I .0200 5-17 I .0265 6.85 1.0330 8.53 I .0006 0.15 1 .0071 1.83 I .0136 3-51 I .0201 5-19 I .0266 6.88 I. 0331 8.56 I .0007 0.18 I .0072 1.86 I. 0137 3-54 I .0202 5-22 I .0267 6.90 1.0333 8.59 1 .0008 0. 20 I .0073 1.88 1 .0138 3.56 I .0203 5-25 1.0268 6.93 1.0333 8.6i I .0009 0.23 1 .0074 1. 91 I. 0139 3.59 I .0204 5.27 I .0269 6.95 I -0334 8.64 I .0010 0. 26 1.0075 1.94 I .0140 3.62 I. 020s 5.30 I .0270 6.98 1-0335 8.66 8.69 8.72 8-74 8-77 1 .001 1 C.2« I .0076 1 .96 I .0141 3.64 I .0206 5. 32 I .0271 7.01 1-0336 I .0012 0.31 1.0077 1.99 I .0142 3.67 I .0207 5-35 I .0272 7.°3 1-0337 I .0013 0.34 I .0078 2.01 I. 0143 3-69 I .0208 5.38 1.0273 7 .06 1-0338 I. 0014 0.36 1.0079 2.04 I .0144 3.72 I .0209 5-4° 1.0274 7.08 1-0339 l.oois 0.39 I . 0080 2.07 1.014s 3.75 I .0210 S-43 1.0275 7. II 1.0340 8-79 8.82 8.85 I .0016 .41 I .0081 2 .09 I .0146 3-77 I .0211 S.45 I .0276 7-13 I. 0341 I .0017 0.44 I .0082 2.12 I .0147 3-80 I .021 2 5.48 1.0277 7-16 1-0342 1 .0018 0. 46 I .0083 2.14 I . 0148 3.82 I .0213 5-51 1 .0278 . 7.19 1-0343 8.87 8.90 I .0019 0.49 I .0084 2.17 I .0149 3.85 I .0214 5-53 I. 0279 7.21 1-0344 I .0020 0.52 1.0085 2 . 19 1 .0150 3.87 I .0215 5.56 I .0280 7.24 I -034s 8.92 I .0021 0. 54 I .0086 2.22 1.0151 3 90 I .0216 5.58 I .0281 7 . 26 I -0346 8.95 I .0022 0.57 I .0087 2.25 I .0152 3.93 1 .0217 5. 61 I .0282 7.29 1-0347 8-97 I .0023 O.S9 1.0088 2.27 I.OIS3 3-95 I .0218 5-64 I .0283 7-32 I -0348 9 . 00 1 .0024 0. 62 I .0089 2.30 I .0154 3.98 I .0219 5.66 I .0284 7-34 1-0349 9-03 1.0025 0.64 I .0090 2.32 I. 0155 4.00 I .O220 5.69 I .0285 7-37 1-0350 9-oS I .0026 0. 67 I .0091 2.3S 1 . 1 5 6 403 I .0220 5-71 1.0286 7-39 1-0351 9.08 I .0027 0.69 I .0092 2.38 I. 0157 4.06 I .0222 5-74 I .0287 7-42 I -0352 9. 10 1 .0028 0.72 1 .0093 2 .40 I. 0158 4.08 I .0223 5-77 1.0288 7-45 1-0353 9.13 9. 16 I .0029 0.7s I .0094 2-43 I. 0159 4. II I .0224 5-79 I .0289 7-47 1-0354 I .0030 0.77 1.0095 2.45 I . 0160 4-13 I .0225 5.82 I .0290 7-50 I-03SS 9.18 I .0031 0.80 I .0096 2.48 I .0161 4. 16 I .0226 5.84 I .0291 7.52 1-0356 9.21 I .0032 0.82 I .0097 2. 50 I .0162 4.19 I .0227 5. 87 I .0292 7-55 1-0357 9-23 1.0033 0.85 I .0098 2.53 I .0163 4.21 I .0228 5.89 i.0293 7-58 1.0358 9. 26 1.0034 0.87 1.0099 2.56 I .0164 4.24 I .0229 5-92 I .0294 7 .60 I. 0359 9.29 I .0035 0.90 I .0100 2.58 1.016s 4. 26 I .0230 5-94 1.0295 7-63 I .0360 9-31 I .0036 0.93 I .0101 2.61 I .0166 4.29 I .0231 5-97 I .0296 7-65 I .0361 9-34 1.0037 0.95 I .0102 2.63 I .0167 4-31 I .0232 6.00 1.0297 7.68 1.0362 9-36 I .0038 0.98 I .0103 2.66 I. 0168 4-34 1.0233 6.02 I .0298 7.70 I -0363 9-39 I .0039 1 .00 I .0104 2.69 I .0169 4-37 1.0234 6.05 I .0299 7-73 1 .0364 9-42 I. 0040 I .03 I .0105 2.71 I .0170 4-39 1.0235 6.07 I .0300 7.76 1.0365 9-44 I ,0041 I -OS I .0106 2.74 I .0171 4.42 1.0236 6. 10 1.0301 7.78 I .0366 9-47 I .0042 I .08 I .0107 2. 76 I .0172 4-44 1.0237 6.12 I .0302 7.81 1.0367 9.49 1.0043 I .11 I .0108 2.79 I. 0173 4-47 I .0238 6.15 1-0303 7.83 1.0368 9-5a 1.0044 I.I3 I .0109 2.82 I. 0174 4.50 I .0239 6.18 1.0304 7 .86 I 0369 9-55 1.004s 1. 16 1 .0110 2.84 I. 0175 4-52 I .0240 6. 20 1.0305 7.89 . 1-0370 9-57 I .0046 1. 18 1 .0111 2.87 1 .0176 4.5s I .0241 6.23 I .0306 7.91 1-0371 9.60 9.62 I .0047 1 . 21 1 .0112 2.89 I. 0177 4-57 I .0242 6.25 1.0307 7-94 1.0372 I .0048 1 .24 1 .0113 2 .92 I .0178 4.60 1.0243 6.28 1.0308 7-97 1-0373 9-65 9-68 1.0049 1.26 I .0114 2.94 I. 0179 4.63 I .0244 6.31 I .0309 7-99 1-0374 1 .0050 1 . 29 I .0115 2.97 I .0180 4.65 1.0245 6.33 I .0310 8.02 1.037s 9-70 1 .0051 1 .32 I .01 16 3- 00 I .oi8i 4.68 I .0246 6.36 I .0311 8.04 1-0376 9-73 1 .0052 1.34 I .0117 3-02 I .0182 4.70 I .0247 6.38 I .0312 8.07 1.0377 9.75 1 .0053 1.37 I .0118 3-05 I .01S3 4-73 I .0248 6.41 1-0313 8.09 1-0378 9-73 1.0054 1.39 I .01 19 3-07 I .0184 4.7s I .0249 6.44 I. 0314 8-12 1-0379 9-80 1 .0055 1 .42 I .01 20 3.IO I .0185 4.78 I .0250 6.46 1.0315 8.14 I .0380 9-83 1 .0056 I -45 I .0121 3-12 1. 0186 4.81 I .0251 6.49 I .0316 8.17 1 .0381 9-86 1.0057 I .47 I .0122 3-15 I .0187 4.83 1.0252 6.51 1.0317 8.20 1.0382 9-88 1 .0058 I . 50 I .0123 3.18 1.018S 4.86 I.02S3 6.54 I .0318 8.22 1-0383 9.91 1 .0059 1.52 I .0124 3 -20 I .0189 4. 88 1.0254 6.56 I. 0319 8.25 1 -0384 9.93 1 .0060 i-SS I .0125 3-23 I . 0190 4.91 1.0255 6.59 I .0320 8.27 1.0385 9.96 1 .0061 1-57 I . 01 26 3-26 I .0191 4-94 1 .0256 6.62 I .0321 8.30 1.0386 9-99 I .0062 1 .60 I .0127 3.28 I .0192 4.96 ] .0257 6.64 1.0322 8-33 1.0387 10 .01 I .0063 1.63 I .0128 3-31 I.OI93 4 09 1 . 2 5 cS 6.67 1.0323 8-35 1.0388 10.04 1.0064 1.6s I .0129 3-33 I .0194 1 S-Ol 1.0259 6. 70 1-0324 8.38 1.0389 10.06 728 FOOD INSPECTION AND ANALYSIS. EXTRACT IN \YmE— {Continued). Specific Ex- Specific Ex- Specific Ex- Specific Ex- Specific Ex- Specific Ex- Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. I .0390 10.09 I-045S 11.78 1.0520 13.47 1.0585 i5-i6 I .0650 16.86 1.0715 18.56 I .0391 10. 1 1 10. 14 1-0456 II. 81 1.0521 13.49 1.0586 15.19 I. 0651 16.88 1 .0716 18.58 I 0392 I.0457 11.83 1 .0522 13-52 1.0587 15.22 I .0652 16.91 1.0717 18.61 1.0393 10. 17 1.0458 11.86 1.0523 13. 55 1.0588 15-24 1.0653 16.94 I .0718 18.63 1.0394 10.19 I.04S9 11.88 1.0524 13-57 1.0589 15.27 1.0654 16. 96 I. 0719 18.66 1.0395 10. 22 I .0460 11.91 1-0525 I 3 . 60 1.0590 15.29 1.0655 16.99 I .0720 1S.69 I .0396 10. 25 I I. 0461 11.94 I .0526 13.62 I. 0591 15-32 I .0656 17.01 1 .0721 18.71 1.0397 10.27 I . 0462 II .96 1-0527 13-65 1.0592 15-35 1.0657 17.04 I .0722 18.74 I .0398 10.30 1 .0463 11.99 I .0528 13-68 1.0593 15-37 1.0658 17-07 1.0723 18.76 1.0399 10. 32 I .0464 12.01 1.0529 13-70 1.0594 15-40 I .0659 17.09 1.0724 18.79 1 .0400 10.35 1.046s 12.04 1.0530 13-73 I-0595 15-42 I .0660 17 12 I .0725 18.82 I .0401 10.37 I .0466 1 2 .06 1.0531 13-75 1.0596 15-45 I .0661 17.14 I .0726 18.84 I . 0402 10.40 1.0467 1 2 .09 1-0532 13-78 1-0597 iS-48 I . 0662 17-17 1.0727 18.87 I .0403 10.43 I .0468 12.12 1-0533 13.81 1-059S 15-SO I .0663 17 . 20 I .0728 18.90 I .0404 10.4s I .0469 12.14 1-0534 13-83 1.0599 15-53 I .0664 17.22 1.0729 18.92 I. 040s 10.48 1 .0470 12.17 1-053S 13-86 I .0600 15. 55 1.0665 17-25 I .0730 18.95 I .0406 10.51 I .0471 12.19 1-0536 13-89 I .0601 iS-58 I .0666 17.27 1-0731 18.97 I .0407 10.53 1.0472 12.22 1-0537 13-91 I .0602 15.61 I .0667 17.30 1-0732 19.00 I .0408 10. 56 [( 1 .0473 12.25 1.0538 13-94 I .0603 15-63 1.0668 17.33 1.0733 19.03 I .0409 10.58 1 I .0474 12. 27 I.0539 13-96 I . 0604 15-66 I .0669 17-35 1.0734 19-05 I .0410 10. 61 1.047s 12.30 1 .0540 13-99 I .0605 15. 68 1 .0670 17-38 1.0735 19-08 I .0411 10.63 1.0476 12.32 I-0541 14.01 I .0606 15-71 I .0671 17.41 1.0736 19. 10 I .041 2 10. 66 ] 1.0477 12-35 1-0542 14.04 I .0607 15-74 1 .0672 .17-43 1.0737 19-13 I .0413 10.69 1.0478 12.38 1-0543 14-07 I . 0608 15-76 1.0673 17.46 1.0738 19- 16 I .0414 10. 71 i 1.0479 12.40 1-0544 14.09 1 .0609 15-79 I .0674 17-48 1.0739 19. iS 1.041S 10.74 I .0480 12.43 I.054S 14.12 I .0610 15.81 1.0675 17-51 I .0740 19.21 1 .0416 10. 76 I .0481 12-45 I .0546 14.14 I . 0611 iS-84 I .0676 17-54 1-0741 19-2. 1.0417 10.79 I .0482 12.48 1.0547 14.17 I .0612 JS-87 1.0677 17-56 1.0742 19. 2C 1 .0418 10.82 I I .0483 12.51 1 .0548 14. 20 I. 0613 15-89 1.0678 17-59 1.0743 19-2C I .0419 10.84 1.0484 12.53 1.0549 14. 22 I .0614 15-92 I .0679 17.62 1.0744 19-3] I .0420 10.87 1.048s 12. s6 1.0550 14-25 I .0615 15-94 1 .0680 17.64 1.0745 19-31 I .0421 10 . 90 I .0486 12.58 1.0551 14.28 I .0616 15-97 I. 0681 17.67 I . 0746 19-3- I .0422 10.92 I .0487 12.61 1.0552 14.30 I .0617 16. 00 1.0682 17-69 1.0747 19-3? I .0423 10.9s 1.0488 12.64 1.0553 14-33 I. 0618 16.02 1.0683 17.72 I .0748 19.4: I .0424 10.97 I .0489 12.66 I.05S4 14-35 I .0619 16.05 I .0684 17.75 1.0749 19-41 1.0425 II .00 I .0490 12 . 69 1.0555 14-38 I .0620 16.07 1.0685 17.77 1-0750 19.4- I .0426 II .03 I .0491 12.71 1-0556 14.41 I .0621 16. 10 1.0686 17.80 I. 0751 19-5C I .0427 11.05 I .0492 12.74 1-0557 14-43 I .0622 16. 13 1.0687 17.83 1.0752 19-52 1 .0428 11.08 I -0493 12.77 1.0558 14.46 I .0623 16.15 1.0688 17-85 1-0753 19-5! I .0429 II . 10 1.0494 12.79 1.0559 14.48 I .0624 16.18 I .0689 17-88 1-0754 19-5^ 1.0430 II. 13 I .0495 12.82 I .0560 14-51 I .0625 16.21 I .0690 17.90 1-0755 19. 6c I. 0431 II. 15 I .0496 12.84 I .0561 14-54 I .0626 16.23 j I . 0691 17-93 1-0756 19- 6:3 I .0432 II. 18 1.0497 12.87 I .0562 14.56 1 .0627 16.26 I . 0692 17-95 1-0757 19.65 1 -0433 II . 21 I .049S 12.90 1.0563 14-59 1.0628 16.28 1.0693 17-98 1-0758 19.68 I -0434 11.23 1.0499 12.92 1.0564 14.61 I .0629 16.31 I .0694 18.01 1-0759 19-71 1.0435 II . 26 I .0500 12.95 1.056s 14.64 I .0630 16.33 I .0695 18.03 I .0760 19-73 I .0436 11.28 I .0501 12.97 I .0566 14.67 I .0631 16.36 I .0696 18.06 I .0761 19.76 I -0437 II. 31 I .0502 13.00 1.0567 14-69 1.0632 16.39 I .0697 18.08 I .0762 19-79 I .04.58 11-34 1.0503 13.03 1.0568 14-72 1.0633 16.41 I .0698 18. II 1.0763 19.81 1.0439 II .36 I .0504 13.05 1-0569 14.74 I .0634 16.44 I .0699 18.14 I .0764 19.84 I . 0440 11-39 I. 050s 13-08 1-0570 14-77 1.0635 16.47 I .0700 18.16 1.0765 19.86 I .0441 II .42 I .0506 13-10 1-0571 14.80 I .0636 16.49 I . 0701 18.19 I .0766 I9.8g I .0442 11.44 1.0507 13-13 1 1.0572 14.82 1.0637 16. 52 I .0702 18.22 1.0767 19.92 I .0443 11.47 I . 0508 13-16 1.0573 14-85 1.0638 16.54 1.0703 18.24 1.0768 19-94 1.0444 11.49 1.0509 13.18 1.0574 14.87 1 -0639 16.57 I .0704 18.27 1 .0769 19-97 1.0445 11-52 1 .0510 13.21 1.0575 14.90 I .0640 16.60 1.0705 18.30 I .0770 20.00 I .0446 11-55 1.0511 13.23 1.0576 14.93 1 .0641 16.62 I .0706 18.32 1.0771 20.02 I .0447 11-57 1 .0512 13-26 1.0577 14-95 I .0642 16.65 1.0707 18.35 1.0772 20.05 I . 0448 1 1 . 60 1-0513 13-29 I .0578 14.98 I .0643 16.68 1 . 0708 18.37 I.0773 20.07 I .0449 1 1 . 62 1.0514 13-31 1-0579 15-00 I .0644 16.70 I .0709 18.40 1.0774 20. 10 I .0450 1 1 . 65 1-0515 13.34 I .0580 15-03 I .0645 16.73 I .0710 1S.43 I-077S 20. 12 I .0451 11.68 I -0516 13-36 I .0581 15-06 I .0646 16.75 I .0711 18.45 I .0776 20.15 I .0452 1 1 . 70 1.0517 13-39 1 .0582 15-08 I .0647 16.78 I .0712 1 8. 48 1-0777 20.18 I -0453 11-73 1-0518 13-42 1.0583 15-H I .0648 16.80 1-0713 18.50 1.0778 20. SO I. 0454 11-75 I. 0519 13-44 I .05S4 15-14 I .0649 16.83 1.0714 1S.53 1 1.0779 20. 23 ALCOHOLIC BEVERAGES. 729 EXTRACT IN \NlNE—iCon/!niicd). Specific Ex- Specific Ex- Specific Ex- Specific Ex- Specific 1 Ex- Specific Ex- Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. Gravity. tract. I .0780 20 . 26 I .0845 21 .96 I .0910 23.67 1.097s 25. 38 1 . 1040 27.09 I. 1105 28.81 1 .0781 20.28 1.0846 21.99 I .ogii 23.70 I .0976 25.41 I . 1041 27.12 I . 1106 28.83 1 .0782 20.31 1 .0847 22 .02 I .091 2 23.72 1.0977 25-43 I . 1042 27. IS 1 . 1107 28.86 1.0783 20.34 1.0848 22.04 I. 0913 23-75 I .0978 25.46 1. 1 043 27.17 1 . 1108 28.88 I .0784 20.36 I .0849 22.07 I .0914 23.77 1.0979 25.49 I . 1044 27. 20 1 . 1 109 28.91 1.078s 20.39 1.0850 22.09 I. 0915 23.80 I .0980 25-51 1.104s 27 . 22 1 . 1 1 10 28.94 1.0786 20.41 I. 0851 22.12 I .0916 23-83 I .0981 25.54 I . 1046 27.25 1 .1111 28.96 1.0787 20.44 1.0852 22.15 I. 0917 23-85 I .0982 25-56 I. 1047 27.27 1.1112 28.99 1.0788 20.47 1.0853 22.17 I .0918 23.88 1.0983 25.59 I . 1048 27.30 I -1113 29 . 02 1.0789 20.49 1.0854 22. 20 I .0919 23.91 I .0984 25.62 1 . 1049 27-33 1 . 1 1 14 29.04 I .0790 20.52 1.085s 22. 22 I .0920 23.93 1.098s 25.64 1.1050 27.35 i.ms 29.07 1 .0791 20. ss 1.0856 22. 25 I .0921 23.96 I .0986 25.67 1.1051 27.38 1 . 1116 29.09 1.0792 20. 57 1.0857 22.28 I .0922 23.99 I .0987 25.70 1 . 1052 27.41 1.1117 29. 13 1-0793 20.60 1.0858 22.30 1.0923 24.01 I .0988 25.72 1.1053 27.43 1.1118 29-15 1.0794 20.62 I .0859 1 22.33 I .0924 24.04 I .0989 25.75 1 1.1054 27.46 1 . 1119 29.17 1.079s 20.65 1 I .0860 22.36 1.092s 24.07 I .0990 25.78 1.105s 27.49 I .1120 29 . 20 1 .0796 20.68 i.o86i 22.38 1 .0926 24.09 1 .0991 25-80 I. 1056 27.51 I . 1121 29.23 1.0797 20. 76 1.0862 22 .41 1 .0927 24. 12 1 .0992 25.83 i I. 1057 27-54 1.1122 29.25 1 .0798 20.73 1.0863 22.43 I .0928 24.14 1.0993 25-85 1. 1058 27-57 1.1123 29. 28 1.0799 20.7s I .0864 22.46 I .0929 24.17 1.0994 25.88 I.IOS9 27.59 1 . 1124 29.31 I .oSoo 20.78 1.086s 22.49 1.0930 24. 20 I -0995 25.91 1 1 . 1060 27 .62 I.II2S 29.33 1 .0801 20.81 1.0866 22.51 I. 0931 24. 22 I .0996 25.93 1 . 1061 27-65 1 . 1126 29.36 1 .0802 20.83 1.0867 22.54 1.0932 24-25 1.0997 25.96 1 . 1062 27.67 I . 1127 29.39 1 .0803 20.86 1.0868 22.57 1.0933 24.27 I .0998 25.99 1.1063 27.70 1.1128 29.41 1 .0804 20.89 I .0869 22.59 1.0934 24.30 1.0999 26.01 j I . 1064 27.72 1 .1129 29.44 I .0805 20.91 I .0870 22 . 62 1.093s 24.33 1 . 1000 26.04 1.1065 27-75 1.1130 29.47 I .0806 20.94 I .0S71 22.65 I .0936 24.3s I . lOOI 26.06 I . 1066 27.78 1.1131 29.49 I .0807 20.96 I .0872 22.67 1.0937 24.38 1 . 1002 26.09 1 1 . 1067 27.80 I. 1132 29.52 1.0808 20.99 1.0873 22. 70 1.0938 24.41 I. 1003 26.12 r.io68 27.83 I.II33 29.54 1 .0809 21 .02 I .0874 22.72 1.0939 24.43 I . 1004 26. 14 I . 1069 27.86 1.1134 29.57 I .0810 21 .04 1.087s 22.75 I .0940 24.46 1 . loos 26. 17 1 . 1070 27.88 I.II3S 29. 60 1 .081 1 21 .07 1.0876 22.78 I .0941 24.49 I . 1006 26 . 20 I . 1071 27.96 1.1136 29. 62 1 .0812 21.10 1.0877 22.80 1.0942 24.51 I . 1007 26. 22 I . 1072 27.93 1.1137 29.65 I. 0813 21.12 1.0S78 22.83 1.0943 24-54 1 . 1008 26.25 1.1073 27.96 1.1138 29.68 1 .0814 21 .IS 1 .0879 22.86 1.0944 24.57 I . 1009 26. 27 1 I. 1074 27.99 1.1139 29.70 I .0815 21 . 17 1.0880 22.88 1.0945 24.59 1 I . lOIO 26.30 1.107s 28.01 I . 1140 29.73 I. 0816 21 . 20 I. 0881 22.91 I .0946 24.62 J I . lOII 26.33 1 . 1076 28.04 1 . 1141 29.76 I .081 7 21.23 1.0882 22.93 1.0947 24.64 1 . 1012 26.35 1.1077 28.07 1 . 1142 29.78 1. 08 1 8 21.25 1.0883 22.96 I .0948 24.67 1.1013 26.38 I . 1078 28.09 1.1143 29.81 I .0819 21 .28 1.0884 22.99 1.0949 24.70 1 . 1014 26.41 1.1079 28.12 1.1144 29.83 1 .0820 21.31 1.088s 23.01 1.0950 24.72 I . 1015 26.43 I . 1080 28.1s 1.1145 29.86 I .0821 21.33 1.0886 23.04 1.0951 24.7s I . 1016 26.46 1 . 1081 28.17 I . 1146 29.89 I .0822 21.36 1.0887 23.07 1.0952 24.78: I . 1017 26.49 1 . 1082 28.20 1.1147 29.91 1.0823 21.38 1.0888 23.09 1.0953 24.80 1 . 1018 26.51 1.10S3 28. 22 1 . 1148 29.94 1 .0824 21 .41 , 1.0889 23. 12 1.0954 24.83 j I . 1019 26.54 1 . 1084 28.2s I .1149 29 . 96 1.082s 21.44 I .0890 23.14 1.0955 24.85 I . 1020 26.56 1 . 1085 28.28 I . 1150 29.99 1.0826 21 .46 I .0891 23.17 1.0956 24.88 1 . 1021 26.59 1.1086 28.30 1 .1151 30.02 I .0827 21.49 I .0892 23.20 1.0957 24.91 1 . 1022 26.62 I . 1087 28.33 1.1152 30.04 1.0828 21.52 I .0893 23.22 1.0958 24.93 I. 1023 26. 64 I. 1088 28.36 1.1153 30.07 I .0829 21. S4 I .0894 23.2s 1.0959 24.96 1 . 1024 26.67 I . 1089 28.38 1.1154 30.10 I .0830 21.57 I .0895 23.28 1 .0960 24.99 I . 1025 26. 70 I . 1090 28.41 i.iiSS 30.13 I. 0831 21.59 I .0896 23.30 I .0961 25.01 I . 1026 26.72 1 . 1091 28.43 I.II56 30.15 I .0832 21.62 I . 0S97 23.33 I .0962 25.04 I . 1027 26.75 1 . 1092 28.46 I.II57 30.18 1.0833 21 .65 1.0S98 23.35 1.0963 25.07 1.102S 26.78 I. 1093 28.49 1-1158 30.21 1.0834 21 . 67 . I .0899 23.38 I .0964 25.09 I . 1029 26.80 1 . 1094 28.51 1.1159 30.23 1.083s 21 . 70 I . 0900 23.41 I .0965 25.12 I. 1030 26.83 1.109s 28.54 1.0836 21.73 I .0901 23.43 1 .0966 25.14 I. 1031 26.85 1 . 1096 28.57 1.0837 21.75 I .0902 23.46 I .0967 25.17 I. 1032 26.88 1.1097 28.59 1.0838 ^ 21.78 I .0903 23.49 1 .0968 25 . 20 I.I033 26.91 I . 1098 28.62 1.0839 21.80 1 .0904 23.51 I .0969 25 . 22 I. 1034 26.93 1 . 1099 28.65 I .0840 21.83 I .0905 23.54 I .0970 25.25 I .103s 26.96 I . 1100 28.67 1.0841 21.86 I .0906 23.57 I. 0971 25.28 I .1036 26. 99 1 . IIOl 28.70 I .0842 21.88 I .0907 23.59 I .0972 25.30 I. 1037 27 .01 1 . 1102 28.73 1.0843 21 .91 I .0908 23.62 1.0673 25.33 1.1038 27.04 1 .1103 28.75 1.0844 21.94 1 I .0909 23-65 1.0974 25.36 1. 1039 27.07 I . 1104 28.78 730 FOOD INSPECTION AND ANALYSIS. Fig. 114. — Apparatus for Determining Volatile Acids in Wine. Fig. 115. — Hor'ivct's .apparatus for .D-terniining the \'olatilc Acids in Wine. ALCOHOLIC BEVERAGES. 731 Hortvet Method.^—The apparatus (Fig. 115) consists of a 300-cc. flask into the neck of which is fitted a 2co-cc. cylindrical fiask, with a steam tube, a bulb-trap leading to a condenser, and a stop-cock funnel. The procedure is as follows: Pour 150 cc. of recently boiled water into the larger flask, attach the smalLer flask by means of a section of rubber tubing, run in 10 cc. of wine (previously freed from carbonic acid), close the stop-cock and boil. In extreme cases add to the wine a small piece of paraffin to prevent foaming. When the water has boiled a moment, close the tube at the side of the larger flask and distil until 70 cc. of distillate have passed over. Transfer to a beaker, without discontinuing the distillation, and titrate, using phenolphthalein as in- dicator. Continue the distillation until the last 10 cc. portion requires not more than one drop of tenth-normal alkali for neutralization. Usually 80 or 90 cc. of distillate includes practically all of the volatile acids. Cool the apparatus, thus allowing the wine residue to be drawn back into the lower flask, rinse with boiled water, and reserve the total liquid for deter- mination of non-volatile acids. Criicss and Betloli Metliod.'\ — Shake 75 cc. of the wine with bone black free from carbonates, filter, and titrate 20 cc. of the decolorized filtrate with N/io alkali using phenolphthalein as indicator. Place another aliquot of 20 cc. of the decolorized wine in a 200-cc, Erlenmeyer flask, add 2 grams of sodium chloride, and evaporate rapidly until sodium chloride separates copiously and the liquid begins to spatter. Dilute with 20 cc. of water and repeat the operation. Dilute a second time and titrate with N/io alkali as before. The difference between the two titrations multiplied by 0.03 gives the amount of volatile acids in grams per 100 cc. Detection of Free Tartaric Acid. — Nessler's Method. — Some pow- dered cream of tartar is added to a portion of the wine in a corked flask, which is shaken from time to time, and the liquid finally filtered. To the filtrate is added a little 20% potassium acetate solution. If free tartaric acid is present, on stirring and especially after standing for some time, there will be a precipitate of cream of tartar. Determination of Total Tartaric Acid. — Hartmann and Eoff Method.X — Neutralize ico cc. of the wine with N sodmm hydroxide to counteract the influence of free mineral acids, especially phosphoric; if more than 10 cc. * Jour. Ind. Eng. Chem., i, iQog, p. 31. t Ses. Int. Cong. Vit. Off. Rep., 1915, 263. t U. S. Dept. of Agric, Bur. of Chem., Bui. 162, 1913, p. 72; Jour. Assn. Off. Agric. Chem., 2, II, 1917, p. 182. 732 FOOD INSPECTION AND ANALYSIS. are required evaporate to about loo cc. Dissolve in the solution for each cc. of alkali added 0.075 gram accurately weighed, powdered c.p. tartaric acid, dried for 2 hours at 100° C. Add 2 cc. of glacial acetic acid and 15 grams of potassium chloride, stir until dissolved, then add 15 cc. of 95% alcohol, and stir vigorously until cream of tartar begins to precipitate. Allow to stand for at least 15 hours in an ice box, decant onto a Gooch crucible or Biichner funnel, and carefully wash the precipi- tate and filter three times with a solution of 1 5 grams of potassium chloride in 20 cc. of 95% alcohol and 100 cc. of water, using a total of not more than 20 cc. Return contents of the crucible or funnel to the beaker, rinsing with 50 cc. of hot water, heat to boiling, and titrate the solution while hot with N/io sodium hydroxide using phenolphthalein as indicator. Add to the number of cc, required 1.5 to correct for solubility of cream of tartar and multiply by 0.015 to obtain the total weight of tartaric acid present in the solution. Subtract from the product the weight of tartaric acid added, thus obtaining the total tatraric acid present in 100 cc. of wine. Determination of Cream of Tartar. — Exhaust the ash of 50 cc. of wine with hot water on a filter, add 25 cc. of N/io hydrochloric acid, heat to incipient boiling, and titrate with N/ro alkali solution, using litmus as indicator. Deduct from 25 cc. the number of cc. of N/io alkali em- ployed, and multiply the remainder by 0.0188 to obtain potassium bitar- trate in grams. Determination of Free Tartaric Acid. — Add 25 cc. of N/io hydro- chloric acid to the ash of 50 cc. of wine, heat to incipient boiling, and titrate with N/io sodium hydroxide, using litmus as indicator. Deduct the number of cc. of alkali employed from 25, and multiply the remainder by 0.0075 to obtain the amount of tartaric acid necessary to combine with all the ash (considering it to consist entirely of potash). Deduct the figure so obtained from the total tartaric acid. The difference is the amount of free tartaric acid. Determination of Lactic Acid. — Moslinger Method * Modified hy Bara- giola and Schuppli.'\ — Distil in steam 25 cc. of the sample and 25 cc. of water in von der Heide's fractionating apparatus until 200 cc. have been collected. Transfer the residue to a small dish, add 5 cc. of 10% barium chloride solution and hot saturated barium hydroxide solution to neutral * Zeits. Unters. Nahr. Genussm., 4, 1901, p. 1123. t Ibid., 27, 1914, p. 841. ALCOHOLIC BEVERAGES. 733 reaction, then 2 to 4 cc. in excess, and heat for ten minutes on a water- bath. Add hydrochloric acid until neutral to azolitmin paper, evaporate to 10 to 15 cc, taking care that the reaction remains neutral, transfer to a graduated cylinder, rinsing with water, and make up to 25 cc. Add 95% alcohol gradually with shaking up to 100 cc. and after standing for several hours again adjust the volume to 100 cc. and filter. To 75 cc. of the filtrate add 25 cc. of 5% sodium sulphate solution, shake, filter after stand- ing fifteen minutes, evaporate 75 cc. of the filtrate in platinum, and ignite to whiteness. Take up the ash in water, add an excess of N/io hydro- chloric acid, heat for five minutes on a water-bath, and titrate back with standard alkali using azolitmin paper, methyl orange, or phenolphthalein as indicator. To obtain the lactic acid in grams per liter multiply the corrected number of N/io acid by 0.64. Moslinger Method Modified by Roettgen."^ — Distil 50 cc. of the wine in a fractionating apparatus, provided with a column containing glass beads, until 200 cc. have passed over. To the residue add 5 cc. of 20% sulphuric acid, extract for twenty-four hours with ether in a continuous flow apparatus, add 30 cc. of water to the extract, and remove the ether by cautious distillation. To the residue add barium hydroxide solution to slightly alkaline reaction, heat for fifteen minutes on a water-bath, taking care that the solution remains slightly alkalme, then neutralize with N/4 hydrochloric acid, evaporate to 10 cc, and transfer to a loo-cc graduated flask, rinsing with 5 cc. of hot water and 95% alcohol. Make up to the mark with 95% alcohol, cool to 15° C. with shaking, and after thirty minutes at that tem- perature again make up to the mark, and allow to stand two hours longer at 15° C. Filter into a graduated cylinder, cool to 15°, read the volume of the filtrate, then evaporate in a platinum dish, ignite, cool, and titrate with N/4 hydrochloric acid. Calculate as in the Baragiola and Schuppli modification, taking account of the amount of wine used, the aliquot, and the strength of the standard solution. Determine free lactic acid in the same manner except that no sulphuric acid is added after distillation. Results obtained by Roettgen indicate that all or practically all of the lactic acid present in wine exists in the form of free lactic acid. * Zeits. Unters. Nahr. Genussm., 24, 1912, p. 113; 26, 1913, p. 437; 3°, iQ^S, P- 294; 34, 1917,?- 198. 734 FOOD INSPECTION AND ANALYSIS. Polarization. — Treat a measured amount of wine or cider with one- tenth of its volume of lead subacetate, filter and polarize the filtrate in the 200 mm. tube. The reading is increased by 10% for the true direct polarization. li the reducing sugars are also to be determined, the same solutions may be used for both the polarization and the reducing sugars as follows: Exactly neutralize with sodium hydroxide solution 200 cc. of the wine, using litmus paper as an indicator, and evaporate on the water-bath to about one-fourth its original volume. Wash with water into a 200 cc. flask, add enough normal lead acetate solution to clarify, and make up with water to the mark. Filter and to the filtrate add powdered sodium sulphate or carbonate sufficient to precipitate the lead, again filter and polarize before and after inversion (page 610). Determination of Reducing Sugars. — Determine reducing sugars in portions of the wine treated as described in the preceding section, after dilution so as not to contain above 0.5% of sugar for the Defren and the Munson and Walker methods or above 1% of sugar for the Allihn method. One may assume 2% as the sugar-free extract of wine, the number of volumes of water to be added to the filtrate being determined by the dif- ference between 2 and the total extract as determined. Determination of Glycerol. — In Dry Wines. — Evaporate 100 cc. of the wine in a porcelain dish on the water-bath to about 10 cc, add about 5 grams of fine sand and from 3 to 4 cc. of milk of lime (containing about 15% of calcium oxide) for each gram of extract present and evaporate nearly to dryness. Treat the moist residue with 50 cc. of 95% (by vol.) alcohol, remove the substance adhering to the sides of the dish with a spatula, and rub the whole mass to a paste. Heat on a water-bath, with constant stirring, to incipient boiling and decant through a filter into a small flask. Wash by decantation with 10 cc. portions of hot 95% alcohol until the filtrate amounts to about 150 cc. Evaporate the filtrate to a sirup on a hot, but not boiling, water-bath, transfer to a small glass- stoppered graduated cylinder with 20 cc. of absolute alcohol, and add 3 portions of 10 cc. each of absolute ether, shaking throughly after each addition. Let stand until clear, then pour off through a filter and wash the cylinder with a mixture of absolute alcohol and absolute ether (1:1.5), pouring the wash liquor also through the filter. Evaporate the filtrate to a sirup, dry for one hour in a boiling-water oven, weigh, ignite, and weigh again. The loss on ignition gives the weight of glycerol. ALCOHOLIC BEVERAGES. 735 A more accurate method is that proposed by Ross and described under vinegar, page 80 1. In Sweet Wines. — If the extract exceeds 5% heat 100 cc. to boiling in a flask and treat with successive small portions of milk of lime until the color becomes at first darker and then lighter. Wlien cool add -200 cc. of 95% alcohol, allow the precipitate to subside, filter, and wash with 95% alcohol. With the filtrate thus obtained proceed as directed for dry- wines. Determination of Potassium Sulphate.— Acidify 100 cc. of the sample with hydrochloric acid, heat to boiling, and add an excess of barium chloride solution. Filter, wash, dry, ignite, and weigh as barium sul- phate, calculating the equivalent of potassium sulphate. Determination of Sodium Chloride. — To 50 cc. of the wine add sodium carbonate solution until alkaline, evaporate, burn at low redness and determine chlorine gravimetrically as silver chloride. Detection of Nitrates.— E^^gr 1/d/zofi?.*— Treat a few drops of the wine in a porcelain dish with 2 or 3 cc. of concentrated sulphuric acid which contains about o.i gram of diphenylamin per 100 cc. The deep blue color formed in the presence of nitrates appears so quickly that it is not obscured, even in sweet wine, by the blackening produced by the action of sulphuric acid on the sugar. In the case of red wines clarify with lead subacetate, removing the excess with sodium sulphate. Determination of Tannin. — Neubauer-Lowenthal Method. "^ — The reagents are those given on pages 429 and 430, also finely pulverized bone black extracted with hydrochloric acid and washed with distilled water until neutral. It should be kept covered with water. Dealcoholize 100 cc, dilute with water to the original volume, transfer 10 cc. to a porcelain dish of about 2 liters capacity, add about a liter of water and exactly 20 cc. of indigo solution. Add tenth -normal potassium permanganate solution, one cc. at a time, until the blue color changes to green, then a few drops at a time until the color becomes golden yellow. Designate the number of cubic centimeters of permanganate solution employed as "a." Treat 10 cc. of the dealcoholized wine, prepared as above, with bone- black for fifteen minutes; filter and wash thoroughly with water. Add a liter of water and 20 cc. of indigo solution and titrate with permanganate * U. S. Dept. of Agric, Bur. of Chem., Bui. 107 (rev.) p. 88. 736 FOOD INSPECTION AND ANALYSIS. as above. Designate the number of cubic centimeters of permanganate employed as " Z>." Then a—b = c, the number of cubic centimeters of permanganate solution required for the oxidation of the tannin and coloring matter in ID cc. of wine, i cc. = 0.004157 gram of tannin. Detection and Determination of Preservatives. — See Chapter XVIII. Detection of Colors. — Dupre Method.'^ — Dissolve i part of pure gelatin in 10 parts boiling water, pour upon a plate to harden and cut into 2 cm, cubes. Immerse one of the cubes in the suspected sample, allow to remain for twenty-four hours, wash slightly in cold water, and cut through with a knife. If the color is a natural one, it will lightly tinge the outer surface of the cube, but will not permeate far below the surface, so that the inner portion of the cross-section will be largely free from color. Nearly all foreign coloring matters used in wine, such as most coal-tar dyes, cochineal, Brazil wood, logwood, etc., will be found to deeply per- meate the jelly cube often to the center. Information as to the nature of the color may sometimes be gained by immersing the dyed jelly cube in weak ammonia. If the color be rosanilin, the cube is decolorized; if cochineal, a purple coloration will result, and if logwood, a brown tinge. Cazeneuve Method. — Wliile by no means complete and not of recent origin the scheme of Cazeneuve (page 737) as condensed and arranged by Gautier (La Sophistication des Vins) will often be found helpful. If other colors than these are evidently present, tests should be made as indicated in Chapter XVII. Cazeneuve employs the following reagents: (i) Yellow oxide of mercury, finely pulverized, (2) Lead hydrate, freshly precipitated, well washed, suspended in about twice its volume of water; to be kept in a stoppered bottle; should be renewed after several days' use. (3) Gelatinous ferric hydrate, well washed from ammonia, suspended in about twice its volume of water. (4) Manganese dioxide, pulverized. (5) Concentrated, chemically pure sulphuric acid. (6) White wool, (7) Stannous hydrate, freshly precipitated, well washed, suspended in water, and kept from exposure to light and air. (8) Collodion silk, the artificial silk produced from nitro-cellulose. This fiber has a special affinity for basic dyes, * Jour. Chcm. Soc, 37, p. 572. ALCOHOLIC BEVERAGES. 737 To lo cc. of the wine are added 0.2 gram finely powdered yellow oxide of mercury. Boil and pour upon a double filter. Filtrate colored either before or after acidifying. CL P= Filtrate colored yellow. 10 cc. of the wine are warmed with 2 grams lead hydrate. Filter. Filtfate colored yellow. A large excess of lead hydrate is added and the liquid is boiled. •-( '- r^ >^ 1 u i-i cl3 CO o S 3 C(5 '2'< c 3 c - Q 2 n 3- O (fl & —• ^. ^^ (D 3 CT ^ *-^ £3 3 P P 2 -^ O h-. Q 3 o ^ S S (T 2- 51' 3* "^ p o «-= *. '3 I. ^""^ 2.P S S 3 2. 2.3 "O re ,-s i-f ■— ' -. H^ w >-( ^. ^ -J r: ^ _ rt o 55 _ 3 3_ (T^ j^ p po nc ... L3 "-I Cfl p o" cSo ru ?r o ^ .^ ° X t g o 5 ft o o 3. 5 ^ OQ i£. "-^i i" S 6 rD >~> p . ^ O (TO ^ Filtrate colored red. 10 cc. of the wine are treated with 2 grams lead hydrate and filtered. 3 Filtrate colorless. ■•3 ^pg^ rr ? -a P ni ^ 3 f-» >• fD CL -T- ►J. Ol Filtrate col- orless a f t e I acidifying. 2. r? (Ti It-." 1- ft) n'T3 e^g (TO 3- cr tT> ^ 0- CO ^ (TO o^p " o *^ ITT^ r^ ^T* « ^^3-5 S^3 - 3 ^ CTO ^^ >;! p 5; ID n. 3" t;" c ft (TO T3 era 3- c c . 3 O O '^ " ■ -^ fT O 3 p hJ (D 03 P. m ^ <^ ^ ^• 01 ^ o ■ O 3 >■ 3^ i*> n "^ j:^ '-^ (D lis. 3 3 5 3 a° clOq p 3 I. p- p r3 p 1 ^8 3- p p "-^ 3 _ 3 'og m cr P rr C:'^ n n ^^ ~-: rn ■«■' V ^■' » ^•' n >»^ V «. o c> f o ri s? >t o o _ ^ 5- Q O R O ^ c ft 55 :j Cl (^ 5?- •^ C^ Oo "^ ^..:b ^ *^ i^ ^ ^ r, s •< O o cd w S ^ 0^ ^ i ^ Co §. I 738 FOOD INSPECTION AND ANALYSIS. MALT LIQUORS. BEER. In its widest sense beer may be defined as the product of fermentation of an infusion of almost any farinaceous grain with variov.s hitter extract- ives, but unless otherwise qualified it should be strictly apphed to the beverage resulting from the fermentation of malted barley and hops. In the manufacture of beer two distinct processes are employed, viz., malting or sprouting the grain, and brewing. Many brewers do noth- ing but the latter, buying their malt already prepared. Malting. — For the preparation of malt, the barley is steeped in water for several days, after which the water is drained off and the moist grain is "couched," or piled in heaps, on a cement floor, where it undergoes a spontaneous heating process, during which it germinates, forming the ferment diastase. When the maximum amount of diastase has been produced, indicated by the length of growth of the sprout, or "acrospire " within the grain, the germination is checked by spreading the grain in layers over a perforated iron floor, and finally subjecting it to artificial heat. The character of the malt and of the beer produced from it depends largely on the heat at which the "green" malt is kiln dried. If dried between 32° and 37° C. it forms pale malt, which produces the lightest grades of beer. Most beer is made from malt dried at higher tem- peratures, say from 38° to 50°, the depth of color of the liquor var}ing with the heat to which the malt has been subjected, while the color of the malt varies from the "pale" through the "amber" to "brown," or even black. The darkest grades are sometimes dried at temperatures over 100° C, even to the point where the starch becomes caramelized. A more modem method consists in the so-called pneumatic malting, wherein the whole operation is conducted in a large rotating drum, which holds the grain, and in which the temperature and moisture at different stages is carefully controlled by the admission to the interior of the drum of moisture- laden or dry air, heated to the required degree. The chief object of malting is the production of diastare, which by its subsequent action on the starch converts it into the fermentable sugars maltose and dexrin. i\Ialt contains much more diastase than is necessaiy to convert the starch simply contained therein to maltose, and is capable of acting on the starch of a considerable quantity of raw grain, such as corn or rice, when mixed with it. This practice of using other grains than malt is prohibited in some localities, such as Bavaria. ALCOHOLIC BEVERAGES. 739 Brewing. — The malt, or mixture of malt and raw grain, is first crushed and "mashed" by stirring with water in tubs at 50° to 60° C, finally heating to 70°. During this process the conversion of the starch to mal- tose and dextrin takes place. The re.udting hquor is known as "wort," containirg, besides mahose and dextrin, peptones and amides. The clear wort is then drawn off from the residue, and boiled to concentrate the product and to sterilize it, after which hops (the female flower of the Humiilus lupulus) are added and the boihng continued. Hops contain resins, bitter principles, tannic acid, and a pecdiar essential oil, all of which are to some extent imparted to the wort. After cooling and settling, the clear wort is run into fermenting-vats, where selected yeast, usually saccharomyces cerevisice, is added, and the alcoholic fermentation allowed to proceed. The temperature greatly affects the character of the fermentation. If kept between 5° and 8° C, a slow fermentation proceeds, known as bottom fermentation, during which the yeast settles out at the bottom. This is much more easily controlled than the quick or top fermentation, which takes place at from 15° to 18°, much of the yeast in the latter case being carried to the surface, from which it is finally removed by skimming. In either case the yeast feeds upon the albuminous matter present. At the proper stage the beer is drawn off from the larger portion of the yeast, and run inta casks, or tuns, in which an after-fermentation proceeds. The beer is finally clarified by treatment with gelatin or beech shavings 01 chips, to which the floating yeast-cells and other impurities attach themselves. It is finally stored in barrels coated with brewers' pitch, or pasteurized at 60° C. and bottled. Varieties of Beer. — Formerly the division of beers into "lager," "schenk," and "bock" was made by reason of the fact that beer had to be brewed ujider certain climatic conditions and at certain seasons only. Now, with improved means for artificial refrigeration, and with better methods controlling all stages of the process, these distinctions are less marked. Lager Beer (from lager, a storehouse) is a term originally applied to Bavarian beer, but is now given to any beer that has been stored several months. Formerly lager beer was made early in the winter, and stored in cool cellars till the following spring or summer, during nearly all of which time a slow after-fermentation took place. The best lager beers contain a low proportion of hops, and are high in extract and alcohol. Schenk Beer is a quickly fermented beer made in winter for immedi- 740 FOOD INSPECTION AND ANALYSIS. ate use. It is brewed in from four to six weeks and will not keep long without souring. Bock Beer, according to older systems of nomenclature, occupied a middle place between lager and schenk, being an extra strong beer brewed for spring use and made in limited quantities, not being intended for storage. Berlin Weiss Bier is prepared by the quick or top fermentation of a wort consisting of a mixture of malted barley and wheat with hops. It is high in carbon dioxide, being usually bottled before the second fermen- tation has ended. Ale is virtually the English name for beer. It is usually lighter colored than lager beer, being made from pale malt by quick or top fermentation, and containing rather more hops than beer. It has a high content of sugar, due to checking fermentation at an earlier stage than in ordinary beer. Porter is a dark ale, the deep color of which should be due to the use of brown malt dried at a high temperature, but which is sometimes colored by the admixture of caramel. It has a large extract, chiefly sugar. Stout is an extra-strong porter, being high both in alcohol and extract. Composition of Beer. — Beer is a somewhat complex liquor. Besides water, alcohol, and sugar, it contains carbon dioxide, succinic acid, dex- trin, glycerin, tannic acid, the resinous bitter principles of hops, nitrog' enous bodies (chiefly peptones and amides), alkaline and lime salts (chiefly phosphates), fat (traces), acetic acid and lactic acid. The latter acid constitutes the chief fixed acid of beer. The following analyses of different varieties of beer are due to Konig: I Variety. o ^ J3 *t^t^t^r^t^r^t^t^ r^ r^r^t^r^t^t^t^r^t^ Si 1 O M M ro^io\0 t^oO 0-. o o M M ro-:J-UONO t^OO On Ex- tract in loo cc. Grams. C^C^OOOOwMw o N lOt^O rOVOOO O tO' o \00 t^t^t->.t^r^i>.r^ t^ t^t^t^t^t^r^t^f^r^ 1 IN H N ro^voo r^co c^ 00 H c< co'^vovo r-oo Ov Ex- tract in loo cc. Grams. looo roiOOO M fOO 00 M ponO Ovm ^vO Onm t^t^t^t-^OOCOOOOO On ^ vOOOOOOOOO NO nOnOnOnOnOnOnOnOnO 1 O H M rO'^vovO t^CO On no' M (N ro^voNO r^cO 0\ Extract in loo cc. Grams. ON ■*vO 0\M Tj-t^ONN "*- CnO\OnOOOOmm t^ M 01 M Ol rorOf^f^O"^ lO ioioij-)mDOnOnOnO^ VO sOnOnOvOvOnOvovOvO 1 M C) rO'+lnvO t^OO O M N roTfiovO t^CO On Extract in loo cc. Grams. •^ M irir^o ro^ooO '•O -:t-Tl-^lJ-)lOiOiO\OvO VO NO OOMroNOOOHfOvOOv NO i^r^J^t^oOCOOOOO lO LOVOIOVOVOIOLOIOLO lO lOVOVOVoiOlOVOlOlO 1 O M H N rO'^vOMO t~».c<0 On O H N rO'+lONO t^OO On Extract in loo cc. Grams. CO 00 M roOCO M -^vO Onm CTvOnOnOnO O O O w •i- t^OvM -ft-~ONN lOI^ Mi-iOiriciCNrooOfO ■* ■*'^^'^vo\y-)lovoio lO VolOlOVOlOtOLOVOlO 1 1^ M H « fO-^vnvo r^oo O^ O d H CM rr, Tt- \r> \o t^OO 0-. Extract in loo cc. Grams. 4 T)-TJ-Tj--:)-lOVOtolr)NO NO lOOO roloco M rONO nOnO r^r^r^t^cOOOoO '+-*-*-*'*'^'^'^'* ^ •^■^■^"^^^^■^Tj- 1 M M rO'^VOMO t^CO O CO H M ro-^iovo t^CO On Extract in loo cc. Grams. vO CO w fONOoO w ■+VO 0\ CO OnO^OnOnO O O :: tJ-nO OnN T)-r^OvN 't wMMMMMMroco ro rOrorororO'*^'^^ ■* '+'t'^'*^Tl-^Tl-TS- 1 O VO H O M w c» r^Tl-io>0 t>.00 On 756 FOOD INSPECTION AND ANALYSIS. Example. — Suppose the "extract gravity" is 1.0389 and the specific gravity of the alcoholic distillate is 0.9902, both at 15.6. Then i —0.9902 = 0.0098, the "degree of spirit indication," From the above table the cor- responding "degree of gravity lost" is found to be 0.0432. 0.0432+1.0389 = 1.0821, the original gravity of the w^ort. The calculation in the above simplified form is accurate for normal beer wherein the free acid present, expressed as acetic, does not exceed 0.1%. In case of beer that has developed free acid much in excess of the above limit, a correction should be added to the degrees of spirit indication. This correction, which in practice it is rarely necessary to apply except in extreme cases of old or sour beer, is calculated as follows: If a represents the grams of free acid (as acetic) in 100 cc, then the correction to be added to the spirit indication =0.0013(1 — 0.00014. Example. — Supposing the "extract gravity" to be 1.0413, the specific gravity of the alcoholic distillate to be 0.9890, and the free acid as acetic to be 0.35%. Then 1—0.989=0.0110, the degree of spirit indication. 0.35X0.0013—0.00014=0.0003, correction to be added to the spirit indication. 0.0110+0.0003 = 0.0113, corrected spirit indication. From the above table the corresponding degrees of gravity lost are 0.0506: 0.0506+1.0413 = 1.0919, the original gravity of the wort. Determination of Degree of Fermentation. — This is calculated by 200 A the formula D = — =r— , in which D = degree of fermentation, A = per cent B of alcohol by weight, and 5 = the original extract. Determination of Reducing Sugars. — Dealcoholize 25 cc. of the beer and make up to 100 cc. Determine reducing sugars by the Defren- O'Sullivan or Munson-Walker method, and calculate as maltose. Determination of Dextrin. — Dilute 50 cc. of the beer to 200 cc, hydrolize by heating in a boiling water-bath for 2^ hours with 20 cc. of hydrochloric acid (specific gravity 1.125), nearly neutralize the free acid with sodium hydroxide, make up to 300 cc, filter, and determine the dextrose by copper reduction. Multiply the amount of reducing sugars as maltose by 0.95, subtract this from the dextrce, and multiply the difference by 0.9, thus obtaining the dextrin in the b:er Determination of Glycerol. — Proceed as directed on page 734 under wine. The milk of lime is added during evaporation after the carbon dioxide has been expelled. It is advisable that the filtrate, after being ALCOHOLIC BEVERAGES. 757 evaporated to a syrupy consistency, be treated again with 5 cc. of absolute alcohol and two portions of 7.5 cc. each of absolute ether. If clear, continue as directed. If not clear, it is necessary to repeat the treatment with lime. Determination of Total, Fixed, and Volatile Acids. — A measured volume of the beer, say 10 cc, is freed from carbon dioxide by bringing to boiling. It is then cooled and titrated with tenth-normal sodium hydroxide, using neutral litmus solution as an indicator. Each cubic centimeter of tenth-normal alkali is equivalent to 0.009 gram of lactic acid, in which the total acidity is usually expressed. Fixed acid, also expressed as lactic, though small quantities of suc- cinic, tannic, and malic acids are usually also present, is determined as follows: Dealcoholize a measured amount of the beer, say 10 cc., by evaporation to one-fourth its volume, dilute with water to the original volume, and titrate with tenth-normal alkali, as before. Volatile acid is expressed as acetic, and is usually calculated by dif- ference between total and fixed acid. Each cubic centimeter of tenth- normal alkali is the equivalent of 0.006 gram acetic acid. Determination of Proteins. — Fifty cc. of the beer are first treated with 5 cc. of dilute sulphuric acid, and concentrated by boiling to syrupy consistency. Then proceed by the Gunning method, p. 58. Nx6.25 = proteins. Determination of Phosphoric Acid. — Unless the sample is very dark- colored, sufficiently close results can usually be obtained by direct titra- tion of the beer itself with uranium acetate solution. For very accurate results the ash should be used. Prepare a solution of uranium acetate of such strength that 20 cc. will correspond to o.i gram P^Og. This solution is best standardized against pure, crystallized, imeffloresced, powdered hydrogen sodium phosphate, 10.085 grams of which are dissolved in water and made up to a liter. 50 cc. of this solution contains o.i gram phosphoric anhydride, if the salt is pure. If the solution is of proper strength, 50 cc. evaporated to dryness and ignited in a tared platinum dish should have an ash weighing 0.1874 gram. For preliminary trial about 35 grams of uranium acetate are dissolved in water, 25 cc. of glacial acetic acid, or its equivalent in weaker acid added, and the solution made up to a liter with water. To standardize, 50 cc. of the standard phosphate solution prepared as above are heated to 90° or 100° C, and the uranium solution run in from a burette till the resulting precipitate of hydrogen uranium phos- 758 FOOD INSPECTION AND ANALYSIS. plate is complete. The end-point is determined by transferring a few drops of the solution to a porcelain plate, and touching with a drop of freshly prepared potassium ferrocyanide solution. When the slightest excess of uranium acetate has been added, a reddish-brown color is pro- duced by the ferrocyanide, The uranium acetate solution is purposely made rather stronger than necessary at first, and by repeated trials is brought by dilution with water to the required strength (20 cc. equivalent to 50 cc. of the phosphate solution). Fifty cc. of the beer are heated to 90° or 100° C. and titrated with the uranium acetate solution under the same conditions and in precisely the same manner as when standardizing that solution. Each cubic centi- meter of the uranium acetate corresponds to 0.01% of P2O5. For the phosphoric acid determination in the ash, 50 cc. of the beer are incinerated in the regular manner, and the ash moistened with con- centrated hydrochloric acid. The acid is then evaporated off on the water-bath, after which the ash is boiled with 50 cc. of distilled wate^, and titrated with the standard uranium solution. Determination of Carbon Dioxide.* — In the case of beer and other carbonated drinks put up in corked bottles, the carbon dioxide may be readily determined by piercing the cork with a metal champagne tap, which is connected by a flexible tube, first with a safety flask and then with an absorption apparatus somewhat after the style of that used in the determination of carbon dioxide in baking powder, the liberated carbon dioxide being absorbed for weighing in a concentrated solution of potassium hydroxide contained in a tared Liebig bulb. The beer- bottle thus connected is immersed in a vessel of water, which is heated over a gas-flame, after all the carbon dioxide that will escape spontaneously has been allowed to do so. Before weighing the absorbed carbon dioxide, the beer-bottle is replaced by a soda-lime tube, and a current of air drawn through the tubes. Beer and ale put up in bottles having patent metallic or rubber stoppers cannot thus be treated. In this case a measured quantity, say 200 cc, of the sample is transferred as quickly as possible to a large flask pro- vided with an outlet-tube having a glass stopper, this being connected up- with the safety-flask and absorp lion-tubes. In this case heat may be directly, though cautiously, applied to the flask containing the beer by means of a gas-flame, after all the carbon dioxide has gone over that will * U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 95; Bui. 107 (rev.), p. 92. ALCOHOLIC BEVERAGES. 759 do so spontaneously. Exactly the same apparatus as that shown in Fig. 71 may be used to advantage for determination of carbon dioxide m beer, except that a larger distilling-flask should be used in the case of beer. Detection of Bitter Principles.-Elaborate schemes have been worked out for the systematic treatment of beer and ale for bitter principles. Nearly all of these are complicated and somewhat unsatisfactory. The presence of alkaloids in malt liquors, deliberately introduced during the process of manufacture, is now so rare that the analyst need seldom look for them except in cases of suspected poisoning, when the scheme of Dragendorf * or of Otto-Stas should be employed. While it is somewhat difficult to positively identify the various alkaloids, it is usually easy to prove their absence in clear solutions, if on treatment with either of the general alkaloidal reagents, Mayer's solution, or iodine in potassmm iodide, no precipitate is formed. It is comparatively easy to prove the mere presence or absence of hop substitutes. The bitter principle of hops is readily soluble m ether when a sample of the beer evaporated to syrupy consistency is extracted therewith while the bitters of quassia and aloes, common hop substitutes, are insoluble in ether. Though many varieties of bitters might be em- ployed that are soluble in ether, the absence of a bitter taste from the ether extract is evidence of the absence of hops. ^ The most marked difference analytically between hops and their substitutes in malt liquors lies in the fact that the bitter principle of hops is completely precipitated therefrom by treatment of the beer with lead acetate (either basic or neutral), leaving no bitter taste m the filtrate after concentration, while if any of the hop substitutes are present the concentrated filtrate from the lead acetate treatment will have a bitter taste The excess of lead should be removed from the filtrate, before concentration and tasting, by treatment with hydrogen sulphide If the residue from the ether or chloroform extraction of the concentrated filtrate from a beer after treatment with lead acetate be found to be bitter, there is positive evidence that a foreign substitute has been employed. The following are characteristic reactions that may help to identify some of the common hop substitutes: f Quassiin is readily soluble by chloroform from acid solution. If a residue containing quassiin be moistened with a weak alcoholic solution * Gerichtlich-Chemische Ermittelung von Giften, St. Petersburg, 1876. t Allen, Analyst, 12, 1887, p. 107. 760 FOOD INSPECTION AND ANALYSIS. of ferric chloride and gently heated, a marked mahogany-brown color- ation is produced. On treatment of quassiin with bromine and sodium hydroxide or ammonia, a bright-yellow color is shown. Chiretta is readily dissolved by ether from its aqueous solution. Its ether residue, when treated with bromine and ammonia, gives a straw color, slowly changing to a dull purple-brown. This is not true of its chloroform residue, so that it is not to be mistaken for quassia (Allen). Gentian Bitter may be extracted by treatment of the acid liquor with chloroform. When the residue containing gentian bitter is treated with concentrated sulphuric acid, in the cold, no color is produced, but on warming gently a carmine-red color is shown; if further treated with ferric chloride solution, a green-brown color is formed. Aloes. — This substance is separated from beer by treating the dried residue from 200 cc. of the beer with warm amrhonia, filtering, cooling, and treating the filtrate witn hydrochloric acid. The resin of aloes is precipitated and collected on a filter. It is insoluble in cold water, ether, chloroform, or petroleum ether, but is soluble in alcohol. It has a very characteristic odor, which serves to identify it. The hot-water solution gives a curdy precipitate on treatment with lead acetate. Capsicin is extracted by treatment of the acid liquor with chloroform. It is recognizable by its sharp, pungent taste. Detection of Arsenic. — By ihe Marsh Method. — Measure 100 cc. of the beer (freed from carbon dioxide by agitation) into a seven-inch porce- lain evaporating-dish, add 20 cc. pure concentrated nitric acid, and 3 cc. pure concentrated sulphuric acid, and cautiously heat till vigorous chemi- cal action sets in, accompanied by frothing and swelling of the beer. Turn the flame low or remove it altogether, and stir vigorously till the frothing ceases, after which the liquid may be boiled freely. At this stage transfer to a large casserole, and continue the boiling till nearly all the nitric acid is driven off. Then, holding the casserole by the handle, continue the heating till the mass chars and the fumes of sulphuric acid are given off, giving the casserole a rotary motion to prevent sputtering. The residue should be reduced to a dry, black, pulverulent char soon after the sulphuric acid fumes begin to come off freely. If still liquid, pieces of filter-paper should be stirred in while still heating, till the residue is dry, avoiding an excess of paper. Cool, add 50 cc. of water, and remove the masses of char from the sides 1 ALCOHOLIC BEVERAGES. 761 of the dish by the stirring-rod. Heat to boiling and filter. Use the filtrate for the Marsh apparatus, adding it gradually. The arsenic mirror may be weighed in the usual manner, if of suffi- cient size. Reinsch's Test.* — Two hundred cc. of the beer are acidified with i cc. of pure, concentrated, arsenic-free hydrochloric acid, and evaporated to half its volume. 15 cc. more of hydrochloric acid are then added, and a piece of pure burnished copper foil half an inch long and a quarter of an inch wide is immersed in the liquid and kept in it for an hour while simmering, replacing from time to time the water lost by evaporation. If after the lapse of an hour the copper still remains bright, no arsenic is present. If the copper shows a deposit, remove, wash with water, alcohol, and ether, and dry. Then place the copper in a subliming-tube, and heat over a low flame. Tetrahedral crystals, apparent under the microscope, show the presence of arsenic. Blackening of the copper does not in itself prove arsenic. Detection and Determination of Preservatives. — See Chapter XVIII. Sulphurous acid may be determined by direct titration, as in the case of wine. MALT EXTRACT. True malt extract is a syrupy fluid having a specific gravity of from 1.3 to 1.6, and made up in accordance with the following directions of the 1880 Pharmacopoeia: Upon 100 parts of coarsely powdered malt contained in a suitable vessel, pour 100 parts of water, and macerate for six hours. Then add 400 parts of water, heated to about 30° C. and digest for an hour at a temperature not exceeding 55° C. Strain the mixture with strong pressure. Finally, by means of a water-hath or vacuum apparatus, at a temperature not exceeding 55° C, evaporate the strained liquid rapidly to the consistence of thick honey. Keep the product in well-closed vessels in a cool place. Such an extract has a residue of at least 70%, consisting chiefly of maltose, and contains about 2% of diastase. It should furthermore l:>e capable of converting its own weight of starch at 55° C. in less than ten minutes. The following are analyses of three samples of pure malt extract: f * Jour. Soc, Chem. Ind., 20, p. 646. t Penn. Dept. of Agric. An. Rep., 1898, p. 85. 762 FOOD INSPECTION AND ANALYSIS. >^ •d.a c < C8 W (U c 4-* ■3 Q 4 < 1^ Diastatic Action. A I -,^87 72.31 0.231 0.0333.32962.52 5-25 1. 21 0.483 Complete in less than s min. B 1. 421 76.65 0.275 o.o2i'3. 116,65.41 6.94 1. 190. 556 " " " " 10 " C 1.498 79.81 0.386 1 0.0534.872 61.32 12.39 1.230.428 " " " " 5 " There are on the market many so-called malt extracts widely advertised for their tonic and medicinal virtues, having the taste and consistency of beer or ale. In fact they are virtually beer, differing therefrom mainly in respect to price. Such "malt extracts" have no diastase, and their value as nutrients depends almost entirely on their sugar content. Harrington * has analyzed twenty-one of the best known of these alleged malt extracts, the maximum, minimum, and mean results of his analyses being as follows: Specific Alcohol. Gravity. Total Residue. Ash. Maximum 1-0555 I. 0149 7-13 0.74 3-94 13-63 8.78 0-53 0.20 Minimum Mean None of them contained any diastase, and several were preserved with salicylic acid. DISTILLED LIQUORS. These beverages differ from those hitherto considered, by reason of their high alcoholic content and low extract or residue. Indeed, when first distilled they are entirely without residue, but from long storage in casks, they absorb certain extractives from the wood, that impart more or less flavor as well as color. When any fermented alcoholic infusion is subjected to distillation under ordinary circumstances, a distillate results which consists of a mixture with water of a large number of alcohols, chief among which is ethyl alcohol. The high boiling alcohols — amyl, butyl, propyl, etc., with their esters — exist in the distillate in small amount, constituting what is known as fusel oil. The various distilled liquors of commerce * Boston Medical and Surgical Journal, Dec. 31, 1896. ALCOHOLIC BEVERAGES. 763 are made by just such a process of distillation, the product varying widely in flavor and character with the basis from which it was distilled. The so-called pot-still (the old-fashioned copper still and worm) IS well adapted for the production of potable spirits such as whiskey, brandy, gin, and rum, as these products should contain the congeneric substances which give the liquors their special character; it is not, however, suited for the manufacture of pure alcohol, because repeated distillation would be required for purification. Now, however, by the use of improved apparatus, such as the Coffey still, involving the principle of fractional condensation, it is possible to obtain what is known as " silent spirit," or ethyl alcohol, free from fusel oil. With proper appurtenances for rectifying, one can now obtain 95% alcohol by two distillations. Standards for Spirits. — The following are the standards adopted by the Joint Committee of the Association of Official Agricultural Chemists and the Association of State and National Food and Dairy Departments: Distilled Spirit is the distillate obtained f'^om a fermented mash of cereals, molasses, sugars, fruits, or other fermentable substance, and contains all the volatile flavors, essential oils, and other substances derived directly from the material used, and the higher alcohols, ethers, acids, and other volatile bodies congeneric with ethyl alcohol produced during fermentation, which are carried over at the ordinary tempera- ture of distillation, and the principal part of which are higher alcohols estimated as amylic. Alcohol, Cologne Spirit, Neutral Spirit, Velvet Spirit, or Silent Spirit, is distilled spirit from which all, or practically all, of its constituents except ethyl alcohol and water, are separated, and contains not less than 94.9% (189.8 proof) by volume of ethyl alcohol. Composition of Fusel Oil. — Fusel oil varies considerably in compo- sition with the source from which it is derived. Amyl alcchol, being in all cases its chief constituent, is frequently known commercially as fusel oil. The alcohols found in fusel oil with their formulas, specific gravity, and boiling-points are as follows: Formula. Boiling-point. Ethvl alcohol C^HjOH Propyl " C.H7OH Butyl " C.HgOH Amyl " ' C,Hj,OH Hexyl " 1 CeHigOH 78.4° C. 97° C. 115° C. 130° c. 764 FOOD INSPECTION AND ANALYSIS. The following acids have been found in fusel oil, usually combined with the alcohols to form compound ethers: Acetic HC2H3O2 Caproic HCeHnOj Propionic HC3H5O2 CEnanthylic HC7H13O2 Butyric HC4H7O2 Caprylic HCgHijOz Valerianic HC5H9O3 Pelargonic HCaHi^Oz Aging. — Freshly distilled liquors all contain notable quantities of substances, which render them harsh and unfit for use, but during aging, they become in several years mellow and palatable. The chemi- cal changes which take place during aging are discussed under whiskey. WHISKEY. Process of Manufacture. — Whiskey is the liquor resulting from the distillation of a fermented infusion of grain, the process being carried out in a pot-still, or some other form of still, constructed so that the resulting liquor contains not only the alcohol, but also the greater part of the congeneric substances which are vaporized with the alcohol. The fermented infusion known as the "mash" is obtained by steeping in water the starch-containing material, usually barley, rye, corn (maize), or oats mixed with malt, and subjecting the mixture to the action of the diastase contained in the malt, in much the same manner as the mashing process in the brewing of beer, except that for whiskey the process of saccharous fermentation is carried further, with a view to obtaining a maximum yield of maltose and a minimum of dextrin. Yeast is afterwards added, and alcoholic fermentation allowed to proceed with proper precautions. The fermented wort from whatever source obtained is subjected to distillation, purposely avoiding rectification or separation of the fusel oil and other congeneric substances which are valuable as flavors. The product of the first distillation is called "low wines," and is redistilled; the product of the second distillation is commonly divided into three fractions, of which the middle portion, or " clean spirit " is retained for the whiskey, while the first (" foreshots ") and the last fraction ("faints") are mixed with the next portion of low wine to be redistilled. If the whiskey is too high in alcohol, it is diluted to the proper strength. As new whiskey is crude and harsh in taste, it is subjected to " aging," or storing in casks for a number of years. The aging process softens and refines the flavor, but recent investigations have proved that this ALCOHOLIC BEVERAGES. 765 is not due, as formerly believed, to transformation of fusel oil into esters although the esters increase in amount during aging, as do also the acids — especially the volatile acids — the aldehydes, and the furfural. As a matter of fact, the percentage of fusel oil increases instead of diminishes on aging, due to the evaporation of water and, in a lesser degree, of alcohol through the wood; the actual amount, however, remains prac- tically the same as at the start (see table, p. 769). When first distilled, whiskey is perfectly colorless, but during the aging it extracts more or less color and some flavor from the casks in which it is stored. This color is especially pronounced in American whiskies, owing to the pre- vailing custom of charring the inside of the cask. Its flavor varies considerably with the nature of the grain used in its preparation. U. S. Rulings. — The following decision of President Roosevelt, based on an opinion of Attorney- General Bonaparte, was promulgated by Sec- retary Wilson, April 11, 1907: " Straight whiskey will be labeled as such. " A mixture or two or more straight whiskies will be labeled ' blended whiskey,' or ' whiskies.' " A mixture of straight whiskey and ethyl alcohol, provided that there is a sufficient amount of straight whiskey to make it genuinely a ' mixture,' will be labeled as compound of, or compounded with, pure grain distillate. " Imitation whiskey will be labeled as such," This decision was overruled by President Taft, whose opinion is the basis of Food Inspection Decision No. 113 (Feb. 16, 1910), signed by the secretaries of the Treasury, Agriculture, and Commerce and Labor. The chief points of this decision follow: " All unmixed distilled spirits from grain, colored and flavored with harmless color and flavor, in the customary ways, either by the charred barrel process, or by the addition of caramel and harmless flavor, if of potable strength and not less than 80° proof, are entitled to the name whiskey without qualification. "Whiskies of the same or different kinds (i.e., straight, rectified, redis- tilled, and neutral spirits whiskies) are like substances and mixtures of such, with or without harmless color or flavor used for purposes of coloring and flavoring only, are blends. "Potable alcoholic distillates from sources other than grain (e.g., cane, fruit, or vegetables), colored and flavored, are imitations and mixtures of such with grain distillate are compounds. 766 FOOD INSPECTION AND ANALYSIS. " A distillate [of grain (e.g., corn) flavored to simulate a whiskey of another kind (e.g., rye) is an imitation of that whiskey." Attorney- General Wickersham (F. I. D. No. 127) has further decided that the name " Canadian Club whiskey " is distinctive and it is therefore unnecessary to place the word " blend " on the label. Joint Standards. — The following are the standards of the Joint Com- mittee of the A. O. A. C. and the A. S. N. F. D. D.: New Whiskey is the properly distilled spirit from the properly pre- pared and properly fermented mash of malted grain, or of grain the starch of which has been hydrolyzed by malt; it has an alcoholic strength corresponding to the excise laws of the various countries in which it is produced, and contains in 100 liters of proof spirit not less than 100 grams of the various substances other than ethyl alcohol derived from the grain from which it is made, and of those produced during fermentation, the principal part of which consists of higher alcohols estimated as amylic. Whiskey {Potable Whiskey) is new whiskey which has been stored in wood not less than four years without any artificial heat save that which may be imparted by warming the storehouse to the usual tem- perature, and contains in 100 liters of proof spirit not less than 200 grams of the substance found in new whiskey, save as they are changed or eliminated by storage, and of those produced as secondary bodies during aging; and, in addition thereto, the substances extracted from the casks in which it has been stored. It contains, when prepared for consumption as permitted by the regulations of the Bureau of Internal Revenue, not less than 45% by volume of ethyl alcohol, and, if no statement is made concerning its alcoholic strength, it contains not less than 50% of ethyl alcohol by volume, as prescribed by law. Rye Whiskey is a whiskey in the manufacture of which rye, either in a malted condition or with sufficient barley or rye malt to hydrolyze the starch, is the only grain used. Bourbon Whiskey is a whiskey made in Kentucky from a mash of Indian corn and rye, and barley malt, of which Indian corn forms more than 50%. Corn Whiskey is whiskey made from malted Indian corn or of Indian corn the starch of which has been hydrolyzed by barley malt. Blended Whiskey is a mixture of two or more whiskeys. Scotch Whiskey is whiskey made in Scotland solely from barley malt, in the drying of which peat has been used. It contains in 100 liters of ALCOHOLIC BEVERAGES. 767 proof spirit not less than 150 grams of the various substances prescribed for whiskey exclusive of those extracted from the cask. Irish Whiskey is whiskey made in Ireland, and conforms in the pro- portions of its various ingredients to Scotch whiskey, save that it may be made of the same materials as prescribed for whiskey, and the malt used is not dried over peat. Composition. — Whiskey consists chiefly of alcohol and water, with relatively small amounts of fusel oil, acids, esters, aldehydes, and fur- fural. Its extract, derived mainly from the casks in which it is stored, should consist only of small amounts of tannin, sugar, and coloring matter. British Whiskies. — Scotch and Irish whiskies are aged in uncharred barrels, hence they are of a lighter color than the American product. Scotch whiskey is further characterized by its smoky taste, due to the peat over which it is dried. The following analyses by Vasey * illustrate the composition of Scotch and Irish whiskey of different ages, of neutral spirits used in compounding (" blending ") and adulterating, and of the compounded liquors: Grams per loo Liters of Absolute Alcohol. Volatile Acids. Esters. Alde- hydes. Furfural. Fusel Oil. Pot-still Scotch whiskey, 8 years old . Pot-still Scotch whiskey, 25 years old Irish whiskey, new Irish whiskey, 7 years old Neutral spirit for "blending" " Blended " Scotch "Scotch," probably all neutral spirits 48.0 64.8 20.9 41.8 8.4 39-1 16.8 89.7 125. 1 7-7 20.9 23.8 106.8 14.2 66.1 6.5 11.2 200.0 180.0 174.0 204.0 trace 108. S none It will be noted that the congeneric substances in whiskey increase on aging, although in the case of fusel oil this apparent increase is doubtless due merely to concentration dependent on evaporation. The sample of neutral spirits contained only small amounts of the congeneric substances, while the " blended " whiskies were deficient in most of these substances. American Whiskies. — These have a deeper color than the British whiskies (due to the charred barrel) and a rich fruity flavor without the suggestion of smoke. * Potable Spirits, pp. 82, 83, and 87. 768 FOOD INSPECTION AND ANALYSIS. In the table below are given analyses by Shepard * of fourteen leading brands, including both rye and bourbon, varying in age from four to eight years; also of two samples of neutral spirits used for com- pounding and adulterating. A summary of the results obtained by Crampton and Tolman f in the analysis of fourteen brands of rye and seventeen brands of bourbon whiskey at differing stages of aging appear in the table on p. 769. The barrels were kept in U. S. bonded warehouses during aging, and samples Rye Bourbon Standard Hand-made sour mash, Hand-made sour mash. Hand-made sour mash. Bourbon Special reserve Sour mash ... Neutral spirits. 5 4i 4 4 6 6 7 5h 7 5 7h 4 50.1 50.1 50.0 49-8 SO. 2 49-9 50-4 50 50 49-9 49-8 50-1 49-8 50-1 95-6 94-4 Grams per loo Liters of the Liquor. 160 162 148 132 138, 153 180 129 212 124 177 139 ID 3-2 Acids. 92 68.4 66.8 67.1 62.4 49-2 74.8 58.8 74-4 60.9 93-0 58.2 66.5 50-3 7-5 6-3 12.8 9-3 10.2 10.2 7-5 7-5 8.6 9.9 9.9 7-2 13-5 7-2 9.0 6.3 1.2 1.4 79-2 59-1 56-6 56.9 54-9 41-7 66.2 48-9 64-5 53-7 79-5 51. c 57-5 44-0 6-3 4-9 W 81.8 60.7 55-9 74-8 55-9 39-6 61.6 69.6 70.8 49-3 94.0 64.0 76.6 54-6 15-4 64.2 17-5 17-5 lO.O 12.0 15-C 8.C 10-5 14.0 12.5 9-5 22.5 9-5 lo.o 7-5 2-5 II. o 3-0 3-2 2-4 2.6 2.6 I.O 1-3 0.7 2-5 0.8 5-0 0-5 1.7 1-5 102 160 130 152 107 192 137 117. o 141. 7 119-5 95-3 193.6 152.0 30.0 39-6 were withdrawn at intervals of a year for eight years. As the minimum figures for certain constituents are abnormal, the next to the minimum figures are also given. It will be noted that during the first few years there was a marked increase in actual amounts of aU the constituents determined, except fusel oil, over and above that due to concentration, but after three or four years the acids and esters do not materially change. The rye whiskies contained larger amounts of solids, acids, esters, etc., than the bourbons, but this was attributed to the fact that heated warehouses are used for rye, and unheated for bourbon whiskey. The authors state that the characteristic aroma of American whiskey, * The Constants of Whiskey, S. Dak. Food and Dairy Commission, March, 1906. t Jour. Am. Chem. Soc, 30, 1908, p. 98. ALCOHOLIC BEVERAGES. 769 SUMMARY OF ANALYSES OF AMERICAN WHISKIES OF DIFFERENT AGES Proof. Grams per 100 Liters of 100 Proof Spirits. Color Extract. Acids. Esters. .\lde- hydes. Fur- fural. Fusel Oil. Rye Whiskey. New: Average . .. 101.2 0.0 13.3 4.4 16.3 5.4 1.0 90.4 Maximum . I02.0 0.0 30.0 72.0 21.8 15-0 1.9 161. 8 Minimum * lOO.O 0.0 5-0 12.0 4-3 0-7 trace f 61.8 I 43-7 One year old: Average .-. . 102.5 8.8 119.7 46.6 37.0 7.0 1.8 111.5 Maximum . 104.0 13-8 171. 60.5 64.8 15-5 Z-3 194.0 Minimum * lOI.O r 7-2 \ 6.6 93-0 92.0 31-1 5-8 6.8\ 6.8/ 2.8 0.4 r 80.4 I 66.4 Two years old: Average . .. 104.9 11.6 144.7 51.9 54.0 10.5 2.2 112.4 Maximum . 109.0 16.7 199.0 75-6 75-1 18.7 5-7 214.0 Minimum * lOO.O r 8.8 \ 8.6 121. 94.0 44.3 II. 4i-5\ 31-2/ 5-4 0.7 / 83.4 1 82.2 Three years old : Average . . . 107.7 13.2 171.4 62.7 61.5 12.5 1.5 112.7 Maximum . 112. 18.3 224.0 81.8 79.8 20.8 6.1 202.0 Minimum * 104.0 / II. 4 \ lO.I 145-0 119. 52-3 16.4 47-61 34-3 J 6.5 0.7 / 79-0 \ 60.0 Four years old: Average... 111.2 14.0 185.0 65.9 69.3 13.9 2.8 125.1 Maximum . 118. 18.9 238.0 83-8 89.1 22.1 6-7 203.5 Minimum * 105.0 rii.6 I11-3 156.0 153-0 58-6 17-3 57-7\ 36-3/ 6.4 0.7 r 83.8 I 67.8 Eight years old: Average . .. 123.8 18.6 256.0 82.9 89.1 16.0 3.4 154.2 Maximum . 132.0 24.2 339-0 112. 126.6 26.5 9-2 280.3 Minimum * 112. /13-8 214.0 73-7 68.4 1 40.9/ 7-9 0.8 r 109.0 \107.1 \13-7 200.0 31.7 BoxTRBON Whiskey. New: Average . .. 101.0 0.0 26.5 10.0 18. 4 3.2 0.7 100.9 Maximum . 104.0 0.0 161. 29.1 53-2 7-9 2.0 171-3 Minimum * 100. 0.0 4.0 12.0 13.0 I.O trace / 71-3 I 42.0 One year old: Average . .. 101.8 7.1 99.6 41.1 28.6 5.8 1.6 110.1 Maximum . 103.0 10.9 193-0 55-3 55-9 8.6 7-9 173-4 Minimum * 100. / 5-4 I 4-6 61.0 54-0 24.7 7.2 17. 2I 10.4/ 2-7 trace / 58-0 I 42.8 Two years old: Average . .. 102.2 8.6 126.8 45.6 40.0 8.4 1.6 108.9 Maximum . 104.0 II. 8 214.0 61.7 59-8 12.0 9-1 197. 1 Minimum * 100. / 6.9 I 5-7 81.0 78.0 25-5 23-3 24-4 1 II. 2 J 5-9 0.4 / 86.2 I 42.8 Three years old : Average . . . 103.0 10.0 149.3 54.3 48.1 10.5 1.7 112.4 Maximum . 106.0 13.8 245.0 64.8 73-0 22.1 9-5 221.8 Minimum.* 100. / 8.9 I 7-0 95-0 90.0 38.4 32.1 27-2I 12. 1 J 5-9 0.6 f 88.0 I 43-5 Four years old : Average . . . 104.3 10.8 151.9 58.4 53.5 11.0 1.9 123.9 Maximum . 108.0 14.8 249.0 73-0 80.6 22.0 9.6 237-1 Minimum * lOO.O f 8.6 I 7-4 lOI .0 92.0 40.4 40.4 28.2 1 13-8/ 6.9 0.8 / 95-0 I 43-5 Eight years old : Average . . . 111.1 14.2 210.3 76.4 65.6 12.9 2.1 143.5 Maximum . 124.0 20.9 326.0 91.4 93-6 28.8 10. 241.8 Minimum * 102.0 /12.3 I 10-5 152.0 141. 64.1 53-7 37-7\ 22.x J 8.7 1.0 r iio.o I 47-6 * Minimum and next to the minimum. 770 FOOD INSPECTION AND ANALYSIS. also the oily appearance and the " body " (sohds), are due to the charred barrels. Thirty-seven samples of whiskey, purchased by the glass from various Massachusetts saloons, were examined by the Massachusetts State Board of Health in 1894, with the following results: Per Cent Alcohol by Weight. Per Cent Extract. Maximum 45-96 30.70 36.51 1.68 0.08 0.50 Minimum Mean Seven of these samples had an excess of tannic acid, three had no tannic acid at all, and two or three had insoluble residues. Adulteration of Whiskey. — Imitation whiskey is often concocted by diluting alcohol or neutral spirit to the proper strength, coloring with caramel, sometimes adding for body prune juice, and adding for flavor certain essential oils, such as oil of wintergreen, and artificial fruit essences, such as oenanthic and pelargonic ethers. As a rule, a small amount of pure whiskey is mixed with the artificial to give it flavor. What has long been known as " blended whiskey " is either an imitation pure and simple, or a compound of whiskey and neutral spirits, artificially colored and flavored. According to the U. S. decisions, the term " blended whiskey " is restricted to a mixture of different kinds of grain distillate, colored and flavored. Among Fleischman's recipes for " blended " whiskey is the following, which he claims to be the very lowest grade: Spirits : 32 gallons Water 16 Caramel -. 4 ounces Beading oil i ounce "Beading oil" is prepared by mixing 48 ounces oil of sweet almonds with 12 ounces C. P. sulphuric acid, neutralizing with ammonia, adding double the volume of proof spirits, and distilling. This preparation is so called because it is largely used for putting an artificial bead on cheap liquors. A little creosote is sometimes added to give a burnt taste in sem- ALCOHOLIC BEVERAGES. 771 biance of Scotch whiskey. Pungent materials such as cayenne pepper are said to be used as adulterants, but no record is Icnown of any substance being used more injurious than the alcohol. Sugar is a frec^uent adulterant. Some doubt exists as to the injurious effects of fusel oil on the system. The following analyses by Ladd * show the composition of neutral spirits, and imitation whiskey consisting of neutral spirits diluted with water, colored with caramel and flavored: C Cherry and Beet Juices, Eosin (512), Erythrosin B (517)5 Rose Bengal (520), Phloxin (521), Ponceau 2 R (55), Ponceau R (55), Bordeaux B (65), Cerasin, Ponceau 2 G (15), Acid Magenta (462), Archil Substitute (28), Orange I (85), Congo Red (240), Azorubin S (103), Amaranth (107), Fast Red E (105), Crocein Orange (13) Fuchsin (448). Yellow and Orange: Annatto, Saffron, Safiflower, Turmeric, Naphthol Yellow S (4), Brilliant Yellow (5), Crocein Orange (13), Acid Yellow G (8), Acid Yellow R (9), Azarin S (70), Orange I (85), Orange GT (43), mixtures of harmless red and yellow colors. Green: Spinach Green, Chinese Green, Malachite Green (427), Dinitrosoresorcin (394), mixtures of harmless blue and yellow colors. Blue: Indigo (689), Litmus, Archil Blue, Gentian Blue 6B (437), Coupler's Blue (600), in general such blues as are derived from triphenylrosanilin or from diphenylamin. Violet: Methyl Violet (451), Wool Black (166), Naphthol Black B (188), Azoblue (287), Mauvein (593), Brown: Caramel, Licorice, Chrysamin R (269). *A Systematic Survey of the Organic Coloring Matters, founded on the German of Schultz and Julius. London, 1908. 816 FOOD INSPECTION AND ANALYSIS. MINERAL COLORS. It is impracticable to name all the mineral colors that might be added to food, as the list would include all known pigments. Even a list of the colors reported in the literature of the past generation as having been detected in foods would be of little value owing to changing conditions. Fortunately only a few comparatively harmless pigments, such as Prussian blue, ultramarine, and iron oxide, are now used to any considerable extent and these only in special classes of products. The coloring of meat products and saccharine foods with pigments is taken up in Chapters VIII and XIV respectively, the facing of tea and coffee, in Chapter, XI, and the greening of fruits and vegetables, in Chapter XXI. Detection of Mineral Colors. — Still more impracticable than to list the possible colors is to give adequate descriptions of methods for their detection and for the determination of the elements contained in them, as this would cover a wide field in qualitative and quantitative analysis. In general it may be stated that the pigments appear as colored particles under the microscope and the chief elements occur in the ash prepared with special precautions. The pigments may be extracted from some foods by acids, alkali solutions, or other solvents, either directly or after evaporation. Microscopic examination and microchemical tests of the sediment, obtained by shaking or dissolving the sample with water, are useful in the case of tea, coffee, sugar, confectionery, etc. Particles of the pigments making up the facing of tea may be found by examining the siftings from the sample under a lens. Special methods for the detection of mineral colors are given in the chapters above mentioned; the following tests are for a few colors of common occurrence: Prussian Blue. — This pigment is insoluble in water. It is decom- posed and decolorized by treatment with potassium hydroxide. If the filtered alkaline solution of the coloring matter be treated with hydro- chloric acid and ferric chloride, a precipitate of the original Prussian blue will be produced. Ultramarine Blue is decolorized by hydrochloric acid with evolution of hydrogen sulphide, which blackens filter-paper moistened with lead acetate. Tests for the detection of both ultramarine and Prussian blue in tea are described on page 388 and in sugar oh'^page 613. Chromate of Lead has never been used to any extent in food products with the exception of confectionery. For its detection, see page 678. ARTIFICIAL FOOD COLORS. 817 LAKES. Coal-tar Lakes.— Berry * has compiled lists of the coal-tar colors combined to form lakes, the mineral and organic substances used in their preparation, and the substances mixed with them to modify their color or properties. Over fifty dyes are listed but of these few are now used. Lakes of acid dyes are prepared chiefly with barium chloride, lead nitrate, lead acetate, zinc sulphate, aluminum sulphate, aluminum acetate, alums, tin chloride, antimony chloride, tartar emetic, double fluorides of antimony and sodium or potassium, calcium nitrate, and calcium acetate; those of basic dyes, with tannic acid, sodium phosphate, sodium arsenite, stannic and stannous acids and salts, antimony acids, resinic and various fatty acids. The principal materials used to modify the colors are barium sulphate, kaolin, calcium sulphate, infusorial earth, red lead, zinc oxide, lead sulphate, aluminum hydroxide, aluminum arsenite, barium phosphate, lead carbonate, calcium phosphate, lampblack and green earth. Lakes of Vegetable and Animal Dyes.— The list given by Berry includes alum, ammonia, soda, and lime lakes of the following colors: buckthorn, Persian berries, yellow berries, quercitron, weld, gamboge, young and old fustic, barberry, annatto, turmeric, saffron, safflower, Indian yellow, Chinese yellow, cochineal (carmine), lac, dyewoods, indigo sulphonic acid, chlorophyl, lokao, and unripe Persian berries. Alum lakes, particularly of cochineal, appear to be most used. DETECTION OF LAKES.— Like inorganic pigments lakes are insoluble in water and therefore under the microscope appear as colored particles. The inorganic portion of a lake is tested for in the ash or charred mass, the organic portion whether of coal-tar, vegetable, or animal origin, by the usual tests after liberation by acid or alkali, according as the original color was acid or basic, and separation by dyeing or by immiscible solvents as described in subsequent sections. VEGETABLE AND ANIMAL COLORS. These with a few mineral pigments were formerly almost exclusively used for coloring food products, and are still used to some extent. * Coloring Matters for Foodstuffs and Methods for their Detection, U. S. Dept. of Agric. Bur. of Chem., Circ. 25, p. 7. Jennison, Manufacture of Lake Pigments, 1900. 818 FOOD INSPECTION AND ANALYSIS. Detection of Vegetable and Animal Colors.— Most of the soluble red colors of fruits and vegetables, according to L. Robin,* react with ammonia to form a coloration, -usually passing from violet to blue, then to a brownish green, when the ammonia is added little by little in excess to the color in solution while the yellow colors of such fruits as apples, peaches, plums, quinces, and apricots, according to Martin- Claude,! change to brown with ammonia. Dyeing Tests and Reactions on the Fiber. — The natural colors of fruits and vegetables in an acid bath (page 841) impart scarcely any color to unmordanted wool or silk even by single dyeing. Most of the commercial vegetable dye stuffs also do not dye wool without a mordant, at least by the double dyeing method, while a few, notably the lichen colors (archil, cudbear, and litmus) impart a decided color although by no means of such a brilliant hue as many of the coal-tar dyes. Many of these colors dye cotton, previously mordanted by boiling in a solution of aluminum acetate or potassium bichromate, in a bath acidified with acetic acid. Mathewson gives the reactions on the fiber of cochineal (page 855), azo- litmin, the dyeing principle of litmus (page 855), and curcumin, the dyeing principle of turmeric (page 856). The reactions obtained by Loomis J with twenty-one natural dyes fixed on wool or cotton appear in the table on page 819. In mordanting the fiber Loomis employs the following methods: Alum Mordanting. — Dissolve i gram of crystallized aluminum sulphate and 1.2 grams of cream of tartar in 500 cc. of water. Stir 10 grams of fat-free wool in the solution for one hour, let stand two to three hours, wring, and dry at room temperature. Tin Mordanting. — Dissolve 0.8 gram of tin crystals and 0.4 gram of oxalic acid in 500 cc. of water. Boil 10 grams of fat-free wool one and one- half hours in this solution. Chrom Mordanting. — Heat to boiling 500 cc. of water containing 10 grams of fat-free wool, then add 0.2 gram potassium bichromate 0.35 gram of cream of tartar, and o.i cc. of concentrated sulphuric acid, and boil one and one-half hours. Dry at low temperature and keep from light. Extraction by Immiscible Solvent from Various Solutions. — Mathew- son, in connection with the table on page 868, makes the following state- ments : * Girard et Dupre, Analyse des Matieres Alimentaires, Paris, 1894, pp. 678, 679. t Jour, pharm. chim., 13, 1901, p. 174. X U. S. Dept. of Agric, Bur. of Chem., Circ. 63, pp. 47 and 48. ARTIFICIAL FOOD COLORS. 819 o o in o h-i o u < Pi H < H Q W Q pi; w >—* o o l-H H U < w p^ p^ o l-I o u ^d S3 37; •2 ^ c^ ^ ^ ^ „^ m « i = E ^ z 'z ■z O Q ■-, a; 2 & ^ ^ > a. S 2 « be M ;:; M iz; 2 •n c ^ •^ ^ 2 & & >H (D<1 fe f= g ^ & g o S o o S = P = = i Q « & & "a; "a! I—, >^ >H " ^ o ° m o « >< eq m ^3 bo 60 £ S p^ 2; Q P m Q o 2; 2 ^ 2 ^ .ti ■::;•:? o & ^ ^ fe ^ O U ^ ^ ^ H I -^ 1-. nl 03 oo^Kj^jmmocoOM^Hoife^fflM^ 820 FOOD INSPECTION AND ANALYSIS. Colors of fustic, quercitron, Persian berries after hydrolysis, and alkanet are extracted in large part by amyl alcohol and amyl alcohol-gasoline (i : i) from N/64 acetic acid or N/64 to N hydrochloric acid, also by ether from N/64 hydrochloric acid, but not by amyl alcohol-gasoline or ether from N/64 sodium hydroxide solution. Annatto, not alkali treated, behaves similarly but is extracted in large part by amyl alcohol-gasoline from N/64 sodium hydroxide. Colors of barwood, camwood and sandalwood resemble Nos. 483 and 510 in behavior, but are less soluble in aqueous solvents. They are ex- tracted almost completely by amyl alcohol from salt solution and by amyl alcohol, amyl alcohol-gasoline, and ether from N/64 hydrochloric acid. They are not extracted by amyl alcohol-gasoline or ether from N/64 sodium hydroxide. Ether extracts the chief part from N but not from 4N hydro- chloric acid. The color of Brazil wood is similar but more soluble in aqueous solvents. That of logwood is also similar but still more soluble. It is nearly all extracted by amyl alcohol from salt solution or N/64 hydrochloric acid, and the larger part by amyl alcohol-gasoline from N/64 hydrochloric acid. Onl)/ the smaller part is extracted by ether from N/64 and very little from 4N hydrochloric acid. A very small part is extracted by ether or amyl alcohol-gasoline from N/64 sodium hydroxide. The colors of archil, saffron, and cochineal also are easily extracted by amyl alcohol from slightly acid solutions but only in small amount by ether. The colors of leaves, egg yolk, fats and oils, carrots, and tomatoes, all similar or identical, are taken up by ether from neutral solutions and removed from this solvent by dilute alkali. Reactions in Aqueous Solution and with Sulphuric Acid. — The table by Loomis * on pages 822 and 823 gives the colors of a 0.1% solution of natural dyes as observed in a |-inch test-tube, the reactions of 10 cc. of the solution with 5 to 10 drops each of hydrochloric acid (sp.gr. i.i), of 10% sodium hydroxide solution, and of ammonia water (sp.gr. 0.95), the reac- tions of 5 cc. of the solution with 0.2 gram of zinc dust and 10 drops of concentrated hydrochloric acid; also the colors obtained by shaking 0.05 gram of the dry color with 5 cc. of concentrated sulphuric acid and after dilution (cautiously with the first 20 cc.) until the change of color is merely in intensity. * Loc. cit., pp. 59-61. ARTIFICIAL FOOD COLORS. 821 Specl/vl Tests for Vegetable Colors.— Archil, Cudbear, and Litmus, all derived from lichens, by the double dyeing method dye wool red in acid bath.* The colored fiber is turned blue, purple, or violet by treatment with ammonia. For other reactions on the fiber see tables, pages 819 and 835. Robin's Test for Archil in aqueous solution consists in shaking it with ether, which, if archil is present, is colored yellow. On treatment of the ether with ammonia, the yellow color is changed to blue, and, by adding acetic acid, goes over to a reddish violet. Other reactions of lichen colors are given on pages 820 and 822. Logwood, according to Robin, in aqueous solution colors ether yellow, and on treating the ether with ammonia the color becomes red or faintly violet. Potassium bichromate gives a violet coloration, mingled with greenish yellow. If cotton is first mordanted by boiling with aluminum acetate, it is dyed violet when boiled in a solution of logwood. Reactions of chrom mordanted cotton dyed with logwood are given on page 819 and of the solution of the dye on page 822. Turmeric is best extracted from a dry residue with alcohol, which it colors yellow. The color is transferred to a piece of filter-paper by soak- ing the paper in the alcoholic tincture, the paper is dried and dipped in a dilute solution of boric acid or borax slightly acidulated with hydro- chloric acid. On again drying the paper, it will be of a cherry-red color if turmeric is present, and when touched with a drop of dilute alkali will turn dark olive. For solubilities of curcumin, the coloring principle of turmeric, see page 872, and for reactions on the fiber see page 856. Caramel. — Care should be taken in testing for caramel not to subject the sample to long-continued heating, even on the water-bath. Indeed, caramel is sometimes developed spontaneously in saccharine food prod- ucts during their process of manufacture when heat is used, by the charring of the sugar. If solutions are to be concentrated or brought to dryness before testing for caramel, this should be done in a vacuum desiccator over sulphuric acid, or at a temperature not exceeding 70°. For detection of caramel in milk, vinegar, and liquors, special tests are given elsewhere. Fradiss Test.-\ — Extract the dried residue of the sample to be tested with warm, pure methyl alcohol, which, if caramel be present, is colored brown. Filter, and to the filtrate add amyl alcohol or chloroform. In *Tolman, Jour. Amer. Chem. Soc, 27, 1905, p. 213. fOestr. ungar. Zeits. Zuker Ind., 1899, 28, 229-231; Abs. Zeits. Unters. Nahr. Genussm., 2, 1899, p. 881. 822 FOOD INSPECTION AND ANALYSIS. w q < O o I— I H U < H P^ Q < Pi < w p^ p^ < 3 OJ OJ N^ o go; .« .2t3 c a 2^' as &t2 O +J >. «^ 1-30 ao ° m f= o ° h — ; . o .Sffi ° £1 u o q c . & i* is c C 1J •^ 'C S a OS'S DO o o •a- rn C <" o 3 -na 3 u o S i* ' MO- ■a-a.S '"'""ca 5 .2 P^ o« B -3 ^ a := o,5f ! Q « f^ c 1 •a c c 1 o o <: P P N c O SO n! .ti N O I-. j <; hj m ARTIFICIAL FOOD COLORS. 823 gc; 1 "d ■ - +J 1 .*-' rt 'o aS o 3 _3 6 c 3 c "o'a P. S M 5 (Ll "a! >■ >■ 0) 2 >< > "3 >< ^ rt •a 01 < (5 ^O (_ nj rt-d i; OJ c "S ^rt § d a o _o + u o _3 Q o o o o 130 u a rt CJ o "o OJ m S OJ OJ !-• M O S > tH O >H > >^ > o C >> £ rt Q a o -• u, 3 H rt u u ■o >> 1 .^ '~^ V j^-d ° sa •d o o ij a. O 3 •o M M br. Cl ' is ° rt K IS J-c C n c c 1- c rt "rtT: c •a< Mo a, J3 o O ■z P. •s c oj-d M a S ^^ M "a _ a. "o r/i C 1J 3 --of 2.2 > 2 S o di •5.2 & fe & & & C >> i C 3 C 3 o c c c c 1 c "o U o ffl "3 >: "3 >■ > ■t-> O _o B o 0) c c c o ^ Ih E n! 2 1- o c a !-• 0. o rt E .2 X E C J: < t^ J CM fr ff {2 c a 1 824 FOOD INSPECTION AND ANALYSIS. presence of caramel, a brown flocculent precipitate is formed, which slowly settles to the bottom of the tube. Amthor Test.* — Mix in a cylinder lo cc. of the solution, 30 to 50 cc. of paraldehyde, and sufficient absolute alcohol to make the liquids miscible. After the brown caramel precipitate has settled decant off the liquid, wash with absolute alcohol, dissolve in a few cc. of hot water, and filter. Note the intensity of the color of the solution, then pour into a freshly prepared solution of two parts of phenylhydrazine hydrochloride, 3 parts of sodium acetate and 20 parts of water. A considerable amount of caramel will give a precipitate in the cold. Heating hastens the separation and long standing is essential if the amount is small. Lasch^'s modification of this test is described on page 784. Indigo, both natural and synthetic, is insoluble in alcohol and in water and therefore suited only for solid foods. It has been used for coloring confectionery and facing tea. With concentrated sulphuric acid the dry material becomes yellowish changing slowly to blue-green. Sidphonated Indigo, also known as indigo carmine, indigo extract, indigotine, and indigo disulpho acid, being soluble in both alcohol and in water and allowed under federal ruling, is the basis of most blue food colors and also mixed with red and with yellow dyes of violet and green shades respectively. Its reactions in solution and on the fiber are given on pages 868 and 854, Cochineal. — This animal dyestuff is used in ketchups, cordials, con- fections, and other food products. Robin Test. — Acidulate the aqueous solution with hydrochloric acid, and shake out in a separatory funnel with amyl alcohol. Cochineal imparts to this solvent a yellowish color, the depth depending on the amount present. Wash the separated amyl alcohol with water till neutral, and divide into two portions. To one of these add a little water, and then drop by drop a solution of uranium acetate, shaking each time a drop is added. In presence of cochineal the water is colored a very characteristic emerald- green color. To the other portion add ammonia. If cochineal has been used, a violet coloration is produced. COAL-TAR COLORS. So many of the coal-tar dyes can be used in food products that it would be impossible to even name them all, especially in view of the fact that * Zeits. Anal. Chem., 24, 1885, p. 30. ARTIFICIAL FOOD COLORS. 825 new colors are from time to time being added to the list. No attempt will be made in the present work to give the nature and composition of the dyes named, as such descriptions would lead beyond its scope. For detailed information along this line the reader is directed to the works of Schultz and Julius, Green, Mulliken, etc. Green's list compiled in 1903 includes 688 coal-tar colors but does not claim to be complete. Mulliken described 1475 ^Y^^ found on the American market in 1909. Although some natural dyes and possibly a few mixtures are included the total of these is more than offset by definite individuals of coal-tar origin which are not enumerated because obsolete or for other reasons not available or have been discovered since the date of publication. Various classifications of these colors are attempted, based on (r), their origin, as anilin dyes, naphthalin dyes, anthracene dyes, etc.; (2) their chemical composition, as nitro, nitroso, azo, diazo, azin, and other com- pounds; (3), their solubility in water and other solvents; and (4), their mode of application to the fiber, as basic dyes, acid dyes, direct cotton dyes, mordant dyes, etc. These dyes are sold in the form of powder, and are readily made into solutions for food colors in the case of the water-soluble varieties, and into pastes in the case of the insoluble forms. Most of the coal-tar colors employed in foods are naturally of the soluble variety, especially such as are found in jellies, jams, fruit products, canned foods, ketchups, beverages, and milk. Pastes made from insoluble dyes are adapted mainly for exterior coatings of hard substances such as candies. Colors in the dry form are to be looked for in such spices as cayenne, mustard, and mace, but a commoner method of coloring these spices high in oil is to mix with them a solution of the color in oil (usually cottonseed) . Oil solutions of coal-tar dyes are also employed for coloring butter and oleomargarine. The chief concern of the food analyst, as regards artificial color is its recognition in food products. Coal-tar dyes may usually be iden- tified as such, but it is not always possible to name the particular individ- ual dye or combination of dyes employed, even though the class to which they belong may be determined. One reason for this is that not infre- quently mixtures of two or more colors are employed. Coal-tar Colors Allowed under the Federal Law.* — The use of any dye, harmless or otherwise, to color food in a manner whereby damage * Food Inspection Decisions, Nos. 76, 77, 106, 117, 129, and 164. 826 FOOD INSPECTION AND ANALYSIS. or inferiority is concealed is in violation of Sec. 7 of the Food and Drugs Act of June 30, 1906. The addition of all mineral or metallic dyes, and all coal-tar dyes, other than those specially provided for, is also prohibited. Pending further investigation the following coal-tar colors are permitted in foods, provided they are certified to be true to name and to be free from mineral and metallic poisons, harmful organic constituents, and contamina- tions due to improper or incomplete manufacture : * Red Shades. — 107. Amaranth [M.] [C.]. Synonyms: Fast red D [B.] Bordeaux S [A.], azoacidrubine 2B [D.\, fast red EB [B.]. 56. Ponceau 3R [^4.] {B.[ [M.]. Synonyms: Ponceau 4R [A.], ciimidin red, cumidin ponceau. 517. Erythrosin [B.] [M.] [B.S.S.]. Synonyms: Erythrosin D [C], erythrosin B [A.], pyrosin B [Mo.], iodeosin B, eosin bluish, eosin J [B.]. Orange Shade. — 85. Orange I. Synonyms: Alphanaphthol orange, naphthol orange [A..\ tropseolin 000 No. i, orange B [L.]. Yellow Shades. — 4. Naphthol yellow^ S {B.\. Synonyms: Naphthol yellow, acid yellow S, citronin A (Z,.). 94. Tartrazin [B.] [/.] [H.]. Synonym: Hydrazin yellow [O.]. Green Shade. — 435. Light green SF yellowish [B.]. Synonyms: Acid green [By.] [M.] [T.M.] [O.], acid green extra cone. [C.]. Blue Shade. — 692. Indigo disulphoacid. Synonyms: Indigo car- mine, indigo extract, indigotine [B.], sulphonated indigo. None of these colors is patented, hence their manufacture is not likely to become a monopoly. They may be used in combinations, thus secur- ing any desired shade. For example, violet may be obtained by mixing indigo disulphoacid and one of the red colors, a blue-green by mixing indigo-disulphoacid with naphthol yellow S or light-green SF and so on. EXAMINATION OF COAL-TAR FOOD COLORS.— The testing of synthetic colors designed for foods differs from the task confronted in the dyeing industry in that the number of dyes is more limited and the presence of injurious substances, especially metallic by-products, is of paramount importance. A knowledge of the probable and possible dyes is naturally a great aid in examining samples; with this information the various analyti- * The numbers preceding the dyes are those given by Green; the letters in brackets represent the manufacturers who originated the names. ARTIFICIAL FOOD COLORS. 827 cal schemes and tables covering the whole field can be used to best advan- tage. These same data are also of value in detecting colors in foods, and on the other hand, the tables of solubilities and reactions, as well as general methods, designed especially for the examination of foods for foreign colors, apply also to the food colors themselves. Analytical Schemes. — Witt,* the pioneer in the identification of dyes, devised a scheme employing the reactions and color tests with acids, alkalies, and other reagents, reduction with zinc dust and subsequent oxidation by exposure to air, as well as dyeing tests, and spectroscopic examination. As a means of learning whether or not a dye was a mixture, he devised the very useful test of dusting the powder over con- centrated sulphuric acid, noting the color as the individual particles dis- solved. Weingartner t revised Witt's scheme, adding new dyes and employing tannin solution to differentiate acid and basic colors. In testing for mixtures he sprinkled the powder over a filter paper moistened with water. Green J introduced chromic acid as an oxidizing agent, following reduction with zinc dust, but later, with his associates Yoeman and Jones, § rejected both reagents in favor of sodium hydrosulphite (" T blankite ") and potassium persulphates, both of which are colorless. Rota in his scheme (pages 827 to 832) departs quite radically from class reactions developed by Witt and others of his school. Of special value are the tables of Green || (based on Schultz and Julius), and Mulliken.^ The latter has the advantage of being more recent, more distinctly analytical, and broader in its application owing to the greater number of dyes included and the wider variety of tests (including spectro- scopic) employed. Rota's Analytical Scheme ** is based on the structure of the dyes as shown by their reactions with certain reagents. The colors are divided into two main groups, according to whether or not they are reducible by stannous chloride. These two groups are each further subdivided into * Zeits. anal. Chem., 26, 1887, p. 100. tibid., 27, 1888, p. 232. J Jour. Soc. Chem. Ind., 12, 1893, p. 3. § Jour. Soc. Dyers, Colorists, 9, 1905, p. ^36. II A Systematic Survey of the Organic Coloring Matters, London, 1904. If Identification of Pure Organic Compounds, Vol. VI, New York, 19 17. ** Chem. Ztg., 22, 1898, p. 437. 828 FOOD INSPECTION AND ANALYSIS. two classes, the reducible colors being classed according to whether the color remains unchanged, or is restored by treatment with ferric chloride, and the non-reducible colors according to their action with potassium hydroxide. The tests are carried out on a dilute aqueous or alcoholic solution of the coloring matter, the strength being about i in 10,000. Treat about 5 cc. of this solution with 4 or 5 drops of concentrated hydrochloric acid and about as much 10% stannous chloride solution, shake the mix- ture, and heat if necessary to boiling. With some colors the process of decolorization is a slow one, especially if the solution is too concentrated, and it is well to repeat the experiment, if in doubt, diluting the original sample still further with water. Tin in solution in concentrated hydro- chloric acid may be employed instead of stannous chloride, if desired. Here, as in all cases of color testing, it is well to make comparative tests with known colors. CLASSIFICATION OF ORGANIC COLORING MATTERS. [A portion of the aqueous or alcoholic solution is treated with HCl and SnClj.j Complete decolorization. Reducible coloring matters. Colorless solution is treated with Fe_,Cle, or shaken with exposure to air. The color changed no further than with HCl alone. Nonreducible colors. A part of original solution is mixed with 20% KOH and warmed. The liquid remains unchanged. Color- ing matters not re- oxidizable. Class I. Nitro, nitroso, and azo colors, including oxyazo and hydrazo colors. Picric acid, naphthol yellow, ponceau, Bordeaux, and Congo red. The original color re- stored. Reoxidiz- able coloring mat- ters. Class II. Indogenide and imido- quinone coloring matters, methylene blue, safranin, in- digo carmine. Decolorization, or a precipitate. Imido- carbo-quinone color- ing matters. Class III. Amido-derivatives of di and triphenyl methane, a u r a - m ins, acridins, quinolins, and color derivatives of thio benzenil. Fuchsin, rosaniUn, suramin. No preci p i t a t i o n. Li(juid becomes more colored. Oxy- carbo-quinone col- oring matters. Class IV. Nonamide diphenyl methane, oxv-ke- tone, and most of natural organic col- oring matters. Eosins, aurin, aliz arin. g c^ O Q W ARTIFICIAL FOOD COLORS. 829 kJ -^ fl 2 bU ^ o W ^ ^ •'-' ^ ^ ctf 3u d ^ S d u^'H d ^ ^ ^ -^ d-d 'O ±1 n u OJ I« Cll aiJ Ih -i^ r;^^ t^.-iJdTj cAi--iic:g U^ ^ IdS i^ ^ "-S«J^ .^-5.5 ^d ;r:!H>i-5 '"S'So otj_~S V dJL'iloj.a; i3'i3 I "^^^ sy >,:« ^o I § ^^ ii I pf "^^^^ ^0^'d|g^-2^^c^l-;ggd ^^ S[Ti=^S^ •S :z § S i^ n -c b 6 ^— 'j^ i^ S d ?i S -S w 5 =« S •£^ 'f S^^gogg^^^ro ^ II oj-Sug g Z 50 ^ d 830 FOOD INSPECTION AND ANALYSIS. to , t-153 4J O fe C u ^-^ wi > oj 43 Ph •Tl ^ > *-■ I ]^ ii "^ CO s.s s tn t3 o o ,2 bO color red 1 eld is C!_ r^ -3^ 3 bo •^ C S .-d W id hfi P^ 12^ .s h'^ 2 i2 ^ 3 S2 >> n1 ^-2 0^ c IS "u e CO be C (h* -d X 'V 0) u ^K .. c , *3 o U u s i" « y ^ 1.5.: :&x U5 (U ^ a! ij 2 « tn fcS 0) '>,' s .5 (1) ClJ K) -d d J3 U 7^ ^ -r) (U "-^ c (J • •-H a c ID bC CO .3 i •sonsuapuj^q.T poxsuu-B aqi stjq j3]T3a\ qim paqsBM uopnjos ji^ajaqia aqjL •jatps qijM p3pBj;x3 puB HO:a H^l^^ pa^^aj; si uopnps jiioqoDiB jo snoanb^ aqx ARTIFICIAL FOOD COLORS. 831 < . *J3X{;3 v{}]JA papBj^xa puB H03! W^ pai^aj; uoi;nios diioi^odi-b jo snoanb^ aqx 832 FOOD INSPECTION AND ANALYSIS. PQ Pi .o o Pi pf p< < D 13 < a. a CO Pi ^ Pi \8/ p: II \8/- O w o g X o w w H -o 2.S tJ3 JJ S X' JJ 3 (u -f^ ^ -7^ ^^ h-, « O r; c-2 5 fe o u rt > O S" be o .5 O d CL, ^ ^'$ S ^ '13H P SS3DX3 -OS suijBJU'B sqj^ ^^ «J »'> * bO C b CT3 .S-d-^ • S P ^ rtS y .-y 3 .>- s a a, le free c ter precip sually sol r, and ind rs. >> u 4-5 e o o So 3 oj t* ^ e •ptDB opaoB pagipiDB uop aui[B2iiT3 aqx " q;iM -njos 2j h i>D rt ° C O ' (3j c •s's ^ S ? OJ _ o . ^ ^ m r^ iH "-.So PiZ^ 1^-^ C C P "11 u V or ellow noke (5 >,Td ■5.2 O a; g '^ QJ >H -*-* CO J-J 'U OJ C CD flJ •(;u3D jad I 'HO:a) igj'BAi. 3Uq-B5J]B XpUIBJ q}IA\ p3}B3JJ SI jajjBui guuopo {-BuiSuo aqjL c h ■-! bD o *^"S £ ^ ^ ^ S:S.S.§ •(0001 : i) 'l3*3J JO uoiinfos ajnup v jo sdojp M3J 13 q;iA\ pajBaji aaiiBiu SuuGjoa aqi jo uonnjos DijoqoDjB aqj. ARTIFICIAL FOOD COLORS. 833 Separation and Identification of Allowed Colors. — Price * devised a method for the identification of the seven colors allowed under Food Inspection Decision 76, 1907. The addition of tartrazin to the list neces- sitated a modification of the method. Price-Estes Method. '\ — The scheme is given on page 834. Price-Ingersoll Method.% — Ingersoll states with regard to the Price- Estes method that when small amounts of the dye are taken out of the original mixture on extraction with the ammonium sulphate reagent the separation is difficult or impossible, furthermore, that while some tartrazin, like naphthol yellow S, is soluble in that reagent, the larger part is not, following Price's directions. He accordingly proposed the following modification of the Price method: Rub from o.i to 0.2 gram of the dye sample, depending upon the amount of foreign salts in the mixture, with 25 cc. of saturated ammonium sulphate solution in a mortar and filter through a dry filter. If the filtrate comes through red, wash the color residue in the mortar and on the filter with successive 10 to 15 cc. portions of the ammonium sulphate solution until the washings are no longer colored red. The filtrate and washings contain the greater part of the amaranth together with some naphthol yellow S and also some tartrazin. Combine the filtrate and washings and shake with successive portions of acetic ether until the acetic ether is no longer colored yellow. The acetic ether removes that portion of the naphthol yellow S which was dissolved by the ammonium sulphate solution and may be discarded, since the greater part of this dye is recovered later in the scheme. Shake the ammonium sulphate solution containing amaranth and some tartrazin with acetone to remove these colors ; discard the ammo- nium sulphate solution, dilute the acetone portion with an equal volume of water, and drive off the acetone on a steam bath. Saturate with sodium chloride, add 10 cc. of alumina cream, agitate, warm, settle, filter, and wash with warm saturated sodium chloride solution until the washings are no longer colored yellow. To recover the amaranth, suspend the alumina cream precipitate in saturated ammonium sulphate solution and shake with acetone. The filtrate contains tartrazin and is to be discarded, or, when dealing with small amounts, if desired, can be saved and the tartrazin identified with the greater portion of this color separated further in the scheme. * U. S. Dept. of Agric, Bur. of Anim. Ind., Circ. 180, 191 1. t Jour. Ind. Eng. Chem., 8, 1916, p. 11 23. Jlbid., 9, 1917, p. 955. 834 FOOD INSPECTION AND ANALYSIS O ^ Q A p^ o kJ o o u a o . JJ w (U O u rt "O 1— 1 ^.l « (1* O M S C o S .Sfrt H ^^ ^ =" O o •o " Z^ CM-, b9 WW 3Q Pi -2 o5 2; o 13 (H OK CL, lU n) w . "" C C 0) !> O t O D w +^ p. c2; . to 4) S;Ui3 a o "> o c •d j2 ^- ^ J "d 1- w a! & rt 3 CtJ ^ 4) { C nJ & c-d ^ ca'"''" H M HJ " ,trl > I- Jj^'S V, ptnJ3 C O,: J3-S Sou- !5o i'Bo EC 'n 3 ca o p-^ m ^ •3 <-^< 4J S t.-?0 ^ ■Hit: 3 Z,s2 p ft ,:, _• 3 yq ^„- i**^ S*^ ca O 4j 3 ^ •2 4) g 2 -2 S °S y " fe o o tr, 'O ta y: > y3 r^ 8|^ ; .2< I* 4/ M 2< o-d^SiS 00 ca 5 4)Ph ca oj Za1.s OJ P 4> rt gHS J c-d 3i : o cJ3 '•^3 ta** 3 IC ' 4^ Hi^ ta cy ' ; g c !,cft2 ; +j ta 4J o-r > o ta > 4) ta -IJ 4) 5 XI > -J o lu . Cop ft iH "d "*1 M-i ca o .^ S S 2 O ra ta t)o " bo tn ^ K '60 u be in o t3 all « £i 3 .2 -. * 3-^ a ARTIFICIAL FOOD COLORS. 835 Dissolve in water the portion of the original sample not dissolved by ammonium sulphate, acidify with acetic acid, and shake with successive portions of ethyl ether until the ether is no longer colored. The ether contains erythrosine, which it is very essential to remove completely from the other dyes before proceeding further. Wash the ether solution several times with water and finally extract the erythrosine from the ether with dilute ammonia solution. Remove the ammonia by evaporation on the steam bath and observe if this solution, when very dilute, has any fluorescence which might indicate the pressure of prohibited colors having similar reac- tions. Remove the ether from the acetic acid aqueous solution by warming on a steam bath, saturate with sodium chloride at steam bath temperature, and add sodium chloride in excess; cool and filter through a dry filter. Wash with saturated sodium chloride solution until the washings are color- less. When a bulky precipitate is obtained here, which is difficult to wash, it may be time-saving to redissolve the precipitate and excess salt in water and repeat the salting and washing process, adding the filtrate and washings to those of the first saturation. The combined filtrate and washings con- tain light green SF yellowish, naphthol yellow S, tartrazin, traces of orange I, and possibly amaranth, since the latter dye may not be entirely removed by the first extraction of the dry sample with the ammonium sulphate reagent. To separate the naphthol yellow S, extract with successive portions of acetone until the acetone fails to remove any more color. Combine the acetone extracts and wash with several portions of saturated sodium chloride solution to remove traces of tartrazin and light green SF yellowish from the acetone. Add to the acetone solution an equal volume of water and drive off acetone on the steam bath. Acidify the water solution and shake with amyl alcohol to remove traces of orange I that may be present; discard this amyl alcohol solution. Drive off all amyl alcohol mechanically held in the aqueous solution by warming on the steam bath and test this solution for naphthol yellow S. To separate the light green SF yellowish from the tartrazin, remove the acetone from the aqueous salt solution by heating on the steam bath, and add fuller's earth in the proportion of 0.5 gram to each 10 cc. of warm dye solution. After mixing well and heating, allow to settle; then filter and wash with water. The light green SF yellowish remains on the filter and can be dissolved in strong, hot acetic acid and further identified. If tartrazin was present in the original mixture, the filtrate from the precipita- tion of the light green SF yellowish will be yellow or golden yellow, not 836 FOOD INSPECTION AND ANALYSIS. decolorized by hydrochloric acid. Imperfect removal of naphthol yellow S, previously, would result in a yellow filtrate here which could be decolor- ized by hydrochloric acid. The tartrazin can be further isolated from a possible trace of amaranth by adding lo cc. of alumina cream to each loo cc. of solution, mixing, warming, and filtering, when the tartrazin will be found in the sodium chloride filtrate. To isolate from the salt, evaporate and redissolve in alcohol. Dissolve the precipitate containing orange I, ponceau 3R and indigo disulfo acid, together with excess sodium chloride on the filter paper, in water and extract with three successive portions of acetic ether. Orange I is taken up by acetic ether. Combine the acetic ether extracts and wash with saturated sodium chloride solution, until no more color is removed. Extract the acetic ether solution with water to obtain the Orange I in an aqueous solution and free from acetic ether by warming on the steam bath. Warm the water solution containing ponceau 3R and indigo disulfo acid, from which the greater part of the Orange I has been removed on the steam bath until free from acetic ether, cool, add 10 grams of granu- lated calcium chloride, allow to stand fifteen minutes, and then add 15 cc. of a freshly prepared stannous chloride solution containing the equivalent of 3% metallic tin and 12% of hydrochloric acid (sp.gr. 1.19). Mix well and allow to stand until the solution shows no blue color. If ponceau 3R is present, it will be precipitated. Filter immediately, wash the precipitate twice with 25% calcium chloride solution to remove all the reduced indigo disulfo acid, dissolve the remaining residue in dilute ammonia solution and test for ponceau 3R. To the filtrate, which should be practically colorless, add 3% hydrogen peroxide solution. A deep blue coloration indicates the presence of indigo disulfo acid. Quantitative Separation of Acid Coal-tar Colors. — Mathewson Method."^ — This process, like the preceding, is for the colors themselves, but may be adapted for the detection of the colors in food products after separation by means of solvents or less satisfactorily by dyeing. Mathew- son's table is given on pages 837 and 838. In applying the data given in the table proceed essentially as follows: Treat the solution containing 0.2 to 0.4 gram of color (depending on the nature of the dyes) with sufficient water and hydrochloric acid to bring * U. S. Dept.of Agric. Bur. of Chem., Circ. 89. ARTIFICIAL FOOD COLORS. 837 its volume to about 50 cc. and its acid concentration to that point for which the difference in percentage of color extracted for the two dyes is near its maximum. Shake the solution with the immiscible solvent, passing it in succession through three or four separatory funnels each containing 50 cc. of the latter. Wash the portions of the solvent with 50 cc. of hydrochloric acid of the same normality as the solution, passing it MATHEWSON'S TABLE SHOWING PERCENTAGE OF COLOR IN THE WATER SOLUTION AFTER SHAKING WITH AN EQUAL VOLUME OF IMMISCIBLE SOLVENT. solvent: amyl alcohol. Colors. Naphthol Yellow S No. 4 . . Orange I No. 85 Ponceau 3 R No. 56 Amaranth No. 107 ....... Light Green S F No. 435 . . , Erythrosin No. 517 Indigo Carmin No. 692 . . . . Fast Yellow No. 8 Crocein Orange G No. 13 . . Orange G No. 14 Ponceau 2 R No. 55 Crystal Ponceau No. 64 . . . Fast Red B No. 65 Resorcin Yellow No. 84 . . . Orange II No. 86 Brilliant Yellow S No. 89 . . Tartrazin No. 94 Metanil Yellow No. 95 ... . Fast Red A No. 102 Fast Red C No. 103 Fast Red E No. 105 New Coccin No. 106 Scarlet 6 R No. 108 Resorcin Brown No. 137 . . . Cotton Scarlet 3 B No. 146. Congo Red No. 240 * Azo Blue No. 287 t Chrysophenin No. 329 Guinea Green B No. 433. . . Acid Magenta No. 462 ... . Normality of Hydrochloric Acid in Water Layer before Shaking 2 I 1 1 4 1 8 ^ Percentage of Color in Water Solution after Shaking. S 90 34 36 41 75 IS 95 SI IS 3 52 97 61 73 47 95 93 7 82 99 96 14 II 0-5 93 99 99 58 8 16 5 90 4 17 75 32 17 I 43 27 64 39 62 II 2 20 10 25 43 4 78 17 3 * Color acid nearly insoluble in both layers. t Similar to Congo Red but color acid i.iore soluble in alcohol. 838 FOOD INSPECTION AND ANALYSIS. I MATHEWSON'S TABLE SHOWING PERCENTAGE OF COLOR IN THE WATER SOLUTION AFTER SHAKING WITH AN EQUAL VOLUME OF IMMISCIBLE SOLVENT— {Continued). solvent: dichlorhydrin. Colors. Normality of Hydrochloric Acid in Water Layer before i_ Shaking. Percentage of Color in Water Solution after Shaking. Naphthol Yellow S No. 4 . Ponceau 3 R No. 56 Orange I No. 85 Amaranth No. 107 Light Green S F No. 435 . Indigo Carmin No. 692. . . Acid Magenta No. 462 .. , 15 37 4 95 15 91 17 Naphthol Yellow S No. 4 . Ponceau 3 R No. 56 . . . . solvent: amyl acetate. 95 33 96 97 Naphthol Yellow S No. 4 . Orange I No. 86 solvent: ether. 94 97 97 97 successively through the separatory funnels in the same order as was the original solution, and repeat this operation with one or two fresh amounts of the hydrochloric acid. The dye relatively more soluble in water is determined in the combined washings and extracted solution. Remove the second dye from the solvent by shaking with water, very dilute caustic soda, or, more quickly, with dilute caustic soda after the addition of some gasoline, or similar substance in which the color is insoluble. The table given above shows the percentage of the color in the water solution after shaking with an equal volume of the immiscible solvent. Assuming the distribution ratios to remain constant, this procedure using four funnels and making three washings gives for a pair of colors whose " distribution numbers " (as the percentage numbers given in the ARTIFICIAL FOOD COLORS. 839. table may be called) are 80 and 20, respectively, a separation of 98.30 per cent for each color. With distribution numb^^rs 90 and 10 four funnels and three washings give a calculated separation of 99.73%, and the same is obtained with distribution numbers 81.8 and 5.3 if the solvent in which the dyes are relatively more soluble be taken in portions one-half the volume of those of the other liquid. If the second, third, and fourth funnels be given a fifth washing, the third and fourth funnels a sixth, and the last funnel a seventh washing, the calculated loss for the color more soluble in the solvent layer is 0.76%, while the percentage of the other dye removed is relatively much increased (to 99.99%). In most mixtures the progress of the separation is always apparent. In practice, because of incomplete extraction and separation, and especially on account of uncertainty due to small amounts of subsidiary dyes always present, it is necessary to increase the number of successive extractions. The formation of esters of the color acids is a possible source of difficulty, but is not believed to take place. With amyl alcohol as solvent it is usually desirable to make the original solution more strongly acid than is indicated by the distribution data and use relatively more portions of the washing liquid. Of the permitted colors, Naphthol Yellow S is best separated from Orange I by washing the amyl alcohol solution of the color acids with strong salt solution, care being taken that not too much color is present. With a solution containing 20 grams of salt and 0.04 gram Naphthol Yellow S per 100 cc. and shaken with an equal volume amyl alcohol, 97% of the color is retained by the water. With a similar solution contain- ing 0.07 gram Orange I, the water layer contains 1.5% of the total color. With higher concentrations some color may be salted out in solid form, but this does not interfere if the amount is small. Erythrosin being quantitatively removed from slightly acid solutions by amyl acetate, ether, or amyl alcohol, its separation from sulphonated colors presents no difficulty. Analysis of Food Colors. — Seeker and his co-workers have devised methods for the analysis of the seven coal-tar colors allowed by federal decision in the United States. The methods are for the determination of the ultimate constituents and for impurities, including arsenic and other heavy metals. The reader is referred to Hesse's report * for details of these processes. * Loc. cit., pp. 210-226. ,840 FOOD INSPECTION AND ANALYSIS. Loomis * has prepared a table giving the solubiHty of food colors in various solvents, and another table showing the relative amounts extracted from neutral, alkaline, and acid solutions, shaking with amyl alcohol, ethyl acetate and acetone, the aqueous solution in the latter case being saturated with salt. Spectroscopic Examination. — The absorption spectra of dyes, both of coal-tar and vegetable origin, in various solvents, have been described by Vogel t and by Formanek | on the Continent, by Sorby § in England, and by Mulliken || in the United States. These data, although specially designed for the dye chemist, are none the less valuable for the food analyst. Unfortunately, few chemists are equipped with suitable spectroscopic apparatus or are acquainted with the details of manipulation. Detection of Coal-tar Colors in Foods.— The examination of foods for foreign colors involves usually at least two distinct steps: First the extraction of the dye from the product, and second the identification of the dye thus removed; where more than one color is present a third step or series of steps is necessary to separate these colors previous to identification. Extraction of Colors from Foods. — There are various methods for the separation of coloring matters from food products, and these may be divided into three general classes: First, dyeing silk or wool with the color by boiling the fiber in a solution of the sample to be examined; second, extracting the color from a solution of the sample by the use of an immiscible solvent; and third, extracting the color from the dried residue of the sample by means of a suitable solvent. Of these the method of dyeing v/ool lends itself most readily to the analyst's use, by reason of its simplicity, and from the fact that the coal-tar dyes adapted for food colors, with few exceptions (i.e., auramin), being substantive dyes are readily taken up by wool, whereas the natural colors of foods are left in the solution. Some vegetable and animal dyes, such as lichen colors and cochineal, also dye wool, but these are readily distinguished from coal-tar colors by special tests. The Separation of Colors is best carried out by fractioning between * Loc. cit., pp. 8-21. t Praktische Spektralanalyse iridischer Stoffe, 1889. X Spektralanalytischer Nachweis kiinstlicher organischen Farbstoffe, 1900; Qualita- tive Spektralanalyse anorganischer und organischer Korper 1905; (with Grandmougin) Untersuchung und Nachweis organischer Farbstoffe auf spektroscopischem Wege. § Proc. Royal Soc, 92, p. 1867. 1 1 Loc. cit. ARTIFICIAL FOOD COLORS. 841 aqueous solutions and immiscible solvents according to Mathewson's method, page 859. Identification of Colors. — Three types of methods are mostly used: First, spot tests, that is the application of reagents directly to the dyed fiber or dry color (pages 854-858) ; second, reactions in the solution of the color (pages 86S-875); and third spectroscopic examination. Most analysts are limited to the first two; those equipped with spectroscopic apparatus are referred to the work named on page 840. Basic and Acid Dyes. — The soluble coal-tar dyes are either basic or acid. Basic dyes are precipitated from their aqueous solution by tannin. Acid dyes are not so precipitated. Theoretically, all the basic colors are taken up by wool from a faintly alkaline or neutral bath, while the acid colors are left in solution. Thus if a dilute solution of the color be made faintly alkaline with ammonia and boiled with the wool, only basic colors will be taken up. If both acid and basic dyes are present in the same solution, the basic color should first be exhausted by the use of fresh pieces of wool in the ammoniacal solution, till they no longer take out color, after which the solution should be made slightly acid with hydrochloric acid and again boiled with wool, which under these conditions takes out any acid colors. Comparatively few basic colors are employed in foods. Basic colors can be removed from the fiber by boiling with 5% acetic acid. Acid colors are removed therefrom by boiling with z^^^q ammonia. Having dissolved the dye from the fiber by the appropriate solvent as above, the decolorized fiber may be removed, and the solution evaporated to dryness on the water-bath. The residue consists chiefly of the dyestuffs, and may be put through various reactions for identification. Methods of Dyeing Wool from Food Products. — The wool employed should be white worsted, or strips of white cloth, such as nun's veiling or albatross cloth. Care should be taken that the color is pure white and not the more common cream white. The woolen material should be freed from grease by boiling first in 0.1% sodium hydroxide solution and finally in water. Strips of the woolen cloth, or pieces of the worsted thus cleansed, are boiled in diluted unfiltered solutions of jams, jellies, ketchup, and other solid or semi-solid preparations, or in undiluted fruit juices, carbonated beverages, and of wines, the liquid, previous to the boiling being slightly acidified as described below. Arata * was the first to employ dyeing tests in an acid bath in food * Zeits. anal. Chem., 28, 1889, p. 639. 842 FOOD. INSPECTION AND ANALYSIS. examination, but limited his observations to wines. Winton * later found that the method was well adapted to the detection of coal-tar colors in various foods. The method consists in boiling the wool in a dilute solution of the food material to which potassium bisulphate has been added, using lo cc. of a 10% solution of the bisulphate to loo cc. of the solution to be tested. If the color solution is neutral, the wool may first be boiled in this before acidifying, to separate out any basic dyes. The dyed wool, after removal from the solution, is boiled first in water, and afterwards preferably in an alkali-free soap solution. It is then washed and dried. The dried fiber may then be subjected to the various reactions given in the table, pages 854-858, for recognition of the dye. This method of identifying colors by means of reactions on the dyed fiber is one of the most con- venient — in fact Arata's test, supplemented by reactions on the fiber, suffices in many cases of suspected coloring. Some of the vegetable dyes (including lichen colors), also cochineal, dye wool directly, and these may be identified by special reactions. Other vegetable colors, and the natural colors of fruits nearly always give a slight dull coloration or stain to the wool, but this is not, as a rule, to be mistaken for the vivid hues of the coal-tar dyes. Moreover, most of the vegetable colors on the fiber turn green when treated with ammonia. Care should be taken to thoroughly wash the wool after the dyeing, so that colored particles simply held thereon mechanically may be removed. Sostegni and Carpentieri | recommend a method of double dyeing, applicable when acid dyes are employed. The wool is boiled in a solution of the food sample acidulated with hydrochloric acid, after which the fiber is removed and boiled, first in very dilute hydrochloric acid solution, and then in water, till free from acid. The color is next dissolved from the fiber by boiling the latter in a weak ammoniacal solution, some of the colors being more readily dissolved than others. The fiber is then removed from the solution, the latter is acidified with hydrochloric acid, and the color fixed on a fresh piece of wool by boiling therein. Tfie second dyeing fixes coal-tar and lichen colors on the fiber, but fruit colors and most others of vegetable origin remain in solution after this treatment. Any color left on the first fiber, after treatment with ammonia, is probably due to the natural vegetable color of the sample, and is usually no more than a dull stain. * Jour. Amer. Chem. Soc, 22, iqoo, p. 582. t Zeits. anal. Chem., 35, 1896, p. 397. ARTIFICIAL FOOD COLORS. 843 Extraction of Colors from their Solution by Amyl Alcohol. — Methods based on this principle have for years been used in examining wines in the municipal laboratory at Paris* and were found by Wintonf to be adapted for various foods. Sangle-Ferriere uses the following method: 50 cc. of the wine or solution to be tested for color are rendered slightly alkaline by ammonia, and cautiously shaken with about 15 cc. of amyl alcohol. If acid dyes are present, they will be dissolved, and will impart to the amyl alcohol a distinct color. | Basic dyes also are dissolved, but when they are present the amyl alcohol solution is colorless. Remove the amyl alcohol by means of a separatory funnel, wash with water, and finally, if the alcohol is colored, dilute with about an equal volume of distilled water and evaporate on the water-bath with a piece of white wool. The wool should be kept in the solution till the odor of the amyl alcohol has disappeared, and, if not then colored, for a short time longer, as with some colors the wool will dye more readily in the aqueous solution than in the amyl alcohol. Remove the wool, and evaporate the solution to dryness. Test for color in the dried residue, and on the fiber also. Archil and other lichen colors, like the acid colors, is extracted by the amyl alcohol under the above conditions, the color being a light violet. If the amyl alcohol extract after separation, washing, and filtering is colorless, acidify with acetic acid; if a basic color is present, it will be indicated by a coloration at this stage; if there is no coloration on the addition of acetic acid, no basic color is present excepting fuchsin, which is separately tested for. In case a basic dye is indicated, add dis- tilled water and evaporate with wool as before. Test the dried residue with pure concentrated sulphuric acid. Fuchsin is mdicated by a yellow-brown color with sulphuric acid, which by dilution with water becomes rose; safranin, by a green color becoming first blue, then red, when diluted with water, and magdala red by a dark blue color, turning red on the addition of water. Many coal-tar colors are extracted by amyl alcohol in acid solution, but some fruit colors as well as cochineal are also dissolved under these conditions. The coal-tar dyes thus dissolved will, however, dye wool and the fruit colors will not. The test for cochineal in the amyl alcohol solution * Girard, Analyse des Matieres Alimentaires, pp. 183, 681. t Loc. cit. % Acid fuchsin forms an exception to this rule by dissolving colorless like basic dyes. Special tests are given on p. 845. 844 FOOD INSPECTION AND ANALYSIS, is described on page 824. Fruit colors are not extracted from acid or alka- line solution by ether, nor from alkaline solution by amyl alcohol. Extraction of Colors from their Solution by Acetic Ether. — Basic colors are extracted readily, according to Robin, by making the solution to be tested alkaline with sodium hydroxide, and shaking with acetic ether. The solvent is removed, washed, and evaporated with wool (on . which the tests are to be made), or the evaporation is carried to dryness and the tests made on the residue. Separation of Acid and Basic Colors with Ether.* — Rota's Method.— To 100 cc. of the aqueous solution containing the color add i cc. of 20% potassium hydroxide and shake in a separatory funnel with several portions of ether. Basic dyes are dissolved by the ether, leaving behind as a rule the acid colors.f Wash the ether extract with faintly alkaline water, and shake out with 5% acetic acid. Some colors remain in the ether, others are dissolved in the acid. Separate the two solvents, and evaporate each to dryness on the water-bath. The acid colors left in the slightly alkaline, aqueous solution after removal of the basic colors by ether as above, may, if desired, be separated into several groups by successive extraction, as follows: first slightly acidulate with acetic acid and extract with ether, then acidify with hydro- chloric acid and again extract, and finally examine the residual solution for colors that are insoluble in ether. Thus erythrosin and eosin are soluble in ether when shaken with their aqueous solution made acid with hydrochloric acid, while acid fuchsin is insoluble. Separation of Colors from Dried Food Residues by Solvents. — This method is rarely employed, excepting in the case of colors insoluble in water, but soluble in ether or alcohol. The dried pulp' of canned vege- tables, ketchups, etc., may be acidified with hydrochloric acid, and the color extracted therefrom directly with alcohol. In this case, however, there is no obvious advantage over the previous methods of dyeing the fiber directly in the acid solution of the sample. Robin's Test for Acid Colors. — Add to the liquid to be tested an excess of calcined magnesia, and a little 20% mercuric acetate solution, boil, and filter. If the filtrate is colored, or if by the addition of acetic acid to the colorless filtrate a color is developed, a coal-tar dye is indicated. * Analyst, 24, p. 45. t A few acid dyes are exceptional in being soluble in ether with alkali, as for example, qui noli n yellow and the sudans. ARTIFICIAL FOOD COLORS. 845 Girard's Test for Acid Fuchsin.* — Acid 2 cc. of 5% potassium hydroxide to 10 cc. of the wine or other solution to be tested, or enough of the alkah to neutralize the acid. Then add 4 cc. of 10% acetate of mercury and filter. The filtrate should be alkaline and colorless. If the solution remains uncolored after acidifying with dilute sulphuric acid, no acid fuchsin is present. If, however, there is produced a red to violet coloration, and no other coal-tar colors have been found by the amyl alcohol extraction, the presence of acid fuchsin is shown. Bellier's Test for Acid Fuchsin. — Presence of acid fuchsin is indicated by adding to 20 cc. of wine or other solution to be tested about 4 grams of freshly precipitated yellow oxide of mercury, boiling and filtering. The filtrate, if acid fuchsin is present, i? colored red, tinged with violet. According to Blarez, all red coal-tar colors, with the exception of acid fuchsin, and all red vegetable colors are completely decolorized by acidulating their aqueous solution with tartaric acid, and digesting with lead peroxide.! Loomis' Scheme for Preliminary Identification of Colors in Foods.| — This scheme covers certain coal-tar, animal, and vegetable dyes commonly used in foods. The strength of the aqueous solution should be approxi- mately 0.01% for coal-tar colors and 0.1% for animal and vegetable (" natural ") colors. The following reagents are required: Weingartner^s Tannin Reagent. — A solution of 10 grams each of tannic acid and sodium acetate in 100 cc. of water. Hydrochloric Acid. — Equal volumes of concentrated acid and water. Sodium Hydroxide Solution. — Ten grams in 100 cc. of water. Ammonia Water. — Approximately 10% NH3. Lead Siihacelate Solution. — See p. 610. Normal Lead Acetate Solution. — Ten grams in 100 cc. of water. Reactions in aqueous or alcoholic solution are carried out with 10 cc. of color solution and 5 to 10 drops of reagent; unless otherwise noted, each test is made on a part of the original solution. To determine whether a large or small amount is extracted by an immiscible solvent from an aqueous solution, separate the former, filter, evaporate (with addition of water if necessary), take up in water, add a little acid or alkali to correspond * Analyse des Substances Alimentaires, p. 185. t Allen, Commercial Org. Analysis, 4 Ed., Vol. V, p. 250. I Loc. cit., pp. 62-69. 846 FOOD INSPECTION AND ANALYSIS. O § Q - O I" s - 8 ° O 13 <^ -S •-' s H § <; Z U 1-1 W w w H O W u ^ a -d >» >> xi to ^ 00 ^ fcuO g Pi o o o Pi < o u ;? w H Pi • ^ s O ni •^ a M T3 .-: ^ S < -3 3 to O^ '^ T-i -2 5 3 O P .2 o O XI U < P4 o 1-1 o u H W 1-1 O ^ '^ fe, to S K S "^ :i .2 S "o c 9 CJ o ffi 2 + < r1 0) W _2 "o W bjO o --^ '^ ■*-> 2 >» ^ -^ S .S 8 :S cr ^ O ■" B 2a >. ^ -5 d ^-o 8 cr u ^ a ^ xi *^ c ^ 03 o 5 h o 2 3 S 3 tn C rt -^ w lo O IT) 00 lO •* ID <3 ;^ ^ ^ o >> "> CJ u + + OJ t/l tfi 2 :o ° ;^ ^ BQ .a ^ « 5 0) .S PM w 1-^ iz; ^ ;zi 0) » M C/2 2 9 10 rij CQ •3 CO ^ '^ ^ "i bi . . . "^ f 1 .2 ^ M ^ "o « Q ^ c < . "o -a 3 tfi _0J O t« 3 2 O 3 3 O O 3 cr O o ■q. oJ H < O 12; v„ u c« ti^ X! HJ o O c o TJ ii i! :5 i m 2 a, -^ c o ^ -a O TS ni O o o in « -g g >.ii ya U 2 S .S a, 3 60 u e 5 CJ5 bC K ™ a ^ o o . o O is + "u? m aj + -w ^ .- o rt O !-; • r3 fl> o '^ «j tH , C 3 rt rr jU nj O < Q 3 '2 9" aj .ti ^ C ii *i _«' 5 H ca ^ ^" b '-' — a o o o :;2 « -^. -s ii & !" S" fe> tfi > — -s !« "O P -r ^ .-e ^13 C 3-01: i- >,0 ^ g -2 o C O JO "^ -^ JS ^ V ii ±i u O O a; •- •« ^ 2 J ^ H 2 W M a CL, 0) 2 3 • 3 > en 3 tn 3 3 e2 U U 3 CJ -Q bi) 3 « te cr CT ft 8 « « Jz; o ^ o s 3 O c 9 ^ -2 Ki i^ (11 *^ "q, c^ O OJ ;-< CI. il ^ a^ ^ 7? U O ei ^ H 2 II -o + a & -i^ ?« -r S i/i c* — ?r C 3 O O u ^ ^ 2 O -T3 ij & .ii C oi OJ rn SP <" + .2 o; rt s •- p 3 ti "o i 2 C ^ E "Q- T1 ^ ^-^ Lj o -o o •Z ^ t-f.P^Ji.o-s^b^ -= s p J2 ^ u it :2 PQ CJ fL, Q ^ J3 O Ji O .5 O 8 '31 O O rt Q CQ. 2 .s: -« c -3 f~^ "2 O "^ s ^ O Xi '^ ■=■ c :2 O y 00-= T3 =3 CL tuo «3 S a -0 c 1) a he ^ . "5 -s c fc "5 o >. .0 ll 0) 45 & ■" -4-> -C Q 3 "" = O U BQ ARTIFICIAL FOOD COLORS. 849 R5 ° -y ^ w •^■2 H .iii 1^ ►-^ s C/J CO W T3 -G 0) & ■*-l c C ^ i ^ « J ■& o <« 5 :5 ^ o 'xs S 6C ^ ^ -a fcC c pq o *^ H 6 "^ 2 •c o .S H aj «-5 S '-' ^ ^ C« g 3 o o K^ t/3 QJ — . X a «3 cr o -^ s u > S en 6 i ^.5 w ^ ir, lO 1^ ^ O , % uj uj ►-, O £ '3. oj 2 I .^ S S i= -^ ^ (U rJ^ O ^ O O — s ^ -2 cj o -a ^ ^^ ^^ - 1) -^ "-I .« o & o It •2 o , o aj 00 ^ <; (U OJ -a >. o ^ ^ 3 O (D <51 W t3 o H r= r= .9 5 ^ 1-1 2i o o -^ ^^-^ ■^ 1) -o "o r2 O lU in ^ -a o 6 ^ . ^, ctl Q 850 FOOD INSPECTION AND ANALYSIS. ^^ o S 05 tq ftj I P^ O >A O U Q H HH O z QJ u Pd >? ■q O c/} u i3 « "« u >> O ^ o -5 P<4 •i o s ti cr < s s '"i O H O O (J "o 12 '35 c3 «H in O T3 « !& hi ^ E 2 < a, "o o ^ .s P 3 Q o ^ "o BQ (» . S 3 is ^ cd C . ^ > o S >> 02 .S u oj en tn r D & O p s ^ QJ OJ l-i >-i y tfl >-.'■£ *-■ -E ^ OJ >< o =^ .£ >- "o -y — — O 1) c in > o o <-j •- ^ t: o C 33 O .22 .n pi; (3 O *i> 1^ 3 pq ^ ■" ^ ^ -S cr 4J o o d o «' "=^' -X . o *^ SQ o< Os -S. fq u d VO W _o T3 D rt "o c 03 in .o C a; o _3 P- 4j o3 ^^ (U O T3 >> " . , I- <" 2i IH 13 ^ cd J3 CJ .i« O ol :z; Q £ ^ ^ o ^ ARTIFICIAL FOOD COLORS. 851 00 r^ ro O *^ 5S ^ K) a o^ fc. O fc. 0^ •:« O ^fi: ffl Ei O u o .2 o fs f5^ U a " u, o a. M 5 o g .2 ui 2 *-i ^ ^ .00 -^ — "i [fi Q — . oj 3 I- in ^ 1-1 O il a- ^ 3 O S -^ ^ =^ i2 S y S c y T3 o .2 e ^ c c o ■" M cq _ -« C § cq •^ O ^^ ?; ^ -^ ^ 2 o o Td o £ ^ *j _2J > <-J .h o ID 3 CM o Q Q ^ o c a D '" "i n ii 'T3 5 2 o ^ ^ 51 rt S < < d "o ^ go a "o I " •c 2 t- ?r -sen U O BQ K) 3 d ^ i rt .2 c! .ti H-^ 3 .ii in ^ O) & i o o ■ ■ — P-l [iH 1; .3 Si OJ "o C/3 O ffi Ol C cu K ^ T3 Q OJ u O 3 c ?^ CC Ut _c 1-, -a 03 OJ o O "S td "S C CJ "o C C t/: 'S, C C 4) _o o u O {J o _o :: i-i a o "o M "o in 1 2 u 3 s "o ID -a o "o o 3 '5 (U 0. "3 .g o (J -a . C .2 "a 6 3 o tfi • -^ _c ■3 CJ ^ T3 "cS V C a "-' ^ ■n rt > a ^ 6 o U fc .^ ^ !> •^ u > ^ M 1 c3 _C « -3 _>. ^ IH 1m "o J3 IZi X CQ O Q ARTIFICIAL FOOD COLORS. 853 with the aqueous layer, and compare with the latter. Dyeing tests may be made on the solution thus obtained. When the solution is decolorized by acid or alkali during shaking with an immiscible solvent, separate both layers and neutralize both in order to find the relative portions of color in the two. Direct Identification of Colors. — In identifying the colors commonly used in food, it is frequently possible to ascertain the color or group of colors present by making direct tests with various reagents, either on the dyed fiber or on the dry coloring matter, or in a solution containing it. Many tables for this purpose are prepared, but they are never com- plete by reason of the many new dyestuffs constantly introduced. Such tables are to be found in the works of Allen, Schultz and Julius, and Mulliken. While it is true that the limitation of the dyes suitable for pur- poses of food coloring imposes a somewhat lighter task on the food analyst than that on the chemist who has to deal with all varieties of commercial colors, yet it is obviously impossible to make a complete list covering even the restricted field of food colors. Doubtless there are colors long well known that would serve admirably for this purpose, but have never yet been tried. Reactions of Dry Colors or Dyed Fibers.— For the purposes of the food analyst the table of Mathewson* (pages 854 to 858) is well adapted as it includes colors which actually have been found in foods, being the same colors as are also included in the table on pages 868 to 875. The analyst should be provided, for standards, with as complete a collection of known purity dyestuffs as possible covering the colors he is likely to meet with in foods, and should make comparative tests, if the slightest doubt exists. If the unknown color is apparently not found in the table, and the more exhaustive tables are unavailable, it is still possible to locate the dye, by making similar tests on other standard colors sug- gested by the behavior of the unknown color, and carefully comparing them. Most difficulty is encountered when the coloring matters are mixtures instead of simple dyes. In this case it is recommended to resort to syste- matic separation by immiscible solvents as elaborated by Mathewson (page 859). * Separation and Identification of Food-coloring Substances, U. S. Dept. of Agric, Bui. 5, pp. 37-45- 854 FOOD INSPECTION AND ANALYSIS. ^ •- o en E jg e W o w jj 1/5 H < 60^ f/) Q > >> J3 Pi O d rt T3 M O J3 v-j o •- 3 u f^^ >^ n! 0) ■.3 fa ^ * O f!* "" >. rt V,-^ O 1— 1 tx > XI <: •0 K H ■t; p:) H i-T 1 (U 1) X! D Oj OJ CJ 0) 'C rt 1^ •d -d T) ^ M M M •d tu bo u •d bO bo CJ bo bo CJ OJ bo •d ° OJ ^? (U 0) OJ !3 t' •^ -c ^ f M M C _3 C C bo C C bo bo 3 . p bo N .2 .2 !-• C C 0) 3 o> w iH S to a! C n! rt c C Oj CJ 3 V 3 'C tH U T3 'Q (D a! rt X x: x; 0) X X a OJ X •d & CJ CJ OJ a! . _o _o _o .^^ j_^ 60 43 x: C X " u x; X u •d bo "O X S i- "o CD 0) (^ c u CJ OJ OJ CJ ^ CJ CJ OJ Vh 34-0 M CJ d) i> -f-> Cd 2 2; ■,3 en J ^35 Z 2 3 s < c c T) •d -d 1 ^ (D (U ui bo i-c OJ bo c x; bo CJ CJ OJ bo bO •0 2 •d 3 3 .23 ° S> .2o •aw a) (u a) § § § 000 ^ ^ £ J^ :^ _a> Lj Lj "rt ■-1 '-I fL, C C c CJ ® 'S c DO C c a & Ih X5 "3 P OJ & 2 X •d (5 DC M ■4-> •c -n -c 000 "o "o "o 000 1) (U (U POP •si •c ^ n & m '►J c OJ 2 c -? p ©•2 s "3 "3 OJ XI C 0! rt oj x; X J3 " CJ CJ T3 -n ^22 S V 3 u m •d CJ 3 S "3 ■5 ^^ 3 x: OJ S .Sfrt 55 "^ P3 a C C c: c c c & & fe & & fe "S Q •d*^ £ 2 2 2 Ih tH #-. ^ XI -S ft ft 2 u u <^ ° ° s iH 'S Ih X3 Ih ^£S 1 2 2 >. DO DO 1 s s ft ft J3 ^ bO bo C C •d Ih i 3 a •d _>. 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"d CJ ^ DO K 3 OJ 2 bO CJ 3 •d OJ Pi CJ > m .2 > R Ih ^< > > »J f^ "3 2 S m m >H C J N n 10 a M N 00 00 Oi 0\ « Oi vO t- "di 00 10 >* 00 ^ ^ 00 PO ro . c vO fO w ro fO Oi ■* * 00 e> a o> a CO M N M 0\ 00 10 < ■g o u o o ij o ■v; c S; oj o p ^ t: ^ 3 -p 3 W w Q P Q Q ^ -2 C & "d ^ °i ii ''^ •« , > -M ^^ S 0) ■*-> 60 M _^ S ° "^ X > -a " CI - a; > -d J pa ■^ c g j:: >, ol U ■MOV. 60 =3 ^ +J ■^ 3 W Q 0) n1 < c n c jn o J_, u 3 .■S Di ii . - .- .2 « M ^ J3 « -2 S 3-«3 60 ^ 60 4i _■ C p C O > 2 o O 60 3 J!i >d S .2 •S m r '-a -o .^ (5 iS g •s< 0) 0) _3 7i 'n 60 0) 60 •a 0) 60 r.S. c _o C C ^ ^J c o >. o o J3 •s o o di^ V ^j o > > a> Sg 60 _>, P :t^ o^ k4 w ca hJ J _) a •^ OJ ^ O) C3.M p^ o t; >•. c Spa t« '-p^'oj'o >■— ^Eq^kT ^ £ ^ 1 ■n -a T3 +J is ui V -tJ ii; ii o Pi "3 a u o Di "o > o "o > > Pi Qi G) > >^ '2 S .2 > o Pi Q > C > 60 ^ r; «i ■ „ tj .2 J- -d 32 .-S ►^ Pi Q > i ^ e^ Q fa o Pi o I— I > <: w u 0) &> u & & 4) rt ^ 0) M U (U lU 60 t30 OJ o o O 60 (U (U (U O V V 4> 60 -d gz ° 2 ^ o •d ^? bO C bc ta 60 C . c 01 III cfl (u i 1; 60 60 O c c 60 C 60 60 60 60 60 60 60 c -d 0) C c« c c c ^ M C rt C C C C C C C Oj 4J -W .2 IH '^ O rt ^ cs ca -G ^ nJ 0) * rt ^ I- ^ k^ 4) o o X J3 o o o o S o J3 o O o o o 4) ^ ^ ^ o o o o o o X J3 J3 o o o o o o J3 o o " >. 2 5 13 ^ ■z 3 ■z z .J>Z 3 ^ 3 3 o o 2; 3 z 2 2 2; z z z c fe d o •d ■d o (A V M s'^ o _a) 4) 60 ^^ "3 >.'d •d -d .2o "•a 1 ^ 60 60 C C i 60 c ^ -d c ID 60 C ■*-> 60 60 60 C C C 60 60 60 C C C 60 C nJ 60 +^ U "3 Q 60 3 g Z Z Z Z Z Z Z 4J ^ "o ffi s o W ^ •d & ^ ^ & ^ 5 4> 4) Q "o m a o o O OJ u .S'o *^ 3 •o « > +-> > >> s O JJ 3 •d T) o a) 4) 60 >- '- C -M *J ci > 60 C 2 o "3 'c e o _o Vi ^ 4J 4) lU 4) " J* 60 60 60 60 r , c c c c 4) 4) cS cU ca a! 60 60 t-" ^- *- ^^ c c O O O O rt ci u *-. o o o "3 >> c & o l-i J3 _4) "a o o "3 "3 >• >> u & & -d O O 4) 3 3 •3 M c >• S r 1 rt p C J: 2 & ° •? S3 ■d ffl -d (5 S |(2 2:§ 41 ^ S ■d & s £ ca pq Pu Q PU CL, (L, M ^ T3 4) •d •d "d 1. S s >. 4) OJ 1 CJ •s< « •o -0 Td (u §5 0) 60 C o _o X! ^ O 2 o .2 .2 o o t. 4) J3 "o Pi 4) C C See n) o & o "3 "3 ^ >. >. o 4> 4; ^ 60 6D .^ III o 4) ■d o ° fe OOP 41 0) O •d TD ^d —, SO i ^ S ?P p^ 2 g C O O u _3 O O o CJ > > > (^ O W PQ '3 >< S 2 o 11^ S o^ o^ >- O O _s g J^ 2-s K < < < < S ftH PU o o o o •d "d "d (u -d -d •d "d ■£ o •o ^ i "3 "3 & 5 ^ & fe 4J t. (U D ' Ih (-1 V V.2 "3 fe. 4) 4; fe 4J J, ^ 2 2 g 2 -1 >H o o >« o > c o B :s c 60 60 o & =3 o •d V o 60 S C « >. o o 1^^ T3 4) ^ -s t; c ii iJ 2 .2 .2 4J +J '> i 60 c •:- 41 o oi rt O > o > > > > »; 2 ^ S o OO o o ;^ W o 3 C & & & & fe & o >. _4J 5 ^ ■" 5 >. V "5 ii so _4) a rt & & c o'5 -4J ■> 1 c ■q "o > > •a 4i 3 o > o O -W ■!-> s; o o rr> 60 t3 "d C 4) CU o o "3 o _o o "3 "3 "3 c c c & & & 4) 4) 4) 60 60 60 C C C u u u O O O a ^ 2 fe Si 00c & 2 Xi ^1 Pi CQ > o Qpi Pi o o o o ? dl £ bo 4) I-. "3 •5< m o m CQ PQ n o > >. >< ^ a ^ * r^ lO 00 N M p) (V5 o o o o M ~ ^ t» 00 O M ro p) ro o ^ N. 00 >* 00 . c ■5 m Oi 00 a o o M N vO ►H tH M N N CI * ro M VO >0 ro o y. ro 1- * * M M •q- lO N M lO lO 1/) le >n lO to lO lO t", * ■* ■* 'I- ^5 * * « » * * * ARTIFICIAL FOOD COLORS. 857 O < w H Q p o p^ o (n f< O o u >^ Q fa O P^ o t-H > w •a •0 -d "3 "5 -g _ _ 1- V. 1- T) 0) OJ QJ u CL> , 6^ o Q •;3 73 o u '^ O 3 ■2 B E 1 s;^ >;>;>: ||«§ U CO CO < "3 < < d •o o f s'-s •a Si g y -s •d -d -d •d -d •d -d ^" Ui 1^ L- oj u 53 S 1H :3':=: >>>_>•>' s^ O u >> o Q ~ ^ -5 ^ .•s P 2: o (J QPOQOQO 5 5 -c .c w 55 55 55 55 ffi Oh ^ •T3 ■d •d "d •d -d Q "o 0) & 3 ■d 91* u c ■S "S c c V c fe a & & 4J O 3 •d "3 .2 60 > >. Q 'C r. ^s > >. <: 2 2 < < 'a> o 13 bo Id T3 fe .2 •d b 0) •d >> >> c 0) <" :S 5 3 "S "S _o vH "C (U a! " O 1- i i 5 (U (u bo .2 -3! 3 1 OJ 4J 0) fe "o 'S ■§ j5 J5 t-. 0) 0) So £ c c bo bo § IP s s 01 •s ?i-« iJ •« "« fe s 2 00 o "is o i; O E >< i^ -S -d -d "« "« C C "i "^ w 0. 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"3 "3 fc fe 2 2 ° ° ^ 3 5 g g ^ s s o Ih H >H >< >H pq cq >. >% X2 X3 — ° "3 "3 J ^ M M vO O t~ N 00 Oi •* 00 10 t~ 00 J^ M I^ 00 i« Oi Tf N . 13 f^ ^ i^ -^ r* vO vn a ifl ro 00 ^ N N Ifl iO « w w m 0) Ov V (L 0) . si o o o o 2 o Z ii 01 Q 3 s •d 4) Pi ■4^ 1 _4J jj M |j '.J s ^ J c 3t3 C Ofl 6 c bo a bo C aj bo C ■d' 13 4; ■d 3 bo c ft •d •d' I 3 3 O O -tJ C J3 "3 >> ^^ ^ 4J o o (U _a) .2 .2 bo R ca 01 4) Q 3 s •d V Pi Pi ii S c 3 > _4) 3 > % HC J Ij 3 J t5 3 £ M m W 'd T3-d fe 6 &■ & ^< _o o _o _0 3 _3 •d' 3 _3 3 d 4) •d' Q «J 3 >, cm C 01 "3 i bO C i bO "o > > "3 >, > 13 4) 4) d 4) •d' (5 t-. *-> _4) "o d 4) BO 41 3 3 o o 2 2 > Q s > O 3 o o o PQ n! •d d ^ '_3 •d Pi •d c & o PQ bo 2 o "3 Q •d" •d Pi i "3 >. bO C ca t-i •d OJ u > _2 i S _3 s •d' £ ci) bo C ca •d 4) p^ li 4) 3 3 >. BO £ c V ■2 3 3 3 3 > •d £ 4) bo c ca W > & 6 & d d "3 13 o "3 ^' 3 BO c ca u C 3 bo C ca •d 4) -d 4J •d •d' £ i-w >> >. >. ^ ^ S •d 4) tH •d' 1 o « i bo i bo i bo & ^ ? S (S bo 3 (S 41 3 > "q^ • C ClJ 2 c ■3 _o >« m ca 5 £ o o O >H >^ c & o^ o i "3 >, bo C a! > Pi ■4-> "3 > 3 _3 C 41 £ d 4) •d' (2 •d 4) "o > ■*-> _4) 3 '> i 3 S d 4) £ d 41 £ •d' ^< 3 > < o 3 X X ft ca C 3 c "6 si i 3 si cd si ft j: U c "?. Si ca ca ft 4-» 6 'e XI Si X c 41 c ca IS (U rt Si -t-i 4) ft , 'e a "o si ca "ca ■q , J3 ca 3 v^ nl O O c 6 0. c si ft ca c ca 41 5 ft a 'S e J3 c c '3 c CD c 4) ca a Si u ca ca i5 <; O m pq Z P5 a PQ P< o t^ *■ (> 1^ d d n «' ^ -0 ^ ^ fO * « « ♦ * * ARTIFICIAL FOOD COLORS. 859 Separation of Colors by Immiscible Solvents and their Identification. — Mathewson' s Method* — (a) Preparation of the Solution. — Make a 0.05 to 0.01% solution of commercial colors. Take up randies, syrups and other saccharine products in hot water. Evaporate or dilute wines and liquors to less than 10% alcohol content. Extract fruit products, flesh foods, and similar products with 80% alcohol containing a very little acetic acid to remove basic colors, cochineal, etc., and the residue with 65 to 80% alcohol containing 3 to 5% of ammonia. Boil both extracts until the alcohol is reduced to less than 10% and ammonia is nearly removed from the second, then combine. It is often preferable to add strong HCl directly to strongly colored jams, sausage, etc., extract with amyl alcohol, and shake with salt solution and other aqueous solvents. For procedure with cereal pastes see pages 366 to 369 and with butter and other fats, pages 557 to 560. Whatever the method of solution treat the aqueous liquid with sodium carbonate if acid, or with acetic acid if alkaline, until neutral or slightly acid. Suspended matter, other than precipitated dye, should not be present in considerable amount. Too great color concentration (over 0.1%) of food extracts is rarely encountered. Large amounts of sugar, glycerol, etc., affect somewhat the solubilities. (b) Separation. — Since most coal-tar dyes are accompanied by sub- sidiary dyes those present in largest amount should be first carried through until identified. Colors of fruits and flowers being usually unstable, especially in alkaline solution, are best tested for in a separate portion. The table on pages 868 to 875, based on 0.01% concentration, is more useful than an analytical key. The following outline is for complicated .mixtures. Ordinarily the analyst will vary the procedure according to probabilities. A preliminary dyeing test is advisable. 1. Add to the solution NaCl equivalent to 5 to 6% and shake with 20 cc. or more of amyl alcohol, repeating the treatment once or twice if considerable color is extracted. Wash the combined extracts, if colored, once or twice with small portions of 5% NaCl and add the washings, if also colored, together with any suspended matter, to the extracted solution. 2. Add to the extracted NaCl solution half its volume of concentrated HCl and shake with amyl alcohol as before. If the extract is colored wash once with 4N HCl (i : 2) and proceed according to sec. 6; if colorless, even after adding NH4OH, reject as most strongly sulphonated azo colors are absent. For procedure when naphthol green is present see sec. 18. * Loc. cit., pp. 8-53. 860 FOOD INSPECTION AND ANALYSIS. 3. Make the extracted acid NaCl solution, which may be nearly color- less, slightly alkaline with NH4OH, then slightly acid with acetic acid. If then colorless reject as strongly sulphonated triphenylmethane green and blue dyes are absent. If green or blue shake with enough dichlorhydrin to give a lower layer after separation of 20 cc. or less. If a blue color is extracted repeat once or twice, wash the combined extracts with a little NaCl solution and examine according to sec. 5. 4. The solution after the preceding extraction may still contain natural colors (fruits, etc.), acid magenta (No. 462), and large fractions of acid yellows (Nos. 8 and 9) although these latter are chiefly extracted from the acid solution (sec. 2). To detect No. 462 apply the nitrous acid test, dye test, etc.; to separate it add HCl until over N/4, allowing for ammonium acetate, shake with anilin, wash the extract with 5 to 6% NaCl in N/4 HCl, and remove the dye with water. Before testing make alkaline and remove the dissolved anilin with several portions of carbon tetrachloride or benzene. Commercial acid magenta contains various sulphonates and yields derivatives of greater solubility in organic solvents. If the color of the extracted acid salt solution is entirely due to Nos. 8 or 9 it will be orange red, becoming yellow on neutralization. Nitrous acid, etc., give characteristic reactions. 5. Dilute the dichlorhydrin extract (sec. 3) with 3 to 4 volumes of car- bon tetrachloride and remove the color with a few small portions of water. Shake the combined washings once with carbon tetrachloride to remove dissolved dichlorhydrin. The washings may contain higher sulphonated triphenylmethane dyes or sulphonated indulin, with large amounts of subsidiary products. Their solubilities cannot be definitely established. Compare their properties as given in the tables. 6. Wash the amyl alcohol extract of the acid salt solution (sec. 2), if colored, 4 to 5 times with N/4 HCl, keeping the washings separately and reserving the washed solvent for treatment according to sec. 7 or 8. Nos. 108 and 692 predominate in the first washings, which owing to HCl dis- solved in the amyl alcohol, is high in acidity; Nos. 106, 107, and 94 come out chiefly in the third. Vary the procedure according to probabilities. The color of the washings will usually show if more than one dye is present in considerable amount. Separate Nos. 106, 107, and 94 from No. 108 by 2N HCl and amyl alcohol and from Nos. 692 and 8 by 8N H2SO4 and amyl alcohol-gasoline (i : i). Wash Nos. 106, 107, and 94 out of the latter solvent with a little water, add at least half the volume of concentrated HCl, re-extract with amyl alcohol, remove H2SO4 with a few portions of 4 to 6 ARTIFICIAL FOOD COLORS. 861 N HCl, and finally wash out the dye with water and evaporate to dryness on a water-bath. Test with cyanide, etc. Separate >the dyes in the H2SO4 solution with anilin (page 868). Use anilin and 5 to 6% NaCl in N/4 HCI to separate No. 94 from Nos. 106 and 107, removing the anilin from the solutions, after making faintly alkaline, with carbon tetrachloride. No. 692, which like No. 8 is of indefinite composition, may be separated from azo dyes by cautiously adding powdered sodium hydrosulphite (Na2S204) to the acid solution, then shaking with air to restore the blue color. Reduction by this reagent in an ammoniacal solution, avoiding an excess, destroys Nos. 106 and 107 while No. 8 is merely converted into the hydrazo compound and may be restored by shaking with air. No. 692 is destroyed by warming in an acid solution containing a little urea and a drop of 7% sodium nitrite solution, while Nos. 106, 107, and 108 are scarcely attacked. Dyes of this group are much used in foods. 7. Wash the amyl alcohol extract with N/16 HCl same as previously with N/4 HCl. Omit if Nos. 14 and 188 appear to be absent. 8. Dilute the amyl alcohol with an equal volume of gasoline (sp.gr. 0.65) then wash successively 2 or 3 times with N/4 HCl, N/16 HCl, N/64 HCl, N/64 C2H4O2 and N/64 NaOH. Wash with the alkaline solution even if the preceding appear to remove all the color as some weakly acid dyes (mostly of other groups) are nearly colorless in neutral or acid solvents. Study the solubilities as given on pages 869-872 inclusive. When the fractions appear to contain more than one dye, refraction until pure. Test for No. 4 (nearly colorless in acid solution) by adding HCl to the first strongly acid washings until 2N, shaking with washed ethyl acetate, and treating the latter with alkali. If a yellow color is obtained treat in like manner the remainder of the fractions containing it. Reserve the N/64 C2H4O2 and NaOH washings until the neutral NaCl amyl alcohol extract has been tested, as this will contain the bulk of the dyes, or mix these wash- ings with the corresponding ones of sees. 11 and 12, or omit these washings entirely and mix the amyl alcohol-gasoline extract after washing with N/64 HCl with the similar mixture of sec. 10. 9. Chemical methods of separating closely related dyes: (i) cyanide test (page 866) for separating R-salt derivatives (Nos. 55, 56, 65, 15) from mix- tures with isomers; (2) reduction and subsequent oxidation methods for de- struction of azo and nitro colors in presence of most other colors (see pages 866 and 867) ; (3) cautious reduction in Na2C04 or NH4OH solution whereby oxyazo dyes tend to be attacked more rapidly then aminoazo dyes, allowing for new dyes formed by partial reduction of polyazo or 862 FOOD INSPECTION AND ANALYSIS. nitroazo derivatives; (4) bromine oxidation (page 864), halogenated fluores- cin derivatives (fully substituted) being more resistant than most other colors in acid solution and No. 4 than most azo dyes in alkaline solution, but the test is seldom so satisfactory as extraction with ethyl or amyl ace- tate and fails when Nos. 6*2, 64, 65, and 188 are present owing to blue substances formed. 10. Dilute the amyl alcohol extract of the NaCl solution (sec. i), which contains practically all the basic dyes and most acid dyes of low sulphur content, with an equal volume of gasoline, wash a few times with N/64 HCl, and treat the washings, if colored, according to sec. 11. Wash the extract with N/64 C2H4O2 and treat the washings according to sec. 12; then, to remove eosins and (in general) unsulphonated, water soluble, acid (phenolic) dyes, wash with a few portions of N/64 NaOH and treat the washings according to sec. 13. Finally wash once with very dilute C2H4O2 and, if still appreciably colored, evaporate to dryness on the water- bath, and examine the residue according to sec. 14. 11. Make a small portion of the N/64 HCl extract (sec. 10) alkaline with NaOH, shake with ether, and treat the usually colorless ether solution with dilute C2H4O2.* If a color appears, indicating basic dyes, extract the alkaline portion once or twice more to learn if acid dyes are also present. In the presence of both, add NaOH to the main portion until of normal alkalinity, shake with ether, and remove the basic dyes from the combined ether extracts first with N/64 C2H4O2 and finally with dilute HCl. Omit this treatment if acid dyes are absent, since most basic dyes (especially auramin) decompose in alkaline solution. The basic dyes may be further fractioned from amyl alcohol with dilute HCl, from ether with dilute alkali, etc. After removal of the basic dyes with ether add to the alkaline solution HCl to normal strength and shake with amyl alcohol-gasoline. If a color is extracted it will probably be a minor portion of one obtained according to sec. 8 and may be further fractioned with the main portion or separately. Reduce the N HCl to N/4 by adding NaOH and shake with carbon tetra- chloride-dichlorhydrin (3 : i) to extract lower sulphonated triphenyl- methane dyes, then add more tetrachloride and wash out these dyes with water. 12. Fraction any monosulphonated monazo dyes in the acetic acid solutions of sec. 10 (chief part) and sec. 8 (small part) with amyl alcohol and N NaCOs or with ether and dilute HCl. *Witt, Zeits. anal. Chem., 26, 1887, p. 100; Wcingartncr, ibid., 27, 1888, p. 232. ARTIFICIAL FOOD COLORS. . 863 13. The main part of the eosins and unsulphonated water-soluble dyes are found in the N/64 NaOH of sec. 10. Fraction the eosins between N NaOH and amyl alcohol or amyl alcohol-gasoline (3:1). Acid dyes with basic tendencies (Nos. 510, 95, etc.), differ from the others in being extracted in smaller amount from strongly than from weakly acid solutions (pages 871 and 872). The amyl alcohol-gasoline solution (sec. 8) may also contain these dyes although usually in small amount. Most natural colors appear in the N/64 NaOH solution. 14. Moisten the amyl alcohol-gasoline residue (sec. 10) with a small drop of alcohol, add ether, and N/64 HCl, and shake. If the acid layer is colored (rhodamins, possibly basic dyes) wash the ether with further portions. If the ether is colored, wash a few times with 4N HCl, neutralize the washings, and treat according to sec. 15. Finally wash the acid out of the ether with water, evaporate to dryness on the water-bath, and treat the residue according to sec. 16. 15. Dissolve the oil soluble dyes from the neutralized solution (sec. 14) in gasoline and fraction with 70 to 90^ methyl alcohol (page 875). Ortho- tolueneazo-/3-naphthylamine, although decomposing rather rapidly in strongly acid solutions, like its lower benzene homologue, is extracted slowly by acid from an ether solution. Probably the dyes undergo rearrangement before forming water-soluble salts, both forms decomposing by prolonged standing with acid. 16. Add to the ether residue (sec. 14) methyl alcohol, water, and NaOH solution, sufficient to make the alcohol strength 8c% and the alkalinity N/4, and shake with gasoline. No. 666 anda-naphthol derivatives remain chiefly in the alkaline liquid. Treat the gasoline again. If necessary, then according to sec. 17. 17. Separate sudans further with gasoline and 90% methyl -alcohol. Shake the gasoline solution with 85% phosphoric acid to which has been added 10 to 20% of H2SO4, thus separating from oily impurities although with probable destruction of some of the dye. These colors, like those of sees. 15 and 16, may be almost quantitatively removed from gasoline by 90% phenol and purified by redlsolving in alkali and again taking up with ether or gasoline. 18. To avoid decomposition of No. 398 In acid solution, extract the neutral NaCl solution with dichlorhydrin, wash once with benzene to remove the dissolved solvent, make N/2 with HCl, and shake with anilin, adding the latter first. Fraction from the anilin solution with N/4 to N/64 HCl containing 5 to 6% NaCl. 864 FOOD INSPECTION AND ANALYSIS. (c) Bromine Test. — This is useful in examining the fractions for azo and azin dyes in the presence of natural colors. To 5 cc. of the solution (0.005 ^o o-oi%) S'dd drop by drop slightly more 1% bromine water than is required to destroy the dye, then a few drops of 3% hydrazin sulphate solution. To half of the solution add a few drops of freshly prepared 10 to 20% alcoholic a-naphthol and an excess of Na2C03; to the other half only Na2C03. With azo compounds sodium formate may be sub- stituted for the hydrazin salt. The reactions belong in classes as follows: A. Azo dyes which with bromine in acid or neutral solution become colorless, pale yellow or orange and with hydrazin sulphate are colorless, pale brown, or pink, the color being more marked when nearly neutral. With a-naphthol and Na2C03 a pronounced color appears but with Na2C03 alone no marked coloration. If the first component of the original dye was an unsulphonated amin the new color (e) may be removed by ether from the alkaline solution imparting usually an orange color changing with a large excess of strong HCl in most cases to violet or blue; if the new dye (w) is sulphonated it will not be extracted by ether. The new dye may be fixed on wool from a suitable solvent and identified by spot tests. The following dyes belong in this class. A (e) : 14, 21, 20, 53, 55, 56, 146, 154, 13, 54, 157, 26, 10. ^ or C (e) : 7, 18. A (w) : 108, 8, 9, 89, 399, 106, 94, 105, 164, 169, 163, 170, 84, 328, 85, 86, 97, 139, 95, S8, 92, 102. A or AA (w): 107, 93, 103, 139, loi. A or C: 197, 201. A (imperfectly) 318, 287, 220, 269, 240. Of the oil soluble colors in the tables all belong in class A but quinophthalon which in 60% C2H4O2 gives reactions of class B. Class A also includes 277 and 78, the latter requiring addition of some alcohol before a-naphthol. A A. Azo dyes reacting like those of class A in HCl (N/2 or above) solution. In neutral solution the reaction is less trustworthy as other oxidations take place, blue and other colors being produced with Na2C03 alone which, excepting 62, 64, and 65, is less intense than those of the origi- nal dyes. Bromine bleaches 62, 64, and 65 in N/4 Na2C03 but an intense blue appears on adding hydrazin sulphate. A A (e) includes 62, 64, and 65, AA (w), 188. B. Azin derivatives, etc., bleached by bromine in neutral or acid solution, the color being restored by hydrazin sulphate. With typical members the color may be again bleached and restored. Na2C03, also a-naphthol and Na2C03 give no change other than that shown by the original dye with alkali. Class B includes 604, 605, 667, 606, 534, and 562. 546 reacts im- perfectly and 584 belongs to class B or C. ARTIFICIAL FOOD COLORS. 865 C. Dyes giving precipitates at dilutions as high as o.oi%. This class includes most basic dyes. D. Dyes giving marked color changes in neutral or faintly acid solu- tion. As the color usually appears w^ith a trace of bromine and is destroyed by an excess the reactions are unsatisfactory. Hydrazin sulphate produces no color change except that due to removal of excess of bromine. The color v^ith a'-naphthol plus Na2C03 is the same as with Na2C03 alone. Most yellow colors become brownish, other colors usually ill-defined. In acid solution the dye, as a rule, is merely destroyed by bromine same as with class E. Class D includes 434, 435, 436, 480, 507, 438, and 433; class D or C, 496, 427, 428, 505, 499, 504, and 502. E. Dyes similar to those of class D but showing with bromine no change other than bleaching. Class E includes 439, 440, 602, 692, 398, 4, 706. 710, I, 329, 483, 512, 515, 516, 517, 518, 520, 521, 523, 2, 3, 6, 707, 468, 464, 442, 476, and 658, class E or C, 650, 425, 426, 451, 452; class E or D, 491, 462, 639, and 448. F. Halogenated fluorescin derivatives and similar dyes very resistant to bromine. Non-fluorescent iodine compounds tend to become yellower and develop a green fluorescence. No. 510 gives eosin. ((/) Nitrous Acid Test. — Most common coal-tar dyes in dilute solution do not react readily, but some show marked changes due to diazotization of free amino groups, formation of nitroso compounds, or direct oxidation. To the water solution add 2 to 3 drops of strong HCl and i to 2 drops of "]% sodium nitrite solution. Add i cc. or an excess of 3% hydrozin sulphate solution, after standing a few minutes in case of blue and green dyes. To half of the solution, after \ to i minute, add a few drops of alco- holic cK-naphthol solution and Na2C03 to strong alkaline reaction ; to the other half for a check add only Na2C03. The following gives reactions; others in the table pages 868 to 875 show no color changes except those due to the acid or alkali. 462: NaN02, blue, then colorless; a-naphthol — Na2C03, orange. 439: NaN02, yellow. 491: NaN02, violet (slowly). 8: NaN02, much paler; a-naphthol — NaCOs, deep blue (Hesse). 9 : NaN02, much paler; a-naphthol — Na2C03, red (Hesse). 89: red solution; NaN02, yellow; hydrazin sulphate, red again. 692: NaN02, slowly oxidized to yellow isatin derivative. 398: NaN02, brown. 21: NaN02, slightly darker; a-naphthol — Na2C03, dull green black. 318: NaN02, pale and redder. 480: NaN02, slowly attacked. 84: NaNO 2, redder. 507: NaN02, bluer. 85: NaNO 2, paler. 95 and 88: HCl, crimson; NaNOo, yellow; hydrazin sulphate, crimson. loi: NaN02, paler. 220 and 229: 866 FOOD INSPECTION AND ANALYSIS. NaN02; slightly paler. 562: scarcely attacked; in 50% acetic acid NaN02 gives same change as bromine. 584: NaN02, blue; hydrazin sulphate, red, 448: a-naphthol — Na2C03, wine red; in acetic acid solu- tion, NaN02, first blue, then colorless. 427: NaN02, reddish. 17 and 18: NaN02, paler; a-naphthol — Na2C03, redder. 505, 499, 504, 502: may appear bluer with a-naphthol — Na2C03. 16: NaN02, slowly de- stroyed. 7 and aminoazotoluene : NaN02, paler; other reagents red. (e) Cyanide Test. — This is based on the reaction, discovered by Lange, of the second component of certain ortho-azo dyes with KCN the 3-sulphonic group being replaced by cyanogen. Heat 10 cc. of the color solution, I cc. of 20% KCN solution, i cc. of 20% NH4CI solution in a test-tube in a boiling water-bath for 5 to 8 minutes. Carry along tests with known dyes at the same time. The common nitro dyes become brownish or red- dish, certain azo dyes react as follows : 108 : warmed 8 minutes dye nearly all changed to orange or yellow substances; warmed until dark red (i to 2 minutes), strongly acidified, and washed with 2 N HCl, practically no color removed; subsequent washing with N/4 HCl, blue red dye removed. Azorubin S. G.: apparently unchanged by cyanide. 106: solubility un- unchanged but much color destroyed on long heating; 10 cc, amyl alcohol extracts the color from the cyanide mixture acidified with 5 cc. cone, HCl and gives it up to N/4 HCl. 107: cyanide mixture pale brown; treated same as 106, color remains largely in amyl alcohol; color destroyed on long heating, 14, 20, 21, 52, 53, 62, 64: dye unchanged; cyanide mixture acidified with i cc, glacial C2H4O2 gives up little color to 5 to 10 cc. amyl alcohol. 15, 55, 56, 65: cyanide mixture pale brown; treated like pre- ceding dyes, gives up most of the color to amyl alcohol. (/) Reduction and Reoxidation. — The reagents are those introduced by Green, Yeomans, and Jones. Drop into the neutral solution a few particles of powdered sodium hydrosulphite (Na2S204). If no color change appears at once, warm and add more reagent, avoiding an excess. If reduction and consequent decolorization takes place shake thoroughly with air and, if no color reappears, warm and allow to stand a few minutes. If still practically colorless drop in a little potassium persulphate. Dis- regard slight yellowish or brownish tints produced by air or persulphate. The reactions with most of the dyes on pages 868-875 belong in three classes : A. Decolorized (or nearly) with hydrosulphite; remain colorless (or nearly) with air and persulphate: 108, 8, 9, 89, 106, 107, 94, 398, 198, 14, 20, 93, 53, 55, 105, 4, 56, 62, 64, 65, 103, 139, 164, 163, 84, I, 328, 85, ARTIFICIAL FOOD COLORS. 867 13, 86, 97, 54, 329. 139. 157. 95' 88, 92, loi, 102, 26, 220, 269, 2, 3, 10, 240, 197, 201, 17, 18; slowly decolorized, 21, 287, 78; bluer, then decolor- ized, 318, 169, 170, 146, 154; browner then decolorized, 277. B. Decolorized with hydrosulphite but original color restored by air or persulphate: 440, 692, 483, 468, 464, 650, 639, 584, 448, 451, 452, 427, 428. The following are nearly decolorized with hydrosulphite or change to the colors noted and the original color is restored with persulphate : nearly decolorized, 462, 710, 438; slowly paler, 439, 442; much paler, 480, 510; much paler (with excess), 512, 515, 516, 517, 518, 520, 521, 523; pale olive, 602; pale orange, 604, 605; pale yellow, 606. The following are nearly decolorized with hydrosulphite and the color is partly restored with persulphate: 434, 435, 491, 496. C. No change with hydrosulphite: 399, 667, 706, 546, 507, 707, 658, 425, 426, 505, 499, 504, 502. No. 476 is not readily reduced. Certain dyes do not belong in any of the preceding classes: 436 becomes very slowly paler'with hydrosulphite ; 6 becomes dark, then pale and with persulphate pale reddish; 433 is paler with hydrosulphite and greener with persulphate; 534 and 562 in alkaline solution become red (slowly) and yellow respectively with hydrosulphite and the colors are restored by per- sulphate. 868 FOOD INSPECTION AND ANALYSIS. w a o u m '^ o H < CD ^ Q r/1 m ^ O nt H 13 ^ o w eq I— I u PH l-i m rt CO 4) Tl (li (U O ►-] >> O OJ u •o -2> uk ■^ o fi z CD o w 1— 1 H •n O < cl oi "V H d >^ u w «« O^. < or. Si ^ O^ 3 o n! 3 S 6-2 iT 4 ro • "^ O ^••|oe Zn a)T3 00 Oi o 6 Fi • -o o i:2; o. oj :' r^ o o "o.ti 0! . Moo o Z O O CTi •sz U <^-i ■^6 u CO V^ c CO Xi CO B < Off . " cO-O O 0) OV-C!0 1-i 00 5 cuic M 'a-°° aZ '^ n o t^ Z St^o 4^h'-i -*j ™ CO o, •^2;^^J".z . c ° O " iH t/5 •- o a> o^Z~ Z "1 -" ^ cO\.<» 3 u « O g'^. rt t- ° ^ o >^ *^ ctJ N 2 "• I" S CO O .ii C Q) o ■<-■ O .5 .-i^ 1 o ^ O O) O O 4J w a, Z ei, ^ (U o»; o .S ^^^ !o I >• ^ ^ 2, Si .•-'60'^ 00 Ov Oi M u B >" _>^ 6 -3 c S o 0.2 u ••J C^ "MO •o ARTIFICIAL FOOD COLORS. 869 ^'^< "Oi •^ 1= c o S^ -=-d h o " •• °«2 7-. 2; w 3 1 Ale line ( [rom Solut -^o _ tj as o <3 J3 O . •9 •* rtvo CZ 4J ca Vh -.6 J* 2; < z O^ 3 (U ii CUI ao (D >> c o c 01 60 01 W) Oi .a CIS >.& ^ c % >. (U . x: !3 o j: +J S. - ►J m y. M J '4. >- w Oj Q O V. g o Ola ;=; OJ PiS rt 0) (-. > O ^ V -r P PQ S S WWW PQ O 6 E •o O < < :z; o Sm Ji O •" i3 ?! ^ a Ol dc a, ft, 2: Z,V 870 FOOD INSPECTION AND ANALYSIS. O I— I H O C/3 m O I— I > (4 O hJ O o o o I— I H U Amyl Alcohol- Gasoline (I : I) from N/64. NaOH Solution. s lU •* A c c I'd— "^ <- S t; ■d 1 . (U a c oj^"^ ago -2 aa rt •- a> < ^ Z 2 -M _^ "n 3il 2 vO •- DO ?° --S=55 ^.^=3 < 2; ^rt« C § 4) -:i-s^°iL E|.SS!g"i^«2 *:> g.Q M 60 CTa 4) < '►J lU 4) S S -S >.s-g .C j: > C ,„ .XI JS VI ^ u Darker, nally No cha Same ai Darker Darker nally violet Little c (4 .-S --Ti.ti 2; J w J _0J "»3 s fc T) -d .2 S S >3 60 .S .a g « m w S C 60 c m lilt. 1 >i W K t-. > •d ■3 > vl 3 & s . ^ a ■^> lU *;> 0) r\ ?, a c e ein scarle xtra oline yell ;er solubl ein scarle rich scarl eaux G rein yell( £ CI C 3 ■4J .2 3 2 1 s ^ ^ -s u w 2 'B&S .2 S S s ^ I d v^ a 'u N 'C N cu clh m < Ph m CQ p^ PQ <: w < ^5 « N •* lO ro a ■<*• t~ .Oi to ■>!• -0 r~ 00 10 %o ^o ro -0 vO t^ 00 ■«t 00 t^ »^ * « * M M M IH M M *H M «^ « « * « * '~' ARTIFICIAL FOOD COLORS. 871 o Pi < > o oi H > o w « u Ether from N/64 NaOH Solution. u 1 tj ►4 Amyl Alcohol- Gasoline from N/64 NaOH Solution. •3" "o ^ 1-1 ■3 ^ as.2 _4J l-i^Z^ E E < CO < or- n- on ilorid from on. a E o u "ca 1 tn '^ 2 « — 01^ -M t? u ^ a >>^ "■ — w Ethe from HCl lutio 0)<< „ ■* 3 o t 6 <: a ^-w Pi AmylAlcoh Gasoline (1:1) f roi N/64 C2H4O2 Solution. _5> 57, more than hal others le; than hal 3 " ■3 E . J3 4) J2 C t^ u N, more than half; N/16, half or less; N/64, smaller part •H^ •d "a bo u o--'~— 2 S W^ HI x; . . - .J2 ■Is S j;.S" ^ d E g^ :2;5 Mj3 4) 3S \myl Icohol from HCl ilution. ■^ -1 vo^E < c^ 2 "* "" 1^ d CD 0.C.5 (-• S^ci ■•5 c "'■« ■(3 term etwei edini ucce roup u E •53JD u) 00 rt ►4 5 & s & & m _ i^S-2 1 1 rt bor3 ca >> V a, > ffi 2 t; ffi c "s _>. .a J +-» ft c« ft ►J 2"^ ^ u a •3^ >>o •0 1 ^ -M O — ■« 2 ^ m CO ►,« c — "-^ -2j3 ■*^-.^ g 2 2 2 2" O ^ _^ ^ P-H o t w> H * Tl- 2; o "o •* J5 "is > (5 ►4 2 > "o ^ _>. IlL w P5 U < C •a =3-^ in ^o S r- "^ (-• 1— 1 el iC.2 <3 o rt ^ 2 to s "3 Q o 1 o';3 "rt "iS 01 a "3 o — sz ° < o 4J u at < hJ 2 K 2 & & & & & c^ _o _o _p _g c ;jh U CO "3 "oj CJ __ ^ "s '3 ^c. o § 1— 1 H Pi •d s a; 4) >. cm C 2 s G l-dTJ-o-d C 4) . V V ? Si, ScQ pa C 2 - 2« .2'S2 >piO U "o O "o a •d 0) m 'S ■it c 'a Pi o« •S .s.s § --PPg S? oj "qj "3 >. 3 .3 c V- 3 C ta CD oj M w rt 1° u '-'";!£>. >.'=' a ^< N 1ht3 z CJ V. PS t3 J3 X o^ CC^ OWmWWO, 00 .y piW Pi > S 3 < '•S 3 3 "c" M M N r<5 0. N mot- 00 M n N i^ 'J-t^O ►5« o> 00 11 « M M >->lH M NO N * t<1 « * H Tt 10 « M mm 1/1IO lo U5 10 m ■^t^* ^ t * * * o ♦ * • ARTIFICIAL FOOD COLORS. 873 o I— I H != h-1 o tn o < > o H > O w h-1 P3 I— I U O u o o H O < H a Dichlorhy- drin- Carbon Tetrachlorid from N/64 C2H4O2 Solution. : I, nearly all; I : J. half or more " - 1 i her N/6 OH tion. u 4J - nl m .•s C ►4 •d Tt Ether from N/6, HCl or C2H4O2 Solution. ►J iJ "o „ Tf ^ ^ ^lo^Kg l-i 0! a 01 t-l ol a 1 AmylAlc Gasol (I : from N NaO Soluti .2 13 _4) B lU c 2 en j -p C "3 -r _ 0. u E en U HI > o a < > fVmylAlcoh Gasoline (I :i) from N/6 C2H4O2 Solution. _5j "3 Xi u > 0. p4 "o ■* 0. ■6 -6 _2 AmylAlcoh Gasoline (I :i) from N/6 HCl Solution. "a ■Sft +3 OJ oj a "■d .2 u > 13 E ES t- •d 0) lU > S 0] 0! IS C >, ^. i?-d^- OJ rf •t •^ •d V- +j 43 < 2=^ ^=3 0. 1 "o ^ I, "3 >> . frorr tral htly . sol. 13 •n'B 13 e2 w ca 2 Extd neu slig alk S ft 2" -d Si c & ^ g 01 ^ M 4J 4J "o "o > > 4> s CQ Oi 2 § 1 -sLl-sl m S >- P^m>P^u ffl 0) ffl ■* 3 ■ -0 DO 3 oJ e E 'T^ bo J3 0! c IP Methyl Congo z 1 ^ BO Z, '5 00 ■^ 00 *c t- « 00 vO 0. 'too ^ ti -4 t^ xO w 0.10 fOOO M- 6 u <* t N M 10 -O TOxO >« •* ^;s * * * 874 FOOD INSPECTION AND ANALYSIS. O I m '^ O I— I H O in O < > o m > o oi w hJ P5 I— I O P3 m O o u o o I— I H U H X "3 6 « -0.2 . 0) 0. 2"*^ E 2^^ o u ft u ■3 >> c u c "^ -\ Z z"^ Z z z Z • " o •-"^ o S c •d u O u 1 ^s ^ +j tj J M 1 --^ >« I*-, c 3 O < 11 £^« 4J U ft u c ■3 1 c4 4^ "3 S 1 (U o 13 ol V Z Ci ^ "^ « C8 &•• t ^ « 4J .^ .c ^•-EW-2 1- ft c a, ■a *-> ft iJ t- ft c3 ft u ci E V 'a E (U "3 E w >-) o iiK o ^e'^ Eiw < "3 E 2 w 2 "^sj •a •a •a -a -^s & & ^ ■*-> c C c c u V §£ U V V V V r=;^-i _o _o ^ — & & c 5 V V zi u tg "3 "S o "o u ^ o Hi « _3 3 3 3 > > > > o c a ca o o 5 5 S 5 - ei _o c c c c O o o c c 'i "e > *-> "> o u DO 1) e £ Pi c .5 (25 C c c E c4 "a IS o o 5 5 "o o 'e nl •a 'e 'e 'e •a T3 2 3 3 < < 4) O — Pi « Pi c lo o H* „ r- 00 t^ w r^ 00 u^ o» ^ « «* o N M lO o. o 0. s. s ■t •* •^ t •^ tr in ^ 10 10 Z ^- ^ * » » ♦ ♦ S * * • * • • ARTIFICIAL FOOD COLORS. 875 1 o I— I Pi < > o C/) H > CO W m u C/3 n CO p^ O hJ O U o o l-H H U < H X a *s ^ Ji 4^ l-< (3 0) t o ^o "rt Oi n) a J3 >H ij a rt 4J '(3 lis u _>■ l^^ 3 O — '3 >> _u 4J tl] 0^ J3 a 1) OJ c ^Z < > w > J z 3 ^ ■*-» l-l l-< +-» lU 0) rt tU CJ wi o n ♦J 0. a CO ft "3 Gd >, '•^ s '•^ _>. 3 O 1^ 11 >- ^< 0) > a a u > Z s;g a> u t QS3 o P, — Ih 4^ ft iH "3 ft u •s^ CO Sj3 V "3 a "3 a cd •o "o ►J > en w > ►J z hJ 0) •§ % o t ■s ^ -e < fe5 o OJ s 0) _ft 0! ft ft CA (U Oi n > •;3 >. u > ■3 1 "3 3 o s 4-> J a a a < -. .J^ ^"rt ■* -o 1 •3 il wo z'^ Z^ 3 w e ° .6 Z rt Z2 Co « ol Zft •o-' i^ |ozg < "o 3 u 3 8 „ 3 S a a ^ 00 a a u ■ "o ">. +^ "o X M X -*J 1 1 .0 1^ x: •0 6 ^ ■z Color Value. 1 Per Cent ! of Total Color in Lead Filtrate. Ratio of Red to Yellow. Extract (Total Color). Lead Filtrate.* 030 Variety of Bean. 13 -d (U Pi v Jo a 13 cm. 23 15 19 22 10 16 22 10 16 23 II 16 21 10 15 % 0.20 o.is 0.17 0.22 0.13 0.18 0.21 0.16 0.19 0.30 0. 16 0.22 0.31 0.12 0.18 0.23 0.19 0.21 0.08 0.07 0.08 % 0.68 0.47 0.58 0.63 0.44 0.52 0.60 0.4s o.si 0.63 0.40 0.50 0.74 0.40 0.59 0.58 0.49 0.52 0.67 0.S7 0.62 56 19 32 55 22 30 SO 22 33 47 25 34 40 22 31 50 42 46 61 40 48 45 44 44 17 15 16 42 S 5 S 56 IS 32 17 4 9 154 55 97 127 65 94 162 77 107 148 85 III 140 70 99 ISS 117 134 195 I4S 162 177 130 ISO SO 40 4S 107 19 18 19 177 40 102 62 21 32 2.0 i.o i.S 2.4 1-4 1.9 3.4 1.0 1.8 2.6 1.4 2.0 2.6 1.4 1.9 2.6 1.8 2.3 7.6 1.4 4-3 3.2 2.4 2.9 0.6 0.6 0.6 1.4 O.S o.S O.S li 1.8 0.5 O.I 0.3 8.0 4.8 6.5 8.2 S.8 7.0 14.6 S-O 7.9 ii-S 6.2 8.7 12.6 6.0 7.7 10.4 6.8 8.S 32.6 6.4 18.2 13.4 10.4 13. I 3.5 3.1 3.3 6.6 2.4 2.4 2.4 14.6 3.1 7.6 2.2 0.8 1.2 % 6 4 5 8 4 6 7 4 5 7 i 8 5 6 6 4 S 12 4 8 7 5 6 4 4 4 3 10 10 10 8 4 6 7 2 3 % 9 5 7 10 S 8 9 6 8 9 6 8 9 6 8 6 6 6 17 4 II 10 6 8 8 7 8 6 13 13 13 10 5 8 6 2 4 I : 3.8 2.6 3.1 3.9 2.3 3.2 3.6 2.5 3.2 3.5 2.7 3-2 3.8 2.8 3.2 3.1 2.5 2.9 3.6 3-2 3.4 3.9 3.0 3-4 3.0 2.7 2.9 2.5 3.8 3.6 3.7 3.9 2.3 3.2 5-7 2.5 3.4 i: 5.6 4.0 4-S 5.0 2.8 3.8 5.0 4.0 4-S S-i 3-5 45 5.3 3.4 4.1 4.0 3-5 3.8 4.6 4.1 4-3 4-3 4.1 4.2 5.8 5-2 5-5 4-7 4.8 4.8 4.8 5.8 2.8 4.2 6.5 3.0 4.6 24.4 19.0 21.2 16 30.3 21.3 26.6 Seychelles 9 29.4 22.7 25.6 Madagascar 9 30.3 23.2 26.8 16 30.3 20.4 26.7 South American. . . 3 29.4 20.0 23-3 3 20 12 16 20 10 IS 50.0 22.7 36.1 3 0.24 0.61 0.22 0.44 0.23 O.'JO 35. 7 32.2 34 5 Tahiti 2 0. II 0. II 0. II 0.06 o.so 0.44 0.47 0.S2 0. 11 0. II O.II 0.74 0.40 0.S4 O.II 0.03 0.05 18.8 16.0 17.4 Vanillons Tonka Beans t- • • • I 2 22.2 31.2 30.3 30.8 All Analyses t 71 23 10 16 23 10 16 0.31 0. II 0. 19 0.07 O.OI 0.03 35.7 25-5 All Analyses J (2d Extraction) 71 * Calculated to volume of extract. t Coumarin: Maximum, 0.27%; minimum, 0.22%; average, 0.25%. J Excluding Ceylon, Vanillons, and Tonka Beans. 916 ■ FOOD INSPECTION AND ANALYSIS. COMPOSITION OF AUTHENTIC VANILLA AND TONKA EXTRACTS Variety of Bean. Acidity of Extract, cc. N/io Alkali per loo cc. Mexican: Maximum. . . Minimum. . . Average Bourbon: Maximum. . . Minimum. . . Average Seychelles: Maximum. . . Minimum . . . Average Madagascar: Maximum. . . Minimum . . . Average Comores: Maximum. . . Mmimum . . . Average South American Maximum. . . Minimum. . . . Average Ceylon: Maximum. . . Minimum . . . Average Java: Maximum. . . Minimum . . . Average Tahiti: Maximum . . . Minimum . . . Average Vanillons Tonka beans: Maximum. . . Minimum . . . Average All Analyses: * Maximum. . . Minimum . . . Average 52 42 46 51 35 40 42 35 39 47 42 45 47 34 40 52 44 49 49 33 39 52 45 33 30 31 38 5 5 5 52 30 42 o 35 26 31 39 14 28 37 32 35 45 28 34 37 30 33 26 23 24 34 5 5 5 42 14 30 Ash, Gram per 100 cc. 0.422 o. 297 0.359 0.373 0.263 0.317 0.316 0.251 0.293 0.326 o. 220 o. 284 0.432 o. 229 0.333 0.344 0.30s 0.32s 0.443 0.361 0.409 0.349 o. 290 0.3II 0.288 0.221 a. 254 0.263 o. 132 o. 163 0.147 0.432 o. 220 0.319 v2 0.349 o. 246 0.301 0.319 o. 220 0.259 o. 262 0.213 0.243 0.271 0.193 0.239 0.3S7 o. 182 o. 272 0.29s 0.261 0.276 0.386 0.313 0.354 o. 299 o. 246 0.26s 0.249 0.179 o. 214 o. 214 O. 122 o. 156 0.139 0.3S7 o 179 0.26s 0.073 0.037 0.058 0.080 0.043 0.058 0.058 0.038 0.050 0.060 0.027 0.045 0.037 0.061 O.OS4 0.044 0.049 0.060 0.048 0.05s 0.050 0.044 0.046 0.042 0.039 0.040 0.048 o. 010 0.007 0.008 0.081 0.027 0.054 Alkalinity of Ash, cc. N/io Acid per 100 cc. S3 36 45 47 35 40 47 34 39 46 34 39 54 45 42 38 40 56 43 49 49 38 42 37 ■30 33 38 IS 16 IS 54 30 42 40 29 35 34 25 27 30 24 27 13 26 28 38 30 26 28 44 33 38 38 31 34 29 23 26 30 14 t* Excluding Ceylon, Vanillons, and Tonka beans. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 917 The Tonka Bean forms the basis of many of the cheaper so-called vanilla extracts on the market. It is the seed of the large tree, native to Guiana, known as Dipterix (or Coumarouna) odorata. The pods arc almond-shaped, and contain a single seed, from 3 to 4 cm. long, shaped like a kidney bean, of a dark-brown color, having a thin, shiny, rough, brittle skin, and containing a two-lobed oily kernel. Coumarin (CgHgOa), the active principle of the Tonka bean, is the anhydride of coumaric acid. It occurs in the crystalhne state between the lobes of the seed kernel. Coumarin occurs also in many other plants. It may be extracted from the beans by treatment with alcohol. It crys- tallizes in slender, colorless, needles, melting at 67° C. It has a fragrant odor and burning taste. It is very slightly soluble in cold water, but readily soluble in hot water, ether, chloroform, and alcohol. One pound of cut beans yields by alcoholic extraction about 108 grains of coumarin. The latter may be synthetically prepared by heating salicylic aldehyde with sodium acetate and acetic anhydride, forming aceto-coumaric acid, which decomposes into acetic acid and coumarin. The author has found that an aqueous solution of coumarin, unhke vanillin, forms a precipitate when iodine in potassium iodide is added in excess, the precipitate being at first brown and flocculent, afterwards, on shaking, clotting together to form a dark-green, curdy mass, leaving the liquid perfectly clear. U. S. Standards. — Vanilla extract is the flavoring extract prepared from the vanilla bean, with or without sugar or glycerin, and contains in 100 cc. the soluble matters from not less than 10 grams of the vanilla bean. Vanilla bean is the dried, cured fruit of Vanilla planifolia Andrews. Tonka extract is the flavoring extract prepared from tonka bean, with or without sugar or glycerin, and contains not less than 0.1% by weight of coumarin extracted from the tonka bean, together with a correspond- ing proportion of the other soluble matters thereof. Tonka hean is the seed of Coumarouna odorata Aublet {Dipteryx odorata (Aubl.) Willd.). The Adulteration of Vanilla Extract consists chiefly in the use of coumarin or extract of the Tonka bean, and in the substitution of artifi- cial vanillin, either alone or with coumarin, for the true extractives of the vanilla bean. Imitation vanilla flavors more often consist of a mixture of either tincture of Tonka or coumarin with vanillin in weak alcohol, colored with caramel, or occasionally with coal-tar colors. Or the exhausted marc from high-grade vanilla extract is macerated with hot water and extracted, the extract being reinforced with 918 FOOD INSPECTION AND ANALYSIS. artificial vanillin or coumarin, or both. A pure vanilla extract possesses certain peculiarities with regard to its resins and gums that distinguish it from the artificial, or indicate whether or not it has been tampered with. While it is possible to introduce artificial resinous matter in the adulterated brands with a view to deceiving the analyst, it is almost impossible to do this without detection, since different reactions are readily apparent in this case from those of the pure extracts. Prune juice is said to be used to give body and flavor to vanilla extract. The writer has found spirit of myrcia or bay rum in a sampk of alleged vanilla extract, containing also vanillin and coumarin. The adulterant in this sample was present to such an extent as to be unmis- takable by reason of the odor. Factitious Vanilla Extracts are ordinarily indicated (i) by the presence of coumarin, (2) by the peculiar reactions of the resinous matter, or by the entire absence of these resins, (3) by the scanty precipitate with lead acetate, and (4) by the abnormally low or high content of vanillin. The following figures show the content of vanillin and coumarin in a few typical cheap " vanilla " extracts, selected from a large number examined by the author. All of these were entirely artificial, and ranged from 5 to 20 per cent by weight of alcohol. Vanillin, Coumarin, Per Cent. Per Cent. A 0.040 0.074 B None 0.172 C None 0-330 D 0.250 None E., 0.025 0.144 As a rule these cheap artificial preparations possess considerable body and flavor, but the latter is of a much grosser nature than the genuine vaniUa extract, with the delicate and refined flavor of which they are not to be mistaken by any one at all familiar with both varieties. Winton and Bailey* have found as high as 2.55% of vanillin in imitation extracts. They also have detected the presence of acetanihde in amounts varying up to 0.15%. This substance at one time was extensively employed as an adulterant of vanillin, hence its presence in imitation extracts prepared from such vanillin. It is not only worthless as a flavor, but is a menace to health. * Conn. Agric. Exp. Sta., Rep. 1905, p. 131. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 919 In the limits of composition for standard vanilla extract given on page 915, the range in vanilla content is from o.ii to 0.31%. METHODS OF ANALYSIS OF VANILLA EXTRACT Detection of Artificial Extracts. — The presence of coumarin or Tonka tincture to any appreciable extent in vanilla extract is usually recognizable by the odor, to one skilled in examining these flavors. The odor of cou- marin is more pungent and penetrating than that of vanillin, and in mix- tures is apt to predominate over the milder and more delicate odor of vanillin. Add normal acetate of lead solution to a suspected extract. The absence of a precipitate is conclusive evidence that it is artificial. If a precipitate is formed, much information may be gained by its character. A pure vanilla extract should yield with lead acetate a heavy precipitate, due to the various extractives. The precipitate should settle in a few minutes, leaving a clear, supernatant, partially decolorized liquid. If only a mere cloudiness is formed, this may be due to the caramel present, and in any event is suspicious. Examination of the Resins. — Resin is present in vanilla beans to the extent of from 4 to 11 per cent, and the manufacturer of high-grade essences endeavors to extract as much as possible of this in his product. This he can do by the use of 50% alcohol, in which all the resin is readily soluble, or by employing less alcohol and relying on the use of alkali to dissolve it. A pure extract free from alkali should produce a precip- itate, when a portion of the original sample is diluted with twice its volume of water and shaken in a test-tube. When, moreover, the alcohol is removed from such an extract, the excess of resin is naturally precipitated. The character of the resins extracted from the vanilla bean is so dif- ferent from that of other resins as to furnish conclusive tests, worked out by Hess * as follows: 25 to 50 cc. of the extract are de-alcoholized by heating in an evaporating- dish on the water-bath to about one-third its volume. Make up to the original volume with water, and, if no alkali has been used in the manufacture of the preparation, the resin will be in the form of a brown, flocculent precipitate. To entirely set free the resin, acidify, after cooling, with dilute hydrochloric acid, and allow to stand till all the resin has settled out, leaving a clear supernatant liquid. The resin may be quantitatively determined, if desired, by filtering, wash- , * jour. Am. Chem. Soc, 21 (1899), p, 72.1, 920 FOOD INSPECTION AND ANALYSIS. ing, diying, and weighing, but in this case should stand for a long time before filtering. The resin is collected on a filter, washed, and subjected to various tests. A piece of the filter with the attached resin is placed in a beaker, containing 'dilute potassium hydroxide. Pure vanilla resin dissolves to a deep-red color, and is reprecipitated on acidifying with hydrochloric acid. Dissolve another portion of the precipitate in alcohol, and divids the alcoholic solution into two portions, to one of which add a few drops of ferric chloride, and to the other hydrochloric acid. Pure vanilla resin shows no marked coloration in either case, but foreign resins nearly all give color reactions under these conditions. Tannin. — Test a portion of the filtrate from the resin for tannin by the addition of a few drops of a solution of gelatin. A small quantity of tannin only should be indicated, if the extract is pure, a large excess tending to show added tannin. Determination of Vanillin and Coumarin. — Modified Hess and Prescott Method. — This process, in its original form devised by Hess and Prescott,* has been modified by Winton, collaborating with Silverman, f Bailey,J Lott,§, and Berry, || in order to prevent loss of coumarin, detect the presence of acetanilide, and permit the determination of normal lead number in the same weighed portion. It depends on the principle that ammonia water, acting on the ether solution of vanillin and coumarin, forms with^ the aldehyde vanillin a compound soluble in water, but does not affect the coumarin, which remains in solution in the ether. "Weigh 50 grams of the extract directly into a tared 250-cc. beaker with marks showing volumes of 80 and 50 cc, dilute to 80 cc, and evapo- rate to 50 cc. in a water-bath kept at 70° C. Dilute again to 80 cc. with water and evaporate to 50 cc. Transfer to a loo-cc. flask, rinsing the beaker with hot water, add 25 cc. of standard lead acetate solution (80 grams of C. P. crystallized lead acetate, made up to one liter), make up to the mark with water, shake, and allow to stand eighteen hours at a temperature of from 37° to 40° C, in a bacteriological incubator, in- a water-bath provided with a thermostat, or in any other suitable apparatus. * Jour. Am. Chem. Soc, 21, 1899, p. 256. t Ibid., 24, 1902, p. 1128. X Ibid., 27, 1905, p. 719. § A. O. A. C. Proc. 1909, U. S. Dept. of Agric, Bur. of Chem., Bui. 132, p. 109. II U. S. Dept. of Agric, Bur. of Chem., Circ. 66. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 921 Filter through a small dry filter and pipette off 50 cc. of the filtrate into a separatory funnel. If a determination of normal lead number is desired, pipette off 10 cc. of the filtrate into a beaker, and proceed as described on page 925. In the latter case, the water used throughout the process should be boiled until free from carbon dioxide. If coloring with caramel is suspected determine the color value of the original extract and the filtrate (p. 926). To the 50 cc. of the filtrate in the separatory funnel, add 20 cc. of ether and shake. Draw off carefully the aqueous liquid, together with any ether emulsion and then remove the clear ether solution to another sepa- ratory funnel. Repeat the shaking of the aqueous liquid with ether three times, using 15 cc. each time. Shake the combined ether solutions four or five times with 2% ammo- nium hydroxide, using 10 cc. for the first shaking and 3 cc. for each subsequent shaking. In drawing off the ammoniacal solution, care should be taken not to allow any of the ether solution to pass through with it. Reserve the ammoniacal solution for the determination of vanillin. Transfer the ether solution to a weighed dish and allow the ether to evaporate at room temperature. Dry in a sulphuric acid desiccator and weigh. If the residue is pure coumarin, it should have a melting- point of 67° C, respond to the Leach test, and be completely soluble in three or four portions of petroleum ether (boiling-point 30° to 40° C), stirring with each portion fifteen minutes. If a residue remains in the dish after decanting off the last portion of the petroleum ether solution, acetanilide should be looked for (p. 925). Add to the ammoniacal solution 10% hydrochloric acid to slightly acid reaction. This should be done without delay, as the ammoniacal solution on standing grows slowly darker with a loss of vanillin. Cool, and shake out in a separatory funnel with four portions of ether, as described for the first ether extraction. Evaporate the ether solution at room temperature in a weighed dish, dry over sulphuric acid, and weigh. The residue should be pure vanillin free from any appreciable amount of color and with a melting-point of 80° C. If the percentage of vanillin is not desired, and coumarin only is to be separated for gravimetric determination, the author has found that good results are usually obtained by simply treating the dealcoholized original sample with ammonia, extracting it with 3 or 4 portions of chloroform in a separatory funnel, and evaporating the combined chloroform extract in a tared dish at a temperature not exceeding 60° in the oven. 922 FOOD INSPECTION AND ANALYSIS. Many of the precautions employed in carrying out the above processes for vanilHn and coumarin determination may be dispensed with if these substances are simply to be tested for qualitatively. Determination of Vanillin. — Folin and Denis Method."^— This method is based on the fact that vanillin (as well as other mono-, di-, and tri- hydric phenol compounds), when treated in an acid solution with phos- photungstic-phosphomolybdic acid, gives on addition of an excess of sodium carbonate, a beautiful deep blue color. It yields accurate results, requires but 5 cc. of the material, and is exceedingly rapid. An analyst familiar with the process can make ten or twelve determinations in an hour, whereas, working under favorable conditions, he would not be able to make the same number of determinations by the Hess and Prescott method in less than three days. For inspection purposes the latter method has the advantage that the vanillin and coumarin are obtained in crystalline form for sub- sequent tests; furthermore coumarin, normal lead number, and color value of the lead filtrate are determined in one weighed portion. 1. Reagents, (a) Standard Vanillin Solution. Dissolve o.i gram of pure vanillin in water and make up to i liter. (b) Phosphotungstic-phosphomolybdic Acid Reagent. To loo' grams of pure sodium tungstate and 20 grams of phosphomolybdic acid (free from nitrates and ammonium salts) add ico grams of syrupy phosphoric acid (containing 85 per cent H3PO4) and 700 cc. of water. Boil over a free flame for one and one-half to two hours, cool, filter, if necessary, and make up with water to i liter. An equivalent amount of pure molybdic acid may be substituted for the phosphomolybdic acid. (c) Sodium Carbonate Solution. Prepare a solution of the c.p. salt, saturated at room temperature. (d) Lead Solution. Dissolve 50 grams each of basic and neutral lead acetate in water and make up to i liter. 2. Process. Pipette 5 cc. of the extract or substitute into a graduated loo-cc. flask, add about 75 cc. of cold tap water and 4 cc. of lead solution, make up to the mark with water and shake. Filter rapidly through a folded filter paper and pipette 5 cc. of the filtrate, corresponding to 0.25 cc. of the extract, into a 50-cc. graduated flask. Into another 50-cc. graduated flask pipette 5 cc. of the standard vanillin solution, which volume contains 0.0005 gram of vanillin. To each flask add from a pipette 5 cc. of the phospho- tungstic-phosphomolybdic reagent, directing the stream against the neck * Jour. Ind. Eng. Chem., 4, 191 2, p. 670. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 923 in such a manner as to wash down any adhering vanilHn. Shake the flasks by a rotary motion, allow to stand for five minutes, then fill to the mark with saturated sodium carbonate solution. Thoroughly mix the con- tents of the flask by inverting several times and allow to stand for ten minutes in order that the precipitation of sodium phosphate may be com- plete. Filter rapidly through folded filters and compare the color of the deep-blue solutions, which must be clear, in the colorimeter. In this, as in all colorimetric methods, a slight cloudiness of the solution of the unknown, by cutting off more light than the standard, gives a low reading and correspondingly high result. Calculate the grams of vanillin per loo cc. as follows: P = ^ = — o.2^r 5^ in which P is the grams of vanillin per loo cc, R is the reading of the standard solution and r is the reading of the unknown solution in the colorimeter. Estes Method."^— 1. Alcoholic Extracts.— To 5 cc. of the vanilla extract in a 50-cc. graduated flask, add 6 cc. of water and 1.5 cc. of acid mercuric nitrate reagent, prepared by dissolving metallic mercury in twice its weight of concentrated nitric acid (sp.gr. 1.42) and diluting with 25 times its weight of water. Make up at the same time a standard solution, using 5 cc. of 1% aqueous vanillin solution, 6 cc. of water, and 0.5 cc. of the reagent. Heat the two flasks in boiling water for twenty minutes, cool rapidly, make up to the mark, filter, and compare the intensity of the violet to violet red colors formed. 2. Non-alcoholic Extracts. — Proceed as above except that i.o cc. instead of 1.5 of acid mercuric nitrate reagent is used. Detection of Coumarin. — Leach Test. — The residue, believed to be coumarin, obtained by the Hess and Prescott method, is identified by the following test: Add a few drops of water, warm gently, and add to the solution a little iodine in potassium iodide. In presence of coumarin a brown precipitate will form, which, on stirring with the rod, will soon gather in dark-green flecks. The reaction is especially marked if done on a white plate or tile. Wichmann Test.-\— Dilute 25 cc. of the extract with 25 cc. of water, slightly acidify, if alkaline, with sulphuric acid, and distil to dryness. To * Jour. Ind. Eng. Chem., g, 191 7, p. 142. t U. S. Dept. of Agric, Bur. of Chem., Bui. 95, 1912. 924 FOOD INSPECTION AND ANALYSIS. the distillate, containing the vanillin and coumarin, add 15 to 20 drops of I : I potassium hydroxide, hastily evaporate to 5 cc, transfer to a test- tube and heat over a free flame until the water completely evaporates and the residue fuses to a colorless, or nearly colorless mass. Cool the melt and dissolve in a few cubic centimeters of water, transfer to a 50-cc. Erlenmeyer flask and acidify slightly with 25% sulphuric acid. Finally distil the solution (which should not exceed 10 cc.) into a test-tube contain- ing 4 or 5 drops of neutral 0.5% ferric chloride. If coumarin is present in the original extract, a purple color will develop, the intensity being proportional to the amount of coumarin. The Dean Modification * eliminates saccharin and salicylic acid as interfering substances in the foregoing test. Dealcoholize 25 cc. of the sam- ple or use the residue from the alcohol determination, add 5 cc. of ammonia water, and shake with 15 cc. of ether in which vanillin, salicylic acid, and saccharin are insoluble in the presence of ammonia, while coumarin is readily soluble. Separate the ether layer, evaporate to dryness on a water- bath, add 5 drops of 50*^1 potassium hydroxide solution, dry carefully, fuse at the lowest possible temperature taking care to avoid blackening. Dissolve the mass in a few cc. of water, acidify with dilute sulphuric acid, and shake vigorously in a test-tube with 5 cc. of chloroform. Remove the chloroform with a small pipette, filter through a small plug of cotton, add I to 2 cc. of water containing i to 2 drops ferric chloride solution, and shake, noting whether or not a purple coloration is formed. Vanillin and Coumarin Crystals under the Microscope. — These sub- stances are best examined when crystallized from ether solution, and several crystallizations may be found necessary, before the best results are obtained. For examination, pour a few drops of the ether solution of the purified vanillin or coumarin directly on a slide, and allow to evapo- rate spontaneously. Under best conditions vanillin crystallizes from ether in long, slender needles, often radiating from central points, or forming star-shaped bundles. Coumarin crystals are shorter and thicker than vanillin. With polarized light pure vanillin crystals give a brilliant play of colors between crossed nicols, even without the selenite plate, while pure cou- marin ciystals without the selenite are almost lacking in varying colors, and show very little play, even when the selenite is employed. This sharp distinction is not true when crystallized from chloroform. * Jour. Ind. Eng. Chem., 7, 1915, p. 519. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 925 Determination of Normal Lead NumheT.—Winion and Lott Method.^— Mix the lo-cc. aliquot of the filtrate from the lead acetate precipitate, obtained in the determination of vanillin and coumarin (p. 921), with 25 cc. of water, boiled until free from carbon dioxide, and a moderate excess of sulphuric acid. Add 100 cc. of 95% alcohol, and mix again. Let stand overnight, filter on a Gooch crucible, wash with 95% alcohol, dry at a moderate heat, ignite at low redness for three minutes, taking care to avoid the reducing flame, and weigh. The normal lead number is calculated by the following formula : ^_ . 00x0.683. (5 -IF) ^^^^^^^^_^^^ 5 in which P = normal lead number, 5 = grams of lead sulphate corre- sponding to 2.5 cc. of the standard lead acetate solution as determined in blank analyses, and W = grams of lead sulphate obtained in 10 cc. of the filtrate from the lead acetate precipitate, as above described. The standard of the lead acetate solution as determined by blank analyses does not change appreciably on standing; it should, however, be checked from time to time, especially if the bottle is opened frequently, thus permitting absorption of carbon dioxide. In all steps of the process only water free from carbon dioxide should be used. Pure vanilla extract of standard strength should have a normal lead number not less than 0.40. Dilution diminishes the number propor- tionately. For example, a mixture containing 50'^ of vanilla extract should have a normal lead number not less than 0.20 and so on. Determination of Acetanilide.— TFmto« and Bailey Method. — If in the determination of vanillin and coumarin (p. 921) a residue is found after thoroughly stirring the coumarin with three or four 15-cc. portions of petroleum ether and decanting off the liquid; allow this residue to stand at room temperature until apparently dry and finish drying in a sul- phuric acid desiccator. Weigh and deduct the weight from that previously obtained, thus obtaining the true amount of coumarin. The residue, if acetanilide, should melt at 112° C. and respond to Ritsert's tests as given below. If aeetanilide is found in the coumarin it will also be present in the vanillin, although in smaller amount. Dissolve the weighed residue of impure vanillin in 15 cc. of 10% ammonium hydroxide solution, shake twice with ether, evaporate the ether solution at room temperature, dry * U. S. Dept. of Agric, Bur. of Chem., Bui. 132, 1910, p. 109; Circ. 66. 926 FOOD INSPECTION AND ANALYSIS. in a sulphuric acid desiccator, and weigh. Deduct this weight from the weight of impure vanillin, thus correcting for the amount of acetanilide present. The total weight of acetanilide is found by adding the weight of the portion separated from the coumarin to that separated from the vanillin. Ritsert's Tests for Acetanilide.* — Boil the acetanilide, obtained as described above, in a small beaker for two or three minutes with 2 to 3 cc. of concentrated hydrochloric acid, cool, divide into three portions, and test in small tubes (4 to 5 mm. inside diameter), or by spotting on a porce- lain plate, as follows: (i) To one portion add carefully i to 3 drops of a solution of chlorinated lime (i : 200) in such a manner that the two solutions do not mix. A beautiful blue color formed at the juncture of the two liquids indicates acetanilide. (2) To another portion add a small drop of potassium permanganate solution. A clear green color is formed if any appreciable amount of acetanilide is present. (3) Mix the third portion with a small drop of 3% chromic acid solu- tion. Acetanilide gives a yellow-green solution, changing to dark green on standing five minutes, and forming a dark blue precipitate on addition of a drop of caustic potash solution. These tests are conclusive only when taken in conjunction with the melting-point. Determination of Glycerol. — The presence of any considerable quantity of glycerol is apparent by the character of the residue obtained on evapora- ting 5 grams to dryness, in the determination of total solids. The residue, if glycerol is present in notable amount, appears of a moist consistency, even when a practically constant weight has been attained at 100° C. To determine glycerol, proceed as with wines (page 734). Determination of Alcohol. — Measure out 25 cc. of the sample, dilute to 50 cc. with water, and distil off about 20 cc. into a 25-cc. graduated receiver. Make up to the mark with water, determine the specific gravity at 15.6°, and find from the alcohol table the per cent corresponding. Cane Sugar and Glucose are determined as in the case of preserves and jellies. Detection of Caramel. — Lead Acetate Method. — Dealcoholize, precipi- tate with lead acetate, and filter, as described for the determination of vanillin and coumarin (page 920). If the extract is pure, the filrate will * Pharm. Ztg., 2,2,, 188S, p. 383. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 927 be light yellow; if colored with caramel, the filtrate will be yellow brown or deep brown, according to the amount present. More definite conclusions may be reached by determining the color values of the original extract and the lead acetate filtrate in terms of yellow and red of the Lovibond scale and calculating the ratio of the two colors, also the percentage of each color remaining in the filtrate. The reading of the extract is made in the i-inch cell after diluting 2 cc. to 50 cc. with 50% alcohol, while that of the filtrate is made directly in a i-inch cell or, if very dark in i- or ^-inch cell. Color Insoluble in Amyl Alcohol. — Evaporate 25 cc. of the extract on a water-bath until no odor of alcohol is apparent and the liquid is reduced to a thick sirup, then proceed as described on page 785. Determination of Acidity. — Total. — Dilute 10 cc. of the extract to 200 cc. and titrate with N/io alkali, using phenolphthalein as indicator. Calcu- late to 100 cc. of extract. Vanillin Acidity. — Multiply the percentage of vanillin by C5.8. Determination of Ash. — Total. — Evaporate 10 cc. of the extract in a platinum dish and burn below redness. Solubility and Alkalinity of Ash. — See page 657. Coal-tar Colors are detected by the usual tests (pages 840 to 875). LEMON EXTRACT. Spirit or essence of lemon of the National Formulary and former editions of the Pharmacopoeia, is a 5% solution (by volume) of lemon oil in deodorized alcohol, colored with lemon peel. This preparation was dropped from the eighth revision of the Phar- macopoeia, and Tinctura limonis corticis or tincture of lemon peel added. The following are the directions for the preparation of the latter as given in the ninth revision : Lemon peel, grated from the fresh fruit 500 grams To make 1000 mils Prepare a tincture by type process ilf , macerating the drug in 1000 mils of alcohol and completing the preparation with alcohol. Use purified cotton as a filtering medium. U. S. Standards. — Lemon Extract is the flavoring extract prepared from oil of lemon, or from lemon peel, or both, and contains not less than 5% by volume of oil of lemon. 928 FOOD INSPECTION AND ANALYSIS. Oil of Lemon is the volatile oil obtained, by expression or alcoholic solution, from the fresh peel of the lemon {Citrus limonum L.), has an optical rotation (25° C.) of not less than +60° in a loo-mm. tube, and contains not less than 4% by weight of citral. Terpendess Extract of Lemon is the flavoring extract prepared by shaking oil of lemon with dilute alcohol, or by dissolving terpeneless oil of lemon in dilute alcohol, and contains not less than 0.2% by weight of citral derived from oil of lemon. Terpeneless Oil of Lemon is oil of lemon from which all or nearly all of the terpenes have been removed. The U. S. standard for lemon extract (5% of lemon oil by volume) is a fair one. In fact there are commercial extracts on the market containing as high as 12%. An extract of lemon to contain 5% of lemon oil must contain at least 80% by volume of alcohol, lemon oil being insoluble in dilute alcohol. Deodorized, or puriiied alcohol, com- monly known as cologne spirits or perfumers' alcohol, is used in the highest-grade preparations, since the odor of ordinary commercial alcohol produces a slightly deleterious effect. Adulteration of Lemon Extracts. — For making a cheap extract the cost of the lemon oil is not so important an item as that of the alcohol, and as little as possible of the latter is employed, though pure oil is doubtless used. These terpeneless extracts are made by rubbing the oil in carbonate of magnesia in a mortar, stirring in slowly a little strong alcohol, and allowing the mixture to soak for some time. A varying amount of water is added a little at a time, and the whole is shaken and again allowed to stand, sometimes for a week, before filtering. Finally the extract is filtered, and the coloring matter added, consisting sometimes of turmeric tincture and sometimes of coal- tar dyes. In these cheap extracts the per cent of alcohol often runs below 40, and as little as 4.5% by volume of alcohol has been found by the author in a commercial extract. With less than 45% of alcohol by volume, no appreciable amount of oil is dissolved, only a portion of citral, though such preparations are sometimes bottled as " pure extract of lemon." Time and again manufacturers have protested to the author that the purest oil was used by them, when notified that their brand contained no oil, or when prosecuted in court, and were with difficulty convinced that the trouble with their goods was that, on account of weak alcohol employed, the lemon oil used failed to get into the final product. It is true that a certain taste or odor of the lemon is present, even in cheap varieties wherein no oil is found, due to the fact that FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 929 even dilute alcohol, when slowly percolating through the magnesia in which the oil is finely distributed, does abstract therefrom a certam amount of citral, which is, however, but a mere shadow of the sub- stance and body possessed by a strong alcoholic solution of oil of lemon. In many instances, where formulas appear stating the name and per cent of ingredients, these formulas are entirely deceptive and mis- leading, in that the statements are not borne out on analysis. The flavor of the cheap extracts is sometimes reinforced by the addition of such substances as citral, oil of citronella, and oil of lemon- grass, but minute quantities only of these pungent materials can be used, not exceeding /o.33% in the case of citral, ando.i% in the case of the two last mentioned oils. Cane sugar and glycerin are sometimes found. U. S. P. tincture of lemon peel owes its color to natural substances extracted by the alcohol. This color, however, readily fades on exposure to light. Other coloring matters employed are largely coal-tar dyes, and occasionally tincture of turmeric or saffron. During 1901 practically all the brands of lemon extract sold in Massa- chusetts were collected and analyzed. 167 samples were examined, representing about 100 brands, and 139 samples were classed as adul- terated, based on 5% lemon oil as a standard, and depending on whether or not the contents conformed to the labels on the bottles. The typical analyses, given in tables on page 930, are selected from the tabulated results of the above examination.* Forty-two samples contained no lemon oil, ranging in content of alcohol from 4% to 45%. METHODS OF ANALYSIS OF LEMON EXTRACT. A. S. Mitchell was the earliest among food chemists to systematically examine lemon extract, and to him are due the methods for determining oil of lemon, as well as various other tests now adopted provisionally by the A. O. A. Ct Detection of Lemon Oil in Alcoholic Lemon Extract. — If on adding a large excess of water to the extract no cloudiness occurs, the oil may *An. Rep. Mass. State Board of Health, 1901, p. 459; Food and Drug Reprint, p. 41. t Jour. Am. Chem. See, 21, 1899, p. 1132; U. S. Dept, of Agric, Bur. of Chera., Bui. 65, p. 73; Bui. 107 (rev.), p 159. 930 FOOD INSPECTION AND ANALYSIS. LEMON EXTRACTS OF STANDARD QUALITY. Polarization Lemon Oil, Specific Alcohol, in 2oo-mni. Per Cent by Gravity at Per Cent by Foreign Ingredients. Tube. Volume. 15.6° C. Volume. 30.8 9.1 0.8280 84-39 Turmeric 26.0 7.6 0.8402 80.49 23-5 6.9 0.8352 81.74 Dinitrocresol 21.8 6.4 0.8396 82.88 20.0 5-9 0.8335 84.24 18.0 5-3 0.8268 86.82 17.0 5-0 0.8496 80.06 INFERIOR OR ADULTERATED LEMON EXTRACTS. Polarization Lemon Oil, Specific Alcohol, in 200-mm. 1 er Cent by Gravity at Per Cent by Foreign Ingredients. Tube. Volume. 15.6° C. Volume. 14.0 4-1 0.8592 77.62 Dinitrocresol 12.2 3-6 0.8644 76.08 < ( II. 3-1 0.8620 77-50 A coal-tar dye 9-9 2-9 0.8615 77-90 8.0 2-3 0.8531 81.61 Dinitrocresol 6.8 2.0 0.8416 87-55 Tropffiolin 5-0 i-S 0.8832 71. 10 < c 3-5 I.O 0.8939 67.68 2.8 0.8 0.8995 65-23 Dinitrocresol 2.2 0.6 0.8941 67.69 " 1-4 0.4 0.9136 59-40 A nitro dye 0-3 O.I 0.9408 46.40 Dinitrocresol 0.0 0.0 0-9937 4-49 Tropseolin -8.0 0.0 Invert sugar 27.0 0.0 27.49 Cane sugar 0.0 0.0 47-35 Oil other than lemon fairly be inferred to be absent. The degree of cloudiness produced is proportional to the amount of lemon oil present. Determination of Lemon Oil in Alcoholic Lemon Extract. — Mitchell Polarization Method. — Polarize the undiluted extract in a 200-mm. tube at 20° C. Divide the reading on the Ventzke scale by 3.4, and if cane sugar or other optically active substances are absent, the quotient expresses the per cent of lemon oil by volume. With instruments reading in circular degrees, divide the rotation in minutes at 20° C. by 62,5, If the Laurent instrument with sugar-scale is used, divide the sugar-scale reading by 4.8. Cane sugar, though rarely found in lemon extract, is occasionally used in small amount. It is said to aid in the solution of the oil. If it is present, wash the solid residue from 10 cc. of the sample (dried on a water-bath) with three portions of 5 cc. each of ether, to remove waxy FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 931 and fatty matters, dry and weigh the residue of cane sugar, deducting 0.38 from the reading for each o.i^c of sugar so found. Mitchell Precipitation Method. — Pipette 20 cc. of the extract into a Babcock milk-flask, add i cc. of dilute hydrochloric acid (i : i); add 25 to 28 cc. of water previously warmed to 60° C; mix, and stand in water at 60° for five minutes; whirl in a centrifuge for five minutes; fill with warm water to bring the oil into the graduated neck of the flask, and repeat the whirling for two minutes; stand in water at 60° for a few minutes, and read the per cent of oil by volume. WTiere the oil of lemon is present in amounts over 2%, add to the percentage of oil found 0.4% to correct for the oil retained in solution. Where less than 2% and more than 1% is present, add 0.3% for correction. Save the precipitated oil for the determination of refraction. When the extract is made in accordance with the U. S. Pharma- copoeia, the results by the two methods just given should agree within 0.2%. To obtain per cent by weight from per cent by volume, as found by either of the above methods, multiply the volume percentage by 0.86, and divide the rei:ult by the specific gravity of the original ex- tract. Howard's Modification of MitchelVs Precipitation Method.^ — Pipette 10 cc. of the extract in a Babcock milk bottle, and add in the following order, 25 cc. of cold water, i cc. hydrochloric acid (specific gravity 1.2), and 0.5 cc. chloroform. Close the mouth of the bottle with the thumb, and shake vigorously for not less than one minute. Whirl the bottle in a centrifuge for one and one-half to two minutes, thus forcing the chloro- form and oil to the bottom of the bottle, and remove all but 3 or 4 cc. cf the clear supernatant liquid by means of a glass tube of small bore connected with an aspirator. To the residue add i cc. of ether, agitate thoroughly, plunge the bottle to the neck in a boiling-water bath, holding at slight angle, and rotate in the bath for exactly one minute. This step is best carried out by removing one of the small rings from a water- or steam-bath and holding the bottle in the live steam. The ether serves the purpose of steadily and rapidly sweeping out every trace of chloroform with- out appreciable loss of oil. Finally, cool the bottle, fill nearly to * Jour. Am. Chem. Soc, 30, 1908, p. 608. 932 FOOD INSPECTION AND ANALYSIS. the top of the neck with water at room temperature, centrifuge for one- half minute, read the column of separated oil to the top meniscus, and multiply the reading by two, thus obtaining the per cent of oil. This method may also be used for determining the oil in extracts of orange, peppermint, clove, cinnamon, and cassia, employing in the case of the heavier oils dilute sulphuric acid (i : 2), instead of water, in filling the bottles before the last centrifuging. Determination of Lemon Oil in Non-alcoholic Lemon Extract. — The following methods are applicable to extracts consisting of emulsions of lemon and other essential oils in mucilage of acacia, tragacanth, karaya, or other gums with or without glycerol. Boyles Precipitation Method.^ — Measure 10 cc. of the emulsion into a graduated cylinder, transfer as much as possible to a 50-cc. flask, rinse the cylinder with lo-cc. portions of 95% alcohol, and with the aid of a glass rod transfer all of the emulsion and precipitated gum to the flask. Fill to the mark, shake thoroughly, and let stand about thirty minutes. Filter through a folded filter and determine the oil in a 20-cc. portion of the filtrate as in alcoholic extracts. Multiply the per cent of oil found in the filtrate by five to obtain the per cent of oil in the original emulsion. The method is applicable also to orange, almond, anise, and nutmeg extracts of the non-alcoholic type. Boyles Distillation Method.^ — Measure 10 cc. of the extract into a graduated cylinder and transfer it by means of about 35 cc. of water to a side-neck distilling flask and distil with steam into a ico-cc. cassia flask. Since only 95% of the oil is recovered the amount found must be multiplied by 100 and divided by 95. The method is also applicable to non-alcoholic orange and peppermint extracts, in the latter case the amount recovered is divided by 90 instead of 95. Determination of Alcohol. -Mitchell has shown that the difference in specific gravity between oil of lemon and stronger alcohol is not so great, but that a very close approximation to the true percentage of alcohol in lemon extracts may be obtained from the specific gravity itself, assum- ing, of course, that foreign substances, such as sugar, glycerol, etc., are absent. In the absence of such foreign substances determine the specific gravity of the sample, ascertain from the alcohol tables on pages 690 to 703 the per cent of alcohol by volume corresponding. This gross figure * Jour. Ind. Eng. Chem., 10, 1918, p. 537. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 933 includes the lemon oil, the per cent of which should be deducted for the correct per cent of alcohol. In the absence of oil of lemon, a measured portion of the original sample may be distilled, and the percentage of alcohol determined from the distillate in the usual manner, but when lemon oil is present, this should first be removed by diluting 50 cc. of the extract with water to 200 cc. exclusive of the oil In the sample, and shaking the mixture with 5 grams of magnesium carbonate in a flask, filtering through a dry filter, and determining the alcohol by distillation in a portion of the filtrate. The result is multiplied by four to correct for the dilution. Determination of Total Aldehydes. — Chace's Method* — i. Reagents. ■ — (a) Aldehyde-free Alcohol. — Allow alcohol (95% by vol.) containing 5 grams of metaphenylene diamine hydrochloride per liter to stand for twenty-four hours with frequent shaking. Previous treatment with potassium hydroxide is unnecessary. Boil under a reflux cooler for at least eight hours, allow to stand overnight and distil, rejecting the first 10 and the last 5 per cent which come over. Store in a dark, cool place in well-filled bottles. Twenty-five cc. of this alcohol, on stand- ing for twenty minutes in the cooling bath with the fuchsin solution (20 cc), should develop only a faint pink coloration. If a stronger color is developed, treat again with metaphenylene diamine hydro- chloride. (b) Fuchsin Solution. — Dissolve 0.5 gram of fuchsin in 250 cc. of water, add an aqueous solution of sulphur dioxide containing 16 grams of the gas, and allow to stand until colorless, then make up to i hter with distilled water. This solution should stand twelve hours before using, and should be discarded after three days. (c) Standard Citral Solution. — Use i mg. of c. p. citral per cc. in 50% by volume aldehyde-free alcohol. This solution deteriorates on standing, and should not be kept over three or four days, 2. Apparatus. — {a) A Cooling Bath. — Keep at from 14 to 16° C. The aldehyde-free alcohol, fuchsin solution, and comparison tubes are to be kept in this bath. (6) Colorimeter. — Any form of colorimeter, using a large volume of solution and adapted to rapid manipulation, may be used. The comparison may also be made in Nessler or Hehner tubes. * Jour. Am. Chem. Soc, 28, 1906, p. 1472. U. S. Dept. of Agric, Bur. of Chem., Bui. 122, p. 32. 934 FOOD INSPECTION AND ANALYSIS. 3. Manipulation. — Weigh in a stoppered weighing flask approxi- mately 25 grams of extract, transfer to a 50-cc. flask, and make up to the mark at room temperature with aldehyde-free alcohol. Measure at room temperature and transfer to a comparison tube 2 cc. of this solution. Add 25 cc. of the aldehyde-free alcohol (previously cooled in a bath), then 20 cc. of the fuchsin solution (also cooled), and finally make up to the 50-cc. mark with more aldehyde-free alcohol. Mix thoroughly, stopper, and place in the cooling bath for fifteen minutes. Prepare a standard for comparison at the same time and in the same manner, using 2 cc. of the standard citral solution. Remove and compare the colors developed. Calculate the amount of citral present and repeat the determination, using a quantity sufficient to give the sample approximately the strength of the standard. From this result calculate the amount of citral in the sample. If the comparisons are made in Nessler tubes, standards con- taining I, 1.5, 2, 2.5, 3, 3.5, and 4 mg. should be prepared, and the trial comparison made against these, the final comparison being made with standards between 1.5 and 2.5 mg., varying but 0.25 mg. It is absolutely essential to keep the reagents and comparison tubes at the required temperature. Comparisons should be made within one minute after removing the tubes from the bath. Where the comparisons are made in the bath (this being possible only where the bath is glass), the standards should be discarded within twenty-five minutes after adding the fuchsin solution. Give samples and standards identical treatment. Determination of Citral. — Hiltner's Method."^ — i. Reagents. — (a) Metaphenylene Diamine Hydrochloride Solution. — Prepare a 1% solution in 50% ethyl alcohol. Decolorize by shaking with fuller's earth or animal charcoal, and filter through a double filter. The solution should be bright and clear, free from suspended matter and practically colorless. It is well to prepare only enough solution for the day's work, as it darkens on standing. The color may be removed from old solutions by shaking again with fuller's earth. {b) Standard Citral Solution. — Dissolve 0.250 gram of c. p. citral in 50% ethyl alcohol and make up the solution to 250 cc. (c) Alcohol. — For the analysis of lemon extracts, 90 to 95 per cent alcohol should be used, but for terpeneless extracts alcohol of 40 to 50 per cent strength is sufficient. Filter to remove any suspended mat- * Jour. Ind. Eng. Chem., i, 1909, p. 798. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 935 ter. The alcohol need not be purified from aldehyde. If not prac- tically colorless, render slightly alkaline with sodium hydroxide and distil. 2. Apparatus. — The Schreiner colorimeter (page 66) or Eggertz tubes may be used. With this latter apparatus, alcohol is added, small quantities at a time, to the stronger colored solution until after shaking and viewing transversely, the colors in the two tubes are exactly matched. Calculations are then made by estabhshing a proportion between the volumes of samples taken and the final dilutions. 3. Manipulation. — All of the operations may be carried on at room temperature. Weigh into a 50-cc. graduated flask 25 grams of the extract, and make up to the mark with alcohol (90-95 per cent). Stopper the flask and mix the contents thoroughly. Pipette into the colorimeter tube 2 cc. of this solution, add 10 cc. of metaphenylene diamine hydro- chloride reagent, and complete the volume to 50 cc. (or other standard volume) with alcohol. Compare at once the color with that of the standard, which should be prepared at the same time, using 2 cc. of standard citral solution and 10 cc. of the metaphenylene diamine reagent, and making up to standard volume with alcohol. From the result of this first determination, calculate the amount of standard citral solution that should be used in order to give approximately the same citral strength of the sample under examination, then repeat the determination. Methyl Alcohol has been used by unscrupulous manufacturers in lemon extracts. It is detected and determined by the refractometer method of Leach and Lythgoe (page 781). As a confirmatory test for methyl alcohol the distillate, after testing by the Leach and Lythgoe method, may to advantage be subjected to the method of IMuUiken and Scudder,* which depends on the conversion of the methyl alcohol to formaldehyde. The latter method is also useful cs a rough prehminary test on the original extract without distillation, the extract, being, however, first diluted until the liquid contains approxi- mately 12% by weight of alcohol, shaking with magnesium carbonate, and filtering when lemon oil is present. Oxidize 10 cc. of the liquid in a test-tube as follows: Wind copper wire I mm. thick upon a rod or pencil 7 to 8 mm. thick, in such a manner as to inclose the fixed end of the wire, and to form a close coil 3 to 3.5 cm. long. Twist the two ends of the wire into a stem 20 cm. long, and bend *Amer. Chem. Jour., 23, 1899, p. 266. 936 FOOD INSPECTION AND ANALYSIS. the stem at right angles about 6 cm. from the free end, or so that the coil may be plunged to the bottom of a test-tube, preferably about i6 mm. wide and i6 cm. long. Heat the coil in the upper or oxidizing flame of a Bunsen burner to a red heat throughout. Plunge the heated coil to the bottom of the test-tube containing the diluted alcohol. Withdraw the coil after a second's time and dip it in water. Repeat the operation from three to five times, or until the film of copper oxide ceases to be reduced. Cool the liquid in the test-tube meanwhile by immersion in cold water. Test for Formaldehyde. — Divide the oxidized liquid in the test-tube into two parts, testing one for formaldehyde with pure milk by the hydrochloric acid and ferric chloride test. Test the other portion by the resorcinol test for formaldehyde, page 882, avoiding an excess of the reagent.* Tests for Colors. — Evaporate a portion of the sample to dryness, dissolve the residue in water, and extract coal-tar colors if present by Arata's method, page 841, or with hydrochloric acid. Much information may often be gained by treatment of the original extract with strong hydrochloric acid. If the color employed be turmeric, no change in color will be evident on addition of the acid. If tropoeolin or methyl orange is present, the solution will turn pink, while partial decoloration of the solution indicates naphthol yellow S, and complete decoloration shows presence of dinitrocresols or naphthol yellow. Test for turmeric by boric acid, page 821. Detection of Lemon and Orange Peel Coloring Matter. — Alhrech Method.^ — Place a few cubic centimeters of the extract in a test-tube and add slowly 3 or 4 volumes of concentrated hydrochloric acid. Place a few cubic centimeters of the extract in a second tube and add several drops of concentrated ammonia. In the presence of lemon or orange peel color the yellow tint of the original extract will be materially deep- ened in both cases. Determination of Total Solids and Ash. — Total Solids are estimated by evaporating on the water-bath 10 grams of the sample in a tared dish, and drying at 100° to constant weight. If glycerol be present, it is dif- ficult if not impossible to get a constant weight. Cane sugar and glycerol, if present, will be apparent in the residue. If capsicin has been used, it will be noticed by the taste. * Amer. Chem. Jour., 24, 1900, p. 451. t U. S. Dept. of Agric, Bur. of Chem., Bui. 137, p. 71. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 937 Burn to an ash the residue from the soHds in a muffle at a low red heat, cool in a desiccator, and weigh. Glycerol is determined as in wine, page 734. Detection of Tartaric or Citric Acid. — To a portion of the extract in a test-lube add an equal volume of water to precipitate the oil. Filter and add one or two drops of the filtrate to a test-tube half full of cold, clear lime water. If tartaric acid is present, a precipitate will come down, which is soluble in an excess of ammonium chloride or acetic acid. Filter off the precipitate, or, if no precipitate is visible, heat the con- tents of the tube. Citric acid will precipitate in a large excess of hot lime water. Examination of Lemon Oil. — The oil separated from the extract in the process of determining the lemon oil by precipitation (p. 931), is most readily examined for its purity, after drying with calcium chloride, by determination of its specific gravity, its index of refraction, or its refractometric reading with the Zeiss butyro-refractometer, and its polari- scopic reading. The specific gravity and refractometric readings are determined as with fixed oils, using with the butyro-refractometer a sodium flame or y^ellow bichromate color-screen, which gives perfectly sharp readings without dispersion. The table given below shows readings on the Zeiss butyro-refractometer of pure lemon oil at various temperatures, using the sodium light. For examination of high polarizing essential oils like oil of lemon, the author employs a 50-mm. tube, in order to get the readings on the undiluted oil well within the limits of the cane sugar scale on the polar- iscope. If such a tube is not available, dilute the oil with an equal READINGS ON ZEISS BUTYRO-REFRACTOMETER OF LEMON OIL. Tempera- Scale Tempera- Scale Tempera- Scale Tempera- Scale ture, Centigrade. Reading. ture, Centigrade. Reading. ture, Centigrade. Reading. ture, 1 Centigrade. Reading. 40.0 59-4 35-0 62.8 30.0 66.3 25.0 69.7 39-5 59-7 34.5 63.1 29-5 66.6 24-5 70.0 39-0 60.1 34-0 63-5 29.0 67.0 24.0 70.4 38-5 60.4 33-5 63.8 28.5 67-3 23-5 70.7 38.0 60.8 33-0 64.2 28.0 67-7 23.0 71. 1 37-5 61.0 32-5 64-5 27-5 68.0 22.5 71.4 37-0 61.5 32.0 64.9 27.0 68.4 22.0 71.8 36-5 61.8 3I-S 65.1 26.5 68.7 21.5 72.1 36.0 62.1 31.0 65.6 26.0 69.0 21,0 72-5 35-5 62.4 30-5 65.9 25-5 69-3 20.5 72.8 35-0 62.8 30.0 66.3 25.0 69.7 20.0 73-2 938 FOOD INSPECTION AND ANALYSIS. volume of alcohol, and use the loo-mm, tube. The table given below expresses constants of pure lemon oils and of various commonly employed adulterants, as determined in the laboratory of the Massachusetts State Board of Health. CONSTANTS OF SOME ESSENTIAL OILS. Oil Butyro-refractometer (Sodium Light) at — Rotation in 100- Millimeter Tube, Ventzke Scale. Temp. Reading. 25- 25- 22-5 69-5 71.2 96.9 173-0 184.5 -10.8 22.5 87.1 — 10.2 23- 87.9 — 22.0 23- 91.0 -5-6 22.5 95-0 -3-6 Specific Gravity at 15.6° C. Oil of lemon (lowest) , '• " " (highest) , " " '• grass (A. Giese) , " " citronella (A. Giese) Terpeneless oil of lemon (Hansel's) " ti it (t grass (Hansel's). Citral (A. Giese) 0.8580 0.8610 0.9309 0-9437 0.9463 0.9232 0.9296 Oil of Lemon is a light-yellow liquid, having the pleasant odor of fresh lemons, and an aromatic, mild, somewhat bitter after taste. It is obtained from the grated rind of the lemon either by treatment with hot water, skimming off the oil which rises to the surface, or by pressure, or by distillation with water. It is rapidly changed by action of air and light, becoming "terpeney," and under these conditions its solubility in alcohol seems to increase. Its composition is somewhat uncertain, but according to Wallach * nearly 90% consists of hydrocarbons, mostly terpenes, the most important of -hich is the terpene limonene f of the dextro-gyrate variety, also known as citrene. Another important constituent of lemon oil is the aldehyde citral, present to the extent of from 4 to 5 per cent. To this the odor of the oil is largely due. A second aldehyde, citronellal, is also present. A frequent adulterant of lemon oil is turpentine oil, which lowers the rotation considerably, and is thus most easily rendered apparent. Chace J detects small quantities of turpentine by the difference in crystalline form of pinene nitroso-chloride from that of limonene nitroso- chloride. Citral (CioH,gO) is an aldehyde present in lemon oil and in oil of lemon-grass, and, while it may be separated from these oils, is prepared * Liebig's Annalen, 227, p. 290. t There are two limonenes, one of which is dextro- and the other laevo-rotary. two are completely alike in their behavior, differing only in their optical rotation. t Jour. Am. Chem. Soc, 30, 1908, p. 1475. The FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 939 artificially by oxidizing geraniol with chromic acid.* It is a mobile oil, and when perfectly pure is optically inactive. The commercial citral is, however, slightly laevo-rotary, due no doubt to impurities. Oil of Lemon-grass is distilled from lemon-grass, Andropogon citratus (D. C), cultivated in India. It is reddish yellow in color, and has an intense lemon-Uke odor and taste. Very little is known of its composi- tion, but it seems to contain several aldehydes, one of which is citro- nellal, and another citral. The latter, however, is its chief constituent, being present to the extent of 70 to 75 per cent. Citronellal (CioHigO) is an aldehyde found in various oils, especially in citronella oil, from which it is readily separated. It is made artificially by the oxidation of the primary alcohol citronellol (QoHjoO). It is quite strongly dextro-rotary. Oil of Citronella is distilled from the grass Andropogon nardus (L.j, growing chiefly in Ceylon, India, and tropical East Africa. It is a yel- lowish-brown liquid with a pleasant and lasting odor. Citronellal is present in this oil to the extent of from 10 to 20 per cent, and the oil contains also from 10 to 15 per cent of terpenes, among which are camphene. Tests for Citral, Citronellal, and Limonene.t— Shake 2 cc. of the sample to be examined in a corked test-tube with 5 cc. of a solution of 10 grams of mercuric sulphate in sufficient 25% sulphuric acid to make 100 cc. Citral yields a bright-red color, which rapidly disappears, leav- ing a whitish compound, which floats on top. Citronellal forms a bright- yellow color, remaining for some time. Limonene forms an evanescent, faint flesh color, and leaves a white compound. METHODS OF ANALYSIS OF LEMON OIL. The following are the methods of the A. O. A. C.J They apply to orange as well as lemon oil. Determination of Specific Gravity. — Determine the specific gravity by means of a pycnometer or a Sprengel tube at 15.6° C. Determination of Index of Refraction. — Determine the index of refrac- tion with any standard instrument, making the reading at 20° C. Determination of Rotation. — Determine the rotation at 20° C. with any standard instrument using a 50-mm. tube and sodium light. The * Tiemann, Berichte, 31, p. 331 1. t Burgess, Chem. and Drugg., 57, p. 732. X U. S. Dept. of Agric, Bui. 137, 191 1, p. 72. 940 FOOD INSPECTION AND ANALYSIS. results should be stated in angular degrees on a loo-mm. basis. If instruments having the sugar scale are used, the reading on orange oils is above the range of the scale, but readings may be obtained by the use of standard laevo reading quartz plates. Determination of Citral. — Kleher Method. — i. Reagents. — (a) Phenyl Hydrazin. — A io% solution of the purified chemical in absolute alcohol. A sufficiently pure product can be obtained by rectification of the com- mercial article, rejecting the first portions coming over which contain ammonia. ih) Hydrochloric Acid. — A half normal solution. 2. Manipulation. — Weigh 15 grams of the sample into a small glass- stoppered flask; add 10 cc. of the phenyl hydrazin solution. After allow- ing to stand for half an hour at room temperature, titrate with half normal hydrochloric acid, using either methyl or ethyl orange as indicator. Titrate 10 cc. of the phenyl hydrazin reagent in the same manner. The difference in cubic centimeters of half normal acids between this titra- tion and that of the sample, multiplied by the factor 0.076, gives the weight of citral in the sample. If difficulty is experienced in detecting the end point of the reaction, carry out the titration until the solution is distinctly acid, transfer to a separatory funnel, and draw off the alcoholic portion. Wash the oil with water, adding the washings to the alcoholic solution, and titrate back with half normal alkali, making the necessary corrections. Hiltner Method. — Proceed as under lemon extract (p. 934) weighing 2 grams of the oil, diluting to 100 cc, and using 2 cc. of this solution for the comparison. Determination of Total Aldehydes. — Proceed as under lemon extract (p. 875), using from 2 to 5 grams of the sample in 100 cc. of aldehyde- free alcohol. This method should be used on orange oils the aldehydes of which are not determined by the other metliods, although valuable information as to the content of added citral in the oil can be obtained by use of the Hiltner method. Determination of Physical Constants of the Ten Per Cent Distillate. Schtmmel 6* Co. Method. — Place 50 cc. of the sample in a 3-bulb Laden- burg flask in which the main bulb has a diameter of 6 cm, and is of 200 cc. capacity and which has the condensing bulbs of the following dimensions: 5.5 cm., 5 cm., 2.5 cm., and in which the distance from the bottom of the flask to the opening of the side arm is 20 cm. Distil the oil at the rate of 2 cc. per minute until 5 cc. have been distilled. * U. S. Dept. of Agric, BuJ. 137, 191 1, p. 72. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 941 Determine the refractive index and rotation of this distillate as directed above. Detection of Pmene.—Chace Method.— ^Mix the io% distillate as obtained above with 5 cc. of glacial acetic acid, cool the mixture thoroughly in a freezing bath, and add lo cc. of ethyl nitrite; then add slowly, with constant shaking, 2 cc. of a mixture of 2 parts concentrated hydrochloric acid and i part water which has been previously cooled. Keep this mixture in the freezing bath during this operation and allow it to remain therein for 15 minutes. Filter off the crystals formed, using vacuum and washing with strong alcohol. Return the filtrate and washings to the freezing bath and allow them to remain for 15 minutes. Filter off the crystals formed, using the original filter-paper. Wash the two crops of crystals thoroughly with alcohol. Dry at room temperature and dis- solve in the least possible amount of chloroform. Reprecipitate the nitroso- chloride crystals with methyl alcohol and mount for examination under the microscope with olive oil. Pinene nitroso-chloride crystals have irregular pyramidal ends while limonene nitroso-chloride crystallizes in needle forms. Determination of Alcohol.— The amount of alcohol present in oils which have been used for the manufacture of terpeneless extracts may be approximately determined by washing repeatedly with small portions of saturated sodium chloride solution and determining the alcohol in these washings in the usual way. ORANGE EXTRACT. Orange Oil is a yellowish liquid, having the characteristic odor of orange, and a mild aromatic taste. It is prepared from orange peel in an analogous manner to that of lemon oil, which it somewhat resembles in chemical composition. At least 90% of orange oil, according to Walach, consists of dextro-limonene (citrene). It has a much higher specific rotatory power than lemon oil. U. S. Standards. — Oil of Orange is the volatile oil obtained, by expression or alcoholic solution, from the fresh peel of the orange (Citrus aurantium L.) and has an optical rotation at 25° C. of not less than + gS° ^^ ^ loo-mm. tube. Terpeneless Oil of Orange is oil of orange from which all or nearly all of the terpenes have been removed. Orange Extract is the flavoring extract prepared from oil of orange, 942 FOOD INSPECTION AND ANALYSIS. or from orange peel, or both, and contains not less than 5% by volume of oil of orange. Terpeneless Extract of Orange is the flavoring extract prepared by shaking oil of orange with dilute alcohol, or by dissolving terpeneless oil of orange in dilute alcohol, and corresponds in flavoring strength to orange extract. Method of Analysis, — Orange oil and orange extract are analyzed by the same methods as lemon oil (p. 940) and lemon extract (page 929). In the determination of orange oil by Mitchell's polariscopic method divide the direct reading on the Ventzke scale, calculated for the 200- mm. tube, by 5.3 to obtain the per cent of orange oil by volume. To obtain the per cent by weight, multiply the per cent by volume by 0.85 and divide by the specific gravity of the extract. ALMOND EXTRACT. Oil of Bitter Almonds is obtained by distilling crushed bitter almonds, peach seeds, or apricot seeds with water. It should be remembered that both sweet and bitter almonds yield a bland fixed oil on pressure, which is not to be confounded with the volatile oil yielded on distillation of the bitter almonds after the fixed oil has been pressed out. Bitter almonds contain a glucoside, amygdalin, together with a ferment known as emulsin or synaptase, which, acting on the amygdahn in the distillation, produces benzaldehyde and hydrocyanic acid as follows: C20H27NO11 + 2H2O = C^HgO + HCN 4- aCeHiaOg. Amygdalin Benzalde- Hydro- Glucose hyde cyanic acid The unpurified oil of bitter almonds consists largely of benzaldehyde, with a small amount of the poisonous hydrocyanic acid. Nearly all of the commerical oil is made from the cheaper apricot and peach seeds rather than those of the bitter almond, but the product is practically identical. The oil is freed from hydrocyanic acid by agitating with calcium hydrate and a solution of ferrous chloride, distilling the mixture, and drying the oil which comes over with calcium chloride. Benzaldehyde constitutes 90 to 95 per cent of oil of bitter almonds, having a bitter, acrid, burning taste, and a marked almond odor. The specific gravity of the crude oil varies from 1.052 to 1.082, while that of the purified oil (benzaldehyde) at 20° is 1.0455. Its boihng-point is FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 943 1 80° C. On standing it becomes readily oxidizable to benzoic acid. It is readily soluble in alcohol and ether. Its solubility in water is slight, 1:300. Its index of refraction at 20° C. is 1.5446. It should be noted that the refractive indices of almond oil, whether wdth or without hydro- cyanic acid, and of artificial benzaldehyde are nearly the same. Benzaldehyde is produced artificially in a variety of ways, but is chiefly prepared by the action of chlorine on hot toluene. The result- ing benzyl chloride is distilled with lead nitrate and water in an atmos- phere of carbon dioxide, which forms benzoic aldehyde. Synthetic benzaldehyde has the same properties as the purified oil of bitter almonds, and has largely displaced it in the market, not the least of its advantages being its freedom from hydrocyanic acid. Almond Extract. — Essence of bitter almonds, or Spiritus amygdala amarcd, is thus prepared according to the U. S. Pharmacopoeia: Oil of bitter almonds 10 cc. Alcohol 800 cc. Distilled water sufficient to make 1000 cc. Thus 1% of almond oil is present in the product. U. S. Standards. — Oil of Bitter Almonds, commercial, is the volatile oil obtained from the seed of the bitter almond {Amygdalus communis L.), the apricot {Prunus armeniaca L.), or the peach (Amygdalus persica L.). Almond Extract is the flavoring extract prepared from oil of bitter almonds, free from hydrocyanic acid, and contains not less than 1% by volume of oil of bitter almonds. Adulteration of Almond Oil. — The official essence of the Pharma- copoeia does not specify that the almond oil used be perfectly free from hydrocyanic acid, in spite of the fact that its highly poisonous nature is well known, and that it exists in the crude oil to the extent of from 4 to 6 per cent. True, but httle of it is found in the extract, but in these days, when the unannounced presence in foods of such substances as antiseptics and coloring matters is regarded as questionable from a sanitary stand- point, in spite of the fact that their toxic effects on man are still matters of controversy, there thould be httle hesitancy in pronouncing the presence of prussic acid objectionable, especially when a pure almond oil entirely free from it is readily obtainable. The presence of nitrobenzol or oil of mirbane as a substitute of 944 FOOD INSPECTION AND ANALYSIS. almond oil is to be looked for. This substance is sometimes, though incorrectly, called artificial oil of bitter almonds. It is a heavy, yellow liquid of the composition C6H5NO2, readily soluble in water. Its specific gravity at 20° C. is 1.2039. Its boiling-point is 205° C. It is formed by the action of nitric acid on benzol. It possesses a highly pungent odor, somewhat like that of oil of bitter almonds, though more penetra- ting and less refined. Its index of refraction at 20° C. is 1.5 5 17. METHODS OF ANALYSIS OF ALMOND EXTRACT. Determination of Benzaldehyde. — The following methods are appli- cable to alcoholic extracts. In the case of non-alcoholic extracts convert first into alcoholic extracts as described for lemon extract, page 932. Denis and Dunbar Method.^ — i. Reagent. — Mix 30 cc. of glacial acetic acid with 40 cc. of water, then pour in 2 cc. of phenyl hydrazine. The reagent should be made up immediately before use and discarded when more than an hour old. 2. Method. — Measure out two portions of 10 cc. each of the extract into 300-cc. Erlenmeyer flasks and add 10 cc. of the reagent to one flask and 15 cc. to the other. Shake, stopper tightly, and allow to stand in a dark place overnight. Add 200 cc. of distilled water and filter the pre- cipitate of hydrazone on a tared Gooch crucible provided with a thin coat of asbestos. Wash first with cold water, finally with 10 cc. of 10% alcohol, and dry for three hours in a vacuum-oven at 70° C, or to con- stant weight over sulphuric acid. The weight of the precipitate multi- plied by the factor 5.408, will give the weight of benzaldehyde in 100 cc. of the sample. If duplicate determinations do not agree, repeat the operations, using a larger quantity of the reagent. Hortvet and West Method.-^ — Measure 10 cc. of the extract into a loo-cc. flask, add 10 cc. of a 10% sodium hydroxide solution, and 20 cc. of a 3% hydrogen peroxide solution, cover with a watch-glass and place on a water-oven. Oxidation of the aldehyde to benzoic acid begins almost immediately and should be continued from five to ten minutes after all odor of benzaldehyde has disappeared, which usually requires from twenty to thirty minutes. If nitrobenzol be present, it will be indicated at this point by its odor. When the oxidation of the aldehyde is complete, remove the flask from the water-oven, transfer the contents * Jour. Ind. Eng. Chem., i, 1909, p. 256. t Ibid., p. 86. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 945 to a separatory funnel, rinsing off the watch-glass, add lo cc. of a 20% sulphuric acid solution, and cool the contents of the funnel to room temperature under the water tap. Extract the benzoic acid with three portions of 50, 30, and 20 cc. of ether, respectively, wash the combined extracts in another separatory funnel with two portions of from 25 to 30 cc. of distilled water, or until all the sulphuric acid is removed. Filter into a tared dish, wash with ether, allow to evaporate at room tempera- ture, and finally dry over night in a desiccator, and weigh. The per cent of benzaldehyde (B) is obtained from the weight of the acid {W) by the following forniula: _ 0.869X10XTF £> = . 1.045 If desired the benzoic acid may be titrated, and the benzaldehyde calculated from the amount of standard alkali required for neutraliza- tion. The process is as follows: Dissolve the benzoic acid obtained as above described, except that it need not be dried in a desiccator, in 95% alcohol made neutral to phenolphthalein with tenth-normal sodium hydroxide, dilute with an equal volume of water, and titrate with tenth- normal sodium hydroxide, using phenolphthalein as indicator. The per cent of benzaldehyde (B) is calculated from the cc. of tenth-normal alkali (F) by the following formula: FX0.01061XT0 B — . 1.045 Detection of Nitrobenzol.* — Boil 15 cc. of the extract in a test-tube with a few drops of a strong solution of potassium hydroxide. Nitro- benzol produces a blood-red coloration. Distinction between Benzaldehyde and Nitrobenzol. — Treat 20 cc. of the extract with 5 to 10 cc. of a cold, saturated aqueous solution of sodium bisulphite in a test-tube, and shake vigorously. Transfer to an evaporating-dish, and heat on the water-bath till the alcohol is driven off. At this stage benzaldehyde remains in the hot solution as a crystal- line salt, and the solution gives off no almond odor. Nitrobenzol, on the contrary, does not combine with the bisulphite and is insoluble, forming globules of oil on the surface of the hot liquid, and in addition giving off the pungent odor so characteristic of the sub- stance. * Holde, Jour. Soc. Chem. Ind., 13, 1893, p. 906. 946 FOOD INSPECTION AND ANALYSIS. Separation of Nitrobenzol and Benzaldehyde. — If by the qualitative test nitrobenzol is found, shake vigorously as before 50 cc. of the extract with ID cc. of the saturated sodium bisulphite solution in a corked flask, and transfer with 100 cc. of vi^ater to a large separatory funnel. Shake out the nitrobenzol from the solution with four successive portions of petroleum ether of 15 to 20 cc. each, and after washing with water the combined petroleum ether, transfer it to a tared dish, in which it is allowed to evaporate spontaneously. It is extremely difficult to avoid loss- of some of the nitrobenzol by this process, but even if the weighed residue fails to show the full amount originally used, enough will usually be extracted to admit of testing on the refractometer, and of otherwise verifying its character. After removal of the nitrobenzol, make the residual solution in the separatory funnel strongly alkaline with sodium hydroxide, and shake out the benzaldehyde, if present, with petroleum ether as previously described. If after making the solution alkaline no odor of benzalde- hyde is apparent, the absence of benzaldehyde may be inferred. Distinction between Artificial Benzaldehyde and Pure Almond Oil. — Test the final residue from the ether extract by shaking with an equal volume of concentrated sulphuric acid in a test-tube. With natural oil of almonds a clear, brilliant, but dark currant-red color is produced, while with artificial benzaldehyde^ the acid produces a dirty brown color with the formation of a precipitate. Determination of Alcohol. — In the absence of other flavoring sub- stances than nitrobenzol and benzaldehyde, which are rarely present to an extent exceeding 1%, a sufficiently close approximation for most purposes can be gained by estimating the alcohol from the direct specific gravity of the extract. Detection of Hydrocyanic Acid, — To a few cubic centimeters of extract in a test-tube add a few drops of a mixture of solutions of ferrous sulphate and ferric chloride, the ferrous salt being in excess. Make alkaline with sodium hydroxide, and add enough dilute hydrochloric acid to dissolve the precipitate formed by the alkali. Presence of a blue coloration or precipitate, due to the formation of Prussian blue, indicates hydrocyanic acid. The reaction is very delicate. Determination of Hydrocyanic Acid.*^ — Hydrocyanic acid may be determined by titration with tenth-normal silver nitrate solution. 25 cc. * Vielhaber, Arch. Pharm. (3), 13, p. 408. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 947 of the extract are measured into a flask, and 5 cc. of freshly prepared magnesium hydroxide suspended in water are added, or enough to make the reaction alkaline. A few drops of a solution of potassium chromate are then introduced, and the tenth-normal silver nitrate solution added till, with shaking, the formation of the red silver chromate indicates the end-point, i cc. of silver solution equals 0.0027 gram of hydrocyanic acid. WINTERGREEN EXTRACT. Wintergreen Oil. — True oil of wintergreen is obtained by distillation from the leaves of the wintergreen plant {GauUheria procumbens L.). Gildermeister and Hoffmann* state that the specific gravity at 15° is 1. 180 to 1.187, the boiling-point 218 to 221° C. It is slightly lasvo- rotatory (a^=— o.o°25' to —1°). Oil of betula or sweet birch is distilled from the bark of the black birch (Betula lenta L.). It has the same specific gravity and boiling- point as oil of wintergreen, but unhke the latter is optically inactive. It differs somewhat from oil of wintergreen in taste and odor, but is hardly distinguishable in these respects from synthetic methyl salicylate. Both oil of wintergreen and oil of sweet birch consist almost entirely of methyl salicylate, the former containing, according to Power and Kleber,t as much as 99.8% of this substance, U. S. Standards. — Oil of Wintergreen is the volatile oil distilled from the leaves of the GauUheria procumbens L. Wintergreen Extract is the flavoring extract prepared from oil of wintergreen, and contains not less than 3% by volume of oil of winter- green. Spirit of Gautheria of the U. S. P. is a mixture of 50 cc. of oil of wintergreen and 950 cc. of alcohol. It accordingly contains 5% by volume of the essential oil. Adulteration of Wintergreen Extract. — Synthetic methyl salicylate is very commonly substituted for both wintergreen and sweet birch oil, and sweet birch oil in turn for wintergreen oil. The production of true wintergreen oil is smafl, the so-called natural wintergreen oil of com- merce being usuaUy sweet birch oil. The sense of smell is the best *The Volatile Oils. Translated by Kremers, Milwaukee, 1900, p. 588. t Pharm. Rund., 13, p. 228. 948 FOOD INSPECTION AND ANALYSIS. means of distinguishing the two oils ; polarization is of rather uncertain value, owing to low rotatory power of the wintergreen oil. Determination of Wintergreen Oil. — Hortvet and Wesfs Method.^ — Measure lo cc. of the extract into a loo-cc. beaker, add lo cc. of io% potassium hydroxide solution, and heat the mixture over a boiling water- bath until the odor of oil of wintergreen has disappeared and the hquid is reduced to about one-half its original volume. By this treatment the methyl salicylate is converted into the potassium salt. Liberate the salicylic acid by the addition of an exciess of io% hydrochloric acid, cool, and extract in a separatory funnel with three portions of 40, 30, and 20 cc. of ether respectively. Pour the combined ether extracts through a dry filter into a weighed dish, wash the filter with 10 cc. of ether, evaporate filtrate and washings slowly at 50° C, dry one hour in a desiccator, and weigh. The per cent of wintergreen oil by volume (M) is obtained from the weight of salicylic acid (6) by the following formula: i.ioiXioX5 M= i.i{ Howard^ s Method. — Proceed as described on page 931, except that the heavy oil is brought into the graduated portion of the Babcock bottle by addition of dilute sulphuric acid (1:2), taking care that the acid is not over 25° C. and avoiding agitation. PEPPERMINT EXTRACT Peppermint Oil is obtained from various plants of the genus Mentha, which are commonly classed as sub-species or varieties of M. piperita. Owing in large part to the botanical differences in the plants from which American 0.905(00.920 English 0.900 to 0.910 Japanese 0.895 to 0.900 Saxon 0.900 to 0.915 German 0.899 to 0.930 French I 0.918 to 0.920 Russian | 0.905 to 0.910 specific Gravity. Rotation, arj. -18° to -T,T,° • 22° to — ^^1° -30° to -42° -25° to -33° -27° to -33° - 5° to - 9° -17° to -22° Total Menthol, Per Cent. 48 to 60 56 to 66 70 to 91 54 to 68 43 to 46 50.2 * Jour. Ind. Eng. Chem., i, 1909, p. 90. FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 949 it is made, peppermint oil from different regions differs greatly in its chemical and physical constants as shown by the table on bottom of page 948, compiled from figures given by Gildermeister and Hoffmann.* U. S. Standards. — Peppermint is the leaves and flowering tops of Mentha piperita L. Oil of Peppermint is the volatile oil obtained from peppermint, and contains not less than 50% by weight of menthol. Peppermint Extract is the flavoring extract prepared from oil of pepper- mint, or from peppermint, or both, and contains not less than 3% by volume of oil of peppermint. Analysis of Peppermint Extract. — Owing to the wide variation in the rotatory power of peppermint oil, only a roughly approximate idea of the oil content of peppermint extract can be gained by polarization. The variation in the percentage of menthol in the oil is also too great to perm.it of a method based on the amount of this constituent. Mitchell's precipitation method, as originally described (page 931), does not effect a complete separation of the oil, but Howard's modification (page 931) gives satisfactory results, and is well adapted for purposes of inspection. Boyles' distillation method (page 932) may also be used. SPEARMINT EXTRACT. U. S. Standards. — Spearmint is the leaves and flowering tops of Mentha spicala L. Oil of Spearmint is the volatile oil obtained from spearmint. Spearmint Extract is the flavoring extract prepared from oil of spear- mint, or from spearmint, or both, and contains not less than 3% by volume of oil of spearmint. SPICE EXTRACTS. Alcoholic solutions of the essential oils of spices are used to some extent instead of the spices themselves. The following are the definitions of these extracts and the oils from which they are prepared, as adopted by the joint committee on standards and the U. S. Secretary of Agri- culture : U. S. Standards. — Anise Extract is the flavoring extract prepared from oil of anise, and contains not less than 3% by volume of oil of anise. * The Volatile Oils. Translated by Edward Kremers, Milwaukee, 1900. 950 FOOD INSPECTION AND ANALYSIS. Oil of Anise is the volatile oil obtained from the anise seed. Celery Seed Extract is the flavoring extract prepared from celery seed or the oil of celery seed, or both, and contains not less than 0.3% by volume of oil of celery seed. Oil of Celery Seed is the volatile oil obtained from celery seed. Cassia Extract is the flavoring extract prepared from oil of cassia, and contains not less than 2% by volume of oil of cassia. Oil of Cassia is the lead-free volatile oil obtained from the leaves or bark of Cinnamomum cassia BL, and contains not less than 75% by weight of cinnamic aldehyde. Cinnamon Extract is the flavoring extract prepared from oil of cinna- mon, and contains not less than 2% by volume of oil of cinnamon. Oil of Cinnamon is the lead-free volatile oil obtained from the bark of the Ceylon cinnamon {Cinnamomum zeylanicum Breyne), and contains not less than 65% by weight of cinnamic aldehyde and not more than 10% by weight of eugenol. Clove Extract is the flavoring extract prepared from oil of cloves, and contains not less than 2% by volume of oil of cloves. Oil of Cloves is the lead-free, volatile oil obtained from cloves. Ginger Extract is the flavoring extract prepared from ginger, and contains in each 100 cc. the alcohol-soluble matters from not less than 20 grams of ginger. Nutmeg Extract is the flavoring extract prepared from oil of nutmeg, and contains not less than 2% by volume of oil of nutmeg. Oil of Nutmeg is the volatile oil obtained from nutmegs. Savory Extract is the flavoring extract prepared from oil of savory, or from savory, or both, and contains not less than 0.35% by volume of oil of savory. Oil of Savory is the volatile oil obtained from savory. Star Anise Extract is the flavoring extract prepared from oil of star anise, and contains not less than 3% by volume of oil of star anise. Oil of Star Anise is the volatile oil distilled from the fruit of the star anise (Jllicium verum Hook). Sweet Basil Extract is the flavoring extract prepared from oil of sweet basil; or from sweet basil, or both, and contains not less than 0.1% by volume of oil of sweet basil. Sweet Basil, Basil, is the leaves and tops of Ocymum hasilicum L. Oil of Sweet Basil is the volatile oil obtained from basil. Sweet Marjoram Extract, Marjoram Extract, is the flavoring extract FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 951 prepared from the oil of marjoram, or from marjoram, or both, and con- tains not less than i% by volume of oil of marjoram. Oil of Marjoram is the volatile oil obtained from marjoram. Thyme Extract is the flavoring extract prepared from oil of thyme, or from thyme, or both, and contains not less than 0.2% by volume of oil of thyme. Oil of Thyme is the volatile oil obtained from thyme. Determination of Essential Oil in Alcoholic Cinnamon, Cassia, and Clove Extracts. — Howard's Method. — Proceed as with wintergreen extract, page 948. Hortvet and Wesfs Method.'^ — Place 10 cc. of the extract and 50 cc. of water in a separatory funnel, and extract with three portions of ether measuring respectively 50, 30, and 20 cc. Wash the combined extracts successively with 25 and 30 cc. of distilled water, and filter through a dry funnel into a wide-mouth flask, washing out the funnel and filter with a little ether. In the case of cinnamon extract, transfer the ether extract before filtering to a 150-cc. flask, shake for a few minutes with some granulated calcium chloride, then filter in the manner described. Evaporate off the ether as rapidly as possible on a boiling water-bath until only a few drops remain. At this point remove the flask from the bath, and rotate rapidly for a- few minutes, spreading the residue over the sides of the flask. The rapid evaporation of the remaining ether cools the flask to near room temperature. When the odor of ether has dis- appeared, stopper the flask and weigh. In the case of cassia and clove oils, where the ether extract is not first dried with calcium chloride, a slight cloudiness gathers on the flask as the last traces of ether disappear, due to the presence of a little moisture. In such case allow the flask to stand on the balance-pan until the film dis- appears, requiring not longer than two or three minutes, then stopper, and weigh. The per cent of oil by volume (F) is calculated from the weight of oil (W) by the following formula: looXW V- 10 X 1.050 The oil thus extracted may be used for determination of the refractive index. After dissolving in a little alcohol it may be tested with ferric chloride solution. By this test cinnamon oil gives a green, cassia oil a brown, and clove oil a deep blue, coloration. * Jour. Ind. Eng Chem., i, 1909, p. 88. 952 FOOD INSPECTION AND ANALYSIS. Determination of Essential Oil in Non-alcoholic Cinnamon, Cassia, and Clove Extracts.— ^o^'/e^ Modification of the Howard Method.'^— Dilute lo cc. of the sample with 95% alcohol to 50 cc, as in the case of lemon, and filter. Place 10 cc. of the filtrate in a separatory funnel con- taining 50 cc. of water, add i cc. of hydrochloric acid (i : i), and shake out four times with 25-cc. portions of ether. Wash the combined ether extracts twice with water and then shake for a few minutes with about 5 grams of granular calcium chloride. Place a small piece of cotton in the outlet of the separatory funnel and draw the ether into a tared beaker. Evaporate the ether on a boiling water-bath, place in a desiccator for three minutes, and weigh. Divide the weight found by the specific gravity of the oil to obtain the per cent of oil by volume. Determination of Essential Oil in Nutmeg Extract.— Follow Mitchell's precipitation method (page 931). In the case of non-alcoholic nutmeg extracts convert first into an alcoholic extract as described for non-alcoholic lemon extract (page 931). Determination of Solids in Ginger ^Extract. f— Evaporate 10 cc. on a boiling water-bath to dryness, dry for two hours in a boiling water oven and weigh. Determination of Alcohol in Ginger Extract. f— Proceed as with vanilla extract (page 926). Detection of Ginger in Ginger ExtTact.-\— Seeker Method.— Dilute 10 cc. of the extract to 30 cc, evaporate off 20 cc, decant into a separatory funnel and extract with an equal volume of ether. Evaporate the ether spontaneously in a porcelain dish and to the residue add 5 cc. of 75% sulphuric acid and 5 mg. of vanillin. Allow to stand for fifteen minutes and add an equal volume of water. In the presence of ginger extract an azure blue color develops. Detection of Capsicum in Ginger ExtrsiCt—Nelso7i-La Wall-Doyle Method.^ — To 10 cc of the extract cautiously add dilute sodium hydroxide until the solution reacts very slightly alkaline with litmus paper. Evapo- rate at about 70° C. to about one-quarter of the original volume, render slightly acid with dilute sulphuric acid, testing with litmus paper. Trans- fer to a separatory funnel, rinsing the evaporating dish with water, and extract with an equal volume of ether, avoiding emulsilication by shak- * Jour. Ind. Eng. Chem., 10, 1918, p. 537. t U. S. Dept. of Agric, Bur. of Chem., Bui. 137, 1911, p. 75. t Jour. Ind. Eng. Chem., 2, 1910, p. 419; U. S. Dept. of Agric, Bur. of Chem., Bui. 137, 1911, p. 75; Bui. 152, 1912, p. 137. 1 FLAVORING EXTRACTS AND THEIR SUBSTITUTES. 953 ing the funnel gently for a minute or two. Draw off the lower layer and wash the ether extract once with about lo cc. of water. Transfer the washed ether extract to a small evaporating dish, render decidedly alkaline with alcoholic potassium hydroxide, and evaporate at about 70° until the residue is pasty; then add about 20 cc. more of half-normal alcoholic potash and allow to stand on a steam bath until the gingerol is com- pletely saponified, which usually requires about one-half hour. Dis- solve the residue in a little water and transfer with water to a small sepa- ratory funnel.- The volume should not exceed 50 cc. Extract the alkaline solution with an equal volume of ether. Wash the ether extract repeatedly with small amounts of water until no longer alkaline to litmus. Transfer the washed extract to a small evaporating dish, allow the ether to evaporate spontaneously, and finally, ^ast the residue for capsicum by moistening the tip of the finger, rubbing it around on the bottom and sides of the dish, and then applying the finger to the end of the tongue. A hot, stinging, or prickly sensation, which persists for several minutes, indicates capsicum or other foreign pungent substances. ROSE EXTRACT. U. S. Standards. — Rose Extract is the flavoring extract prepared from otto of roses, with or without red rose petals, and contains not less than 0.4% by volume of otto of roses. Otto of Roses is the volatile oil obtained from the petals of Rosa damascena Mill., R. centifolia L., or R. moschata L. Determination of Rose Oil.— Hortvet and West's Method."^ — Measure 25 cc. of the extract into a separatory funnel, add 50 cc. of water, mix thoroughly, acidify with i cc. of hydrochloric acid (1:1), and extract with three portions of 20 cc. each of ether. Transfer the combined ether extracts to a 150-cc. flask, shake for a few minutes with some granulated calcium chloride, allow to settle until clear, then decant through a dry filter into a flat bottom glass dish previously weighed together with a cover-glass. Wash the calcium chloride and filter twice with 10 cc. of ether, and add the washings to the glass dish. Cover the dish, place in a vacuum desiccator over sulphuric acid, allow to remain until all traces of ether and alcohol are removed, and weigh. Repeat the drying in the desiccator, for one hour periods, until the weight is practically constant. The final weight, divided by 0.86 and multiplied by 5, gives the per cent of oil of rose by volume. * Jour. Ind. Eng. Chem., r, 1909, p. 89. ^ 954 FOOD INSPECTION AND ANALYSIS. IMITATION FRUIT FLAVORS. Nearly all the fruits possess distinctive flavors, which are desirable in food preparations, and which may be made to impart their ilavor to such substances as confections, ice cream, dessert mixtures, jellies, etc., by simply mixing with these foods the fresh or preserved fruit or fruit juice in sufficient quantity. In many cases, however, it is not found possible or practicable to prepare from the frui.s themselves an extract sufficiency concentrated to give the distinctive fruit flavor, when used in moderate quantity, and hence the use of artificial fruit essences made up of compound ethers, mixed in varying combinations and proportions to imitate more or less closely various fruit flavors. These ethers are usually much more pungent and penetrating than the fruits which they imitate, and, while lacking the delicacy and refine- ment of the original frui.s, serve to impart a certain semblance of the genuine flavor in a convenient and highly concentrated form. Some of the single compound ethers possess a remarkable resemblance to particular fruits, while to imitate other fruits a mixture of various ethers and flavoring materials, such as lemon and other volatile oils, vanilla, organic acids, chloroform, etc., is necessary. These artificial essences should in all cases be sold as such, and not as "pure fruit flavors." Imitation Pineapple Essence is made up by dissolving in alcohol butyric ether, C4H7(C2H5)02, which possesses a distinct pineapple flavor, and is prepared by mixing loo par^s of buyric acid (C^HgOj), loo parts of alcohol, and 50 parts of sulphuric acid, and shaking. Butyric ether is sparingly soluble in water, and boils at 121° C. Imitation Quince Essence depends as a basis on ethyl pelargonate, sometimes called pelargonic or oenanthic ether, CjHsjCgHiyOj, dissolved in alcohol. Pelargonic ether is formed by digestion with the aid of heat of pelargonic acid and alcohol. Pelargonic acid, C. J. > o'c3 u .S m iH nj 13^ ^< ^ fx, U^ ^0-0 i^ < 3 92.5 .8 5-0 .6 1-7 14 94-4 t-5 .1 2.8 •5 1.2 21 68.9 6.9 2-5 19.6 2-5 2.1 29 93-7 I.I .1 3-8 -5 1-3 16 79-5 4.0 •3 14.6 1.2 1.6 I 93-7 1-5 .1 3-4 -5 1-3 52 76.1 2.8 1.2 19.0 .8 •9 88 85-3 3-^ .2 9.8 1.2 I.I 7 91.6 .8 .2 6-7 I.I •7 5 87.6 ■9 •5 10.5 •7 .5 12 75-9 3-^ I.O 18.6 .9 .9 19 94.0 1.2 .2 4.0 •5 .6 I 42.4 •3 2.4 54-4 • 5 I 61. 1 .2 .8 37-2 • 7 I 81.4 .9 17-3 .4 I 40.0 .8 2.1 56.4 .7 3 85.6 .6 .6 12.8 .4 I 77.2 I.I .1 21. 1 -5 3 88.1 •7 .1 10.8 •3 4 81. 1 • 3 •3 18.0 •3 I 61.8 .4 -7 36-4 •7 I 74-8 •7 24.0 -5 > c » gas 5 bow. ,13 Sf a, jS rt a> o) .S i-"c •d 3 u -3 w 1 n! ' C O>o >-• M\0 ChOt^O nr- ^00 0> NmmmOOOO-* I I I I I I II 0< w O 1 + I I vOvO •^cO'^Tl-fOPi •■^•t^rOfO Tt-00 I I I I I I I I I + I I I 1 I I I I ++ I + + + + I HOMOOOM'^i-io0^Of)O ■^ Ti" W M to n M to O to rj- 10 t^ 10 ro O i-i 00 t^co O i-i r^ O toes O rofO'^M M 00000000 01 t^ t^oo O to O O O O w o o o < ^ 00000000000000 t^OO iO>0 00 ^ ^ 00 w rooo N M vo - IJ y Hf (u fL" cti : D- a,-- ^-J oj u ^ bc rt fi g i, g n! 03 >-< qj OJ s s s^ w M ■* 0 00 ^O ^ P) M 1 + I 1 1 T 1 1 + vO ^ <> M M N - moo 00 vO ON o 000 o C4 (N M M --* r^oo i^-O 09 ++++++++++++++ "+ 00 M ^ N O^O M t~~O0 r^ N 00 10 t^ to to ■* t^ N vO Ti- CO CN ro Ti- ro cs (N vO 00 vO 10 (N to n -t ro ■'t w r'J rOO to to tovO CS w iJ M f) "? r^ U-. OJ vO t^ to to r^ to 000 too t^ O O 00 to o r^ Tt- ro j^vo M r— tooo 10, to to r-~>o MMHHMO'^^-'WrOrOC^, Mh-tO 6 6 6 6 6 6 6 6 6 6 6 >^ 6 6 ONtoM ^loH toMOO CI r^ONOt^ t^ t^ t^ CN -^ t^ Tt-OO CS to CI t^ 00 10 On O 00 On 000000 00 0\ ■+ P< ro <^ a. • ■ Ii73. • en _0 =3 >N^ I' FT ^ " -9 M S "u aJS 2 2 2 .2 OOMDnomOOOmn ■^MOMOC4hvOm ++ I + ++++ OvOoO 000 ION fOO 10 i^j^M Ttw r^roo I^ 1 1 1 1 1 1 1 1 M r^vO ro 1V-) On <^ ro n +++ I ++++++ N 00 NO NO 00 to r^ ts CO -' u u t^ CO TJ ■M^ 13 V =« P-- -/— ILI OJ .-, tn u S ni Q ^ S-^ E R- OS t^ 5 5 2 t^ <;muoocPH 1; oi r^ See .C _3 _P Ph Ph (1« 994 FOOD INSPECTION AND ANALYSIS. worked up with apple stock for low-priced jams. Hence the presence of pure fruit stock, or genuine berry seeds and pulp in jams, is in itself no criterion of purity, and furthermore, it is unnecessary to use hay seed and other alleged foreign seeds as adulterants of cheap jam. Compound Goods. — Many states have a law legalizing the sale of "compound" goods, providing they are distinctly so labeled. In other states, as, for instance, Massachusetts, the label must plainly state the name and percentage of the ingredients. In either case the analyst must discriminate, in classifying the inferior or low-grade preparations, between those that are labeled in accordance with the law, and those that are not. Only those not properly labeled can in such cases be classed as adulter- ated within the meaning of the law. Where such a law prevails, probably no class of food-producls is so extensively affected by it as the low-grade jams, preserves, and jellies. The restrictions as to labeling do not in all cases eliminate the element of deception. It is hardly justifiable, for example, to boldly label an alleged "currant jelly" which contains no currant, in the following man- ner: Fruit juice 25% Cane sugar 14% Corn syrup 61% 100% The use of the term "fruit juice" surely implies to the unsuspecting purchaser that so much pure currant juice has entered into the jelly, else- where labeled in large letters " Currant," whereas all the juice is apple, and no currant juice has been used. The following label is a type of those which discriminate between pure fruit and apple juice: Fruit 30% Corn syrup 35% Granulated sugar 15% Apple juice 20% 100% Composition of Cheaper Grades. — Out of 66 samples of jellies, jams, and preserves analyzed by Winton, Langley, and Ogden in Connecticut, the samples being purchased in that state,* 17 samples contained starch * An. Rep. Conn. Exp. Sta., 1901, p. 130. VEGETABLE AND FRUIT PRODUCTS. 995 paste, 35 were artificially colored with coal-tar dyes, and 19 contained salicylic or benzoic acid. The following table has been compiled, showing the sugar content of some of the typical commercial jellies and jams analyzed in the laboratory of the Massachusetts State Board of Health. Nearly all of these were artificially colored, and found to contain little if any fruit, other than apple. JELLY. Apple Currant A B Grape Peach Pineapple Raspberry JAM. Damson A B Apricot Quince Raspberry A B C Pineapple Strawberry A B Direct Polariza- tion. + 64.0 + 29.2 + 41-6 + 62.0 + 119. 8 + 114. o + 112.0 + 107.0 + 95-2 + 99.0 + 49-6 -f 123.6 + 77-6 + 66.0 + 119. 8 + 41-8 + 83.6 Invert Polarization. At 20° C. + 28.0 + 20.0 + 33-9 + 34-4 + 108.8 -f 107.6 -1-92.0 + 94-4 + 90.9 + 93-5 + 43-6 + 119. 2 + 65 . 1 + 29-5 4-108.8 + 21-3 + 72.0 At 87° C. + 36.0 + 36.4 + 40.8 + 46.0 -f- IIO.O + IIO.O + 93-6 + S8.i + 83.6 + 85.6 + 42.0 + 102-5 + 46.9 + 37-2 -f- IIO.O + 32-6 + 78.8 Per Cent Sucrose. 26.8 6.9 5-7 20.6 8.2 4.9 14.9 15 Per Cent Commer- cial Glucose. 22.1 22.3 25.0 28.2 67.4 67.4 57-4 35-6 51.2 52-4 25-7 62.8 28.7 22.8 67.4 20.0 48.3 METHODS OF ANALYSIS. As in the case of canned goods, but little information is to be derived as to adulteration of jams, jellies, and preserves by the ordinary deter- minations of moisture, ash, and nitrogen, and these are rarely made by the public analyst. Of considerable importance in this regard, however, are the sugar determinations, made with a view to ascertaining the varieties of sugar employed, as well as their approximate proportion in the products examined. Still more important are the results of tests for preservatives, dyes, for- eign gelatinous substances, and mineral acids used as coagulators. Preparation of the Sample. — In the case of jams, marmalades, and preserves, separate and weigh the stones, if present, then thoroughly pulp the sample. In the case of jellies rub the sample through a sieve. Stir well before weighing out the portions for analysis. 99G FOOD INSPECTION AND ANALYSIS. Determination of Total Solids. — Weigh 4 to 5 grams of the sample into a large flat-bottomed dish (preferably of platinum) containing from 4 to 5 grams of ignited asbestos and add enough water to uniformly distribute the material. Evaporate to dryness and dry for from twenty to twenty-four hours in a boiling water-oven. The results by this method are not strictly accurate owing to the dehydration of levulose, but for practical purposes they are sufhciently close. If extreme accuracy is required dry in vacuo at 70° or in a McGill oven (page 609). The solids in a jelly may also be calculated from the specific gravity. Determination of Ash. — Burn the residue from the determination of solids, or else a new portion, in a platinum dish at dull redness. Alkalinity of ash is determined as described for insoluble ash in maple products (page 657). Chlorides and Sulphates are detected in the ash by the usual tests. If the portion used for determination of alkalinity is also to be used for the chlorine test the titration must be made with fifth-normal nitric acid. The presence of chlorides is an indication of glucose, as pure fruit products do not contain appreciable amounts of chlorine compounds. Determination of Insoluble Solids. — Kremla Method* — Thoroughly macerate 50 grams of the sample in a mortar with warm water, then transfer to a filter and wash thoroughly with warm water, stirring well after each addition. Wash up to 500 cc, or in extreme cases up to 1000 cc, remove the insoluble solids to a dish, dry in a boiling water-oven, and weigh. Kremla employed a coarse filter paper for collecting the insoluble solids ; Munson and Tolman f found muslin more satisfactory. Reserve the filtrate for determinations of soluble constituents. German Official Method.^ — Transfer a weighed portion of the sample to a graduated flask, add water, shake thoroughly and make up to volume. Allow to settle and either filter or decant off the supernatant liquid. Deter- mine the soluble solids by evaporating and drying an aliquot. The insoluble solids are obtained by subtracting the soluble from the total solids. Determination of Acidity. — Dilute an aliquot of the solution from the insoluble solids of a jam or of a solution of a jelly and titrate with standard alkali. Use phenolphthalein as indicator if the color of the *Zeits. Nahr. Hyg. Waar., 6, 1892, p. 483. t U. S Dept. of Agric, Bur. of Chem., Bui. 65, 1902, p. 76; Bui. 66 rev., p. 13. t Vereinb. Unters. Beurt. Nahr. Genussm. deutsch. Reich., 2, p. 105. VEGETABLE AND FRUIT PRODUCTS. 997 solution will permit, otherwise use litmus paper. Calculate the result as sulphuric acid or as the organic acid known to predominate (see page 1008). Some of the methods for the determination of individual acids in fruit juices (pages 1008 and 1009) ^.re applicable to jams and jellies, but the analyst will do well to test their accuracy on mixtures of known composi- tion, especially if substances other than fruit and sugar are present. Determination of Protein. — Determine nitrogen in 5 grams of the material by the Kjeldahl or Gunning method and calculate protein, using the factor 6.25. Determination of Sugars. — In products of the highest grade, wherein only cane sugar is employed, a large portion of the cane sugar is inverted in the process of boiling the jam or jelly, so that when the analyst exam- ines it, he finds, as a rule, only a small amount of sucrose, and considerable invert sugar. The amount of cane sugar equivalent to the invert sugar may be calculated if this is thought desirable. It is further of interest to calculate, at least approximately, the percentage of commercial glucose, when present, especially in cases where the package contains a formula setting forth the amount of the various ingredients used. In such cases the analyst is naturally called upon to verify the formula, since a wide varia- tion in percentage composition from the statement on the label would constitute an offense under same state laws. Polarization. — Use half the normal weight of the preserve or jelly for the Schmidt and Haensch instrument, namely 13 grams in 100 cc. If fresh fruit or fruit juice is to be examined, use the full normal weight, 26 grams. Clarify, before making up to the mark, with subacetate of lead and alumina cream (using 2 to 3 cc. of each clarifier), filter, and obtain the direct reading; then invert in the usual manner, and obtain the invert readings at 20° C, and in the water-jacketed tube at 87° C, proceeding in detail as directed under honey, page 671. Calculation of Sugars. — Sucrose is determined by using the Clerget- Herzfeld formula: „ (a — b) 100 142.60 — 2 (I) This represents the sucrose actually present as such in the preserve or jelly, and not the amount originally used. If the latter (6"') is desired, it may be roughly calculated by the following formula: 998 FOOD INSPECTION AND ANALYSIS. 5' = -^22*_, (,) 42.66 2 The results by this formula are too high, since part of the invert sugar was a natural constituent of the fruit. If, after inversion, the correct reading at 20° is found to be 12 or more to the left of the zero, it can be safely inferred that no appreciable amount of commercial glucose is present, and it is unnecessary to make a third reading at 87°, unless to confirm the fact. In such a case, v^ith cane sugar alone present, the reading at 87° will not, of course, vary much from zero. Invert Sugar. — In the absence of commercial glucose, the invert sugar is calculated as follows : T , (Sucrose— direct reading) iQi;.^ ,. Invert sugar = -^^ — — ^^-^, • • • (3) 42.66—- 2 or it may be determined directly from the copper reducing power. Any decided reading above zero at 87° is due to the presence of com- mercial glucose, and when the latter is present, it is impossible to deter- mine the invert sugar from the copper reduction or by formula No. 3. The following formula is proposed for calculating approximately the invert sugar from the polarization, in the presence of commercial glucose. While theoretically correct, the method is subject to practical limitations, which admit of only roughly approximate results in such mixtures as jelly or jam. It is perfectly accurate only in mixtures of sucrose, glucose, and invert sugar. /Reading due to glucose and\ /Invert readingX , , \ inverted sucrose at /° / \ at /° / , , Invert sugar = ^ '-^ ^105.3 (4) ±(42.66-- These formulas, (3) and (4), serve at best to indicate the approximate amount of invert sugar present in the sample, resulting from the inversion of a portion of the original sucrose in the natural process of manufacture of the jam or jelly, and not the total invert sugar resulting from the inver- sion by the analyst of all the sucrose. The factor 105.3 is used, since, in the natural process of inversion, 100 parts of sucrose become 105.3 parts of invert sugar. Example. — The invert sugar in the sample of apple jelly first on the list in the table on page 995 is calculated as follows : VEGETABLE AND FRUIT PRODUCTS. 999 Invert reading at /° (20°) = 28.0. Reading due to glucose at 20° =.221 X 175 = 38.68. Reading due to inverted sucrose at 20° = . 268 X —34= — 9.11. T , (38.68 -O.Il) -28 Invert sugar =^^:^ — loc;.^ ^ 28.66 ^ ^ -576%. Determination of Reducing Sugar. — Proceed as described on page 982. Commercial Glucose.— While it is impossible to determine the exact percentage of this substance in preserves and jellies, by reason of the varying composition of its component parts, it is quite feasible to approx- imate very closely to the amount present. Indeed, this approximate method of calculation, wherein glucose is treated as a chemical entity, has been found in practice to be much more close to the actual truth than results gained by methods wherein the copper-reducing power enters as a factor, or methods for determining separately dextrin, maltose, and dextrose. Calculate the commercial glucose in jellies and jams exactly as in the case of honey, page 673. Detection of Dextrin.* — Add alcohol to a somewhat thick solution of the fruit product. A white turbidity is at once apparent, followed by the for- mation of a thick gummy precipitate if dextrin is present. In the absence of dextrin there is no turbidity, but a light flocculent precipitate. Determination of Dextrin. — Bigelow and McElroy Method.] — Dissolve 10 grams of the sample in a loo-cc. graduated flask, add 20 mg. of potas- sium fluoride, and then about one-quarter of a cake of compressed yeast. Allow the fermentation to proceed below 25° C. for two or three hours to prevent excessive foaming, and then place in an incubator at a temperature of from 27° to 30° C. for five days. At the end of that time clarify with lead subacetate and alumina cream; make up to 100 cc. and polarize in a 200-mm. tube. A pure fruit jelly will show a rotation of not more than a few tenths of a degree either to the right or to the left. If a Schmidt and Haensch polariscope be used, and a 10% solution be polarized in a 200-mm. tube, the number of degrees read on the sugar scale of the instru- ment, multiplied by 0.8755, will give the percentage of dextrin, or the fol- lowing formula may be used : C X 1000 X V Percentage of dextrin = 198X^x1^' * U S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 78. t Jour. Amer. Chem. Soc, 15, 1893, p. 668. 1000 FOOD INSPECTION AND ANALYSIS. in which C= degrees of circular rotation; F = volume in cubic centimeters of solution polarized; Z = length of tube in centimeters; W = weight of sample in solution in grams. Determination of Crude Pectin (Alcohol Precipitate). — Munson and Tolman Method.'^ — Evaporate loo cc. of a 20% solution of jelly, or 200 cc. of the washings from the determination of insoluble solids of a jam, to 20 cc; add slowly and with constant stirring 200 cc. of 95% alcohol and allow the mixture to stand overnight. Filter and wash with 80% alcohol by volume. Wash this precipitate off the filter paper with hot water into a platinum dish; evaporate to dryness; dry at 100° C. for several hours and weigh; then burn off the organic matter and weigh the residue as -ash. The loss in weight upon ignition is called alcohol precipitate. The ash should be largely lime and not more than 5% of the total weight of the alcohol precipitate. If it is larger than this some of the salts of the organic acids have been brought down. Titrate the water- soluble portion of this ash with tenth-normal acid, as any potassium bitartrate precipitated by the alcohol can thus be estimated. The general appearance of the alcohol precipitate is one of the best indications as to the presence of glucose and dextrin. Upon the addition of alcohol to a pure fruit product a flocculent precipitate is formed with no turbidity while in the presence of glucose a white turbidity appears at once upon adding the alcohol, and a thick, gummy precipitate forms. Since the precipitate in the latter case consists in part of substances other than pectin bodies the results should be stated as representing " alcohol precipitate " and not " pectin." German Method.-f — This method, designed for juices, may also be used for jams and jellies. It differs from the Munson and Tolman method chiefly in that a smaller proportion of alcohol is used and a correction is^ introduced for protein. Detection of Coloring Matter. — Boil white woolen cloth or worsted in a solution of the jelly or jam, acidified with hydrochloric acid, or with acid sulphate of potassium, according to Arata's method and test for * U. S. Dept. of Agric, Bur. of Chem., Bui. 65, 1902, p. 79; Bui. 66 rev., p. 21. t Koenig, Chemie d. mensch. Nahr. u. Genussm. Ill, 2, 1914, p. 891. VEGETABLE AND FRUIT PRODUCTS. 1001 the^ color on the dyed fabric by methods given in detail in Chapter XVII. Apply also the general methods described in that chapter. Detection of Preservatives and Concentrated Sweeteners.— Extract an acid aqueous solution of the fruit product with ether or chloroform in a separatory funnel, and test for benzoic and salicylic acids and for sac- charin in the ether extract. If dulcin is suspected, extract with acetic ether. Detection of Starch.* — Heat an aqueous solution of the preserve or jelly nearly to the boiling point, and decolorize by the addition of several cubic centimeters of dilute sulphuric acid and afterwards permanganate cf potassium. This treatment does not aflFect the starch, which is tested for with iodine in the ordinary manner in the solution after cooling. In .he clear fihrate from a boiled apple pulp solution, free from added starch, li.tlc or no darkening should occur on the addicion of the iodine reagent. If, however, the reagent is added to the residue of the previously boiled pulp, the presence of starch inherent in the apple is usually recognized by the blue color produced thereon. The presence of any considerable added starch paste in a fruit prepa- ration is thus readily indicated by an intense blue color obtained by adding the iodine reagent to the filtrate (free from fruit pulp). Detection of Gelatin. — Robin's Method.'f — Add to a thick aqueous solution of the preserve or jelly sufficient strong alcohol to precipitate the gelatin. Decant the supernatant liquid after settling, set aside part of the precipitate, and dissolve the remainder in water. Divide the latter soluiion in two parts, to one of which add, drop by drop, a fresh solution of tannin, which precipitates gelatin if present. To the remainder add picric acid solution, which in presence of gelatin forms a yellow precip- itate. The portion of the yellow precipitate set aside is transferred to a test tube, and heated over the flame with a little quicklime. If gelatin is present, ammonia will be given off, apparent by the odor, and by fumes of ammonium chloride when a drop of hydrochloric acid on a glass rod is held at the mouth of the bottle. Lepnann and Beani's Method. X — Boil the sample with water, filter, and boil the filtrate with an excess of potassium bichromate. Cool, and add a few drops of sulphuric acid. A flocculent precipitate indicates gelatin. * U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 81. t Girard, Analyse des Matieres Aiimentaires, p. 676. X Select Methods of Food Analysis, p. 324. 1002 FOOD INSPECTION AND ANALYSIS. Detection of Agar Agar.*— The jelly is heated with 5% sulphuric acid, a little potassium permanganate is added, and, after settling, the sediment is examined by the microscope for diatoms, which will be found in large numbers if agar agar has been used. Detection of Apple Pulp. — A distinct clue to the presence of apple pulp in fruit preparations is often furnished by the characteristic apple odor given off when a small amount of the sample is heated to boiling with water in a test tube. Under such conditions, the apple odor is quite apparent, as distinguished from that of other fruits, especially if the apple is the chief fruit present, or predominates in the mixture. Apple pulp in fruit preserves, free from added starch, may usually be recognized by a microscopical examination, using iodine reagent. The cell contents of the pulp will show the characteristic blue color, undoubtedly due to portions of unconverted starch still remaining in them. Detection of Fruit Tissues under the Microscope. Certaiii of the common fruits are readily identified in jams by their microscopic char- acters. This is especially true of most of the small fruits, the skins, styles and seeds being more or less characteristic in structure. The apple differs from the quince and pear in that stone cells are lack- ing; the starch of the green fruit is noteworthy. Peaches, plums and apricots, while possessing skins and stone peculiar to each, when pared and freed from stones are much alike in structure. Pineapples have peculiar needle-shaped crystals. Figs are identified by the " seeds " and hairs. Citrus fruits are remarkable because of the oil cavities and spongy parenchyma. Fragments of elements of the skins and cores of fruits, although pared and cored before preparation, find their way into the finished products, furnishing evidence to the microscopist. The seeds of berries are highly characteristic. DRIED FRUITS. Desiccation is the oldest and in some respects the most satisfactory method of preserving fruits. It is an economical method, as the apparatus and the process are simple, especially if the sun's heat is utilized for the evaporation; furthermore, the cost of the containers is small and the compact form of the product reduces the cost for transportation and storage * Marpniann, Zeit. f. angew. Mikrosk., 1896, p. 260; U. S. Dept. of Agric, Bur. of Chem., Bui. 65, p. 81. VEGETABLE AND FRUIT PRODUCTS. 1003 to the minimum. From the sanitary standpoint dried fruit has certain advantages, notably the freedom from metallic impurities from the con- tainers; on the other hand, great care is required to protect the material during drying and handling from surface contamination. Xanti currants as well as raisins are dried grapes of certain European varieties. These, together with figs and dates, although produced in California and the Southern States, are imported into the United States in enormous quantities from the regions adjoining the Mediterranean. Apples, prunes, apricots, peaches, and cherries, on the other hand, are produced in the United States in quantities not only sufficient for domestic needs but also for export. California fruits, such as raisins, prunes, apricots, peaches, and pears are sun-dried, as are also raisins, figs, dates and other fruits produced about the Mediterranean. Apples are commonly dried in the United States by artificial heat, although the old process of sun drying is still practiced on a small scale in certain regions. Treatment with Lye.— Preliminary to drying certain fruits, such as raisins and prunes, are often dipped in a hot but weak solution of potash, which removes the bloom and otherwise acts on the skin, thus faciHtating drymg. Oil is also used with the lye in preparing " oil-dipped " Smyrna raisins. These methods of treatment are quite distinct from the lye- peeling process employed in preparing peaches, apricots, and some other fruits for canning. Sulphuring of Fruit.— The treatment of fruits with the fumes of burning sulphur is practiced not only to bleach and prevent discoloration, but also to ward off the attacks of insects, fungi, and bacteria. It is allowed with restrictions in most European countries and also, pending further inves- tigation, in the United States, provided the amount of sulphur dioxide remaining in the fruit does not exceed 350 mg. per kilo, of which not more than 70 mg. is free sulphurous acid.* There is reason to believe that the sulphur dioxide exists in dried fruits in combination largely, if not wholly, with sugar, although possibly to some extent, as in wines, with acetaldehyde, or even with protein and cellulose. Sulphuring when used for purposes of deception, as for example in rejuvenating old or damaged stock or when used in excessive amount, is obviously improper. Analyses by government chemists show that when * U. S. Dept. of Agric, Off. of Sec, Food Inspection Decision 76. 1004 FOOD INSPECTION AND ANALYSIS. no restrictions were placed on sulphuring as high as 3072 mg. per kilo were present in dried peaches, 2842 mg. in California apricots and 1738 mg. in evaporated apples. Moisture Content of Dried Fruits. — An excessive amount of moisture in dried fruit is not only a worthless make-weight, but also facilitates the growth of molds and bacteria, causing rapid deterioration. In 1904 a law was passed in New York State requiring that dried apples contain not above 27% of moisture, determined by drying four hours at the temperature of boiling water. Wormy and Decomposed Dried Fruits. — Figs, dates, and currants from Europe, also dried apples, cherries, and other fruits of domestic production often are infected with worms or are in a moldy or fermented condition due to careless drying or packing. Under the federal law such " filthy, decomposed or putrid " fruit is adulterated. Zinc in Dried Fruit. — Apples dried in contact with galvanized iron trays may contain o.oi to 0,02%, or in extreme cases, according to Loock, 0.09% of zinc as malate. This contamination may be avoided by greasing the trays, covering them with greased cloths, or using wooden trays. FRUIT JUICES. Such preparations, if of the highest purity, should consist of the un- diluted juices of these fruits, separated by pressure and carefully ster- ilized and bottled. They should contain no other fruit juice than that specified on their labels, and should be free from alcohol, added antisep- tics, or coloring matter, unless the label specifies the presence of the added foreign materials. The addition of pure cane sugar to such prepara- tions as grape juice is allowable if declared, as well as charging with carbon dioxide to form so-called carbonated drinks. Composition of Fruit Juices. — Analyses of various fruit juices, pressed out in the laboratory, by Munson and Tolman are given on page 992. The following analyses of pure fruit juices are taken from tables pre- pared by Winton, Ogden, and Mitchell, showing results on samples pur- chased in the Connecticut market, as well as on some samples made in the laboratory:* * Conn. Agric. Exp. Sta. Rep., 1899, p. 136. VEGETABLE AND FRUIT PRODUCTS. 1005 COMMERCIAL FRITIT JUICES. Blackberry Cherry Black currant Red currant Grape Lime fruit Orange Pineapple Plum Quince Black raspberry Strawberry MADE I N LABORA- TORY. Peach Red raspberry Blackberry Huckleberry Pineapple Solids. 12.70 9.41 8-94 11.40 13.90 Acids Other than CO 2 as Citric. 0.65 0.80 2.41 2.og 0.91 6.50 2-44 0.81 1 .00 0.99 1.36 0.99 0-95 1. 19 0-51 0.68 Cane Sugar. 0.0 0.0 0.0 0.0 0.0 0.0 0.0 1-5 0.0 0.0 0.0 0.0 5-4 0.8 0.0 0.6 7-4 Invert Sugar. 4.6 6.5 9.2 7-2 0.0 7-1 5-1 0-3 7.i 5-1 2. 1 8.6 9.1 Polarization. Direct. -1-3 -1-9 -2-7 -2.1 -6.5 0.0 -2.1 0.0 -o. I ■5-0 •2-3 ■1-5 4-8 -1.6 ■2.4 ■4.0 4-7 After Inver- •1-3 ■1-9 ■2.7 -2.1 ■6.5 0.0 -5-0 -2.4 ■4.8 -4.8 Temper- ature C. 29.0 26.0 26.0 27.0 25.0 26.0 26.0 26.0 25.0 26.0 26.0 28.0 26.0 30.0 30.0 28.0 Invert Reading at S6° C. -0.8 Grape Juice. — Following are the averages of analyses of grape juice made from European varieties of grapes reported by Bioletti and dal Piaz :* Alcohol. Solids Calc. from Specific Grav- ity. Sugar. Acidity Calc. as Tar- taric. Vola- tile Acid. Free Tar- taric Acid. Cream of Tartar. Ash. Phos- phoric Acid. Made in — Austria California none none 21.62 20.60 19.62 19- IS 0.78 0.53 O.OI 0.03 0.03 0.07 0.61 OS9 0.37 0.19 0.02 0.04 The table given below, summarized from tables by Hartmann and Tolman,t shows the maximum, minimum, and average of analyses of 93 samples of commercial grape juice obtained under supervision at five factories in New York state and one in Ohio during the years 1912, 1913, and 1914. * Cal. Agr. Exp. Sta., Bui. 130, 1900. t U. S. Dept. of Agric, Bui. 656, 1918. 1006 1 FOOD INSPECTION AND ANALYSIS. Alcohol Vol. per Cent.* Grams per loo cc. Cc. N/io Acid per 100 cc. Solids.t Sugars Calc. as Invert t Acidity Calc. as Tar- taric. § Free and Com- bined Tartaric Acid. II Free Tar- taric Acid.t Cream of Tar- tar. Ash. Tannin and Color- ing Mat- ter.** Alka- linity Water- soluble Ash. Alka- linity Water- in- soluble Ash. Max Min Aver 0-37 0.02 O.I2 20.78 14.20 18.33 17-53 11.52 15-31 1.28 0.81 1. 01 1. 01 0.56 0.74 0.36 0. 12 0.23 0.79 0.36 0.54 0.37 0.22 0.29 0.37 0.07 0.24 42.0 19.0 28.7 8.8 3-1 S-i ♦By immersion refractometer. t Brix. t Direct and invert polarization practically the same. I Spotted into litmus solution. II Total tartaric acid by Hartmann and Eoff. method (p. 731). If Calc. from total tartaric acid and cream of tartar (p. 732). ** Lowenthal method. Sweet Cider. — The composition of pure, freshly expressed apple juice is shown by the following table of analyses by Browne : * Left- Total Unde- handed Specific Invent Su- Total Sugar Free ter- Rotation Gravity. Solids. Sugar. crose. Sugar. after Inver- sion. Mahc Acid. Ash. mined (Pectin, etc.;. Degrees Ventzke 400 mm. Tube. Redastrachan 1-0532 12.78 6.87 .S-63 10.50 10.69 1. 14 0.37 0.77 23.72 Early harvest 1-0552 13.29 7-49 3-97 11.46 11.67 0.90 0.28 0.65 24.32 Yellow transparent. 1.0502 II. 71 8.03 2.10 10.14 10.24 0.86 0.27 0.44 Sweet bough Baldwin, green. . . . 1.0498 1.0488 11.87 11.36 7.61 6.96 3.08 1.63 10.69 8.59 10.8s 8.68 0. 10 39-40 36.16 1.24 0.31 1.22 ' ' ripe. .... 1.0736 16.82 7-97 7-05 15.02 15-39 0.67 0.26 0.87 Ben Davis 1-0539 12.77 7. II 3-85 10.96 11.16 0.46 0.28 1.07 49.00 Determination of sugars in the juice of 15 American and 5 French varieties of apples made by Eoff t showed that in every instance the amount of levulose exceeded that of dextrose and sucrose combined. Bottled sweet cider, properly sterilized, should not differ materially from the fresh juice, and should contain no considerable amount of alcohol. Salicylic acid, sodium benzoate and sodium or calcium bisulphite have been extensively used as preservatives, Benzoate is still used to some extent. Lime or Lemon Juice. — The juice of both the lime and the lemon is known commercially as lime juice and the Canadian standard goes so far * Penn. Dept. Agric, Bid. 58, p. 29. t Jour. Ind. Eng. Chem., 9, 1917, p. 587 VEGETABLE AND FRUIT PRODUCTS. 1007 as to recognize "various species" of Citrus. In former editions of the U. S. Pharmacopoeia C. limonum was specified and the product known as lemon juice was required to conform to the following: Specific gravity at 15° C. at least 1.030, citric acid about 7^1, and ash not more than 0.5%. In the 9th decimal revision neither lemon nor lime juice is given. The table below shows the range in composition of 40 samples classed by McGill * as genuine, together with the Canadian limits fixed by Order of Council, Jan. 28, 191 5. Many of the samples werq preserved with benzoic, salicylic, or sulphurous acid. COMPOSITION OF LIME JUICE (McGill) specific Gravity, 20° C. Total Solids. Acidity Calc. as Citric. Rotation in 200-mm. Tube, ° v. Genuine lime juice: Maximum Minimum Canadian limits: Maximum Minimum I 0531 1.0305 1 .040 1.030 12.12 7.76 8.00 10.18 6-93 7.00 +0.6 — 2.2 +0.5 — I.O Samples examined in previous years at the laboratory of Inland Revenue, Canada, and at the Mass. State Board of Health were often found to be watered, preserved with salicylic, benzoic, or sulphurous acid, artificially colored, or otherwise sophisticated. One sample, examined by Leach purporting to be " pure West Indian lime juice, triple refined," proved to be a mixture of hydrochloric and salicylic acids, colored with a coal-tar dye, and containing no lime juice whatever. METHODS OF ANALYSIS. Total Solids, Total Nitrogen, Ash, and Sugars are determined by the methods employed for jams and jellies (pp. 995 to 1002), Solubility and Alkalinity of the Ash and Phosphoric Acid as described in the chapter on vinegar (p. 795). Colors and Preservatives are detected and determined as described in Chapters XVII and XVIII. Total Acidity. — Titrate 10 grams of the juice, diluted to 250 cc. with freshly boiled water, with tenth-normal alkali. Use phenolphthalein as * Lab. Inl. Rev. Dept., Bui. 321, 1916. 1008 FOOD INSPECTION AND ANALYSIS. indicator if the color of the juice will permit, otherwise delicate litmus paper. Calculate either as sulphuric acid or as the organic acid known to pre- dominate. One cc. of tenth-normal alkali is equivalent to 0.0075 gram tartaric acid, 0.0067 gram malic acid and 0.0064 gram citric acid. Determination of Total Tartaric Acid. — Proceed as directed for wine, p. 731, using only 50 cc. of the sample diluted to 100 cc. and adding 20 instead of 15 cc. of alcohol. Determination of Malic Acid. — Dunbar and Bacon Method.^ — Dilute a weighed or measured amount of the fruit juice, usually 10 grams, with fjuite a large volume of water, add phenolphthalein, and titrate with standard alkali to a decided pink color. Weigh or measure another portion of the liquid (75 grams or cc. is a convenient amount) into a loo-cc. graduated flask, and add enough standard alkali, calculated from the above titration, to neutralize the acidity. A slight excess of alkali is not objectionable. If the solution is dark colored, add 5 or 10 cc. of alumina cream. Dilute to the mark, mix thoroughly, and filter if necessary through a folded filter. Treat about 25 cc. of the filtrate with enough powdered uranyl acetate so that a small amount remains undissolved after two hours, 2.5 grams usually being sufficient, except in the presence of large amounts of malic acid. In case all the uranium salt dissolves more should be added. Allow to stand for two hours, shaking frequently, filter through a folded filter until clear and polarize if possible in a 200-mm. tube or, if too dark, in a 100- or 50-mm. tube. Designate this solution and reading as A. Treat the remainder of the original filtrate with powdered normal lead acetate until the precipitation is just complete, avoiding a large excess and consequent solution of lead malate. Cool in an ice bath and filter through a folded filter until clear. Warm the filtrate to room temperature and add a small crystal of lead acetate. If no precipitate forms, remove the excess of lead with anhydrous sodium sulphate, filter until clear, and polarize. Designate this solution and its polarization reading as B. Solutions which are sufficiently clear and contain less than 10% of sugar may be polarized directly without treatment with lead acetate. If reading B is negative treat a portion of solution B with uranyl acetate in the manner already described and polarize. Designate this as C. If reading B is positive, reading C need not be made. * U. S. Dept. of Agric, Bur. of Chem.. C'\rr , 76. Jour. Ind. Eng. Chem., 3, 1911, p. 826. VEGETABLE AND FRUITS PRODUCT. 1009 Polarize all solutions at a uniform room temperature with white light, using the average of at least six readings and calculating to the basis of a 200-mm, tube. If reading C is numerically less than reading B, the latter should be discarded; otherwise use reading B in the subsequent calcula- tion. Multiply the algebraic difference between this reading and reading A by 0.036, the product being the percentage of malic acid (C4H6O5) in the solution as polarized. PraWs Modification.'^ — Place a weighed amount of juice, generally 100 grams, in a 500-cc. beaker and add, with vigorous stirring, two or three times its volume of 95% alcohol. The pectin bodies are precipitated and usually in such a form that after standing a few minutes they may be gathered into a coherent mass. Decant the liquid through a filter and wash the precipitate twice with 95% alcohol. Evaporate the filtrate in a cur- rent of air on the water-bath to about 75 cc. After cooling make up to 100 cc. in a measured flask, using 10 to 15 cc. of 95% alcohol and dis- tilled water. The temperature when the volume is finally made up to the mark should be close to that at which the polariscope readings are to be taken. Treat this solution exactly as in the original method, except that no clarification is necessary. Determination of Citric Acid. — Pratt Method. "f — This method is applicable in the presence of malic and tartaric acids, but according to Bige- low and Dunbar { does not give accurate quantitative results although it serves to show the presence or absence of citric acid. Willaman's modi- fication § is designed to correct the defects of the method but has not yet been rigidly tested. Dunbar and Lepper 1 1 recomimend the Stahre-Kunz method. The original Pratt method is here given pending further improve- ment or the introduction of a better method. 'i. Apparatus. — This consists of a 500-cc. distilling flask provided with a small dropping funnel drawn down to a small opening and pro- truding h inch below the stopper. In the flask is placed a glass rod with a piece of small tubing >> Inch long, sealed on the lower end to insure steady ebullition. This small tube should be filled with air when the heating begins. A condenser preferably of the spiral type is connected with the flask. * U. S. Dept. of Agric, Bur. of Chem., Circ. 87. f U. S. Dept. of Agric, Bur. of Chem., Circ. 88, 1912. f Jour. Ind. Eng. Ciiem., 9, 1917, p. 762. § Jour. Amer. Chem. Soc, 38, 1916, p. 193. II Jour, .^ssn. Off. Agr. Chem., 2, II, 1917, p. 175. 1010 FOOD INSPECTION AND ANALYSIS. 2. Denigh Reagent. — Add about 500 cc. of water to 50 grams of mercuric oxide; then add 200 cc. of concentrated sulphuric acid with constant stirring, and heat the mixture, if necessary, on a steam bath until the solution is complete. After cooling make up to a liter and filter. 3. Determination. — Weigh 50 grams of the fruit juice into a beaker and add no cc. of 95% alcohol to throw out the pectin bodies. After standing fifteen minutes filter and wash with 95% alcohol. Dilute the filtrate with water to approximately 50% alcohol content and add enough 20% barium acetate solution to precipitate the citric acid. Stir, let stand until the barium citrate partially settles, and filter. Wash twice with 50% alcohol to remove the greater part of the sugar present. Remove all alcohol from the precipitate and filter either by drying in the beaker used for precipitation or else by washing with ether before removing from the funnel. Add 50 cc. of water and 3 to 5 cc. of sirupy phosphoric acid to the beaker containing the filter-paper and precipitate and warm, thus dissolving the barium citrate completely. Filter into a 100 cc. measuring flask and wash up to the mark. Measure an aliquot containing from 0.05 to 0.15 gram of citric acid, into the distilling flask, add 5 to 10 cc, of sirupy phosphoric acid and 400 cc. of hot water. Connect with the condenser, heat and when briskly boiling, add potassium permanganate solution (0.5 gram per liter), i to 2 drops per second, until a pink color persists throughout the solution. Distil off the acetone formed by the oxidation into a liter Erlenmeyer flask containing 30 to 40 cc. of Deniges reagent, continuing the distilla- tion until so to ICO- cc. remain in the flask. Boil the distillate gently under a reflux condenser for forty-five minutes after it turns milky. Filter hot through a Gooch crucible, wash the precipitate with water, alcohol, and finally with ether, and dry in a water-oven for half an hour. The weight of the precipitate multiplied by 0.22 gives the weight of citric acid. FRUIT SYRUPS. Two classes of these preparations are on the market, one for use in soda-fountains, and one for " family trade," intended as a basis for sweet- ened drinks to be diluted with water and sugar. Some are made exclu- sively from fruit pulp or juice and sugar, sterilized by heating and put-up in tightly sealed bottles, while others of the cheaper variety are more apt to be entirely artificial both in color and in flavor, deriving the latter principally from the wide variety of artificial fruit essences now available. VEGETABLE AND FRUIT PRODUCTS. 1011 Commercial glucose is a frequent ingredient. The same classes of coal- tar dyes and antiseptics are found in these preparations as in the other fruit products. Citric or tartaric acid is frequently added to genuine fruit syrups to bring out the flavor and to imitation fruit syrups to better simulate the characters of the genuine product. For purposes of comparison with such fruit-pulp preparations as may come to the analyst for examination, he is referred to the analysis of fruits found on pages 283 and 993. NON-ALCOHOLIC CARBONATED BEVERAGES. Soda Water. — Originally the beverage known as soda water was prepared by the action of an acid on sodium bicarbonate in solution and corresponded to what is now obtained by dissolving Seidlitz powders in water. Later it was found that water charged with carbon dioxide is not only more practicable commercially but also more acceptable to the palate, and this product was substituted for true soda water without change of name. As dispensed by the pharmacist and confectioner in the United States, soda water consists of a syrup, variously flavored, mixed at the " fountain " with carbonated water. The syrup is first placed in the glass, then the carbonated water is drawn into it in a large stream and finally more added in a fine stream to mix and froth the liquid. Ice cream or liquid " cream " is used with certain flavors, eggs and milk in " egg chocolate," " egg shake " and other nutritious mixtures, a solution of calcium acid phosphate in " orange phosphate " and other phosphates — in fact there appears to be no end to the preparations and combinations introduced by ingenious vendors to quench the thirst, gratify the palate, and furnish nourishment in an easily digestible form. Carbonated Water, the basis of all effervescent drinks, is prepared by charging ordinary water with carbon dioxide in a steel drum, known as the fountain. Formerly the gas was generated on the premises by the action of mineral acid on marble, but now it is obtained in liquid form in steel cylinders from mineral springs and the fermentation industries where it formerly went to waste. The process of carbonating consists in allowing the gas to discharge into the water, rocking the fountain continually to aid absorption. A gauge indicates the pressure in the fountain, which should be about 170 pounds per square inch for soda water and somewhat less for ginger ale 1012 FOOD INSPECTION AND ANALYSIS. and root beer. The steel drum or fountain proper is kept in the cellar or other convenient place and the carbonated water is piped to the so-called fountain where the drinks are served, or, in the case of bottled beverages, to the machine for filling the bottles. Needless to say both the water and the gas should be free from con- tamination, and the introduction of metallic salts from the lead pipes and other sources should be guarded against. Soda Water Syrups. — Sugar and flavors are added to carbonated beverages in the form of syrups. At the soda fountain these are drawn into the glass from small reservoirs or poured from bottles, while in the bottling works measured quantities both of syrup and carbonated water are introduced into each bottle by an automatic machine. Fruit Syrups are prepared either by the manufacturer of soda water supplies or else by the pharmacist or confectioner who serves the beverages. More commonly the manufacturer supplies the fruit juice or fruit pulp in bottles or jars, spoilage being avoided either by sterilization or the use of sodium benzoate. The vendor mixes the juice or pulp with sugar syrup as needed. Orange, lemon, and lime syrups are commonly made from the oils rather than from the fresh fruit, the necessary acidity being supplied by citric acid. This acid as well as tartaric acid is also used in strawberry, raspberry and other true fruit syrups to bring out the flavor. Imitation Fruit Syrups flavored with mixtures of ethers such as are described on pages 954 to 956, are frequently substituted for genuine fruit syrups at soda fountains and quite universally in the preparation of cheap bottled soda water. Aside from the deception to the consumer these mix- tures are highly objectionable because of their nauseating and unwhole- some properties. Various Syrups not belonging under the head of fruit syrups are drawn from fountains and used in bottled beverages. Among these are vanilla, coffee, chocolate (really cocoa), ginger, sarsaparilla, and mixtures sold under distincti\'e names. Bottled Carbonated Beverages. — To this class belong various non- alcoholic beverages known as " soda," " soft-drinks " and " temperance drinks." Some of these are high-grade articles of national or even inter- national reputation, so prepared as to keep indefinitely, while others are cheap preparations of local manufacture sold for immediate consumption in pleasure resorts. Ginger Ale, by far the best-known bottled carbonated beverage, is made VEGETABLE AND FRUIT PRODUCTS. 1013 from ginger (or ginger extract) with the addition of lemon juice (or lemon oil and citric acid) and carbonated water. Capsicum extract, known in solid form as capsicin, is frequently substituted in part for the ginger because of its greater pungency. Root Beer was formerly brewed from a sweetened infusion of various roots and herbs, the gas being formed by a true fermentation process. A similar beverage is now made in the household, using so-called " root- beer extract," but the commercial product is commonly charged, like soda water, with carbon dioxide gas. Birch Beer, formerly made by fermentation, is now merely soda water flavored with oil of birch or synthetic methyl salicylate. Sarsaparilla, so called, is flavored with a mixture of oil of birch, natural or synthetic, and oil of sassafras. The dark color is due to caramel or other artificial colors. Lemon Soda and Orange Soda are flavored respectively with terpene- less lemon and orange extract, the acidity being contributed by citric acid. Orangeade belongs in the same class. So-called blood orange soda is probably never made from blood oranges, the color being artificial. Vanilla Soda is more correctly vanillin soda or vanillin and coumarin soda. The term cream soda applied to this colorless beverage is equally misleading. Strawberry Soda, Raspberry Soda and other bottled beverages purport- ing to be made from fruits are commonly imitations flavored with ethers and colored with coal-tar dyes. So-called Cherry Soda is flavored with an extract of cherry bark or benzaldehyde. Sweeteners in Beverages. — Sugar is the only proper sweetener for syrups of botded beverages. Glucose because of its lower sweetening power is unsuited for the purpose, while saccharin and other chemical sweeteners are objectionable both because of their lack of nutritive prop- erties and their possible injury to health. The use of saccharin, which has hitherto been extensive, is now prohibited in beverages entering into interstate commerce. Acids in Beverages. — Citric and tartaric acids are used not only in imitation, but also in true fruit syrups to bring out the flavor. Lemon juice serves the same purpose, but is more expensive and does not keep so well. Calcium acid phosphate is a characteristic constituent of orange and other fruit phosphates. Preservatives.— Sodium benzoate is the common preservative of bev- 1014 FOOD INSPECTION AND ANALYSIS. erages, although its use is by no means universal. Formerly salicylic, boric and sulphurous acids and even fluorides were employed. A recent German patent names /^-chlorobenzoic acid as a harmless preservative many times as effectual as benzoic acid. Artificial Colors.— Cochineal, cudbear, caramel and the eight colors allov^ed by U. S. decisions are most commonly met with. The use of fuchsin, acid fuchsin, rhodamine, and other coal-tar colors has been largely discontinued. Foam Producers. — Froth on soda water is cheaper to produce than the same bulk of liquid, furthermore it is sanctioned by custom. Soap-bark, the bark of Quillaja Saponaria, a common foam producer, contains two saponins, sapontoxin and quilliac acid, both of which are poisonous. In addition these principles combine with the cholesterin of the blood and if in excess dissolve the corpuscles. Commercial saponin, prepared from Saponaria officinalis, and consist- ing largely of sapotoxin, is also extensively used. Foam producers are also used in malt liquors. Glycerrhizin, the characteristic principle of licorice, also serves as a foam producer. Habit-forming Drugs in Beverages. — Caffein, extract of cola leaves, and cocaine are ingredients of certain proprietary syrups and beverages, contributing their well-known stimulating properties. The use of caffein is defended on the ground that it is the active principle of tea and coffee. Opponents of this drug have pointed out that tea and coffee are recognized as improper articles of diet for children and invalids, furthermore, the presence of other constituents tends to prevent the excessive use of these beverages. Again the presence of caffein in carbonated beverages is not usually known to the consumer, and he forms the habit without proper warning. It would be difficult to find an argument in favor of the use of a drug so potent as cocaine or products containing cocaine. METHODS OF ANALYSIS. Transfer the sample to a flask and shake at intervals for an hour or two, at room temperature, thus removing most of the carbon dioxide. Use. the liquid thus obtained for the several determinations, measuring out the portions, if desired, and calculating the weight from the specific gravity. VEGETABLE AND FRUIT PRODUCTS. 1015 Total Solids, Ash, Acidity, and Individual Sugars are determined as directed for jams and jellies (pages 995 to 999) using 25 grams of the liquid except for the polarizations, which may be made on normal quantities. Vanillin, Coumarin, Citral, and Methyl Salicylate are detected and determined by the methods described under the head of Flavoring Extracts, with such modifications as are necessitated by the absence of alcohol on the one hand and the greater dilution on the other. Methods for the detection of Ginger and Capsicum are given on page 952. Detection of Colors, Preservatives, and Sweeteners.— See Chapters XVII, XVIII, and XIX. Determination of Phosphoric Acid.— This determination is made in so-called " orange phosphate," " raspberry phosphate " and other beverages containing calcium acid phosphate. Treat 25 grams of the liquid according to the method described on page 362, except that the entire residue, after ignition with magnesium nitrate, is used for the determination, without aliquoting. Determination of Alcohol — Follow the method prescribed for wines (page 687) . The amount of volatile oil present is seldom sufficient to appre- ciably affect the results. Detection of Saponin.— Of the various color tests that have been proposed none has been found absolutely characteristic, especially if glycerrhizin is present, although the reactions with sulphuric acid and Frohde reagent are of considerable value. The haemolysis test is believed to be reliable even in the presence of glycerrhizin. Whichever test is applied the saponin should be separated from interfering substances as follows : I. Extraction of Saponin by the Riihle-Briimmer Method.^ — In the case of soda water and other products containing organic or mineral acids (other than carbonic), to 100 cc. of the liquid add an excess of pre- cipitated magnesium carbonate and filter. If dextrin is present, as in the case of malt liquors, evaporate 100 cc. of the liquid to 20 cc, pre- cipitate with 150 cc. of 95% alcohol, let stand thirty minutes, then heat to boiling, filter, dilute the filtrate with water and dealcoholize, finally making up the solution to 100 cc. To 100 cc. of the neutral, dextrin-free solution in a separatory funnel, add 20 grams of ammonium sulphate, 9 cc. of phenol and shake thoroughly. Draw off the watery layer and shake the phenol solution with a mixture * Zeits. Unters. Nahr. Genussm., 5, 1902, p. 1197; 16, 1908, p. 165; 23, 1912, p. 566. 1016 FOOD INSPECTION AND ANALYSIS. of 50 cc. of water, 100 cc. of ether, and (if necessary to avoid an emulsion) 4 cc. of alcohol. Allow to stand until the liquids separate, which usually requires twelve to twenty-four hours. Draw off the aqueous solution and evaporate nearly to dryness, finishing the drying either at 100° C. or in a desiccator, the latter being preferable if the residue is to be purified by treatment with acetone, which is usually desirable. Employ this extract, consisting of saponin and impurities, in the following tests : II, Tests for Saponin. — i. Sulphuric Acid Test. — Rub up a portion of the extract with a few drops of sulphuric acid. Saponin is indicated by the appearance in a few minutes of a reddish color changing in half an hour to red- violet and finally to gray. 2. Frohde Test. — Treat another portion in like manner with a few drops of a mixture of 100 cc. of concentrated sulphuric acid and i gram of ammonium molybdate. In the presence of saponin the drops in fifteen minutes become violet, changing later to green and finally to gray. 3. Foam Test. — Shake another portion of the extract with water and note its foam-producing properties. In the presence of glycerrhizin none of the last three tests is reliable. 4. Haemolysis Test. — This process is recommended by Rusconi,* Sormali,t and Rhiile.J The following details are given by Rhiile and are based on the method as described by Gadamer: § (a) Reagents. — (i) Physiological Salt Solution. — Dissolve 8 grams of sodium chloride in water and make up to one liter. (2) One per cent Defibrinated Blood. — Shake vigorously fresh ox blood in a sterilized, salt-mouth, 500-cc. bottle with 20 glass beads 5-7 mm. in diameter. Separate from the clot of fibrin and store in a sterilized container in a refrigerator. Properly cared for it should keep for several days. Dilute with 100 volumes of physiological salt solution for use. (3) One per cent Blood Corpuscles.— Centrifuge 100 cc. of the 1% defibrinated blood in physiological salt solution, pour off the clear solu- tion containing the cholesterol and make up again to 100 cc. with the salt solution. This preparation is more sensitive than solution (2). {b) Process. — Dissolve about o.i gram of the extract in 25 cc, of physiological salt solution, filter, and shake i, 2, and 3 cc. of this solution * Bol. Soc. Med. Chi., Pavia, 1910. t Zeits. Unters. Nahr. Genussm., 23, 1912, p. 562. i Ibid., p. 566. § Lehrbuch der chemischen Toxicologic. Gottingen, 1909, p. 443. VEGETABLE AND FRUIT PRODUCTS. 1017 in small test-tubes with i cc. portions of i% defribinated blood. If saponin is present the liquid becomes clear in from a miunte to an hour or two, depending on the amount of saponin in the beverage and the number of cubic centimeters of the solution used. As a confirmatory test dissolve i mg. of cholesterol in a small amount of ether, shake with lo cc. of the solution of the extract in salt solution, heat at 36° C, for a few hours to remove ether, avoiding concentration, and treat portions of this solution with 1% defibrinated- blood as above described. Cholesterol destroys the hasmolytic action of the saponin, hence the liquids should not become clear in these tests. In order to exert this influence cholesterol should be present to the extent of i part to 5 parts of saponin. If only a small amount of saponin is present the heemolytic action can best be noted under a microscope magnifying to 300 diameters. Mount a drop of the solution of the extract in salt solution and place a drop of either solution (2) or (3) in contact with it. The saponin causes the corpuscles in contact with it to swell, then become strongly refractive, and finally dissolve. Muller-Hossly * neutralizes 500 to 1000 cc. of the sample and blows a current of air into it through a glass tube extending to the bottom of the container, collects the foam which froths over, and makes the test on the liquid obtained by the subsiding of the foam. The saponin in the foam is in much greater amount than in the original liquid. Determination of Cd£Lem.~Fuller ikfe/AoJ.f— Weigh 50 grams or measure an equivalent volume into a small beaker, add 5 cc. of concentrated ammonium hydroxide, allow to digest overnight; then add 2 cc. more of ammonium hydroxide, heat for two hours, transfer to a large separatory funnel, dilute with 3 volumes of acid, add 5 cc. of ammonium hydroxide and shake out with four successive portioijs of chloroform, each of 50 cc. In case any dyestuff is removed by the chloroform, shake out with a satu- rated solution of sodium bisulphite, which will remove some of the color. Distil off the bulk of the chloroform and evaporate the remainder in a porcelain dish. Dissolve the residue in 25 cc. of 2% sulphuric acid, shake out with five portions of 15 cc. each of chloroform, filter the combined chloroform solutions into a flask, distil off the bulk of the chloroform and evaporate in a tared dish ; dry at 100° C. and weigh. * Mitt. Lebensm. Hyg., 8, 1917, p. 113. t U. S. Dept. of Agric, Bur. of Chem., Bui. 137, p. 191. 1018 FOOD INSPECTION AND ANALYSIS J If the caffein is not pure, dissolve in 15 cc. of 10% hydrochloric acid, add an excess of a solution of 10 grams of iodine and 20 grams of potas- sium iodide in 100 cc. of water, allow to stand overnight, filter, and wash twice with 10 cc. of the iodine solution. Transfer filter and precipitate to the original precipitation flask, add sufficient sulphurous acid to dissolve the precipitate, heating gently, filter into a separatory funnel, wash three times with water, and add ammonium hydroxide in excess; shake out four times with 15 cc. portions of chloroform, and filter the chloroform extracts into a flask, using a 7 cm. filter and keeping the funnel covered with a watch glass. Wash the filter with 5 portions of 5 cc. of chloroform. If the chloroform extract is colored, concentrate, add a small amount of animal charcoal, rotate several times and filter. Distil off part of the solvent and evaporate the remainder in a tared dish, dry at 100° C, and weigh. Detection and Determination of Cocaine. — Fuller Method* — To 200 cc. of the sample in a large separatory funnel, add concentrated am- monium hydroxide to alkaline reaction, and shake out with three portions of 50 cc. each of Prolius mixture (4 parts ether, i part chloroform, i part alcohol), collecting the solvent in another separatory funnel. If desired the aqueous solution may be reserved for the detection of salicylic and benzoic acids and saccharin. Filter the combined Prolius extracts into an evaporating dish, and evaporate on a steam bath, removing the dish as the last traces of solvent disappear. Dissolve the residue in normal sulphuric acid, transfer to a separatory funnel and shake out four times with 15 cc. portions of chloroform; wash the combined chloroform solu- tions once with water, reject the chloroform, and add the water extract to the original acid solution. Add 10 cc. of petroleum ether, boiling at 40° to 50° C, and shake; draw off the acid layer, rejecting the petroleum ether, add concentrated ammonium hydroxide in excess and shake out three times with 15 cc. portions of petroleum ether, collecting the ethereal solu- tions in another separatory funnel. To the latter add 10 cc. of water and shake thoroughly; reject the water extract and filter the petroleum ether into a beaker, washing twice with 10 cc. portions of the solvent. Evaporate over a steam bath, using a fan. By this method, if coca alkaloids are present, a nearly colorless residue will be obtained, which will finally crystallize on standing. Dissolve the residue in petroleum ether and divide into four portions, one of which may be small. Evaporate the solvent and to the small * U. S. Dept. of Agric, Bur. of Chem., Bui. 137, p. 192. VEGETABLE AND FRUIT PRODUCTS. 1019 portion add a few drops of normal sulphuric acid, warm gently, filter into a test-tube, and add a drop of potassium mercuric iodide test solution (Meyer's reagent). A precipitate indicates an alkaloid, but does not identify it as cocaine; if no precipitate forms, cocaine is not present and further test is unnecessary. To another portion add a few drops of concentrated nitric acid, and evaporate on a steam bath until the acid is all driven off, then add a few drops of half nornial alcoholic potash and note the first odor that comes off, which, if cocaine is present, is that of ethyl benzoate. The residue of the third portion should be applied to the end of the tongue by riibbing with the finger. Cocaine will cause a numbness which is not apparent immediately, but develops gradually, and persists for a longer or shorter time according to the amount present. Remove a portion of the fourth residue to a microscopic slide, add a drop or two of gold chloride test solution, and stir vigorously, noting the character of the crystals under the microscope. All the above tests should be checked by controls on pure cocaine. If a quantitative determination of coca alkaloids is desired the residue after evaporating the petroleum ether should be weighed, then, as a check on the gravimetric determination, warmed in 50 cc. of fiftieth-normal sulphuric acid until dissolved, cooled, and titrated with fiftieth-normal potassium or sodium hydroxide, using cochineal as indicator. The fac- tor for cocaine is 0.006018. Determination of Caffein and Detection of Cocaine and Glycerol. — Fuller Method.'^ — Weigh 50 grams of the sample into an evaporating dish, add 5 cc. of concentrated ammonium hydroxide, cover with a watch glass and allow to stand twelve hours. Add 2 cc. more of ammonium hydroxide and evaporate on steam bath. Warm the residue with 25 cc. of 95% alcohol on the steam bath, cool, and pour off the alcohol into another evaporating dish, repeating the treatment four times. Evaporate the combined alcoholic extract, dissolve the residue at 25 cc. of 2% sulphuric acid, transfer to a separatory funnel and shake out 5 times with 15 cc. portions of chloroform. Reserve the acid liquid for subsequent tests for cocaine and glycerol. Distil off most of the chloroform, evaporate in a dish on a steam bath, dissolve the residue in 10% hydrochloric acid and transfer to a small flask. Add to the acid solution an excess of iodine solution (10 grams * U. S. Dept. of Agric, Bur. of Chem., Bui. 137, p. 192. 1020 FOOD INSPECTION AND ANALYSIS. iodine and 20 grams potassium iodide in 100 cc. of water), rotate flask, allow to settle overnight, filter, and wash flask and precipitate twice with the iodine solution, then transfer filter and precipitate to the flask. Heat gently with sufificient sulphurous acid solution to dissolve the precipitate, filter into a separatory funnel, cool, add excess of concentrated ammonium hydroxide, and shake out four times with 15 cc. portions of chloroform. Filter the chloroform extract into a flask, using a 7-cm. filter in a small funnel covered with a watch glass, or filter through cotton plugged in the stem of the separatory funnel. Decolorize the chloroform, if neces- sary, with animal charcoal, distil off most of the chloroform, then evapo- rate in a tared dish over steam, dry at 100° C. and weigh. Add an excess of concentrated ammonium hydroxide to the solution from which the cafTein was extracted, shake out three times with petroleum ether, boiling at 40° to 60° C, filter ether solution, divide into four parts, evaporate, and test for cocaine as described in the preceding method. Evaporate the aqueous solution from the cocaine extraction with milk of lime and proceed as in the determination of glycerol in wines (page 734) . The glycerol thus obtained will be only an approximation to the true amount. CHAPTER XXII. DETERMINATION OF ACIDITY BY MEANS OF THE HYDROGEN ELECTRODE. By Gerald L. Wendt, Ph.D. Assistant Professor of Chemistry, the University of Chicago. The usual methods of determining acid and alkali are frequently inapplicable in food analysis because the color change of the indicator, by means of which the end point is observed, is masked by the presence of colored substances or by turbidity. In such cases the use of the hydrogen electrode method is essential. Furthermore, there are many titrations in which it is not so important to know the total quantity of acid present as it is to determine exactly the concentration of hydrogen ions in the original solution. That is, it is desirable to determine the actual acidity as distinct from the total available acidity. A large part of the latter may be present originally in the form of undissociated molecules, and therefore inactive as acid until alkali is added. The hydrogen electrode method offers a simple means for such a determination. Finally, there are many occasions when the analyst wishes to prepare a solution of definite acidity which may t i far from the neutral point, and yet also far from being so acid or so alkaline as to be readily analysed. In such cases also the hydrogen electrode is of great convenience in that it indicates constantly the actual acidity of a solution at any moment, and acid or alkali need therefore to be added only until the instrument records the proper concentration. All three problems are frequently met with in courses of food analysis. In addition, indicator titrations are occasionally impossible because the salts present in the material to be titrated exert such a strong " buffer " action — as in milk, for instance, or in rhubarb juice — that the color change of the indicator is so gradual as to be quite unreliable. Related to this is the fact that the choice of the proper indicator is exceedingly important in such cases. The common indicators may all change at a degree of acidity which wholly unsuits them for some particular titration. And, lastly, the usual titration can give no information as to which acid or which 1022 FOOD INSPECTION AND ANALYSIS. alkali is present in the solution that is being analysed. Thus fruit acids are empirically reported as per cent citric, malic or sulphuric regardless of the acid or mixture of acids present. On the other hand, the electro- metric method frequently reveals the characteristics of the acid that is being determined. For all these reasons, then, a simple form of the hydrogen electrode apparatus is to be recommended as part of the equipment of any food laboratory. Principle of the Method. — The first principle involved in this method of determining acidity is that every aqueous solution must have a definite concentration of hydrogen ions. Even pure water can be regarded as an acid, and equally well as an alkali, in the sense that water contains both hydrogen and hydroxide ions in definite concentration. The dissociation of water into its ions is weak, yet accurate measurements have shown that about one water molecule in five hundred million is dissociated into its ions. In other words, the concentration of hydrogen ions in water is very close to ID"'' grams per liter. Since each molecule of water on dissociation gives rise to one hydrogen ion and one hydroxide ion, the concentration of hydrox- ide ion in water is also io~'' gram ions per liter, i.e., both are io~'^ normal. The product of the two concentrations is consequently iq-^^ According to the simple principles of chemical equilibrium these two concentrations must bear a definite ratio toward each other at all times. That is, in the reaction represented by the equation H20^H++0H~, definite equilibrium concentrations of the reacting substances must always be obtained such that the velocity of the forward reaction is the same as that of the reverse action. This can be the case only if the concentration of hydrogen ions multiplied by the concentration of hydroxide ions be constant ; i.e., if, using the usual chemical symbols, (H+) (OH") = K = iq-i*. This constant is, of course, the dissociation constant of water, and represents the product of the concentrations of hydrogen and hydroxide ions expressed in normality. This constant must hold good for every solution which contains water, and thus for all aqueous solutions, irrespective of the amount of hydrogen or hydroxide ions added from other sources. That is to say, in a normal solution of a strong acid, the hydrogen ion concentration is one, or io°; substituted in the above equation, the hydroxide concentration must be io~i* in order that their product remain lo"^^. Similarly a hundredth normal solution of a strong acid would have a concentration of hydroxide equal to lo"^^. Strong acids therefore contain definite concentrations of hydroxide ions. At the other end of the scale, alkalis similarly contain DETERMINATION OF ACIDITY . 1023 definite concentrations of hydrogen ions. The variation of hydrogen with hydroxide is represented in the following table : TABLE I. If (H+) = ioi (OH- ) = = io-is Ph = — I loO (N) lo-i* o lo-i (O.I N) IO-13 I 10-2 (o.oiN) IO-12 2 IO-3 lo-ii 3 io-» lo-'o 4 lo-s IO-9 5 io-« IO-8 6 10-' lo-^ 7 IO-8 IO-6 8 IO-9 IO-6 9 io-i» lo-" lO IO-" IO~3 II IO-12 IO-2 (o. ,oiN) 12 IO-" IQ-l (o. iN) 13 IO-" lo" (N) 14 10-15 loi 15 The negative exponent of lo in these concentration figures for the hydrogen ion is the distinguishing factor for each case and has come to be used directly in this sense under the name of " Ph" Pure water stands in the center of this scale in that its hydrogen ion concentration is exactly equal to its hydroxide concentration, both being iQ-''. Water is therefore neutral, being as acid as it is basic. This is the exact neutral point, though it is seldom indicated by the indicators in general use. Most indicators will give either their " acid color " or their " alkali color " in water solution. Methyl orange, for instance, shows alkali in pure water, and phenolphthalein shows acid in pure water. Litmus and rosolic acid are two indicators that do change at the neutral point. While each indicator is suited for the determination of some one value of Ph, it is obvious that no one indicator can be used to follow the change of hydrogen and hydroxide ion concentration when a solution is titrated, i.e., when the hydrogen ion concentration may vary all the way from io~^ to lo"^"*. Each indicator has its own definite changing point, and will mark only the point at which that concentration is attained. The changing points for methyl orange and for phenolphthalein are indicated in Fig. 3. The hydrogen electrode method, however, records on a scale the concentration of hydrogen ions at all times, and it is thus possible to follow continuously the change beginning with strong acid all the way to 1024 FOOD INSPECTION AND ANALYSIS. strong alkali or vice versa. The actual hydrogen ion concentration is in- dicated at every instant. Theory of the Method. — The theory of the hydrogen electrode is familiar. Its details need not be discussed here as they are available in any text-book of physical chemistry. Essentially the method consists in the measurement of the voltage between a platinum electrode saturated with hydrogen and the acid solution. The platinum electrode is coated with a layer of platinum black which is allowed to become saturated with hydro- gen gas. Hydrogen is readily soluble in platinum black so that such an electrode is essentially a " hydrogen electrode." That is, for all practical purposes it acts like a rod or electrode of hydrogen inserted into the solu- tion. The other electrode, which is to make direct contact with the solu- tion, i.e., with the hydrogen ions, must be one in which the transition from solution to the metallic connecting wire is made under definite and constant electrical conditions. For this purpose a " caloifiel cell " is used. Thereby the potential of the hydrogen ions is communicated to the rest of the system by, first, a solution of potassium chloride, then mercurous chloride, " cal- omel " solution, then calomel paste in contact with metallic mercury, which in turn contains the connecting wire. In such a system the potential between the coated platinum or hydrogen electrode and the mercury is given by the equation : £ = 0.058 log ('^U.283, where c represents the actual concentration of hydrogen ions in the solution. Transposing, log c = - / ^ j , _/ £-.283 \ E may then be read directly in volts on a voltmeter and the equation needs only to be solved for c or for Ph in order to give the hydrogen ion concentration or " actual acidity " of any unknown solution. The relation between E and c is linear, and the variation of one with the other may be calculated once for all and embodied in a table or curve, as is shown in the figures of this chapter. Indeed the voltmeter itself may conveniently be graduated to read in values of c directly, as well as in values of E. Titration consists then in following the change in £ as c is \'aried by 1I e addition of acid or alkali to the solution. and DETERMINATION OF ACIDITY 1025 The Apparatus. — The necessar}' apparatus consists of the hydrogen electrode, the calomel cell, and a potentiometer arrangement to measure Fig. i2oa. the potential between them. For accurate work an accurate potentiometer is necessary, but for the usual laboratory determinations a potentiometer can 1026 FOOD INSPECTION AND ANALYSIS. be readily built up from an ordinary dry cell, a loo-ohm variable resist- ance, a voltmeter, and a sensitive galvanometer which will determine when no current is passing. This galvanometer should have a sensitivity of one megohm. A diagram of the arrangement of these instruments is shown in Fig. i2ob and a photograph of a typical assembly in Fig. 120a. B represents a dry cell, and is connected directly through the resistance R, and a knife switch to form a complete circuit which must be closed whenever the instrument is in use. By means of the variable contact on the resistance, various potentials may be drawn from this main circuit and sent through the Fig. i2ob. side circuit, which comprises the calomel cell C, the solution to be titrated, the hydrogen electrode H, the galvanometer G, and a spring contact switch. The resistance is set at such a point that the galvanometer indicates the passage of no current. In that case, the potential being drawn from the main circuit is exactly equal and opposite to the potential from the hydrogen electrode-calomel electrode system. In order to measure this potential, a voltmeter V is placed in parallel with this side circuit, and at all times measures the potential. The procedure consists, therefore, simply in adjusting the resistance until on closing the contact key the galvanometer shows no current, and then reading the voltage. As suggested above, the DETERMINATION OF ACIDITY 1027 voltmeter may be graduated to read directly in units of hydrogen ion con- centration rather than in volts. Details of the Apparatus. — i. The Hydrogen Electrode. — This is a plati- num wire I mm. in diameter, somewhat flattened at the lower end, which has been sealed into a small glass tube from which a copper wire leads to the rest of the circuit. This platinum wire must, when immersed in the solution, be about half covered by a larger tube which serves as a sort of bell to keep the upper half of the wire immersed in hydrogen gas while the lower half dips into the solution. The hydrogen is admitted to this bell- tube by a T-joint, and during operation bubbles continuously through the solution from under the bell at the rate of about two bubbles per second. The platinum wire must, before use and before insertion in the bell, be covered with a deposit of platinum black. This is done by first cleaning the wire thoroughly in chromic acid solution or in aqua regia if necessary. Platinum is then deposited on this wire by dipping it into a dilute solution of platinic chloride, and connecting the electrode to the negative pole of a dry cell, the positive being connected to another short piece of platinum wire which dips into the solution and forms the anode in the electrolysis. Deposition for fifteen minutes is ample, but it is desirable that the direction of the current be reversed frequently, as often as twice a minute, in order to give a smooth uniform coating of platinum, which should be black and velvety in appearance. The occluded chlorine may be removed by dipping the electrode into a ferrous or other reducing solution. The electrode is then washed with distilled water, and should thereafter always be kept moistened. When not in active use it should be kept in dis- tilled water. If the electrode dries, the platinum deposit must be wiped with a dry cloth or more thoroughly removed, and a new layer of platinum black must be deposited. The electrode in this condition will absorb hydrogen from hydrogen gas and constitute in effect a hydrogen electrode. Time may be economized however, by saturating the electrode with hydrogen artificially by using this electrode as the cathode in an electrol- ysis of sulphuric acid. Hydrogen is thus evolved on the cathode, and serves to saturate it rapidly. This saturation should be repeated whenever the electrode is removed from its contact with pure hydrogen gas. The coat- ing with platinum black should be serviceable for several weeks before it requires replacement. If solutions containing viscous materials or adher- ing precipitates are used, the platinum layer needs to be replaced more often. This form of electrode may be purchased from supply houses. Other forms are also in use, particularly some in which the platinum is in the form 1028 FOOD INSPECTION AND ANALYSIS. of a large foil or strip. This form is more stable in use but requires a much longer time to become saturated with hydrogen and is troublesome in solutions containing precipitates or other solid or viscous materials such as cream or fruit shreds. For such cases a fine platinum gauze may be attached to the glass bell that surrounds the electrode to prevent its clog- ging, particularly if some stirring device is used. A gold electrode coated with palladium black is probably the most effective form of hydrogen elec- trode. 2. The Calomel Electrode.— A calomel electrode may be made up by any of the various methods recommended in text-books of physical chem- istry. The forms of cell used vary widely. The simplest is a test-tube with a two-hole rubber stopper, fitted with tubes, one of which leads to the solution to be titrated, and the other of which holds a glass tube forming electrical connection with the mercury in the bottom of the test-tube by means of a wire sealed through the glass. The form to be recommended is one in which electrical connection from the mercury is made by a platinum wire sealed directly through the glass where the latter holds the mercury. The tube should have a side-arm forming a bridge to the solution, and unless . a fine capillary is used, this side-arm should contain a glass stop-cock which is kept loosely closed but not greased. The calomel electrode tube should have another side-arm placed somewhat higher through which additional potassium chloride solution can be introduced. Finally, it should have a wide opening through which it can be filled, but which should be tightly closed after filling by means of a well-fitting ground glass stopper. To fill the cell it should be thoroughly cleaned and rinsed with a normal potassium chloride solution. About 3 cc. of carefully purified mercury are then placed in the bottom of the cell. Above this is put a layer of mer- cury-calomel paste. This is prepared by rubbing together in a mortar pure " calomel," mercurous chloride, and metallic mercury with a small amount of the potassium chloride solution. When this paste is in place it is covered with a normal solution of potassium chloride which has been saturated with calomel. A large quantity of accurately normal potassium chloride solution should.be made up, and after preparation should be thoroughly shaken with calomel in order to saturate it with that substance. The calomel electrode tube should then be filled up with this solution, leaving only a small air bubble at the top. The tube should be well stoppered, and permanent connection should be made through the upper side-arm with a reservoir bottle containing the excess of potassium chloride DETERMINATION OF ACIDITY 1029 solution. Before each period of use a small quantity of the potassium chloride solution should be allowed to run through the calomel cell in order to wash out the lower side-arm, which constitutes the electrical connection with the solution to be titrated, and which will otherwise gradually become filled with materials from the latter solution by means of diffusion. 3. The Electrical Instruments.— Thr^t electrical instruments are re- quired, connected as shown in Fig. \2oh, a variable resistance, a voltmeter, and a galvanometer. There are many varieties of resistances or rheostats on the market. Any form which permits the continuous ^'ariation of the resistance is satisfactory. The tubular wire rheostats of about 100 ohms total resistance are most convenient, but should be long enough to have at least 150 turns of wire in order to allow delicate adjustment of the end point. The voltmeter should have a total range of 1.25 volts, which is the maximum obtainable from a dry cell, and should be divided into hundredths of volts. The galvanometer, or other instrument used to detect the passage of cur- rent through the solution being titrated, is the only one of these instruments that needs to be sensitive. It should have a sensitivity of at least i megohm. There are several types of portable direct-reading galvanqmeters on the market with a sensitivity as great as this. By the use of the lamp and scale method, more sensitive and more expensive instruments may also be used with convenience. In very accurate work in which, potential readings are to be made to millivolts, some form of electrometer is often used, such as the capillary electrometer or the quadrant electrometer. These are not rec^uired, however, for ordinary titration. The connections are shown in Fig. 1206, which is self-explanatory. It should be noted, however, that the short thick line of the battery, B, represents the positive or carbon pole of the dry cell. It is to this pole that the positive terminal of the voltmeter and the calomel cell connection are made. Several complete assemblies of this apparatus are on the market. The most accurate, which can be depended upon to millivolts, is that designed by Dr. W. T. Bovie and manufactured by the Leeds & Northrup Co., of Philadelphia. This makes use of the quadrant electrometer, and is pro- vided with a temperature compensating device. An apparatus designed by ' Dr. G. L, Kelley, can also be adapted to this purpose, and is sold by Arthur H. Thomas, of Philadelphia, Pa. The Central Scientific Co., of Chicago, has assembled the simplest forms of the various required in- struments on a single board, the result being inexpensive and well suited for ordinary analytical work. 1030 FOOD INSPECTION AND ANALYSIS. The Titration. — The solution to be titrated is placed in a sufficiently large beaker, the calomel electrode as above prepared is inserted, and the hydrogen electrode, platinized and saturated with hydrogen, is also inserted. A stream of hydrogen is allowed to pass over the hydrogen electrode and bubble through the solution continuously during the titration. The hydrogen should be pure, best made by electrolysis or generated from pure zinc and purified by passing through an alkaline solution. It is usually desirable to stir the solution by some extraneous stirring device. Electrical connections are made and preliminary observations of the voltage may be taken, although at the beginning of the titration the electrode is usually not saturated and does not give a constant \oltage reading during the first few minutes. If the electrode has been saturated by means of the elec- trolysis of sulfuric acid, however, not more than a minute should be required to determine the original P^ or " actual acidity." If the solution is to be titrated acid or alkali may now be added, and readings of the voltage may be taken almost at once. The electrode action is most satisfactory when the potential is built upwards, that is, when alkali is added to acid. Beginning with a definite quantity of acid, the data to be recorded are the amounts of alkali added and the voltage at each addition. These data are best comprehended by plotting them graphically, recording voltage against cubic centimeters of alkali added. Several such curves are reproduced here- with. T3T)ical Curves. — Curve I, Fig, 120c, represents the titration of 25 cms. of tenth-normal hydrochloric acid solution with tenth-normal sodium hydroxide. Ordinates on this curve represent acidity. The voltage scale is represented on the left while the corresponding concentrations of hydrogen ions are given on the right. The voltage 0.69 is that of the neutral point, where (H+) = (0H~) = io~'^. The higher the voltage, the lower the hydrogen ion concentration and the greater the alkalinity. The abscissas represent volumes of the alkaline solution added. The original voltage shown by Curve I is 0.35, which represents a tenth-normal hydrogen ion concentration. The curve shows that the first quantities of alkali added have little effect on the hydrogen ion concentra- tion. The alkali is used up in the formation of sodium chloride and the fraction of the total acid used is so small that there is little change in the hydrogen ion concentration and in the voltage. As more and more acid is neutralized, however, every drop of alkali causes a correspondingly larger proportional change in the hydrogen ion concentration and the voltage rises more and more-rapidly. When a voltage of .45 is attained and the acid DETERMINATION OF ACIDITY 1031 is less than one-thousandth normal the addition of a few drops of alkali causes so marked a change in the hydrogen ion concentration that the voltage rises rapidly and indeed abruptly. At 24.8 cc. of alkali, the poten- tial rises to beyond the neutral pomt and this quantity of alkali therefore represents the total amount of acid originally present. This figure, 24.8, is the one that would be obtained by the usual indicator titration and represents the amount of tenth-normal alkali necessary to neutralize the acid originally present. The acid was therefore very slightly weaker than tenth- normal. Beyond this point the addition of alkali increases the hydroxide ion 1.1 1.0 0.9 0.8 0O.7 0.6 0.5 0.4 0.3 Curve I. 26 C.C. N/10 11 CI Curvell. 25C.C. N/10 HC2H3O2 1 "Neutral Point" Phenolphthalein_ changes Litmus — > 10-" 10-^° 10-" io-« 10-^ 1 1 1 1 1 1 1 I 1 1 "I 1 changes ~ Methyl Orange_ changes 1 1 1 1 I 1 1 ->• 1 10-" 10-^ 10-* 10- « 10-=' 2 -1 G 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 C.C. of N/10 Na OH Fig. 1 20c. concentration and decreases the hydrogen concentration in a lesser propor- tion and the voltage therefore rises more gradually, tending finally to reach the voltage of a tenth-normal alkali solution, which is slightly less than i volt. The further addition of alkali is, however, unnecessary, as the last part of the curve represents merely the dilution of tenth-normal alkali by the volume of solution present in the titrating vessel. The center of the vertical rise in voltage at about 25 cc. of alkali needs further attention. It will be seen that the central point of the vertical line lies at a voltage of about .69. This is the voltage given by a strictly neutral solution and it indicates the point at which hydrogen and hydroxide 1032 FOOD INSPECTION AND ANALYSIS. ions are in equal concentration. Since the central part of the vertical rise of this curve here falls exactly at the true neutral point it follows that the products of the reaction here used are such that they do not react v^^ith water to give a product which is itself acid or alkaline. The products of the particular reaction shown by this curve are, of course, sodium chloride and water, and it is obvious that sodium chloride does not hydrolyze to give an acid or a basic product. Curve 2, Fig. 120c, shows the titration of the same quantity of tenth- normal acetic acid with the same alkaline solution. The curve shows that the same quantity of alkali is required for neutralization and hence that the total acidity of the acetic acid was the same as that of the hydrochloric acid, both being tenth-normal. The course of the voltage during the early part of the titration, however, is quite different in this case. In the first place, the original voltage is higher, indicating a lower actual hydrogen ion concentration in the tenth-normal acetic acid, due, of course to the fact that acetic acid is but slightly dissociated. Its " actual acidity " is, indeed hardly more than thousandth normal. The second point worthy of notice is that in the very beginning of the titration the rise in voltage is much more rapid than in the case of the hydrochloric acid. This means that the addition of alkali has here an abnormally large effect in decreasing the hydro- gen ion concentration. This is due, of course, to the fact that as soon as sodium hydroxide is added, sodium acetate is formed which is highly dissociated and therefore liberates a relatively large number of acetate ions. These, according to the principle of equilibrium have an immediate effect in depressing the already small ionization of the acetic acid, so that the acid which is present becomes still less dissociated ; hence it allows still fewer hydrogen ions and hence causes a noticeable rise in the voltage. This effect is marked only during the first 8 cc. and thereafter the trend of the curve is about the same as that in the titration of hydrochloric acid. Complete neutralization occurs at the same point, and the last part of the curve coincides with that of the hydrochloric acid since it represents only the dilution of the tenth-normal sodium hydroxide by the sodium acetate solution. A third point to be noted is that the length of the vertical portion of this curve is much less than in the other case with the consequence that the center of this vertical portion lies not at a voltage of .69 but rather at about .76 volt. Now the center of the vertical portion represents the hydrogen ion concentration when exactly equivalent quantities of sodium hydroxide and of acetic acid are present ; that is, it represents the conditions when only DETERMINATION OF ACIDITY 1033 water and sodium acetate are present. But sodium acetate hydrolyzes to some extent in water solution giving rise to undissociated acetic acid and thus allowing freedom to an excess number of hydroxide ions. In common terms, sodium acetate gives a basic reaction. This reaction is indicated on this curve by the fact that the center of the vertical position of the curve is at .76 volt, corresponding to a hydrogen ion concentration between 10 -» and io~^. For this titration phenolphthalein is usually employed as indicator. The concentration of hydrogen ion, at which this indicator changes, is seen from Fig. 120c to be such that it is well suited for this purpose. It does not change color at the neutral point, but it does change at a point corresponding to the hydrogen ion Concentration of a solution of sodium acetate in water. It is therefore the correct indicator for this purpose. Litmus would not do. Nor would methyl orange, which changes quite on the acid side of neutrality, and is therefore fitted only for titrations of strong acids with weak bases, since these give salts which hydrolyze in water to liberate hydrogen ions, and thus have an " acid reaction." The Titration of Milk. — The curves on Fig. 1 2od represent titrations car- ried out with a sample of milk at various times. Curve i represents the addition of tenth-normal sodium hydroxide to 25 cc. of fresh milk. The original voltage is .68. The milk is therefore very slightly acid — almost imperceptibly so. The true neutral point is reached with 1.5 cc. of alkali, but it is doubtful whether this quantity has any actual significance, for the steepest rise in the curve comes later at about 5.5 cc. and a voltage of 0.8. This is probably the point corresponding to sodium lactate. Thereafter, the rise of the curve is more gradual, but the entire curve is notably more flattened than "the curves of the strong acids heretofore used. This is no doubt due to the presence of salts, especially the salts of weak alkalis and weak acids like the calcium phosphates. The data obtained from this curve are more reliable than those obtained by the usual indicator titrations used in commercial laboratories. The first point, for instance, is usually determined by the use of litmus, which changes very gradually, and gives a much less accurate determination of the actual hydrogen ion concentration. The second point is determined by the use of phenolphthalein which changes at an acidity corresponding to a voltage of .8. The opacity of milk hinders an accurate determination of the color change. The same sample of milk was kept on ice and its actual hydrpgen ion concentration was determined from day to day. The voltage varied as follows : 1034 FOOD INSPECTION AND ANALYSIS. On June i8. " 19. " 20. " 21. " 24. 68 66 60 58 56 54 After a week, therefore, the acidity had increased so that the milk showed a hydrogen ion concentration of about 10 ~^, that is, the milk was ten- 1.1 1 :/ ^^ "Neutral Point" 10-12 10-" 0.9 io-^» io-« 0.8 10"* 5 0.7 10-' > 1 1 1 1 Curve I Fresh Milk Curve II Same Milk Curve III Same Milk 1 1 1 1 1 1 1 1 1 1 6/18 6/23 6/24 1 1 1 1 1 10"^ O.G 10-^ 10-* 0.5 io-» 0.4 lo-'' ft ^ 2 4 6 8 10 12 14 IC 18 20 22 24 2G 28 30 32 34 36 38 40 C.C. Of N/lONaOH Fig. i2Qd. thousandth normal in actual hydrogen ion concentration. This acidity, however, is due to lactic acid which is but slightly dissociated and the total acid present is undoubtedly more than this quantity. That this is true is shown by curves 2 and 3 of Fig. 1 20^, which represent titrations carried out on this sample on June 23 and June 24 respectively. The general form of these curves is the same as that of the first titration on this sample, being, however, somewhat more flattened. Total neutralization of the acid is reached again at about .8 volt corresponding to 18.6 cc. of alkali on June 23d. By the next day 22.3 cc. were rccjuired to reach the same voltage. The difference is a measure of the growth of lactic acid during the twenty- DETERMINATION OF ACIDITY 1035 four hours that had elapsed. The original \'oltage or '' actual acidity " is, however, an equally good measure of the souring of the milk, and can be readi'ly and speedily determined. Wlie.i milk has become sour or when it is rich in cream, the electrode tends to become clogged with the solid materials unless it is protected by a gauze as suggested above. Tea and Coffee.— Fig. 1 2oe represents the titration of samples of tea and coffee brews. Coffee is obviously more acid both in its actual hydrogen ion concentration, which is fairly high, and in its total acid. The curve 1.1 TT •'•• * - 10-^^ 1.0 "Neutral Point" ' j 10-" 0.9 io-^» '■ , 10-" 0.8 10"* O0.7 10-^ > 1 1 Curve I Curve H 1 1 1 1 1 r Tea Coffee 1 I 1 f 1 10-® 0.6 10-5 0.5 10-* 10"^ . 0.4 10-^ ' n ^ II' 4 6 8 10 12 14 16 18 20 22 24 26 28 30 C.C. of N/lONaOH Fig. i2oe. for tea, on the other hand, is much flatter and indicates thepresenceof weaker acids and of more basic salts. The interesting portions of these titrations are in the voltages lying between 0.6 and 0.8 and the titration should be carried on with hundredth -normal alkali instead of with tenth-normal. The Acidity of Fruit Juices. — For the titration of fruit juices, these are prepared in the usual way by pressing out the juice and straining through a fine cloth or filter. In all cases represented here by curves 25 cc. of fruit juice were used, though it is possible and often necessary to use a smaller quantity. The analyses represented are single instances chosen at random and make no claim to being representative for the different varieties of fruit. 1036 FOOD INSPECTION AND ANALYSIS. Lemon and Strawberry. — Fig. 120/ represents the titration of two common acid fruits, the lemon and the strawberry. It is noticeable that the actual acidity of the strawberry is greater than that of the lemon, being more than hundredth-normal. Yet the total acidity of the lemon is almost five times that of the strawberry. Twenty-five cc. of fruit juice were taken; hence the lemon is almost normal in total acid in that 22 cc. of normal alkali were required to neutralize it. The curve for the lemon is a typical curve for citric acid. The long sloping portion of the curve running from zero to 20 cc. represents the gradual neutralization of the three hydrogens that comprise the acid of this fruit. No distinct vertical parts of the curve 1.1 f "Neutral Point" I f • 10-12 i.O 10-" 0.9 10-1" io-» 08 10"* 0.7 10"^ 1 f f 1 I 1 Curve I Curve II 1 1 I 1 1 1 1 Lemon Juice Strawberry Juice 1 1 1 1 1 1 1 1 10"® 0.6 10^ 0.5 10-* ' ' 10"^ 0.4 . 10-2 n ■? 1 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 CC. of N/1 Na OH Fig. i2o/. are noticed because the reaction of the second hydrogen begins before that of the first is complete, and that of the third also begins very soon. The Citric Fruits. — Fig. 1 2og shows this same titration of the strawberry as executed with one-tenth normal alkali. On the same figure appear the curves representing the orange, the grape fruit and the tomato. The straw- berry is the most acid of these four fruits, especially in its actual acidity. Citric, salicylic and malic acids are present. The total acid of the orange is greater than that of the grapefruit though its actual acidity is less. The flat appearance of the orange curve marks the presence of other salts. The DETERMINATION OF ACIDITY 1037 general slanting appearance of the tomato curve is explained by the complex- ity of its acid constituents. 1.1 1.0 — IZ--^ 10-^^ 0.9 0.8 •^0.7 y y : 10 io-'» ' 10-* 10-* 10-^ 0.6 ^^^^ Curve r. Curve II. Curve III. Curve IV. 1 1 1 1 1 Strawberry Juice Orange Juice Grape Fruit Juice Tomato Juice 1 1 1 1 1 1 1 1 10-" 10-^ 0.5 5S====^^^^^^^^ *" 10 0.4 51 1 1 1 1 [ 1 1 1 1 1 r 1 r 1 1 1 10"* 10"^ "02468 10 12 14_16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 GO C.C. of N/10 NaOH Fig. i2og. It will be noted of all these titrations that the acids are weak and other salts are plentiful. The abrupt rise at the very beginning of the curve always Curve I. Curve II. Curve III. Curve IV. Curve V. Peach Juice Cherry Juice Plum Juice Banana Juice Apple Juice. ^■^ 2 4 6 8 10 12 U 16"l8 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 C.C. of N/10 NaOH Ftg. i2oh. points to the presence of an undissociated acid. In every case the center of the vertical portion of the curve lies on the alkaline side of the neutrality line. The exact position of this point would be a means of identifying the 1038 FOOD INSPECTION AND ANALYSIS. acid present, for the weaker the acid the higher is the voltage given by the sodium salt in water. So many acids and other salts are present, however, that the curves show much " buffer action," i.e., they show few sharp flexions and it is not easy to locate the point of equivalence. For the same reason, however, any indicator would give only an arbitrary and empirical value of the equivalence point, and is even less well adapted to showing what is really present. The Malic Fruits. — Fig. i2oh represents the malic fruits. Of these the peach is most acid (though this may possibly have been due to the use of an unripe sample in this analysis). The apple and the cherry have the same 1.1 1.0 0.9 0.8 3 0.7 0.6 S 0.5 0.4 0.3 Curve I. Valencia Orange after One Week on Ice Curve II. Same after One Week at Room Temperature Curve III. "Special St.Michaelis" Redlands Orange after One Week on Ice Curve IV. Same after One Week at Room Temperature J I 1 I I 1 I [ \ I l_J I I I I I I I I I I I I I I I 1 I L 10 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40 42 44 46 48 50 52 54 56 58 60 C.C. of N/10 NaOH Fig. I20Z. actual acidity, but are widely different in the total amounts of acid avail- able. The curve for the apple is a simple curve indicating the presence of only one type of acid and few salts. The plum and the cherry curves are extraordinarily flat and hence these fruits are complex in their constitution. The banana, as is well known, is among the least acid of the common fruits. The Effect of Ripening. — Fig. 120/ finally shows the effect of ripening in decreasing the fruit acidity. Here Curves i and 2 represent juice from two samples of Valencia orange, one of which was kept on ice for a week while the other was kept at room temperature. The marked change in acidity shows an effectual ripening in the second case. Precisely the same is shown by Curves 3 and 4 of this figure, which represents a similar experiment with DETERMINATION OF ACIDITY 1039 two samples of Redlands orange. The peaches represented in Fig. 120^ appeared to be ripe but the curve indicates unripeness since this fruit is not usually so acid. Ripeness is thus a factor that needs to be determined before such a curve can be considered representative for any fruit. Finally, this hydrogen electrode method is a useful means of determining ripeness. APPENDIX. THE FOOD AND DRUGS ACT, JUNE 30, 1906, AS AMENDED AUGUST 23, 1912 AND MARCH 3, 1913. AN ACT FOR PREVENTING THE MANUFACTURE, SALE, OR TRANSPORTATION OF ADULTERATED OR MISBRANDED OR POISONOUS OR DELETERIOUS FOODS, DRUGS, MEDICINES, AND LIQUORS, AND FOR REGULATING TRAFFIC THEREIN, AND FOR OTHER PURPOSES. Be it enacted by the Senate and House of Representatives of the United States of America in Congress assembled, That it shall be unlawful for any person to manufacture within any Territory or the District of Columbia any article of food or drug which is adulterated or misbranded, within the meaning of this Act; .and any person who shall violate any of the provisions of this section shall be guilty of a misdemeanor, and for each offense shall, upon conviction thereof, be fined not to exceed five hundred dollars or shall be sentenced to one year's imprisonment, or both such fine and imprisonment, in the discretion of the court, and for each subsequent offense and conviction thereof shall be fined not less than one thousand dollars or sentenced to one year's imprisonment, or both such fine and imprison- ment, in the discretion of the Court. Sec. 2. That the introduction into any State or Territory or the District of Colum- bia from any other State or Territory or the District of Columbia, or from any foreign coun- try, or shipment to any foreign country of any article of food or drugs which is adulterated or misbranded, within the meaning of this Act, is hereby prohibited; and any person who shall ship or deliver for shipment from any State or Territory or the District of Columbia to any other State or Territory or the District of Columbia, or to a foreign country, or who shall receive in any State or Territory or the District of Columbia from any other State or Territory or the District of Columbia, or foreign country, and having so received, shall deliver, in original unbroken packages, for pay or otherwise, or offer to deliver to any other person, any such article so adulterated or misbranded within the meaning of this Act, or any person who shall sell or offer for sale in the District of Columbia or the Ter- ritories of the United States any such adulterated or misbranded foods or drugs, or export or offer to export the same to any foreign country, shall be guilty of a misdemeanor, and for such offense be fined not exceeding two hundred dollars for the first offense, and upon conviction for each subsequent offense not exceeding three hundred dollars or be imprisoned not exceeding one year, or both, in the discretion of the court: Provided, That no article shall be deemed misbranded or adulterated within the provisions of this Act when intended for export to any foreign country and prepared or packed according to the specifications or directions of the foreign purchaser when no substance is used in the preparation or pack- ing thereof in conflict with the laws of the foreign country to which said article is intended to be shipped; but if said article shall be in fact sold or offered for sale for domestic use or consumption, then this proviso shall not exempt said article from the operation of any of the other provisions of this Act. Sec. 3. That the Secretary of the Treasury, the Secretary of Agriculture, and the Secretary of Commerce and Labor shall make uniform rules and regulations for carrying out the provisions of this act, including the collection and examination of specimens of foods and drugs manufactured or offered for sale in the District of Columbia, or in any 1041 1042 FOOD INSPECTION AND ANALYSIS. Territory of the United States, or which shall be offered for sale in unbroken packages in any State other than that in which they shall have been respectively manufactured or pro- duced, or which shall be received from any foreign country, or intended for shipment to any foreign country, or which may be submitted for examination by the chief health, food, or drug officer of any State, Territory, or the District of Columbia, or at any domestic or foreign port through which such product is offered for interstate commerce, or for export or import between the United States and any foreign port or country. Sec. 4. That the examinations of specimens of foods and drugs shall be made in the Bureau of Chemistry of the Department of Agriculture, or under the direction and super- vision of such Bureau, for the purpose of determining from such examinations whether such articles are adulterated or misbranded within the meaning of this Act; and if it shall appear from any such examination that any of such specimens is adulterated or misbranded within the meaning of this Act, the Secretary of Agriculture shall cause notice thereof to be given to the party from whom such sample was obtained. Any party so notified shall be given an opportunity to be heard, under such rules and regulations as may be prescribed as aforesaid, and if it appears that any of the provisions of this Act have been violated by such party, then the Secretary of Agriculture shall at once certify the facts to the proper United States district attorney, with a copy of the results of the analysis or the examination of such article duly authenticated by the analyst or ofi&cer making such examination, under the oath of such officer. After judgment of the court, notice shall be given by publication in such manner as may be prescribed by the rules and regulations aforesaid. Sec. 5. That it shall be the duty of each district attorney to whom the Secretary of Agriculture shall report any violation of this Act, or to whom any health or food or drug ofl&cer or agent of any State, Territory, or the District of Columbia shall present satisfactory evidence of any such violation, to cause appropriate proceedings to be commenced and prosecuted in the proper courts of the United States, without delay, for the enforcement of the penalties as in such case herein provided. Sec. 6. That the term " drug," as used in this Act, shall include all medicines and preparations recognized in the United States Pharmacopoeia or National Formulary for internal or external use, and any substance or mixture of substances intended to be used for the cure, mitigation, or prevention of disease of either man or other animals. The term " food," as used herein, shall include all articles used for food, drink, confectionery, or condiment by man or other animals, whether simple, mixed, or compound. Sec. 7. That for the purposes of this Act an article shall be deemed to be adulterated: In case of drugs: First. If, when a drug is sold under or by a name recognized in the United States Phar- macopoeia or National Formulary, it differs from the standard of strength, quality, or purity, as determined by the test laid down in the United States Pharmacopoeia or National Formulary official at the time of investigation: Provided, That no drug defined in the United States Pharmacopoeia or National Formulary shall be deemed to be adulterated under this provision if the standard of strength, quality, or purity be plainly stated upon the bottle, box, or other container thereof although the standard may differ from that determined by the test laid down in the United States Pharmacopoeia or National Formulary. Second. If its strength or purity fall below the professed standard or quality under which it is sold. In the case of confectionery: If it contain terra alba, barytes, talc, chrome yellow, or other mineral substance or poisonous color or flavor, or other ingredient deleterious or detrimental to health, or any vinous, malt, or spirituous liquor or compound or narcotic drug. In the case of food: APPENDIX. 1043 First. If any substance has been mixed and packed with it so as to reduce or lower or injuriously affect its quality or strength. Second. If any substance has been substituted wholly or in part for the article. Third. If any valuable constituent of the article has been wholly or in part abstracted. Fourth. If it be mixed, colored, powdered, coated, or stained in a manner whereby damage or inferiority is concealed. Fifth. If it contain any added posionous or other added deleterious ingredient which may render such article injurious to health: Provided, That when in the preparation of food products for shipment they are preserved by any external application applied in such manner that the preservative is necessarily removed mechanically, or by maceration in water, or otherwise, and directions for the removal of said preservative shall be printed on the cov- ering or the package, the provisions of this Act shall be construed as applying only when said products are ready for consumption. Sixth. If it consists in whole or in part of a filthy, decomposed, or putrid animal or vegetable substance, or any portion of an animal unfit for food, whether manufactured or not, or if it is the product of a diseased animal, or one that has died otherwise than by slaughter. Sec. 8. That the term " misbranded," as used herein, shall apply to all drugs, or articles of food, or articles which enter into the composition of food, the package or label of which shall bear any statement, design, or device regarding such article, or the ingredients or substances contained therein which shall be false or misleading in any particular, and to any food or drug product which is falsely branded as to the State, Territory, or country in which it is manufactured or produced. That for the purposes of this Act an article shall also be deemed to be misbranded: In case of drugs: First. If it be an imitation of or offered for sale under the name of another article. Second. If the contents of the package as originally put up shall have been removed, in whole or in part, and other contents shall have been placed in such package, or if the package fail to bear a statement on the label of the quantity or proportion of any alcohol, morphine, opium, cocaine, heroin, alpha or beta eucaine, chloroform, cannabis indica. chloral hydrate, or acetanilide, or any derivative or preparation of any such substances contained therein. Third.* If its package or label shall bear or contain any statement, design, or device regarding the curative or theraupetic effect of such article or any of the ingredients or sub- stances contained therein, which is false and fraudulent. In the case of food: First. If it be an imitation of or offered for sale under the distinctive name of another article. Second. If it be labeled or branded so as to deceive or mislead the purchaser, or pur- port to be a foreign product when not so, or if the contents of the package as originally put up shall have been removed in whole or in part and other contents shall have been placed in such package, or if it fail to bear a statement on the label of the quantity or propor- tion of any morphine, opium, cocaine, heroin, alpha or beta eucaine, chloroform, cannabis indica, chloral hydrate, or acetam'Jide, or any derivative or preparation of any of such sub- stances contained therein. Third, t If in package form, the quantity of the contents be not plainly and con- spicuously marked on the outside of the package in terms of weight, measure, or numer- ical count: Provided, however, That reasonable variations shall be permitted, and toler- ances and also exemptions as to small packages shall be established by rules and * This paragraph constitutes the amendment of August 23, 1912. t This paragraph is as amended March 3, 19 13- 1044 FOOD INSPECTION AND ANALYSIS. regulations made in accordance with the provisions of Section three of this Act. That this Act shall take effect and be in force from and after its passage: Provided, however That no penalty of fine, imprisonment, or confiscation shall be enforced for any violation of its provisions as to domestic products prepared or foreign products imported prior to eighteen months after its passage. Fourth. If the package containing it or its label shall bear any statement, design, or device regarding the ingredients or the substances contained therein, which statement, design, or device shall be false or misleading in any particular: Provided, That an article of food which does not contain any added poisonous or deleterious ingredients shall not be deemed to be adulterated or misbranded in the follo\ving cases: First. In the case of mixtures or compounds which may be now or from time to time hereafter known as articles of food, under their own distinctive names, and not an imitation of or offered for sale under the distinctive name of another article, if the name be accom- panied on the same label or brand with a statement of the place where said article has been manufactured or produced. Second. In the case of articles labeled, branded, or tagged so as to plainly indicate that they are compounds, imitations, or blends, and the word " compound," " imitation," or " blend," as the case may L^, is plainly stated on the package in which it is offered for sale: Provided, That the term blend as used herein shall be construed to mean a mixture of like substances, not excluding harmless coloring or flavoring ingredients used for the pur- pose of coloring and flavoring only: And provided further, That nothing in this Act shall be construed as requiring or compelling proprietors or manufacturers of proprietary foods which contain no unwholesome added ingredient to disclose their trade formulas, except in so far as the provisions of this Act may require to secure freedom from adulteration or misbranding. Sec. q. That no dealer shall be prosecuted under the provisions of this Act when he can estabhsh a guaranty signed by the wholesaler, jobber, manufacturer, or other party residing in the United States, from whom he purchases such articles, to the effect that the same is not adulterated or misbranded within the meaning of this Act, designating it. Said guaranty, to afford protection, shall contain the name and address of the party or parties making the sale of such articles to such dealer, and in such case said party or parties shall be amenable to the prosecutions, fines, and other penalties which would attach, in due course, to the dealer under the provisions of this Act. Sec. id. That any article of food, drug, or Hquor that is adulterated or misbranded within the meaning of this Act, and is being transported from one State, Territory, District, or insular possession to another for sale, or, having been transported, remains unloaded, unsold, or in original unbroken packages, or if it be sold or offered for sale in the District of Columbia or the Territories, or insular possessions of the United States, or if it be imported from a foreign country for sale, or if it is intended for export to a foreign country, shall be liable to be proceeded against in any district court of the United States within the district where the same is found, and seized for confiscation by a process of libel for condemnation. And if such article is condemned as being adulterated or misbranded, or of a poisonous or deleterious character, within the meaning of this Act, the same shall be disposed of by destruc- tion or sale, as the said court may direct, and the proceeds thereof, if sold, less the legal costs and charges, shall be paid into the Treasury of the United States, but such goods shall not be sold in any jurisdiction contrary to the provisions of this Act or the laws of that jurisdiction: Provided however, That upon the payment of the costs of such hbel pro- ceedings and the execution and delivery of a good and sufficient bond to the effect that such articles shall not be sold or otherwise disposed of contrary to the provisions of this Act, or the laws of any State, Territory, District, or insular possession, the court may by order direct that such articles be delivered to the owner thereof. The proceedings of such libel APPENDIX. 1045 cases shall conform, as near as may be, to the proceedings in admiralty, except that either party may demand trial by jury of any issue of fact joined in any such case, and all such proceedings shall be at the suit of and in the name of the United States. Sec. II. The Secretary of the Treasury shall deliver to the Secretary of Agriculture, upon his request from time to time, samples of foods and drugs which are being imported into the United States or offered for import, giving notice thereof to the owner or consignee, who may appear before the Secretary of Agriculture, and have the right to introduce testimony, and if it appear from the examination of such samples that any article of food or drug offered to be imported into the United States is adulterated or misbranded within the meaning of this Act, or is otherwise dangerous to the health of the people of the United States, or is of a kind forbidden entry into, or forbidden to be sold or restricted in sale in the country in which it is made or from which it is exported, or is otherwise falsely labeled in any respect, the said article shall be refused admission, and the Secretary of the Treasury shall refuse delivery to the consignee and shall cause the destruction of any goods refused deHvery which shall not be exported by the consignee within three months from the date of notice of such refusal under such regulations as the Secretary of the Treasury may pre- scribe: Provided, That the Secretary of the Treasury may deliver to the consignee such goods pending examination and decision in the matter on execution of a penal bond for the amount of the full invoice value of such goods, together with the duty thereon, and on refusal to return such goods for any cause to the custody of the Secretary of the. Treasury, when demanded, for the purpose of excluding them from the country, or for any other purpose, said consignee shall forfeit the full amount of the bond: And provided further, That all charges for storage, cartage, and labor on goods which are refused admission or delivery shall be paid by the owner or consignee, and in default of such payment shall constitute a lien against any future importation made by such owner or consignee. Sec. 12. That the term " Territory " as used in this Act shall include the insular pos- sessions of the United States. The word " person " as used in this Act shall be construed to import both the plural and the singular, as the case demands, and shall include corpora- tions, companies, societies and associations. When construing and enforcing the provisions of this Act, the act, omission, or failure of any officer, agent, or other person acting for or employed by any corporation, company, society, or association, within the scope of his employment or office, shall in every case be also deemed to be the act, omission, or failure of such corporation, company, society, or association as well as that of the person. Sec. 13. That this Act shall be in force and effect from and after the first day of January, nineteen hundred and seven. THE MEAT-INSPECTION LAW. Extract from an act of Congress entitled " An act making appropriations for the Department of Agriculture for the fiscal year ending June thirtieth, nine- teen HUNDRED AND SEVEN," APPROVED JUNE 30, I906. That for the purpose of preventing the use in interstate or foreign commerce, as herein- after provided, of meat and meat food products which are unsound, unhealthful, unwhole- some, or otherwise unfit for human food, the Secretary of Agriculture, at his discretion, may cause to be made, by inspectors appointed for that purpose, an examination and inspection of all cattle, sheep, swine, and goats before they shall be allowed to enter into any slaughtering, packing, meat-canning, rendering, or similar estabhshment, in which they are to be slaughtered and the meat and meat food products thereof are to be used in inter- state or foreign commerce; and all cattle, swine, sheep, and goats found on such inspection to 1046 FOOD INSPECTION AND ANALYSIS. show symptoms of disease shall be set apart and slaughtered separately from all other cattle, sheep, swine, or goats, and when so slaughtered the carcasses of said cattle, sheep, swine, or goats shall be subject to a careful examination and inspection, all as provided by the rules and regulations to be prescribed by the Secretary of Agriculture as herein provided for. That for the purposes hereinbefore set forth the Secretary of Agriculture shall cause to be made by inspectors appointed for that purpose, as hereinafter provided, a post-mortem examination and inspection of the carcasses and parts thereof of all cattle, sheep, swine, and goats to be prepared for human consumption at any slaughtering, meat-canning, salt- ing, packing, rendering, or similar establishment in any State, Territory, or the District of Columbia for transportation or sale as articles of interstate or foreign commerce, and the carcasses and parts thereof of all such animals found to be sound, healthful, wholesome, and fit for human food shall be marked, stamped, tagged, or labeled as " Inspected and Passed;" and said inspectors shall label, mark, stamp, or tag as " Inspected and Con- demned," all carcasses and parts thereof of animals found to be unsound, unhealthful, unwholesome, or otherwise unfit for human food; and all carcasses and parts thereof thus inspected and condemned shall be destroyed for food purposes by the said establishment in the presence of an inspector, and the Secretary of Agriculture may remove inspectors from any such estabUshment which fails to so destroy any such condemned carcass or part thereof, and said inspectors, after said first inspection shall, when they deem it necessary, reinspect said carcasses or parts thereof to determine whether since the first inspection the same have become unsound, unhealthful, unwholesome, or in any way unfit for human food, and if any carcass or any part thereof shall, upon examination and inspection subse- quent to the first examination and inspection, be found to be unsound, unhealthful, unwhole- some, or otherwise ujifit for human food, it shall be destroyed for food purposes by the said establishment in the presence of an inspector, and the Secretary of Agriculture may remove inspectors ir<^m any establishment which fails to so destroy any such condemned carcass or part thereof. The foregoing provisions shall apply to all carcasses or parts of carcasses of cattle, sheep, swine, and goats, or the meat or meat products thereof which may be brought into any slaughtering, meat-canning, salting, packing, rendering, or similar establishment, and such examination and inspection shall be had before the said carcasses or parts thereof shall be allowed to enter into any department wherein the same are to be treated and pre- pared for meat food products; and the foregoing provisions shall also apply to all such products which, after having been issued from any slaughtering, meat-canning, salting, packing, rendering, or similar establishment, shall be returned to the same or to any similar establishment where such inspection is maintained. That for the purposes hereinbefore set forth the Secretary of Agriculture shall cause to be made by inspectors appointed for that purpose an examination and inspection of all meat food products prepared for interstate or foreign commerce in any slaughtering, meat-canning, salting, packing, rendering, or similar estabHshment, and for the purposes or any examination and inspection said inspectors shall have access at all times, by day or night, whether the establishment be operated or not, to every part of said establishment; and said inspectors shall mark, stamp, tag, or label as " Inspected and Passed " all such products found to be sound, healthful, and wholesome, and which contain no dyes, chemicals, preservatives, or ingredients which render such meat or meat food products unsound, unhealthful, unwholesome, or unfit for human food; and said inspectors shall label, mark, stamp, or tag as " Inspected and Condemned " all such products found unsound, unhealth- ful, and unwholesome, or which contain dyes, chemicals, preservatives, or ingredients which render such meat or meat food products unsound, unhealthful, unwholesome, or unfit for human food, and all such condemned meat food products shall be destroyed for food pur- APPENDIX. 1047 poses, as hereinbefore provided, and the Secretary of Agriculture may remove inspectors from any establishment which fails to so destroy such condemned meat food products: Provided, That, subject to the rules and regulations of the Secretary of Agriculture, the pro- visions hereof in regard to preservatives shall not apply to meat food products for export to any foreign country and which are prepared or packed according to the specifications or directions of the foreign purchaser, when no substance is used in the preparation or packing thereof in conflict with the laws of the foreign country to which said article is to be exported; but if said article shall be in fact sold or offered for sale for domestic use or consumption, then this proviso shall not exempt said article from the operation of all the other provisions of this act. That when any meat or meat food product prepared for interstate or foreign com- merce which has been inspected as hereinbefore provided and marked " Inspected and Passed " shall be placed or packed in any can, pot, tin, canvas, or other receptacle or cover- ing in any establishment where inspection under the provisions of this act is maintained, the person, firm, or corporation preparing said product shall cause a label to be attached to said can, pot, tin, canvas, or other receptacle or covering, under the supervision of an inspector, which label shall state that the contents thereof have been " Inspected and Passed " under the provisions of this act; and no inspection and examination of meat or meat food products deposited or inclosed in cans, tins, pots, canvas, or other receptacle or covering in any establishment where inspection under the provisions of this act is maintained shall be deemed to be complete until such meat or meat food products have been sealed or inclosed in said can, tin, pot, canvas, or other receptacle or covering under the supervision of an inspector, and no such meat or meat food products shall be sold or offered for sale by any person, firm, or corporation in interstate or foreign commerce under any false or deceptive name; but established trade name or names which are usual to such products and which are not false and deceptive and which shall be approved by the Secretary of Agriculture are permitted. The Secretary of Agriculture shall cause to be made, by experts in sanitation or by other competent inspectors, such inspection of all slaughtering, meat-canning, salting, packing, rendering, or similar establishments in which cattle, sheep, swine, and goats are slaughtered and the meat and meat food products thereof are prepared for interstate or foreign commerce as may be necessary to inform himself concerning the sanitary conditions of the same, and to prescribe the rules and regulations of sanitation under which such establishments shall be maintained; and where the sanitary conditions of any such establishment are such that the meat or meat food products are rendered unclean, unsound, unhealthful, unwholesome, or otherwise unfit for human food, he shall refuse to allow said meat or meat food products to be labeled, marked, stamped, or tagged as " Inspected and Passed." That the Secretary of Agriculture shall cause an examination and inspection of all cattle, sheep, swine, and goats, and the food products thereof, slaughtered and prepared in the establishments hereinbefore described for the purposes of interstate or foreign commerce to be made during the nighttime as well as during the daytime when the slaughtering of said cattle, sheep, swine, and goats, or the preparation of said food products is conducted during the nighttime. That on and after October first, nineteen hundred and six, no person, firm, or corpora- tion shall transport or offer for transportation, and no carrier of interstate or foreign commerce shall transport -or receive for transportation from one State or Territory or the District of Columbia to any other State or Territory or the District of CoLimbia, or to any place under the jurisdiction of the United States, or to any foreign country, any carcasses or parts thereof, meat, or meat food products thereof which have not been inspected, examined, and marked as " Inspected and Passed," in accordance with the terms of this act and with the rules and 1048 FOOD INSPECTION AND ANALYSIS. regulations prescribed by the Secretary of Agriculture: Provided, That all meat and meat food products on hand on October first, nineteen hundred and six, at establishments where inspection has not been maintained, or which have been inspected under existing law, shall be examined and labeled under such rules and regulations as the Secretary of Agriculture shall prescribe, and then shall be allowed to be sold in interstate or foreign commerce. That no person, firm, or corporation, or officer, agent, or employee thereof, shall forge, counterfeit, simulate, or falsely represent, or shall without proper authority use, fail to use, or detach, or shall knowingly or wrongfully alter, deface, or destroy, or fail to deface or destroy, any of the marks, stamps, tags, labels, or other identification devices provided for in this act, or in and as directed by the rules and regulations prescribed hereunder by the Secretary of Agriculture, on any carcasses, parts of carcasses, or the food product, or containers thereof, subject to the provisions of this act, or any certificate in relation thereto, authorized or required by this act or by the said rules and regulations of the Secretary of Agriculture, That the Secretary of Agriculture shall cause to be made a careful inspection of all cattle, sheep, swine, and goats intended and offered for export to foreign countries at such times and places, and in such manner as he may deem proper, to ascertain whether such cattle, sheep, swine, and goats are free from disease. And for this purpose he may appoint inspectors who shall be authorized to give an official certificate clearly stating the condition in which such cattle, sheep, swine, and goats are found. And no clearance shall be given to any vessel having on board cattle, sheep, swine, or goats for export to a foreign country until the owner or shipper of such cattle, sheep, swine, or goats has a certificate from the inspector herein authorized to be appointed, stating that the said cattle, sheep, swine, or goats are sound and healthy, or unless the Secretary of Agriculture shall have waived the requirement of such certificate for export to the particular country to which such cattle, sheep, swine, or goats are to be exported. That the Secretary of Agriculture shall also cause to be made a careful inspection of the carcasses and parts thereof of all cattle, sheep, swine, and goats, the meat of which, fresh, salted, canned, corned, packed, cured, or otherwise prepared, is intended and offered for export to any foreign country, at such times and places and in such manner as he may deem proper. And for this purpose he may appoint inspectors who shall be authorized to give an official certificate stating the condition in which said cattle, sheep, swine, or goats, and the meat thereof, are found. And no clearance shall be given to any vessel having on board any fresh, salted, canned, corned, or packed beef, mutton, pork, or goat meat, being the meat of animals killed after the passage of this act, or except as hereinbefore provided for export to and sale in a foreign country from any port in the United States, until the owner or shipper thereof shall obtain from an inspector appointed under the provisions of this act a certificate that the said cattle, sheep, swine, and goats were sound and healthy at the time of inspection, and that their meat is sound and wholesome, unless the Secretary of Agriculture shall have waived the requirements of such certificate for the country to which said cattle, sheep, swine and goats or meats are to be exported. That the inspectors provided for herein shall be authorized to give official certificates of the sound and wholesome condition of the cattle, sheep, swine, and goats, their carcasses and products as herein described, and one copy of every certificate granted under the pro- visions of this act shall be filed in the Department of Agriculture, another copy shall be delivered to the owner or shipper, and when the cattle, sheep, swine, and goats or their carcasses and products are sent abroad, a third copy shall be dehvered to the chief ofl&cer of the vessel on which the shipment shall be made. APPENDIX. 1049 That no person, firm, or corporation engaged in the interstate commerce of meat or meat food products shall transport or offer for transportation, sell or offer to sell any such meat or meat food products in any State or Territory or in the District of Columbia or any place under the jurisdiction of the United States, other than in the State or Territory or in the District of Columbia or any place under the jurisdiction of the United States in which the slaughtering, packing, canning, rendering, or other similar establishment owned, leased, operated by said firm, person, or corporation is located unless and until said person, firm, or corporation shall have complied with all of the provisions of this act. That any person,, firm, or corporation, or any officer or agent of any such person, firm, or corporation, who shall violate any of the provisions of this act shall be deemed guilty of a misdemeanor, and shall be punished on conviction thereof by a fine of not exceeding ten thousand dollars or imprisonment for a period not more than two years, or by both such fine and imprisonment, in the discretion of the court. That the Secretary of Agriculture shall appoint from time to time inspectors to make examination and inspection of all cattle, sheep, swine, and goats, the inspection of which is hereby provided for, and of all carcasses and parts thereof, and of all meats and meat food products thereof, and of the sanitary conditions of all establishments in which such meat and meat food products hereinbefore described are prepared; and said inspectors shall refuse to stamp, mark, tag, or label any carcass or any part thereof, or meat food product therefrom, prepared in any establishment hereinbefore mentioned, until the same shall have actually been inspected and found to be sound, healthful, wholesome, and fit for human food, and to contain no dyes, chemicals, preservatives, or ingredients which render such meat food product unsound, unhealthful, unwholesome, or unfit for human food; and to have been prepared under proper sanitary conditions, hereinbefore provided for; and shall perform such other duties as are provided by this act and by the rules and regulations to be prescribed by said Secretary of Agriculture; and said Secretary of Agriculture shall, from time to time, make such rules and regulations as are necessary for the efficient execution of the provisions of this act, and all inspections and examinations made under this act shall be such and made in such manner as described in the rules and regulations prescribed by said Secretary of Agriculture not inconsistent with the provisions of this act. That any person, firm, or corporation, or any agent or employee of any person, firm, or corporation, who shall give, pay, or offer, directly or indirectly, to any inspector, deputy inspector, chief inspector, or any other officer or employee of the United States authorized to perform any of the duties prescribed by this act or by the rules and regulations of the Secretary of Agriculture any money or other thing of value, with intent to influence said inspector, deputy inspector, chief inspector, or other officer or employee of the United States in the discharge of any duty herein provided for, shall be deemed guilty of a felony and, upon conviction thereof, shall be punished by a fine not less than five thousand dollars nor more than ten thousand dollars and by imprisonment not less than one year nor more than three years; and any inspector, deputy inspector, chief inspector, or other officer or employee of the United States authorized to perform any of the duties prescribed by this act who shall accept any money, gift, or other thing of value from any person, firm, or corporation, or officers, agents, or employees thereof, given with intent to influence his official action, or who shall receive or accept from any person, firm, or corporation engaged in interstate or foreign commerce any gift, money, or other thing of value given with any purpose or intent what- soever, shall be deemed guilty of a felony and shall, upon conviction thereof, be summarily discharged from office and shall be punished by a fine not less than one thousand dollars nor more than ten thousand dollars and by imprisonment not less than one year nor more than three years. That the provisions of this act requiring inspection to be made by the Secretary of 1050 FOOD INSPECTION AND ANALYSIS. Agriculture shall not apply to animals slaughtered by any farmer on the farm and sold and transported as interstate or foreign commerce, nor to retail butchers and retail dealers in meat and meat food products, supplying their customers: Provided, That if any person shall sell or offer for sale or transportation for interstate or foreign commerce any meat or meat food products which are diseased, unsound, unhealthful, unwholesome, or otherwise unfit for human food, knowing that such meat food products are intended for human consump- tion, he shall be guilty of a misdemeanor, and on conviction thereof shall be punished by a fine not exceeding one thousand dollars or by imprisonment for a period of not exceeding one year, or by both such fine and imprisonment: Provided also, That the Secretary of Agri- culture is authorized to maintain the inspection in this act provided for at any slaughtering, meat canning, salting, packing, rendering, or similar establishment notwithstanding this exception, and that the persons operating the same may be retail butchers and retail dealers or farmers; and where the Secretary of Agriculture shall establish such inspection then the provisions of this act shall apply notwithstanding this exception. That there is permanently appropriated, out of any money in the Treasury not other- wise appropriated, the sum of three million dollars, for the expenses of the inspection of cattle, sheep, swine, and goats and the meat and meat food products thereof which enter into interstate or foreign commerce and for all expenses necessary to carry into effect the provisions of this act relating to meat inspection, including rent and the employment of labor in Washington and elsewhere, for each year. And the Secretary of Agriculture shall, in his annual estimates made to Congress, submit a statement in detail, showing the number of persons employed in such inspections and the salary or per diem paid to each, together with the contingent expenses of such inspectors and where they have been and are employed. INDEX. Abbe construction, 95 influence of temperature, 96 manipulation, 95 refractometer, 86, 94 Abrastol, 903 Absinthe, 787 Acetanilide in vanilla extract, 918 tests for, 925, 926 Acetic acid, 38, 788 Acetyl value, 514 Achroodextrine, 598 Acid fuchsin, 815, 831, 837, 838, 845, 851, 854, 868 test for, 845 green, 826 magenta, see Acid fuchsin violet N, 856, 873 yellow G, 815, 837, 847, 854, 868 Acidity determination by hydrogen elec- trode, 102 1 apparatus for, 1025 calomel electrode for, 1028 electrical instruments for, 1029 hydrogen electrode, 1027 principle of method, 1022 theory of method, 1024 titration, 1030 of coffee, 1035 fruit juices, 1037 milk, 1033 tea, 1035 typical curves, 1030 Acidity determination by standard solutions, 24-27 Acids, fatty, 497, 501, 518, 529 of acetic series, 486 clupanodonic series, 487 linolenic series, 487 linolic series, 487 oleic series, 487 Acids, mineral, in vinegar, 797 organic, 38, 982, 983, 1008, 1009 Ackermann and Steinmann table for alcohol from refraction, 748 Ackermann table for extract from refraction, 755 Adams fat method, 122 Adenine, 35, 205 " Aerated " butter, 563 Agar agar, in jelly, 991, 1002 Aging of liquors, 764, 765 Alanine, 35 Alantoin, 308 Albrech lemon color method, 936 Albumin, acid, S3 alkali, $$ egg, 270 meat extract, 246, 247, 248, 249 determination, 254 milk, no determination, 133 muscle, 205, 206 determination, 229 Albuminoids, 31 Albumins, 30, 306 Albumose, ^;i, 254 Alcannin, 852 Alcohol, detection, 686 determination, 687 by distillation, 681, 687 ebuUioscope, 704 evaporation, 689 from refraction, 747 specific gravity, 688 extract of spices, 424 in malt liquors, 747 methyl, 781, 935 preparation of, 763 stills, 688 tables, 690, 748 1051 1052 INDEX. Alcoholic beverages, 682. See also Liquors. fermentation, 682 Aldehydes, determination, 777 Aldoses, 36 Ale, 740, 741, 743, 745. See also Beer. ginger, 1012 Aleurone, 77 Alizarin, 815, 832, 856, 872 blue, 857, 873 red, 855, 871 Alkaloids, 29, 35, 759 Alkanna tincture, 79 AUantoin, 308 AUen-Marquardt fusel oil method, 779 Allihn sugar method, 632 table, 633, 634 Allspice, 434 adulteration, 438 composition of, 434 methods of analysis. See Spices and Cloves, microscopj^, 436 standard, 438 tannin in, 435 Almond extract, 942 adulteration of, 943 alcohol in, 943, 946 benzaldehyde in, 942, 944, 945 hydrocyanic acid in, 942, 946 methods of analysis, 945 alcohol, 946 benzaldehyde, 944, 945 hydrocyanic acid, 946 nitrobenzol, 945 nitrobenzol in, 943, 945 standards, 943 meal, 375 Almonds, bitter, oil of, 942 composition of, 284 Alum in baking powder, 350, 351, 352, 360 bread, 342 flour, 324, 334 pickles, 986 wine, 725 Alumina, determination of, 312, 361 Aluminum salts in baking powder, 350, 351 cream of tartar, 348 Amagat and Jean refractometer, 86 Amandin, 31 Amaranth, 815, 834, 837, 851, 854, 868 Amides, 29, 34, 308 Amines, 29 Amino acids, 29, 35 determination, 63 compounds in milk, no determination, 133 Ammonia, determination, 62 in baking powder, 349, 350, 362 foods, 29, 35 milk, 133 Ammonium fluoride, 901 Amthor caramel test, 784 Amygdalin, 35 Amylodextrin, 598 Amyloid, 78, 79 Analyst, functions of, 3, 4 Angostura, 786, 787 Anilin orange, 160, 162 yellow, 858, 87s Animal diastase, 293 Anise extract, standards, 949 oil, standards, 950 Anisette, 787 Annatto, 815, 819, 823, 849 in butter, 557, 558, 559 milk, 161, 162 Antiseptic. See Preservatives. Apiose, 36 Apparatus, 18 Apple butter, 986 essence, imitation, 955 juice, 707, 709 pulp, detection, 1002 Apples, composition of, 283, 284, 993 Apricots, composition of, 283 Araban, 38, 294 Arabinose, 36, 294 Arachidic acid, 29, 487 Arata color test, 841 Archil, 815, 819, 822 Army rations, 265 Arnold peroxide test, 173 and Mentzel formaldehyde test, 881 Arrowroot starch, 291 Arsenic compounds in colors, 813, 815 detection and determination, 63 in baking chemicals, 351 beer, 746, 760 INDEX. 1053 Arsenic in confectionery, 68 1 glucose, 663 vinegar, 811 Johnson-Chittenden-Gautier meth- od, 63 Marsh apparatus, 64 Sanger-Black-Gutzeit test for, 65 Artificial colors, 812 fruit essence, 954, 955 sweeteners, 905 Asaprol, 903 Asbestos fiber, preparation of, 618, 622 Ash analysis, scheme for, 311 determination of, 51 of food, 38 Asparagin, 35, 308 Asparagus, composition of, 282 Auramin G, 848, 857, 874 0,831,848,857,874 Aurantia, 856, 872 Aurin, 832 Azo blue, 815, 829, 837, 846, 855, 870 Azoacidrubine, 826 Azocarmine B, 854, 869 G, 854, 869 Azoflavin, 856, 872 Azofuchsine G, 854, 869 Azolitmin, 819, 822, 855, 870 Azorubin, 815, 837, 851, 855, 870 Babcock asbestos milk fat method, 121 solids method, 121 centrifugal fat method, 123 solids not fat formula, 140 Bacon formic acid method, 899, 901 and Dunbar citric acid method, 982 lactic acid method, 983 Baier and Neumann sucrose test, 189 Baker tin method, 972, 975 Baking powder, 349 adulteration of, 351 alum, 350, 352 cathartics, 352 classification, 349 controversies, 351 methods of analysis, 352 alumina, 361 ammonia, 362 arsenic, 362 Baking powder, methods of analysis, 352 carbon dioxide, avail- able, 355 residual, 355 total, 353 lead, 362 lime, 361 phosphoric acid, 362 potash, 361 soda, 361 starch, 360 sulphuric acid, 362 tartaric acid, 356 phosphate, 349 tartrate, 349 Balances, 19 Bamihl gluten test, 336 Banana essence, artificial, 955 Bananas, composition of, 283 Barbier and Jandrier formaldehyde test, 882 Barium compounds in colors, 784 Bark as an adulterant, 442 Barley, 280, 281 ash, 310 microscopy of, 317 proteins, 309 starch, 290 Barwood, 819, 822, 852 Basic colors, 841 Bast fibers, 76 Baudouin sesame oil test, 538 Beading oil, 770 Bean starch, 291 Beans, 281, 282 in coffee, 400 Bechi cottonseed oil test, 536 Beckmann freezing-point apparatus, 49 test for glucose in honey, 673 Beechnuts, composition of, 284 Beef, composition of, 208 cuts of, 208 stearin, microscopy of, 582 tallow, 550 Beer, 738 adulteration of, 742 aloes in, 742, 760 arsenic in, 746, 760 ash in, 745 birch, 1013 bock-, 740 1054 INDEX. Beer, brewers' sugar in, 741 brewing of, 739 chiretta in, 742, 760 composition of, 740, 743 degree of fermentation of, 756 gentian bitter in 742, 760 lager, 739 malt, 744 substitute, 744 methods of analysis, 747 acidity, 757 alcohol, 747 arsenic, 760 ash, 747 bitter principles, 759 carbon dioxide, 758 degree of fermentation, 756 dextrin, 756 extract, 747 glycerol, 756 phosphoric acid, 757 preservatives, 761 protein, 757 specific gravity, 747 sugars, 756 phosphoric acid in, 745 preservatives in, 746, 761 proteins in, 745 quassiin in, 742, 759 root, 1013 schenk-, 739 standards, 742 temperance-, 746 uno-, 746 varieties of, 739 weiss-, 740 wort, 739 gravity of, 754 Beeswax, 675 refractometer reading of. 675 specific gravity of, 675 Beet sugar, 590 Beets, composition of, 273 Behenic acid, 29, 487 Belfield-Gladding microscopic tallow test, 582 Bellier acid fuchsin test, 845 dulcin test, 908 peanut oil test, 544 Benches, 13 Benedictine, 786, 787 Benzaldehyde, 942, 943, 988 artificial, 943 in almond extract, 943 maraschino cherries, 988 Benzeneazo-^-naphthylamin, 858, 875 Benzoic acid, 890 detection of, 891 determination, 893 in butter, 562 milk, 167 toxicity of, 891 Benzopurpurin 4B, 850, 857, 873 Betaine, 35, 308 Beta-naphthol, 903 Beverages, carbonated. See Carbonated beverages. Biebrich brilliant crocein scarlet. See Bril- liant crocein. scarlet, 815 Birch beer, 1013 Birotation, 608, 666, 667, 668, 671 Biscuit, gluten, 375 soja bean, 375 Bishop arsenic apparatus, 65 Bismarck brown, 815, 829, 851, 874 R, 815, 857, 874 Bisulphites as preservatives, 896 Bitter almonds, oil of, 942, 943 Biuret reaction, 34 Blackberries, composition of, 283 Blank and Finkenbeiner formaldehyde meth- od, 880 Blarez fluorides test, 902 Blast pump, 18 " Blown " cans, 960 Blue colors, 815, 846 Blythe cocoa red method, 416 Bock-beer, 740 " Boiled " butter, 563 Bomb calorimeter, 38 Bombay mace, 483, 484, 485 Bomer phytosterol acetate test, 525 sterol method, 522 Borax, 883. See also Boric acid. Bordeaux B, 65, 829, 837, 851, 855, 870 BX, 856, 871 G, 855, 870 Boric acid, 883 detection, 166, 170, 885 determination, 884, 886 INDEX. 1055 Boric acid, in butter, 560 meat, 216, 238 milk, 166, 170 Bornstein saccharin test, 907 Bouillon cubes, 250 composition, 251 standards, 250 Bourbon whiskey, 766, 768, 769 Bovie electrical apparatus, 1029 Boyles lemon oil methods, 932 t^ Bran, wheat, 320 Brandy, 771 adulteration of, 773 composition of, 772 " drops," 681 methods of analysis, 777 new, 772 potable, 772 standards, 772 Brazil nuts, composition of, 284 wood, 819, 822, 852 ,^ Bread, 338 acidity of, 340 alum in, 342 composition of, 339, 340 copper sulphate in, 342 fat in, 341 methods of analysis, 343 water in, 340 wrapping of, 342 yeast food for, 341 w- Breakfast cereals, 369 Brewing, 739 Brick cheese, 197 Brie cheese, 197 Brilliant crocein, 837, 851 yellow, 855, 871 S, 848, 854, 868 Bromination oil test, 511 Bromine absorption of oils, 509 Brown and Duvel moisture method, 285 Brown colors, 815 sugar, 589 Browne dextrin method, 672 invert sugar test, 674 Buckthorn, 819, 823, 848 Buckwheat, ash of, 310 composition of, 280, 281 flour, 323 microscopy of, 319 Buckwheat, starch, 290 Burgundy wine, 714, 715, 717 Butter, SSI adulteration of, 556 annatto in, S58 apple, 986 azo colors in, SS7, 558, 559 benzoic acid in, 560, s62 boric acid in, 560 carrotin in, S57 coal-tar dyes in, SS7, 558, 559 coloring in, SS7 composition of, 551 curd of, examination, 574 distinction from oleomargarine and process butter, 571 effects of feeding, 552 fat, composition of, 551 constants, 528, 529 standard, S56 filled, 563 fruit, 986 glucose in, S62 methods of analysis, 552 ash, 556 casein, 555 colors, 557 fat, ^'-.i foam test, 572 lactic acid, 556 lactose, 556 preservatives, 560 process butter, detection, 571- 576 salt, 556 sampUng, 552, 553 water, 553 Waterhouse test, 573 microscopic examination of, 574 milk test, 573 nut, 576 Polenske number of, 571 preservatives in, 560 refraction of, 568 renovated, 563, 571 salicylic acid in, 560, 561 standards, 556 turmeric in, 557 water in, 553, 563 Waterhouse test, 573 1056 INDEX. Butter yellow, 849, 858, 875 Butterine, 563 oil, 542 Butyric acid, 29, 486 Butyro-refractometer, 86, 87 critical line of, 92 limits of butter readings, 569 manipulation, 88 oil readings on, 493, 494, 495 olive and cottonseed oil read- ings, 533 sliding scale for, 93 special thermometer for, 570 table of equivalent refractive in- dices, 91, 92 temperature variation of read- ing, 93 testing scale, 90 Cabbage, composition of, 282 Caffeine, 35, 385 in carbonated beverages, 1014, 1017, 1019 determination of, 1017, 1019 cocoa, 409 determination of, 413 coffee, 393, 394 determination of, 397 tea, 380 determination of, 386 Caffeol, 392 Caffetannic acid, 392 determination of, 395 Cake, 338, 342 Calcium carbonate crystals, 77 oxalate crystals, 77 sucrate, 187 detection of, 189 California wines, 718 Calorie, 38, 40 Calorimeter, bomb, 38 oil, 512 respiration, 39 Camembert cheese, 197 Camera, micro, 83 Canada balsam, 73 Candy, see Confectionery. standard, 677 Cane sugar, 587 composition of, 589 Cane sugar, detection of, 608 in cream, 189 milk, 189 determination of, by copper reduction, 642 polarimetry, 610, 656 in cereals, 304 condensed milk, 182 inversion of, 611, 612 manufacture of, 588, 590 methods of analysis, 608 ash, 609 invert sugar, 613 moisture, 609 organic non-sugars, 609 quotient of purity, 610 sucrose, 610 ultramarine, 613 refining, 591 standard, 587 test for, 608 Canned food, 957 composition of, 959 decomposition of, 960 metallic impurities in, 961 method of canning, 957 methods of analysis, 970 preservatives in, 969 fruits, 957 meats, 218, 219 vegetables, 957 Cans, detection of spoiled, 960, 970 gases from spoiled, 960, 970 Capers, 985 Capric acid, 29, 486 Caproic acid, 29, 486 Caprylic acid, 29, 486 Capsaicin, 454 Capsicums, 453, 458 Caramel, 815, 821 in distilled liquors, 765, 770, 771 milk, 161, 169 vanilla extract, 917, 926 vinegar, 810 Carbohydrates, 35, 36, 586-600 classification, 36 of cereals, 288, 304 eggs, 272 Carbon dioxide determination in baking chemicals, 353, 355 •>'^l». INDEX. 1057 Carbon dioxide determination in beer, 758 yeast, 347 Carbonated beverages, loii acids in, 1013 bottled, 1012 caffein in, 1014, 1017, 1019 cocaine in, 1014, 1018, 1019 colors in, 1014 foam producers in 1014 habit-forming drugs in, 1014 methods of analysis, 1014 caffeine, 1017, 1019 cocaine, 1018, 1019 glycerol, 1019 phosphoric acid, 1015 saponin, 1015 preservatives in, 1013 saponin in, 1014,1015 sweeteners in, 1013 syrups for, 1012 Carminaph garnet, 858, 875 Carnitine, 35, 205, 243 Carnosine, 205, 243 Carotin in butter, 557 Carrot, composition of, 282 Carthamin. See SaflSower. Casein, 32, 109, in determination in milk, 132 Caseose, 2,3 determination in cheese, 201 in milk, 133 Casoid flour, 375 Cassia, 438 adulteration of, 442 buds, 439 composition of, 439 extract, 950, 951 methods of analysis. See Spices. microscopy of, 440 oil, 439, 950 standards, 950 standard, 442 Catsup. See Ketchup. Cauliflower, composition of, 282 Caviar, 261 Cayenne, 453 adulteration of, 460 composition of, 454-458 methods of analysis, 461. See also Spices, colors, 461 microscopy of, 458 mineral adulterants in, 460 oil cf, 454 redwood in, 460 standard, 460 Cazeneuve color scheme, 736, 737 Celery, composition of, 282 seed extract, standards, 950 oil, standards, 950 Cellulose, 38, 294 Centrifuge, milk-fat, 123 universal, 20 Cereal breakfast foods, 369 composition, 371 products, microscopy of, 314 Cereals, 280 ash of, 310 carbohydrates of, 288 separation Oi, 304 composition of, 280, 281 methods of analysis, 285 ash, 286 crude fiber, 286, 305 dextrin, 304 ether extract, 286 hemiceliulose, 305 nitrogen-free extract, 287 pentosans, 294, 305 preparation of sample, 285 protein, 286 starch, 292, 304 sugar, 293, 304 water, 285 proteins of, 305 sulphuring of, 287 Chace pinene method, 941 total aldehyde method, 933 Champagne, 714, 717 Chaptalizing, 721 Charcoal, determination of, 312 Charlock, 469, 476, 477 11 1058 INDEX. Charlock, detection, 477 oil, 540 constants, 528, 529, 540 Chartreuse, 786, 787 Cheddar cheese, 197 Cheese, 196 adulteration of, 198 composition of, 196, 197 cream, 199 filled, 199 methods of analysis, 199 acidity, 202 amino acids, 201 ammonia, 201 ash, 202 caseoses, 201 fat, 199 foreign, 202 lactose, 202 paracasein lactate, 202 paranuclein, 201 peptones, 201 protein, coagulable, 201 total, 200 salt, 202 water, 199 water-soluble nitrogen, 201 sampling, 199 skimmed milk, 198, 199, 203 standards, 198 varieties of, 197 whole milk, 199 Cherries, composition of, 283 maraschino, 988 Cherry soda, 1013 Cheshire cheese, 197 Chestnuts, composition of, 284 Chicago blue 6 B, 869 Chicory, 395, 398, 400, 401, 402, 403 Chili sauce, 977 Chiretta, 742, 760 Chlor iodide of zinc, 78 Chloral hydrate, 80 test for charlock, 477 Chlorine in vegetable substances, 313 Chlorogenic acid, 392 Chocolate. See Cocoa, milk, 410 composition of, 411 Chocolate, milk, sucrose and lactose determi- nation in, 415 Cholesterol, 486 crystallization of, 522 determination of, 521 distinction from phytosterol, 521 separation of, 522 Cholin, 35, 308 Chromate of lead, 678, 681 Chromogenic bacteria, 117 Chromotrope 2 R, 854, 869 Chrysamin G, 829, 847, 856, 872 R, 829, 847, 856, 872 Chrysoidin, 848, 857, 874 R, 857, 874 Chrysophenin, 856, 871 Cibrola, 204 Cider, 707 adulteration of, 711 ash of, 711 composition of, 709 fermented, 709, 710 malic acid in, 712 manufactuie of, 707 methods of, analysis. See Wine. sweet, 1006 vinegar, 788, 790. See also Vinegar, watering of, 711 yeast in, 707 Cieddu, 174 Cinnamon, 438 adulteration of, 442 composition of, 439, 440 extract, 950, 951, 952 methods of analysis. See Spices, microscopy of, 440 oil, standards, 950 standard, 442 Citral, 928, 929, 938 determination, 934, 940 in carbonated beverages, 1015 Citric acid, 38 in fruit products, 979, 982, 1009, 1013 ketchup, 979, 982 milk, no, in Citronella oil, 938, 939 Citronellal, 939 Citronin, 826 Clams, 262 INDEX. 1059 Claret wine, 714, 715, 717 Clarifying reagents in microscopy, 79 sugar analysis, 610,644 Clerget formula, 611 Cloth red B, 855, 871 Clove extract, 950, 951, 952 oil, 950 Cloves, 426 adulteration of, 432 cocoanut shells in, 433 composition of, 428 exhausted, 432 methods of analysis, 422, 429. See also Spices, tannin, 429 microscopy of, 430 oil of, 426, 950 standard, 432 stems, 432 tannin in, 429 Clupanodonic acid, 29, 487 Clupein, 32 Coal-tar colors. See Colors, coal-tar. Cocaine, detection of, 1018, 1019 in carbonated beverages, 1014 Cochineal, 815, 819, 822, 824, 855, 869 in sausages, 240 Cocoa, 406 adulteration of, 417 alkali in, 418 ash of, 408 butter, 411, 428, 429, 550 colors in, 421 composition of, 407, 408, 409 compounds, 410 fat, foreign, in, 420 manufacture of, 407 methods of, analysis, 411 ash, 411 caffeine, 413 casein, 412 cocoa-red, 416 crude fiber, 414 lactose, 415 pentosans, 415 protein, 412 starch, 414, 415 sucrose, 415 theobromine, 413 water, 411 Cocoa, microscopy of, 418 nibs, 407, 408, 409 nitrogeneous bodies in, 410 pentosans in, 410 shells, 408, 409, 420 standards, 417 starch, foreign, in, 420 sugar in, 420 theobromine in, 410 Cocoanut, composition of, 284 oil, 549 composition of, 549 constants, 528, 529 pulp, 549 shells, 433, 434 Coffalic acid, 392 Coffearine, 392 Coffee, 392 acidity, 1035 adulteration of, 395, 397 ash of, 392, 393, 394 caffeine free, 404 in, 392, 393, 394 caffeol in, 392 caffetannic acid in, 392 cellulose in, 392, 393 chicory in, 400, 402 | chlcrogenic acid in, 392 coffaUc acid in, 392 coffearine in, 392 coloring of, 398 composition of, 393, 394 constituents of, 392 date stones in, 403 dextrins in, 392 glazing of, 398 hygienic, 404 methods of analysis, 395 acidity, 1035 ash, 39S caffeine, 397 caffetannic acid, 395 crude fiber, 395 ether extract, 395 proteins, 395 starch, 395 sucrose, 395 sugars, reducing, 395 10 per cent extract, 395, 403 water, 395 lUbU INDEX. Cofifee, microscopy of, 399 oil in, 392 'pellets," 398 pentosans in, 392 protein in, 392 pyridine in, 392 standards for, 397 substitutes, 395 sugar in, 393, 394 tannin free, 405 vacuum packed, 405 Cognac, 771. See also Brandy. oil, 773 Collagen, 31, 205 determination of, 228 Colorimeter, Schreiner, 66 Colorimetric analysis, 66 Colors, 812 acid, 841 test for, 844 allowed, 825 identification, 833 separation, 833 animal, 817 detection, 818 dyeing test, 818 extraction by immiscible sol- vents, 818 reactions in solution, 820, 822, 823 reactions on fiber, 818, 819 special tests, 821 arsenic compounds, 815 barium compounds, 815 basic, 841 blue, 815, 846 brown, 815 coal tar, 824 detection and identification in foods, 840 acetic ether extraction, 844 acid dyes, 841 amyl alcohol extraction, 843 Arata dyeing method, 841 basic dyes, 841 bromide test, 864 cyanide test, 866 Colors, coal tar, direct identification, 853 ether separation, 844 extraction, 840, 843 identification, 841, 853, 859 Loomis' scheme, 845 Mathewson method of sep- aration by immiscible solvents and identifica- tion, 859 Mathewson table of reac- tions of dry colors or dyed fibers, 853 nitrous acid test, 865 reduction and reoxidation, 866 Robin test, 844 separation, 840, 859 separation from dried food, 844 Sostegni and Carpentieri dyeing method, 842 examination of, 826 Mathewson quantita- tive separation meth- od, 836 Price-Estes method for allowed colors, 833, 834 Price-IngersoU method for allowed colors, 833 Rota scheme for, 827 schemes for, 827 spectroscopic methods, 840 ultimate analysis, 839 copper compounds, 815 extraction of, by immiscible solvents, 818, 836, 843, 844, 859 green, 815, 846 harmless, 815 in butter, 557 carbonated beverages, 1014 cayenne, 461 confectionery, 677, 681 jams and Jellies, 990 ketchup, 980, 981 milk, 159, 160 mustard, 476, 478 in sugar, 613 INDEX. 1061 Colors, injurious, 814, 815 lakes, 817 lead compounds, 815, 816 mercury compounds, 815 mineral, 815 detection of, 816 mordants for, 818 non-injurious, 814, 815 orange, 815, 847 red, 815, 849 Rota scheme for, 827 separation by solvents, 818, 836, 843, 844, 859 toxic effect of, 813 vegetable, 817 detection of, 818 dyeing tests for, 818 extracticn by immiscible sol- vents, 8i8 reactions in solution, 820, 822, 823 reactions on fiber, 818, 819 special tests, 821 violet, 815, 846 wool dyeing, 818, 841, 842 yellow, 815, 847 Colostrum, 114 Commercial glucose. See Glucose. Compressed j^east, 344 Conalbumin, 270 Concentrated foods, 265 Condensed milk, 195 as a milk adulterant, 171 composition of, 176, 177 methods of analysis, 178 cane sugar, 182 fat, 179, 180 foreign, 183 in original milk, 183 lactose, 181 protein, 181 total solids, 178 standards for, 176 Confectionery, 677 adulteration of, 677, 681 arsenic in, 677 colors in, 677, 681 glucose in, 677 lead chromate in, 677 Confectionery, methods of analysis, 678 alcohol, 681 arsenic, 68i ash, 678 colors, 681 ether extract, 679 lead chromate, 678 mineral adulterants, 678 paraffin, 679 polarization, 680 solids, 678 starch, 680 mineral adulterants, 677 Congo red, 815, 829, 837, 857, 873 Connective tissue, 205 Copper reduction. See Fehling process, salts, 967 determination of, 973, 977 in vinegar. 804, 811 Copra oil, 549 Cordials, 786 analysis of, 787 composition of, 787 Corky tissue, 76 Corn, 280, 281 ash of, 310 bleaching of canned, 969 composition of, 280, 281 flakes, 371 meal, 337 acidity determination in, 338 composition of, 338 manufacture of, 337 spoilage of, 338 microscopy of, 317 oil, 541 constants, 528, 529 proteins of, 309 puffs, 371 starch, 290 syrup, 5q8 Cornelison butter color test, 559 Corning of meat, 215 Cotton cane sugar method, 171 Cotton scarlet 3 B, see Brilliant crocein. Cottonseed, 535 oil, 535 composition of, 535 constants, 528, 529, 530 hydrogenated, 536 1062 INDEX. Cottonseed, oil, methods of analysis, 536, 537. See also Oils. Bechi test, 536 Halphen test, 537 preparation of, 535 standards, 536 stearin, 536 tests for, 536, 537 Coumarin, qiy detection, 923 determination, 920 microscopical structure, 924 Crampton and Simon caramel test, 784 palm oil tests, 565 Cranberries, composition of, 283 Cream, 186 adulteration of, 186 cheese, 199 evaporated, 186 foreign fats in, 186 gelatin in, 186 methods of analysis, 187 alkalinity of ash, 190 calcium oxide, 190 sucrate, 189 fat, 187 foreign, 188 gelatin, 189 preservatives, 188 sucrose, 189 preservatives, 186 standards for, 186 sucrate of lime in, 187 test scale, 187 viscogen in, 187 Cream of tartar, 348 in wine, 717, 732 methods of analysis, 352 Creatine, 35, 205 Creatinine, 35, 205 Creme de menthe, 786, 787 Creme de Noyau, 786 Creuss and Bettoli volatile acids method, 731 Crocein orange, 815, 837, 847, 855, 871 scarlet 8 B, 815, 851, 855, 870 O, extra, 815, 855, 870 Crude fiber, 286, 305 Crustaceans, 262 Crystal ponceau, 837, 855, 870 violet, 857, 874 Crystals, plant, 77 Cucumber, composition of, 282 pickles, 984, 985 Cudbear, 819, 822 Cumidin ponceau, see Ponceau 3 R. red, see Ponceau 3 R. Cuprammonia, 80 Curacao, 786, 787 Curcuma, 467 Curcumin, 467, 856, 872. See also Turmeric. Curd tests in butter, 574, 576 Curing meat, 215 Currants, composition of, 283 Curry powder, 467 Custard powders, 279 Cyan compounds, 29, 35 Cyanol, extra, 846 854, 868 Cystine, 35 Dadhi, 174 Date stones, 403 Decker-Kunze theobromine and caffeine method, 413 Defren-O'Sullivan sugar method, 137, 618 Defren's sugar tables, 619 Denis and Dunbar benzaldehyde method, 944 Desiccated egg, 276 Deutyro-proteose, 33 Dextrin, 38, 597 determination of, in cereals, 304 honey, 672 Jams and jel- lies, 999 molasses, 654 Dextrose, 37, 596 determination of, 615, 618, 622, 632, 656 Diabetic foods, 373 analyses, 374, 375 Diamond yellow, 829 Diastase, animal, 293 in malt extract, 761 starch methods, 292 Dimethylglycolose, 36 Dioses, 35 Dioxin, 829 Dioxyacetone, 36 Disaccharides, 37 Distilled liquors, 762 aging, 764 INDEX. 1063 Distilled liquors, methods of analysis, 777 acids, 777 alcoholsj 687 aldehydes, 777 caramel, 784 color insoluble in amyl alcohol, 785 water, 785 esters, 777 extract, 777 ' furfural, 778 fusel oil, 778, 779 methyl alcohol, 781 opalescence of diluted distillate, 785 standards, 763, 765, 766, 772, 774 Doolittle butter color test, 559 Doremus gas apparatus, 971 Double dilution sugar method, 650 Dough, expansion of, 328 Drained solids determination, 971 Drains, 15 Dried fruits, 1002 decomposed, 1004 lye treatment of, 1003 moisture content of, 1004 sulphuring of, 1003 wormy, 1004 zinc in, 1004 Drugs, habit-forming, 1014 Dry wines, 714, 719 yeast, 344 Dubois salicylic acid method, 890 sugar method, 415 Dubosc saccharimeter, 606 Dulcin, 908 detection, 908 determination, 909 Dunbar and Bacon malic acid method, 1008 Dupouy peroxidase test 173 Dupre color method, 736 Dvorkovitsch theine method, 386 Ebullioscope, 704 Edam cheese, 197 Edestan, ^^ Edestin, 308 Eggs, 267 ash of, 269 Eggs, carbohydrates of, 267, 268 cold storage, 273 composition of, 268, 269 desiccated, 276 frozen, 275 grades of, 272 membrane, 269 methods of analysis, 276 ash, 277 boric acid, 278 ether extract, 277 formaldehyde, 278 lecithin, 278 nitrogen, 277 preservatives, 278 salicylic acid, 278 water, 277 physical examination of, 276 preservation of, 272 shell, 269 spoilage of, 274 structure of, 267 substitutes for, 278 waterglass as a preservative, 273 weights of, 267, 268 white of, 269 ash in, 269, 270 carbohydrates in, 269, 270 cholesterol in, 269 composition of, 269 fat in, 269 lecithin in, 269 ovalbumin in, 270 ovomucin in, 270 ovomucoid, in 270 proteins in, 270 water in, 269 yolk of, 270 cholesterol in, 271, 272 fat in, 269, 270 hematogen in, 272 lecithin in, 271 lutein in, 271, 272 ovovitellin in, 271, 272 proteins in, 271, 272 solids in, 270, 271 sugar, 271, 272 Elaidin oil test, 533 Elastin, 31, 205 Electrolytic apparatus, 634 1064 INDEX. Elm bark, 442 Emergency rations, 265 Emmenthal cheese, 197 Eosin, 815, 832, 849, 856, 872 10 B, 849, 856, 872 Ergot, 323 Erika B, 855, 870 Erioglaucin A, 854, 868 Erucic acid, 29, 487 Erythrodextrin, 598 Erythrosin, 815, 826, 833, 834, 837, 850, 856, 872 Esters, in distilled liquors, 777 imitation flavors, 956 Estes vanillin method, 923 Ether, ethyl, preparation of absolute, 55 petroleum, preparation of, 55 Eucasin, 203 Eugenol, 426 Evaporated milk, 176 Ewe's milk, 113 Exhaust pump, 18 Exhausted cloves, 432 ginger, 464 tea leaves, 388 vanilla beans, 913 Extraction with immiscible solvents, 57 volatile solvents, 52 Extractor, Johnson, 54 Soxhlet, 52 " Faints," 764 Farina, 371 Farinaceous infants' foods, 371 Fast acid fuchsin, 855, 869 brown, 855, 870 N, 856, 872 red A, 837, 850, 856, 872 B, see Bordeaux B. C. See Azorubin. E, 81S, 837, 85s, 869 yellow R, 815, 854, 868 Fat globules, 77 Fats, 28, 486. See also Oils. classification, 29, 486 filtering, 489 measuring, 489 methods of analysis. See Oils. microscopic examination of, 527 paraffin in, 527 Fats, weighing, 489 Fatty acids, 29, 486 constants of, 518 insoluble, 502 solidifying point of, 518 soluble, 501 volatile, 497, 499 Fehling processes, 136, 614 gravimetric, 137, 617 AUihn, 632 Defren-O'SuUivan, 618 Meissl-Hiller, 637 Munson and Walker, 622 volumetric, 137, 615 solution, 614 equivalents of, 616 Fermentation, acetic, 788 alcoholic, 682 lactic, 116 proteolytic, 117 Fermented liquors, 707 Feser's lactoscope, 148 Fibrin, ^;^ Fibro-vascular tissue, 75 Fibroin, 31 Fiehe invert sugar test, 674 Figs, composition of, 283 Filberts, composition of, 284 Filled cheese, 199 Fincke formic acid method, 900 Fish, 259 canned, 263 characteristics of, 261 colors in, 265 composition of, 259, 260 fat in, 259 milt, 261 preservatives in, 265 roe, 261 salted, 263 shell, 262 smoked, 263 Flaked wheat, 371 Flavoring extracts, 911 Flesh foods. See Meats. Fletcher and Allen tannin method, 384 Floor, laboratory, 13 Flour, 320 acidity of, 321, 322 INDEX. 1065 Flour, adulteration of, 324 alum in, 325 ash of, 321 bakers, 320 hsLvley, 323 bleaching of, 325 detection, 334 buckwheat, 323 I ^ by-products of, 320 clear, 320, 322 color of, 3 21/ composition of, 320, 322, 323 corn, 323 damaged, 323 ergot in, 323 gasoline color value of, 326, 327 grades of, 320 \^ Graham, 322 ; hard wheat, 321 inspection, 326 low grade, 320 methods of analysis, 326 absorption, 327 acidity, 333 albumin, 332 alum, 334 amides, 332 ash, 330 baking tests, 328 bleaching test, 334 chlorine, 335 chloroform test, 336 cold water extract, 2,33 color test, Pekar, 326 value, gasoline, 327 dough expansion, 328 test, 327 fat, 330 chlorine in, 336 iodine number of, 333 fiber, 330 fineness, 326 gliadin, 331 globulin, 332 (^ gluten, 331 Bamihl test, 336 glutenin, 332 ^ improvers, 333 nitrous nitrogen, 33s protein, 330 Flour, methods of analysis protein, alcohol soluble, 331 salt soluble, 332 water, 330 soluble nitrogen, 332 microscopy of, 337 milling, 320 patent, 320, 322 red dog, 320 rye, 323 soft wheat, 321 straight, 320 whole wheat, 322 Fluoborates, 901 detection of, 902 Fluorides, 901 detection of, 902 Fluosilicates, 901 detection of, 902 Foam producers, 1014 " Foam " test for butter, 572 Folin ammonia method, 226 and Denis vanillin method, 922 creatin and creatinin method, 255 vanillin method, 922 Food adulteration, 5 analysis, commercial, 3 from dietetic standpoint, 2 general methods, 4 and drugs act, 1041 concentrated, 265 fuel value, 38 inspection, 3, 6 misbranding, 6 nature and composition of, 28 official control of, i preservation, 876 standards, 4 Force, 371 Fore milk, 114 Foreshots, 764 Formaldehyde, 879 detection of, 165, 881 determination of, 165, 880, 883 in eggs, 27s milk, 163 Formic acid, 898 detection of, 899 determination of, 900 1066 INDEX. Fonnyl violet S 4 B, 856, 873 Forster and Reichmann sterol method, 521 Fortified wine, 714, 719, 723 Freas drying oven, 19, 21 Freezing-point, determination of, 849 Fresenius color method, 367 Frozen milk, 116 meat, 214 Fructose, d-, 596 l-b-, 596 Fruit, 283 butter, 986 candied, 678 canned, 957 methods of analysis, 970 composition of, 283 essences, artificial, 954, 955 juices, 1004 methods of analysis, 1007 acidity, 1007, 1037 citric acid, 1009 malic acid, 1008 proximate analysis, 285 tartaric acid; 1008 products, 957 sugar. See Levulose. coated, 678 in, 587 syrups, loio tissues under the microscope, 1002 Fruits, dried. See Dried fruits. Fuchsin, 831, 850, 857, 873 acid. See Acid fuchsin. Fucose, 37 Fuel value, 38 calculation, 40 Fuller caffein method, 1017, 1019 cocaine method, 1018, 1019 Funnel, jacketed, 489, 490 separatory, 56, 57, 58 Furfural, 295 determination, 778, 810 in distilled hquors, 778 vinegar, 810 Furnace, electric, 24, 51 gas, 24 Fusel oil, 763 detection. 778 determination, 779 Fustic, 819, 823, 848 Galatan, 38 Galactose, 37 Game, composition of, 211 Gases, in spoiled cans, 960, 971 Gasoline color value of flour, 326, 327 Geerlig dry substance table, 645 Geisler butter color method, 558 Gelatin,' 31, 258 determination, 228 in cream, 186 ice cream, 193, 195 jams and jellies, 991 standards, 258 Gioddu, 174 Gill and Hatch oil calorimeter, 512 Gin, 776 Ginger, 462 adulteration of, 466 ale, 1012 black, 462 composition of, 462, 463, 464 exhausted, 464 extract, methods of analysis, 952 standards, 950 liming of, 462 methods of analysis, 465. See also Spices, cold water extract, 465 microscopy of, 465 oil of, 463 root, 462 standards, 466 white, 462 Girard and Dupre volatile oil method, 425 Gliadin, 31, 307, 308, 309 determination of, 308, 331 Globulins, 31 Globulose, 33 Glucin, 910 Glucose, commercial, 597 composition of, 598 determination of, in honey, 673 jams and jellies, 999 molasses, 651 healthfulness of, 599 in butter, 562 methods of analysis, 661 arsenic, 663 ash, 663 INDEX. 1067 Glucose, methods of analysis dextrin, 66i, 663 dextrose, 661 maltose, 661 sulphurous acid, 661 standards for, 599 test for, 663 Glucose, d-, 596 Glutelins, 31 Gluten, 308 Bamihl te^t for, 336 biscuit, 375 determination of, 331 flour, 373, 375 Glutenin, 31,. 307, 309 Glycerol in carbonated beverages, 1019 vanilla extract, 913, 914, 926 wine, 716, 734 jelly, 73 Glycerrhizin, 1014 Glyco-leucine, 35 Glycocoll, 35 Glycogen, 205 detection, 233 determination, 234 Glycolose, 36 Glycoproteins, 32 Goat's milk, 113 Gooch boric acid method, 887 Gorgonzola cheese, 197 Gorter caffeine method, 397 Graham flour, 322 Grain, moisture in, 285 sulphuring, detection, 287 Grape juice, 1005 nuts, 371 sugar, 596 Grapes, composition of, 283 Gray water method, 553 Green colors, 815, 846 Grosse-Bohle formaldehyde test, 882 Gruyere cheese, 197 Guanine, 35, 205 Guinea green B, 837, 857, 873 Gums, 76 Gunning-Arnold nitrogen method, 446 nitrogen method, 58 Gutzeit arsenic test, 65 Habit-forming drugs, 1014 Haemoglobins, 32 Hajmolysis test for saponin, 1015 Halphen cottonseed oil test, 537 wine ratio, 723 -Robin benzoic acid method, 562 Hammarsten casein method, 412 Hansen and Johnson tin method, 975 Hanus iodine absorption method, 508 Hartmann and Eoff tartaric acid method, 731 Hauchecorne test, 532 Heeren pioscope, 149 Hefelmann Bombay mace test, 485 Hehner formaldehyde test, 165, 881 number, 502 and Richmond milk formula, 138 Heidenhain carbonic acid method, 353 tartaric acid method, 356 Hemicellulose, 294, 305 Hess and Prescott vanillin and coumarin method, 920 Hetero proteose, 2,2, Hickory nuts, composition of, 284 Hiltner citral method, 934 Hilyer benzoic acid method, 895 Histidine, 35 His tones, 32 Hock wine, 715 Hogg's protein nerve food, 204 Holland acetyl value method, 516 Holstein cows, milk from, 113 Hominy, 371 Homogenized fats, 177, 183, 186 Honey, 664 adulteration of, 668 American, 665, 666 Canadian, 664 composition of, 664, 666, 667, 668 Cuban, 667 dextro-rotatory, 667, 668 European, 664 gelatin in, 670 glucose in, 669 Haitian, 667 Hawaiian, 665, 666 invert sugar in, 670 methods of analysis, 670 ash, 671 dextrin, 672 dextrose, 672 glucose, commercial, 673 1068 INDEX. Honey, methods of analysis glucose, distinction from honey- dew honey, 674 invert sugar, commercial, 674 levulose, 671 polarization, 671 reducing sugars, 671 sucrose, 672 water, 670 Mexican, 667 Honeydew, 666, 667, 668, 674 Hoods, 14, 19 Hops, 739 substitute, 741, 759 Hordein, 31, 309 Horseflesh, characteristics of, 232 composition of, 219 detection of, 232, 236 glycogen in, 233 Horseradish, 985, 986 Hortvet number, of maple products, 659 vinegar, 799 volatile acid method, 731 and West benzaldehyde method, 944 rose oil method, 953 spice oil method, 951 wintergreen oil method, 948 Hoskins electric furnace, 51 Howard microscopic ketchup method, 980 test for gums in ice cream, 196 volatile oil method, 931, 948, 951 Huckleberries, composition of, 283 Hiibl iodine absorption method, 504 Human milk, 113 Hungarian red pepper. See Paprika. Hydrocyanic acid, 942, 946 Hydrogen electrode, acidity by. See Acidity determination by hydrogen electrode. Hydrogen ion concentration. See Acidity de- termination by hydrogen electrode. Hydrogenated oils, 488, 580 Hydrometer, 43 Hypogaeic acid, 29, 487 Hypoxanthine, 35, 205 Ice cream, 191 classification, 192 cones, 193 Ice cream, homogenized, 193 ingredients, influence of, 192 methods of analysis, 193 colors, 196 fat, 193 foreign, 195 gelatin, 196 gums, 196 preservatives, 196 starch, 196 t?iickeners, 195 process, influence of, 192 standards, 191 Ichthulin, 32 Imitation coff'ee, 398 Immersion refractometer, 97 adjustment of scale, 99 distilled water readings on, 99 investigation of small quantities of solutions by, loi of solutions excluded from air by, loi milk examination by, 151 scale readings compared with no, 102 solutions standardized by, 106 temperature corrections for, 107 Incinerator, 158 Indicators, 27 Indices of refraction, 91, 102 Indigo, 815, 824 carmine, 826, 830, 833, 834, 838, 846, 854, 868 disulphosacid. See Indigo carmine. Indigotine. See Indigo carmine. Indol, 79 Indophenol, 830 Induhn, 830 Infants' foods, 371 classification of, 372 composition of, 373 effects of heating on, 376 methods of analysis, 375 carbohydrates, 376 cold water extract, 376 fat, 375 starch, sugar, and dex- trin, 376 microscopy of, 377 preparation of, 372 Inosite, 38 Inspection of flour, 326 INDEX. 10G9 Inspection of foods, 3, 5, 6, 9 liquors, 684 milk, 144 Inulin, 38 Invalids' foods, 371. See also Infants' Foods. Inversion, 611, 612 Invert sugar, 586, 611, 612 commercial, 668, 670 tests for, 674 detection ol, 613 determination of, 613, 622, 637 distinction from maltose and lactose, 655 in honey, 668, 670 lodeosin, 826 Iodine absorption of oils, 504, 507 in potassium iodide, 78 Irisamin G, 857, 874 Irish whiskey, 767 Iron oxide determination, 312 Iso-leucine, 35 -oleic acid, 29, 487 Jams, 989 adulteration of, 990 agar agar in, 991, 1002 apple stock in, 990, 991 coagulator in, 991 coloring matter in, 990, 1000 composition of, 992, 993, 995 compound, 994 fruit tissues in, 1002 gelatin in, 991, looi glucose in, 990, 999 methods of analysis, 995 acidity, 996 agar agar, 1002 ash, 996 colors, 1000 dextrin, 999 fiuit tissues, 1002 gelatin, loor glucose 999 pectin, 1000 polarization, 997 preservatives, 1001 protein, 997 sampling, 995 solids, 996 Jams, methods of analysis solids, insoluble, 996 starch, 1001 sugars, 997 sweeteners, looi starch in, 991 Jellies. See Jams. Jensen-Kirschner number, 501 Johnson extractor, 54 -Chittenden-Gautier arsenic method, 63 Jones soluble fatty acids method, 501 Jorissen dulcin test, 909 salicylic acid test, 889 Juckenack color method, 367 lecithin phosphoric acid method, 366 Kalama, 819, 823 Kefir, 174 Kelley electrical apparatus, 1029 Kenrick tartaric acid method, 357 Keratins, 31 Ketchup, 977 citric acid in, 979 colors in, 980, 981 composition of, 978 decayed material in, 979 foreign pulp in, 980, 984 lactic acid in, 979, 983 manufacture, 978 methods of analysis, 981 acidity, 982 volatile, 981 ash, 981 citric acid, 982 colors, 981 foreign pulp, 984 lactic acid, 983 preservatives, 981 sand, 981 solids, 981 soluble, 982 insoluble, 981 specific gravity, 981 sugars, 982 microscopy of, 980, 984 organisms in, 979 preservatives in, 980, 981 refuse in, 978 1070 INDEX. Ketchup, standards, 977 Ketoses, 36 Kjeldahl nitrogen method, 61 Klostermann digitonin test, 525 Koelner baking test, 328 Koettstorfer saponification method, 503 Konig and Karsch method for distinguish- ing honeydevv and glucose, 674 Krober pentosans and pentoses table, 297- 303 Kumis, 174 Kvimmel, 787 Kuntze mustard oil method, 474 Laboratory benches, 13 stain for, 14 drains, 15 equipment, 12 floor, 13 hoods, 14 lighting, 13 location, 12 sinks, 15 ventilation, 13 Lactalbumin, 30, no, 204 Lactated infants' foods, 372, 373 Lactic acid, 38 in ketchup, 979, 983 tomatoes, 979 Lactoglobulin, no Lactometer, 148 Lactoscope, 148 Lactose, 37, 109, in, 112, 599 Defren table for, 619 detection of, 655 determination of, 615, 617, 618, 622 in milk, 137 distinction from invert sugar and maltose, 655 Munson and Walker table for, 623 Soxhlet table for, 139 Lager beer, 739 Lakes, 817 detection of, 817 Lamb, composition of, 210 cuts of, 210 Lard, 577 adulteration of, 581 back, 577 composition, 577, 581 Lard, composition affected by feeding, 579 " compound," 580, 581 nickel in, 580 constants of, 528, 529, 578, 579, 581 iodine number, 578 leaf, 577, 578 methods of analysis, 582 beef fat, 582 nickel, 584 microscopy of, 5S2 neutral, 564, 565, 578 oil, 579 oily hogs, 579 standard, 579 stearin, 579 substitutes, 580 Laurent saccharimeter, 606 Laurie acid, 29, 486 La Wall chicory test, 403 and Bradshaw benzoate method, 893 Law, food and drugs, 1041 meat inspection, 1045 Leach coumarin test, 923 formaldehyde test, 165, 881 and Lythgoe malic value method, 657 methyl alcohol method, 781 Lead chromate, 647, 816 number, maple products, 658 vanilla extract, 925 vinegar, 791 salts of, 351, 961 determination of, 362, 973, 976 Leavening materials, 343, 348 Lebbin formaldehyde test, 882 Leben, 174 Lecitalbumin, 32 Lecithin, 29, 35 determination of, 278, 366 nucleovitellin, 32 Lecithoproteins, 32 Leeds and Evcrl.art method for potassium myronate, sinapin thiocyanate and my- osin, 473 Leffmann and Beam gelatin method, looi volatile fatty acids method, 499 Legumelin, 30 Legumes, 281 ash of, 310 Legumin, 30, 31, 309 INDEX. 1071 Lemon extract, 927 adulteration of, 928 composition of, 930 methods of analysis, 929 alcohol, 932 aldehydes, 933 ash, 936 citral, 934 citric acid, 937 colors, 936 / glycerol, 937 lemon oil, 929, 930, 932, 9.37 methyl alcohol, 935 solids, 936 tartaric acid, 937 methyl alcohol in, 935 preparation of, 927 standard for, 927 terpeneless, 928 juice, ICX36 oil, 927, 928, 937 determination of, 930, 932 examination of, 937 methods of analysis, 939 alcohol, 941 aldehyde, 940 citral, 940 pinene, 941 refraction, 939, 940 rotation, 939, 940 specific gravity, 939 terpeneless, 929 soda, 1012, 1013 Lemongrass oil, 929, 938, 939 Lemons, composition of, 283 Lendrich and Nottbaum caffeine method, 397 Lentils, 281 Lettuce, composition of, 282 Leucine, 35 Leucosin, 30, 306, 307, 308, 309 Levallois bromine absorption method, 510 Levulose, 37, 596 determination of, 671 Lewkowitsch acetyl value method, 5x4 Ley test for invert sugar in honey, 674 Ley -Emery melting-point method, 583 Lieberman-Storch rosin oil test, 548 Liebig's meat extract, 242, 246, 247, 248 Light green, 826, 833, 834, 837, 838, 846 Lighting, 13 Lignin, 81 Lignoceric acid, 29, 487 Limburger cheese, 197 Lime, determination of, 312, 361 in baking powder, 351, 352 spices, 424 juice, 1006 sucrate of, 187 water, in vinegar analysis, 796 Liming of ginger, 462 Limonene, 938, 939 Linolenic acid, 29, 487 Linolic, 29, 487 Linseed oil, 547 constants, 528, 529 Liqueurs, 786 analysis of, 787 Liquor inspection, 684 Liquors, 682 distilled. See Distilled liquors, fermented. See Fermented liquors, malt. See Malt liquors, malted and non-malted, 743 methods of analysis, 686 alcohol, 686, 687 ash, 706 preservatives, 706 specific gravity, 687 sweeteners, 706 state control of, 683 toxicity of, 684 Litmus, 815, 819, 822, 846 Lobster, composition of, 262 Lowenthal-Procter tannin method, 383 Logwood, 819, 821, 822, 852 Long fermentation baking test, 329 pepper, 445, 446, 452 Loomis color scheme, 845 Lovibond tintometer, 67 . Low butter color method, 558 wines, 764 Lj^e treatment of fruit, 1003 Lythgoe sucrose test, 189 Macaroni, 364. See also Pastes, edible. Macassar mace, 482, 483, 484 Mace, 480, 482 adulteration of, 484 Bombay, 483, 484, 48'; 1072 INDEX. Mace, composition of, 483 Macassar, 482, 483 methods of analysis, 485. See also Spices. Bombay mace, 485 microscopy of, 484 standards, 484 Madeira wine, 715, 717 Magenta. See Fuchsin. Magnesia determination, 312 Maize. See Corn. Malachite green, 815, 846, 857, 874 G, 857, 874 Malic acid, 38 in cider, 709, 1008 fruit juices, 1008 vinegar, 790, 791, 798 wine, 716 value of maple products, 657 Malt, 738 extracts, 761 liquors, 738. See also Beer. substitutes, 741, 744 vinegar, 792, 804 Malting, 738 Maltose, 37, 597 detection of, 655 determination of, 618, 622 distinction from invert sugar and lactose, 655 Mannan, 38 Mannose, 37 Maple sap, 591 sugar, 591. See also Maple syrup, syrup, 591 adulteration of, 594 composition of, 592, 593 methods of analysis, 656 ash, 657 electrical conductivity, 66 1 lead number, 658 malic acid, 657 reducing sugars, 657 sucrose, 657 water, 656 standards, 594 Maraschino, 786 cherries, 988 benzaldehyde in, 988 Mare's milk, 113 Marpmann color method, 241 Marsh arsenic test, 64, 760 test for caramel, 784 Martin color scheme, 557 Martins yellow, 815, 829, 847, 856, 872 " Materna " milk modifier, 144 Mathewson color method for butter, 559 dry colors, 853 dyed fibers, 853 quantitative sep- aration, 836 separation by im- miscible sol- vents, 859 Maumene thermal test, 511 Mayrhofer glycogen method, 234 Mazun, 174 McGill lead number, 659 Meal, corn or maize, 337 Meat, 205 acids in, 216, 230 adenine in, 205 ash of, 206, 230 bases, 205, 219, 230, 247, 248, 249, 256 boric acid in, 216, 238 canned, 218, 219 adulteration of, 218 composition of, 218 carnitine in, 205 carnosine in, 205 cold storage of, 213 collagen in, 205 composition of, 205, 206, 208-212 connective tissue of, 205 cooking, effect of, 217 corning of, 215 creatine in, 205 creatinine in, 205 curing of, 215 drying of, 215 elastin in, 205 extracts, 242 albumoses in, 243 bouillon cubes, 250 carnitine in, 243 carnosine in, 243 chlorine in, 244 composition of, 243, 246-249 creatine, in, 243, 255 creatinine in, 243, 255 INDEX. 1073 Meat extracts, gelatin in, 243 hydrolysis products of, 244 manufacture of, 242 meat bases in, 243 seasonings, 245 methods of analysis, 253 - acidity, 257 ammonia, 253 ash, 253 coagulation point, 258 creatine, 255 creatinine, 255 glycerol, 258 nitrogen, total, 253 preservatives, 258 protein, coagulable, 254 insoluble, 253 proteoses, 254 purine bases in, 256 sugars, 258 tannin-salt precipitate, 254 water, 253 methyl guanidine in, 243 peptones in, 243 preservatives in, 216, 25S proteoses in, 243, 254 purine bases in, 243 standards, 252 yeast extract, distinction from, 252 fat, 205, 224 composition of, 207, 212 glycogen in, 205, 233, 234 guanine in, 205 hypoxanthine in, 205 inosite in, 206 inspection, 207 law, 1045 juices, 244 methods of analysis, 223 acidity, 230 ammonia, 225 ash, 230 benzoic acid, 238, 239 boric acid, 238 collagen, 228 colors, 240 constants, 224 creatine, 230 Meat, methods of analysis creatinine, 230 fat, 224 frozen, 241 gelatin, 228 glycogen, 233, 234 horse flesh, 232, 236 meat bases, 230 myosin, 229 nitrogen, 225 insoluble, 227 peptones, 230 protein, coagulable, 229 proteoses, 230 purine bases, 230 starch, 231, 234, 240 sugars, 237 sulphurous acid, 238 water, 223 methyl guanidine in, 205 mince, 987 muscle fibers of, 205 myogen of, 205 myosin of, 205, 229 {)ickled, 215 plasma of, 205 preservation of, 214 ])reservatives in, 216 ptomaines in, 217 refrigeration of, 214 salted, 215 saltpeter in, 215 sarcolemma of, 215 serum of, 205 smoked, 215 spoilage, 205 standards of, 213 sugar in, 206 sulphurous acid in, 216, 238 unwholesome, 213 xanthine in, 205 Meissl-Hiller invert sugar method, 637 table, 638 Melibiose, 37 Melting point determination, 496 Mercury compounds in colors, 815 Metachrome orange R, 856, 872 Metallic salts in canned goods, 961 determination, 973, 974. 97^ Metanil yellow, 815, 837, 848, 856, 871 1074 INDEX. Metaproteins, 33 Metaraban, 38 Methyl alcohol, detection of, 781, 935 alkali blue, 857, 873 dioses, 36 pentoses, 37 tetroses, 36 violet, 815, 846, 851, 874 Methylene blue, 815, 830, 846, 857, 873 Micro-chemical reactions, 81 Micro-polariscope, 71 Microscope in food analysis, 68 reagents for, 77 stand, 69 Microscopical accessories, 71 analysis, 68 apparatus, 69 diagnosis, 73 reagents, 77 anal3"tiral, 78 clarifying, 79 standards, 69 technique, 72 Microscopy of agar agar, 1002 allspice, 436 arrowroot, 291 barley, 317 starch, 290 bean, 400 starch, 291 buckwheat, 319 starch, 290 butter, 574 cassia, 440 cayenne, 458 cereal products, 314 charlock, 477 chicory, 400 cinnamon, 440 cloves, 430 cocoa, 418 cocoanut shells, 433 coffee, 399 corn, 317 starch, 290 date stones, 403 fats, 527 flour, 315, 337 fruit tissues, 1002 ginger, 465 Microscopy of honey, 664 jams, 1002 ketchup, 980, 984 lard, 582 mace, 484 milk, 108 mustard, 475 nutmeg, 481 oats, 318 oat starch, 291 oils, 527 ^'oleomargarine, 574 olive stones, 450 paprika, 458 pea, 4CX3 starch, 291 pepper, black, 447 long, 452 red, 458 white, 447 potato starch, 291 rice, 319 starch, 291 rye, 316 starch, 290 sago, 291 sawdust, 460 starches, 289 tapioca starch, 291 tea, 391 turmeric, 468 wheat, 315 starch, 289 Micro-technique, 72 Milk, 108, 140 acidity of, 108, 1033 adulteration of, 144 aldehyde reductase in, 112 anilin orange in, 160 annatto in, 160 ash of, III, 112, 121 ass's, 113 bacteria in, 117 benzoic acid in, 167 bitter, 117 blue, 117 boric acid in, 166, 170 cane sugar in, 171 catalase in, 112 INDEX. 1075 Milk chocolate, 410 citric acid in, no, iii color of, 109 coloring matter in, 159 composition of, iii, 112 changes during lactation, 114 influence of age, 115 breed, 115 feed, n6 freezing, 116 / intervals between milking, 116 condensed, see Condensed milk. skimmed in, 171 enzj^mes in, no, 117 evaporated, 176 ewe's, 113 fat of, 109, III, 121 fermentations of, 116 fermented, 174 methods of analysis, 175 fibrin in, no fore milk, 113 formaldehyde in, 163, 165, 170 goat's, 113 homogenized, 172 human, 113 hydrogen peroxide in, 167 inspection, 144 known purity, 146 lactalbumin in, no lactoglobulin in, no lactose in, no, 134 mare's, 113 methods of analysis, 117, 148, 154 acidity, 140, 1033 adsorption, 154 albumin, 133 amino compounds, 133 ammonia, 133 anilin orange, 162 annato, 161 ash, 121 boric acid, 166, 170 capillarity, 154 caramel, 161 casein, 132 caseoses, 133 colors, 160 electrical conductivity, 154 Milk, methods of analysis fat, 121 centrifugal, 122 gravimetric, 121, 122 refractometric, 126 formaldehyde, 165, 170 freezing-point, 153 hydrogen peroxide, 168 lactose, 134 by copper reduction, 136 polarization, 134 oxidation index, 154 peptones, 132 proteins, 132 by calculation, 140 gravimetric, 132 sampling, 117 sodium bicarbonate, 167, 170 carbonate, 167, 170 specific gravity, 118 heat, 154 starch, 171 total solids, 119 by calculation, 140, 141 gravimetric, 119 viscosity, 154 microscopy of, 108 modified, 142 pasteurized, 173 aldehyde reductase test for. 174 peroxidase test for, 173 tests for. 173 peroxidase in, no powder, 184 composition, 185 methods of analysis, 185 fat, 185 lactose, 185 preservatives in, 162 protein preparations, 203 proteins of, 109, ni; 132 records of analysis of, 157 red, 117 reductase in, no ropy, 117 salicylic acid in, 167 sampler, 118 serum, composition, 151 1076 INDEX. Milk serum, nitrates in, 151 preparation of, 150 refraction of, 151 specific gravity of, 151 skimmed, 146 sodium bicarbonate in, 167 carbonate in, 167 sour, analysis of, 172 souring of, 116 standards, 145 strippings, 113 sugar. See Lactose, systematic examination of , 154 ash, 15s fat, 155 total solids, 155 watering of, 146 yellow, 117 Mill bromine absorption method, 510 Millet, composition of, 280 Milliau cottonseed oil test, 536 Millon reaction, 34, 79 reagent, 79 Mince meat, 987 adulteration of, 987 condensed, 987 standards, 987 Mineral colors, 815, 816 content of food, 38 Mirbane, oil of, 943, 945 Mitchell and Smith fusel oil method, 780 lemon oil methods, 930, 931 Modified milk, 142 Mohler benzoic acid test, 892 Moisture, determination of, 49 Molasses, 589 adulteration of, 651 composition of, 589 methods of analysis, 642 ash, 644, 654 dextrin, 654 dextrose, 656 glucose, commercial, 651 raffinose, 650 reducing sugars, 651 solids, 643 sucrose, 644, 656 tin, 655 standard, 651 vinegar, 794 MoUusks, 262 Monosaccharides, 36 Morpurgo dulcin test, 909 Moslinger lactic acid method, 732 Mucins, 32 Munson heavy metals method, 973 and Tolman pectin method, 1000 Walker sugar method, 136, 294, 622 table, 623 Muscle fibers of meat, 205 sugar, 206, 237 Muscovado, 588, 589 Mushroom ketchup, 977 Mushrooms, composition of, 282 Muskmelons, composition of, 283 Mustard, 469 adulteration of, 476 ash of, 473 black, 469 brown, 469 cake, 470 colors in, 476, 478 composition of, 471, 472 flour, 470 Indian, 469 methods of analysis, 473, see also Spices, myrosin, 473 potassium myronate, 473 sinapin thiocyanate, 473 volatile mustard oil, 473 microscopy of, 475 myrosin in, 469 oil, fixed, 470, 540 volatile, 470 pickles, 985 potassium myronate in, 470, 473 prepared, 478 adulteration of, 478 composition of, 478 methods of analysis, 479 ash, 479 ether extract, 479 fiber, 479 protein, 479 reducing matters, 479 salt, 479 solids, 479 sinalbin in, 470 INDEX. 1077 Mustard, sinalbin mustard oil in, 470 sinapin thiocyanate in, 469, 473 sinigrin, 470 standards, 476 starch in, 476 turmeric in, 476 volatile oil of, 470, 473 white, 469 wild, 469, 470, 477 Mutton, composition of, 210 cuts of, 2ICT tallow, 528, 529 Myosin, 31 determination, 229 insoluble, ^^ Myristic acid, 29, 486 Naphthol black B, 815, 854, 869 green B, 815, 829, 846, 854, 869 orange, 826 yellow. See Martius yellow. S, 369, 81S, 837, 838, 847, 85s, 869 Natural wines, 714 Nelson-La Wall-Doyle capsicum method, 952 Nessler free tartaric acid method, 731 Neubauer-Lowenthal tannin method, 735 Neufchatel cheese, 197 New blue, 857, 873 coccin, 815, 837, 851, 854, 868 Nickel salts, 968, 977 detection, 584 determination of, 977 Night green 2 B, 856,' 873 Nigrosin, soluble, 830, 854, 868 Nile blue, 830 Nitrates in food, 29, 35 watered milk, 151 Nitrobenzol, 943, 945 Nitrogen, amino acid, 63 apparatus, 58, 60, 61, 62 compounds in milk, 109, 132 determination of, 58, 60 free extract, 287 protein, 63 Nitrogeneous bodies, 29 classification of, 29 separation of, in cheese, 200 meat, 226 milk, 132, 133 Niviere and Hubert fluorine method,- 902 Noodles, 364. See also Pastes, edible. Notification, 10 Noyau, 786 Nuclein, 32 Nucleoproteins, 32 Nutmeg, 480 adulteration of, 482 composition of, 481 extract, 950, 952 Macassar, 480, 482 methods of analysis. See Spices. microscopy of, 481 oil of, 480, 950, 952 standard, 950 standards, 482 Nutrose, 203 Nuts, composition of, 284 Oats, analyses of, 280, 281 ash of, 310 microscopic structure of, 318 starch, 291 Oil, anise, 950 basil, 950 bitter almond, 942, 943 cakes, eflfects on butter of feeding, 552 lard of feeding, 579 calorimeter, 512 cassia, 950 celery seed, 950 charlock, 540 cinnamon, 950 cloves, 950 cocoanut, 549 corn, 541 cottonseed, 535 ginger, 463 lard, 579 lemon, 928, 929, 930 terpeneless, 928 lemongrass, 929, 938, 939 linseed, 547 marjoram, 951 mustard, fixed, 470, 540 volatile, 470 nutmeg, 950, 952 oleo, 564 olive, 530 orange, 941 1078 INDEX. Oil, palm kernel, 550, 565 peanut, 542 peppermint, 948 poppyseed, 547 rape, 539 rose, 953 rosin, 548 savory, 950 sesame, 537 soy, 545 spearmint, 949 staranise, 950 sunflower, 547 thyme, 95 1 wintergreen, 947, 948 Oils, 486. See also Fats. acetyl value of, 514, 515, 528 bromination test, 511 bromine aBsorption of, 509, 510 cholesterol in, 520, 521 composition of, 486, 487 constants of, 528, 529 constituents of, 486 elaidin test, 517 fatty acids of, 486, 487, 518, 529 insoluble, 503, 518, 529 hydrogenation of, 4S8, 584 iodine, number of, 504, 507, 528 Jensen- Kirschner number, 501 judgment as to purity of, 488 Maumene number of, 528 melting point, 497, 528 methods of analysis, 488 acetyl value, 514, 516 bromination test, 511 bromine index, 509 cholesterol, 521, 522 elaidin test, 517 fatty acids, free, 518 insoluble, 502 soluble, 521 iodine number, 504 Jensen-Kirchner number, 501 Koettstorfer number, 503 Maumene number, 511 melting point, 496 phytosterol, 521, 522 Polenske number, 499 refraction, 493 Reichert-Meissl number, 497 Oils, methods of analysis saponification number, 503 solidifying point, 496 specific gravity, 490 thermal tests, 510 titer test, 518 unsaponifiable matter, 520 Valenta test, 517 viscosity, 492 volatile fatt}' acids, 497 microscopy of, 527 phytosterol in, 520, 521 Polenske number of, 500, 529 rancidity of, 489 refraction of, 493, 494, 528 Reichert-Meissl number of, 497, 500, saponification of, 487 number of, 499, 503, 504, 528 sitosterol in, 542 solidifying point of, 496, 497, 528 solubility of, 486 specific gravity of, 490, 492, 528 factors, 491 thermal tests, 510 titer test, 518, 529 unsaponifiable m^atter in, 520, 529 Valenta test, 517 viscosity of, 492 Oleic acid, 29, 487 Oleo oil, 564 Oleomargarine, 563 adulteration of, 566 coloring of, 565 constants of, 528, 529 distinction from butter, 567, 571 fat, constants, 528, 529, 567 Polenske number of, 571 refraction of, 568 Reichert-Meissl number of, 570 healthfulness of, 567 manufacture of, 563 microscopic examination, 574 odor and taste, 567 palm oil in, 565 refraction of, 568 vegetable, 576 Zega's test for, 576 Olive oil, 530 INDEX. 1079 Olive oil, adulteration of, 534 composition of, 531 constants, 528, 529, 531, 532 methods of analysis, 532, 533, 534, See also Oils, elaidin test, 533 Hauchecorne test, 532 preparation of, 530 refraction of, 533 standard, 531, 532 substitutes,, 531 stones, 450 Olives, pickled, 985 Onions, composition of, 282 Orange 2, 815, 837, 838, 847, 855, 871 I, 815, 837, 838, 848, 855, 871 II. See Orange 2 IV, 815, 848, 856, 871 colors, 815, 847 extract, 941 standards, 942 terpeneless, 942 G, 837, 847, 854, 869 oil, 941 R, 855, 871 soda, IOT2, 1013 Orchil. See Archil. Ortho-tolueneazo-j3-naphthylamine, 858, 875 O'Sullivan-Defren sugar method, 614 Ovalbumin, 32, 270 Oven, drying, 19 McGill, 609 Ovomucin, 270 Ovomucoid, 32, 270 Oxygen absorbed, 429 equivalent, 429 Oxyha;moglobin, 32 Oxy proline, 35 Oysters, 262 Palas rapeseed oil test, 540 Palatine red, 855, 870 scarlet, 854, 869 Palm kernel oil, 850, 865 Palmitic acid, 29, 486 Paprika, 453 added oil in, 461 adulteration of, 460 composition of, 456, 457 Paprika, methods of analysis, 461. See also Spices, olive oil test, 461 microscopy of, 458 standard, 460 Para red, 858, 875 Parafl&n in beeswax, 675 confectionery, 679 fats, 527 oleomargarine, 566 Paranuclein, 201 Parenchyma, 74 Parsnips, composition of, 282 Pastes, edible, 363 adulteration of, 365 artificial colors in, 365, 366 composition, 364 Italian, 363 lecithin phosphoric acid in, 364, 366 methods of analysis, 366 artificial colors, 366 lecithin phosphoric acid, 366 nitrogen soluble in water, 366 precipitin test for eggs, 366 noodles, 364 Patent blue, 846, 854, 868 A, 857, 873 Patrick ice cream thickener test, 195 water method, 553 Paul foreign fats method, 183 Pea, composition, 281 proteins of, 309 starch, 291 Peanut oil, 542 adulteration of, 542 composition of, 542 constants, 528, 529 methods of analysis, 543. See also Oils. Bellier test, 544 Renard test, 543 standards, 542 Peanuts, composition of, 284 Pear cider, 712 essence, imitation, 954, 955 'Pears, composition of, 283 Pecans, composition of, 284 Pectin determination, 1000 Pectose, 38 1080 INDEX. Pekar flour color test, 326 Pentosans, 38 determination of, 294, 305 in cocoa products, 41a table for, 297 Pentoses, 36, 297 Pepper, 442 adulteration of, 449 black, 442 buckwheat in, 451 composition of, 442 long, 445, 446, 452 methods of analysis, 422, 446. See also Spices, nitrogen, in ether extract, 447 total, 446 piperin, 447 microscopy of, 447 olive stones, 450 piperin in, 443, 447 red. See Cayenne and Paprika, shells, 445, 446, 449 standard, 449 varieties of, 442 white, 442 Peppermint extract, 948 methods of analysis, 949 standards, 949 oil, 948 Peptides, 34 Peptones, ^^ in cheese, 201 meat, 205, 230 milk, 133 Perry, 712 Persian berries, 819, 823 Peter benzoic acid test, 892 Petroleum ether, 55 Phenylalanine, 35 Phloroglucide, 295, 296 Phloroglucinol, 296 Phloxin, 815, 849, 856, 872. See also Eosin 10 B. Phosphate baking powders, 350 Phosphin, 831 Phosphoproteins, 32 Phosphoric acid determination, 313, 362, 757 in baking chemicals, 362 beer, 757 Phosphotungstic acid reaction, 34 Photomicrography, 80 camera for, 83 Phytosterol, 486 acetate test, 525 crystallization of, 522 determination of, 521 distinction from cholesterol, 521 separation of , 522 Piccalilli, 985 Pickled meats, 213, 215 Pickles, 984 adulteration of, 986 composition of, 985 Pickling pump, 216 Picric acid, 815, 847, 855, 871 Pie filling, 987 Pimento. See AUspice. Pimiento, 452, 456, 457 Pineapple essence, imitation, 954, 955 Pineapples, composition of, 283 Pioscope, 149 Piperidine, 35, 443 Piperin, 35, 443 determination of, 447 Pistachios, composition of, 284 Piutti and Bentivoglio color method, 368 Plant crystals, 77 Plasmon, 203 Plastering, of wine, 721 Platinum dishes, 119, 155 counterweights for, 155 Plums, composition of, 283 Poisoned foods, 63 Poivrette, 450 Poke berry, 819, 823 Polariscope, 600. See also Saccharimeter. micro, 71 tube jacketed, 671 short, for oils, 937, 939 Polarization at high temperature, 671 of essential oils, 938 honey, 671 jams and jellies, 997 lemon extract, 930 molasses, 644 orange extract, 942 sugar, 610 vinegar, 800 wine, 722, 734 Polenske number, 499 1 INDEX. 1081 Polenske GrujiC fat method, 343 Ponceau 4 GB. See Crocein orange. 2 R, 815, 837, 851, 855, 869 3 R, 837, 838, 851, 855, 870 6 R, 837, 851, 854, 868 Poppyseed, 547 oil, 547 Pork, composition of, 211 cuts of, 211 Port wine, 714, 715, 717, 718 Porter, 740, 743. Seje also Beer. Potash determination, 313, 361 Potassium myronate, 470 Potato starch, 291 Potatoes, composition of, 282 starch of, 291 Poultry, composition of, 211 drawn vs. undrawn, 217 Prall-Kerr nickel method, 584 Pratt citric acid method, 1009 Preparation of sample, 43 Preservatives, 876 commercial food, 878 in butter, 560 canned goods, 969 carbonated beverages, 1013 fish, 265 fruit juices, 1005 jams and jellies, looi ketchup, 980 meats, 216 milk, 162 preserves, 987 wine, 725, 736 of eggs, 272, 278 regulation of, 877 Preserves, 986 Pressure pump, 18 Price-Estes color method, 833 -IngersoU color method, 833 Primulin, 831 Process butter, 563 Prolamins, 31 Proline, 35 Proof spirit, 763 Prosecution, 10 Protamins, 32 Proteans, 33 Protein grains, 77 Proteins, classification, 29 Proteins, coagulated, 33 conjugated, 32 derived, ss factor for, 29 occurrence, 29 of barley, 309 beer, 757 cereals, 305 corn, 309 eggs, 270, 271, 272 milk, 109 calculation of, 140 determination of, 132 peas, 309 rye, 309 wheat, 305 simple, 30 tests for, 34 Proteolytic fermentation, 117 Proteoses, 33, 243, 246, 247, 249, 307, 309 determination of, 254 Proximate analysis, expression of results of, 41 extent of, 41 Prunes, composition of, 283 Prussian blue, 816 in tea, 387, 388 Ptomaines, 213 Publication of adulterated foods, 10 Puffed wheat, 371 Pulfrich refractometer, 86 Pumpkin, composition of, 282 Purine bases, 35 Pycnometer, 45 Pyroligneous acid, 788, 795 in meats, 215 Pyronin, 831 Pyrosin, 826 Quassiin, 759 Quercetin, 832 Quercitannic acid, 429 Quercitron bark, 819, 823 Quevenne lactometer, 118 Quince essence, imitation, 954, 955 Quinoline yellow, 831, 847, 855, 870 Quotient of purity of sugar, 610 Radishes, composition of, 282 Raffinose, 37, 600 1082 INDEX. Raffinose, determination of, 650 Rancidity, 489 Rape oil, 539 test for, 539 seed, 539 Raphides, 77 Rapic acid, 29, 487 Raspberries, composition of, 283 Raspberry soda, 1012, 1013 Reagents, 24 Red colors, 815, 849 ochre in sausages, 222 pepper. See Cayenne and Paprika, wines, 714, 717, 718 wood, 460 Refractometer, 86 Abbe, 86, 94 Amagat and Jean, 86 butyro, 86, 87 heater for, 88 immersion, 97 in oil analysis, 493 Pulfrich, 86 sliding scale for, 93 tables for, 90, 91, 92, 102, 107, 493, 494, 533, S7o Wollny, 86, 126 Reichert-Meissl method, 497 number of butter and oleo fat, 570 Reinsch test for arsenic, 761 Renard peanut oil test, 543 rosin oil test, 548 Renovated butter, 563 distinction from butter and oleomargarine, 571 Resins, 76 Resorcin brown, 856, 871 yellow, 837, 847, 855, 870 Respiration calorimeter, 2, 39 Revis and Burnett starch method, 415 Rhodamin B, 849, 857, 874 3 B, 857, 874 G, 857, 874 S, 831, 857, 873 Rhubarb, composition of, 282 Ribose, 36 Rice, ash of, 310 coating, detection of, 287 composition of, 280, 281 Rice, microscopy of, 319 polished, 282 starch, 291 Rice's expanded Meissl-Hiller table, 639 Richardson water method, 423 Riche and Bardy methyl alcohol method, 783 Richmond cane sugar method, 171 sliding milk scale, 140 Rimini formaldehyde test, 881 Ritsert acetanilide tests, 926 Ritthausen milk proteins method, 132 Robin acid color test, 844 gelatin method, looi Roese-Gottlieb fat method, 193 Roeser mustard oil method, 473 Rohrig tube, 194 Roi and Kohler peroxidase test, 173 Rolled oats, 371 wheat, 371 Romijn formaldehyde method, 883 Roos wine ratio, 723 Root beer, 1013 Ropy milk, 117 Roquefort cheese, 197 Rose, attar of, 953 bengale, 815, 850, 856, 872 3 B, 850, 856, 872 extract, 953 rose oil in, 953 standards, 953 Rosin oil, 548 Rosindulin 2 G, 855, 871 Rosolic acid, 856, 872 Rota color scheme, 827 Rubner's fuel value factors, 40 Riihle-Brummer saponin method, 1015 Rum, 774 composition of, 774 essence, 775 methods of analysis, 777 new, 775 standards, 774 Rye ash of, 310 composition of, 280, 281 microscopy of, 316 proteins of, 309 starch, 290 Saccharimeter, 601 double wedge, 604 INDEX. 1083 Saccharimeter, forms of, 606 normal weights for, 606 scales compared, 606 single wedge, 602 Soleil-Ventzke, 601 triple field, 604 Saccharimetry, 600 Saccharin, 905 detection of, 906 determination of, 907 Saccharine products, 586 Safflower, 819, S23 Saffron, 815, 819, 822, 848 Saffrosin, 856, 872 Safranin, 815, 830, 852, 857, 873 Sago, 291 Saleratus, 348 Salicylic acid, 887 detection of, 888 determination of, 890 in butter, 561 meat, 216 milk, 167 Salmin, 32 Salted meats, 215 Sample, preparation, 43 Sanatogen, 204 Sanger arsenic method, 64 Black-Gutzeit method, 65 Sanose, 204 Saponification, 487, 503 Saponin, 1014, 1015 detection, 1015 Sarcolemma, 215 Sarsaparilla, 1013 Sausages, color in, 222 composition of, 220 methods of analysis. See Meat, starch in, 221 Sauterne wine, 714, 715, 717 Savory extract standards, 950 oil, standards, 950 Sawdust, 466 Scarlet G R, 855, 871 Schardinger aldehyde reductase test, 174 Schenk beer, 739 Schiedam schnapps, 776 Schiff aldehyde test, 882 Schindler acidity method, 338 Schlegel color method, 367 Schmidt saccharin test, 907 Schreiner colorimeter, 66 Schultze reagent, 80 Sclerenchyma, 74 Scovell sampling tube, 118 Sealed samples, 6, 145 Seeker ginger method, 952 Semolina, 363, 364 Separatory funnel support, 58 Seralbumin, 30 Sericin, 31 Serine, 35 Sesame oil, 537 adulteration of, 538 composition of, 538 constants, 528, 529, 538 methods of analysis, 538. See also Oils. Baudouin test, 538 Tocher test, 538 Villavecchia and Fa- bris test, 538 standards, 538 seeds, 537 Settimi soy oil test, 546 Shannon formic acid method, 899 Sherry wine, 714, 715, 717, 7i8 Short cheese fat method, 205 Shorts, wheat, 320 Shredded wheat, 371 Sieve tubes, 76 Silent spirit, 763 Sinabaldi asaprol method, 904 Sinalbin, 47 mustard oil, 470 Sinapin thiocyanate, 469 Sinigrin, 470 Sinks, 15 Sitosterol, 542 Smith and Bartlctt tin method, 975 Smoked meats, 215 Snell electrical conductivity value, 661 MacFarlane and Van Zoeren lead number, 659 " Soaked " goods, 970 Soap-bark, 1014 Soda, cherry, 1013 determination of, 313, 361 lemon, 1012, 1013 orange, 1012, 1013 1084 INDEX. Soda, raspberry, 1012, 1013 strawberry, 1012, 1013 vanilla, 1012, 1013 water, ion syrups, 1012 Sodium benzoate, 890 bicarbonate, 348 methods of analysis, 352 bisulphate, 896 carbonate, in milk, 166, 170 hydroxide, tenth-normal solution, 24 salicylate, 887 Soja bean meal, 375 Soleil-Ventzke saccharimeter, 601 Solid yellow, 829 Soluble blue, 854, 869 Sorbose, 37 Sorghum, 695 Sostegni and Carpentieri dyeing test, 842 Sour milk, 172 Souring of milk, 116 Soxhlet extractor, 52 lactose method, 137, 139 Soy oil, 528, 528, 545 Spaghetti, 364. See also Pastes, edible. Sparkling wine, 714, 715, 717, 720 Spearmint, extract, 949 standards, 949 oil, 949 Specific gravity bottle, 45 of beeswax, 675 liquids, 43 liquors, 686 milk, 118 serum, 151, 152 temperature correc- tion for, 120 oils, 490 vinegar, 795 rotatory power, 607 Spent tea leaves, 388 Spice extracts, 949 Spices, 422 adulterants of, 422, 427 methods of analysis, 422 alcohol extract, 424 ash, 423 crude fiber, 425 ether extract, 424 lime, 424 Spices, methods of analysis, moisture, 423 starch, 425 sulphuric acid, 424 volatile oil, 425 microscopy of, 426 Spiral ducts, 76 Spirit vinegar, 788, 794 Spirits, cologne, 763 distilled, 763 neutral, 763, 767, 768 silent, 763 standards, 763 velvet, 763 Spoon test for butter, 572 Sprengel tube, 48 Springers, 960 Squash, composition of, 282 Stachyose, 37 Stahlschmidt caffeine method, 387 Standard for allspice, 438 almond extract, 943 oil, 943 anise extract, 949 oil, 950 beer, 742 brandy, 772 butter, 556 cassia, 482 extract, 950 oil, 950 cayenne, 460 celery seed extract, 950 oil, 950 cheese, 198 cinnamon, 442 extract, 950 oil, 950 clove extract, 950 oil, 950 cloves, 432 • cocoa, 417 cream, 186 foods, 4 fruit butter, 986 ginger, 466 extract, 950 ice cream, 191 ketchups, 977 lard, 579 I INDEX. 1085 Standard for lemon extract, 927 oil, 928 mace, 484 maple products, 594 meat extracts, 252 meats, 213 milk, 145 mince meat, 987 molasses, 651 mustard, 476 nutmeg, 482 extract, 950 oil, 950 olive oil, 531, 532 orange extract, 941 oil, 941 pepper, 449 peppermint extract, 949 oil, 949 renovated butter, 563 rose extract, 953 oil, 953 rum, 774 savory extract, 950 oil, 950 sesame oil, 538 spearmint extract, 949 oil, 949 staranise extract, 950 oil, 950 starch sugar, 596 sugars, 587, 596, 594 sweet basil extract, 950 oil, 950 marjoram extract, 950 oil, 951 thyme extract, 951 oil, 951 tonka extract, 917 vanilla extract, 917 vinegar, 803 wintergreen extract, 947 oil, 947 wine, 716 whiskey, 766 Standard solutions, equivalents of, 25, 26 refractometric readings of, 106 Staranise extract, standards, 950 oil, standards, 950 Starch, 38, 76, 288 arrowroot, 291 barley, 290 bean, 291 buckwheat, 290 classification of, 289 corn, 290 detection of, 288, 991 determination of, 292, 305 by acid conversion, 392 diastase method, 292 in baking powder, 360 cereals, 292, 305 jams and jellies, 991 milk, 171 sausages, 240 spices, 425 oat, 291 pea, 291 potato, 291 rice, 291 rye, 290 sago, 291 syrup, 598 tapioca, 291 under polarized light, 292 wheat, 289 Stearic acid, 29, 487 Stearin, beef, 582 cottonseed, 536 lard, 579 Sterilized butter, 563 Still, alcohol, 688, 689 fractionating, 56 nitrogen, 60, 62 water, 20 wine, 714 Stilton cheese, 197 Stone carbohydrate separation method, 304 Stout, 740, 743- See also Beer. Strawberry soda, 1012, 1013 Strawberries, composition of, 283 Strippings, 113 Stutzer gelatin method, 228 Suberin, 76 Sucrate of lime, 187, 189 Sucrose. See Cane sugar. Suction pump, 18 Sudan, I, 815, 829, 849, 858, 875 II, 852, 858, 875 1086 INDEX. Sudan, III, 852, 858, 875 IV, 858, 87s G, 849 Suet, 550 Sugar, 586. See also Cane sugar, beet, 590 brown, 589 cane, 588 classification of, 586 composition of,' 589 determination by copper reduction, 614 grape. See Dextrose, in fruits, 587 jams, 987 maple. See Maple syrup, muscovado, 589 raw, 589 refining, 591 standards, 587, 594, 596 ultramarine in, 591, 613 Sulphur, determination of, 313 Sulphuric acid determination, 313, 362 in baking chemicals, 362 vinegar, 748 Sulphuring, 591, 896 of fruits, 1003 Sulphurous acid, 896 detection of, 897 determination of, 897 in butter, 562 meat, 216, 238 Sumac, 819, 823 Sun yellow, 854, 868 Sunflower oil, 547 seeds, 547 Sweet basil extract, standards, 950 oil, standards, 950 marjoram extract, standards, 950 oil, standards, 951 wine, 714, 715, 717, 718, 719 Sweeteners, artificial, 905 Swells, 960 Swiss cheese, 197 Sy lead method, 660 Syrup, analysis of, 642 ashing of, 609 corn. See Glucose, golden, 591 drip, 591 Syrup, maple. See Maple syrup. mixing. See Glucose. sorghum, 596 starch. See Glucose. Syrups, fruit, loio soda water, 1012 Tallow, 550 Tannin in cloves, 429 tea, 379 wine, 716 Tapioca, 291 Tartaric acid, 38 in baking powder, 349, 356 fruit products, 1008 Tartrate baking powders, 349 Tartrazin, 826, 833, 834, 837, 847, 854, 861 Tatte, 174 Tea, 378 acidity, 1035 adulteration of, 387 ash, 381, 382 astringents in, 390 caffeine in, 379, 380, 381, 385 composition of, 379, 380, 381 exhausted leaves in, 388 facing of, 387 foreign leaves in, 388 leaf, characteristics of, 389 methods of analysis, 381 acidity, 1035 ash, 382 alkalinity of, 382 astringents, 390 caffeine, 386 crude fiber, 381 essential oils, 382 ether extract, 381 extract, 383 facing, 387 insoluble leaf, 382 protein, 382 tannin, 383 theine, 385 water, 381 microscopy of, 391 spent leaves in, 388 stems in, 389 tablets, 390 tannin in, 379, 383 INDEX. 1087 Tea, theine in, 386 Teller protein separation method, 307 Tetracyanol S F. See Patent blue. Tetrasaccharides, 37 Tetroses, 36 Theobromine, 35, 410 determination of, 413 Thioflavin T, 857, 873 Thompson boric acid method, 886 Thyme extract, standards, 951 oil, standards,! 951 Tin, action of fruits and vegetables on, 961 963, 964 coating, influence of different weights, 964 determination of, 972, 973, 974 salts in molasses, 651, 655 Tintometer, Lovibond, 67 Titer test, 518 Tocher sesame oil test, 538 Tomato ketchup. See Ketchup. Tomatoes, composition of, 282 Tonka bean, 917 tincture, 917 Trehalose, 37 Trillat methyl alcohol test, 782 Trioses, 36 Trisaccharides, 37 Tropaeolin O. See Resorsin yellow. Tryptophane, 35 Turmeric, 467, 815, 819, 821, 823, 849 as an adulterant, 469 composition, 468 curcmuin in, 467 in butter, 557 methods of analysis. See Spices. microscopy of, 468 tests for, 821 Turnips, composition of, 282 Tyrosine, 35 Ulrich cocoa-red method, 417 Ultramarine blue, 816 . in sugar, 591, 613 tea, 387 Uno beer, 746 Unsaponifiable matter, 520 Uranin, 856, 872 Vacuoles in yeast cells, 347 Valine, 35 Van Slyke protein formul?., 140 separation method in cheese, 200 in milk, 133 Vanilla bean, 911, 912 exhausted, 913 extract, 911 acetanilide in, 918, 925, 926 adulteration of, 917 alkali in, 914 artificial, gi8 color value of, 915, 926 composition of, 912, 914, 915,916 coumarin in, 917, 920, 923, 924 glycerol in, 913, 926 lead number of, 915, 925 methods of analysis, 919 acetanilide, 925, 926 acidity, 927 alcohol, 926 ash, 927 caramel, 926 coumarin, 920, 923, 924 glycerol, 926 lead number, 925 resins, 919 sugars, 926 vanillin, 920, 922, 924 preparation of, 913 prune juice in, 918 resins in, 919 standards, 917 tannin in, 920 tonka in, 917 vanillin in, 913, 915, 920, 922, 924 soda, 1012, 1013 Vanillin, 913 determination, 920, 922, 924 microscopical structure, 924 Vaporimeter, 704 Veal, bob, 217 composition of, 209 cuts of, 209 Vegetable colors. See Colors, vegetable, in sausages, 241 1 1088 INDEX. Vegetables, 282 ash of, 311 canned, 957 composition of, 282 methods of proximate analysis of, 285 Ventilation, 15 Vermicelli, 364. See also Pastes, edible. Vessels, 76 Victor Chemical Works lead method, 362 Victoria yellow, 815, 829, 847, 856, 872 Villavecchia and Fabris sesame oil test, 538 Vinegar, 788 acidity of, 790, 796, 797, 798 acids of, 796, 797 adulterated, 809 adulteration of, 803, 804 alcohol in, 792, 797 apple, 803 ash of, 790, 791, 792, 793, 794, 795, 806 beer, 792 caramel in, 810 cider, 790, 803 artificial, 805 cask, 789, 790 generator, 789, 791 glycerol in, 791, 801 composition of, 790, 791, 792, 793, 794, 806, 809 distilled, 794, 804 generators, 789 glucose, 794, 804 glycerol in, 791, 801 grain, 804 Hortvet number of, 799 hydrochloric acid in, 798 imitation, 774 malt, 792, 804 manufacture of, 789 methods of analysis, 795 acids, fixed, 797 mineral, 797, 798 total, 796 volatile, 797 alcohol, 797 arsenic, 811 ash, 795 caramel, 810 copper, 8n Vinegar, methods of analysis furfural, 810 glycerol, 801 hydrochloric acid, 798 lead, 810 acetate test, 809 number, 799 malic acid, 798 metals, 810 nitrogen, 796 pentosans, 801 phosphoric acid, 795 potassium acid tartrate, 8cxj reducing matters, 801 solids, 795 specific gravity, 795 sugar, 800 sulphuric acid, 798 zinc, 810 molasses, 794, 806 phosphoric acid in, 790, 792, 793, 795 polarization of, 790, 800, 806, 807, 808, 809 reducing matter in, 790, 801, 806 residue of, 805 specific gravity of, 792, 793, 794 795 spices in, 810 spirit, 794, 804, 806 standards, 803 sugar, 804 sugars in, 790, 792, 800, 807 tartrate in, 800 varieties of, 788 wine, 792, 804 wood, 795, 810 Vinous fermentation, 682 Violamin R, 831, 855, 871 Viscogen, 187 Viscosity of cream, 187 oils, 492 Vitafer, 204 Vitellin, 32, 271 Vitellose, 5^ Waage Bombay mace test, 485 Walnut ketchup, 977 Walnuts, composition of, 284 Water-bath, 19 INDEX. 1089 Water glass, 273 Waterhouse butter test, 573 Watermelons, composition of. 283 Weiss beer, 740 Weld, 819, 823, 848 Wendt hydrogen electrode apparatus, 1025 Werner-Schmidt fat method for cheese, 200 milk, 126 West benzoic acid method, 895 Westphal balance, 44 Wheat, 280, 281 ash of, 310 composi'Lion of, 280, 281, 320 microscopy of, 315 proteins of, 305-309 shredded, 371 starch, 289 Whiskey, 764. See also Distilled liquors adulteration of, 770 aging of, 764 American, 767 blended, 766 Bourbon, 766, 768, 769 British, 767 composition of, 767 corn, 766 imitation, 771 Irish, 767 manufacture of, 764 methods of analysis, 777 rye, 766, 768, 769 Scotch, 766 standards, 765, 766 Wichmann coumarin test, 923 Wijs iodine absorption method, 509 Wild saccharimeter, 606 Wiley bromine pipette, 512 and Ewell double dilution sugar method, 136, 650 Wilkinson and Peters test for peroxidase, 1 73 Wine, 713 acetal in, 716 acetaldehyde in, 716 adulteration of, 720 alum in, 725 ameliorated, 720 arsenic in, 716 boric acid in, 716 Burgundy, 714, 715, 717 butyric acid in, 716 Wine, California, 718 cane sugar in, 721 Cazeneuve color method, 736, 737 chaptalizing, 721 chianti, 714, 715, 717 citric acid in, 716 claret, 714, 715, 717 classification of, 714 colors in, 725, 736, 737 composition of, 717, 718 constituents, 715 copper in, 716 corrected, 720 dealcoholized, 714 "dry," 714, 715, 717 Dupre color method, 736 ethers in, 716 fortified, 714, 719, 723 fruit other than grape, 725 furfural in, 716 gallizing, 722 Gau tier's rule, 722 glycerol, 716, 734 Halphen ratio, 723 * hexamethylene tetraamine in, 725 hock, 715 inosite in, 716 lactic acid in, 716 Madeira, 714, 715, 717 malic acid in, 716 manganese in, 716 mannite in, 716 manufacture of, 713 methods of analysis, 726 acids, total, 726 volatile, 726 alcohol, 726 ash, 726 colors, 736 cream of tartar, 732 extract, 726 glycerol, 734 lactic acid, 732 nitrates, 735 potassium sulphate, 735 preservatives, 736 reducing sugars, 734 sodium chloride, 735 specific gravity, 726 tannin, 735 1090 INDEX. Wine, methods of analysis tartaric acid, free, 731, 732 total, 731 methyl pentoses in, 716 modified, 720 Moselle, 714, 715, 717 natural, 714 nitrates in, 723, 735 cenocyanin in, 713, 716 oxalic acid in, 716 pentoses in, 716 phosphoric acid in, 716 piquette, 724 plastering, 721 polarization of, 734 pomace, 724 port, 714, 715, 717 potassium sulphate in, 716, 735 preservatives in, 725, 736 proprionic acid in, 716 quercetin in, 716 red, 714, 715, 719 reducing sugar in, 716, 734 resin, 720, 725 Rhine, 714, 715, 717 Roos ratio, 723 salicylic acid in, 716 sauterne, 714, 715, 717 scheelizing, 725 sherry, 714, 715, 717 sodium chloride in, 725, 735 sparkling, 714, 715, 720 standards, 716 still, 714 succinic acid in, 716 sweet, 714, 715, 717 tannin in, 716, 735 tartaric acid in, 716, 731, 732 Tokay, 715, 717 varieties of, 714 vinegar, 788, 792 watering of, 722 white, 714, 715, 719 yeast of, 713 Wintergreen extract, 947 adulteration of, 947 wintergreen oil in, 947 oil of, 947 Winton lead number, 658, 799, 925 moisture apparatus, 50 Winton, Ogden, and Mitchell alcohol extract method, 424 insoluble leaf method, 382 piperine meth- od, 447 Wolfbauer titer test method, 518 Wollny milk fat refractometer, 86, 126 tables for using, 128 table for converting Woll- ny degrees into wjj, 138 Wood vinegar, 795, 810 Woodman and Burwell formic acid test, 899 Davis benzaldehyde method, 988 Taylor caffetannic acid meth- od, 396 Wool, double dyeing method with, 818, 821, 842 dyeing of, 841 for color tests, 841 green S, 854, 868 vegetable colors on, 818, 821 Wormy fruit, 1004 Xanthine, 35, 205 Xantho-proteic reaction, 34 Xylan, 38 Xylose, 36 Yeast, 343 adulteration of, 346 composition of, 345 compressed, 344 dry, 344 extracts, 252 in cider, 707 wine, 713 leavening power, determination of- 347 microscopy of, 346 standard, 346 starch in, 346 Yellow colors, 815, 847 fat color, 858, 875 Yogurt, 174 Zega oleomargarine test, 576 Zein, 31, 309 Zinc salts, 966, 1004 determination of, 973 PLATE I. CEREALS. Fig. 121. — Barley, Xiio. Transverse section, showing in order, pericarp, seed coats, aleurone layer, and starch cells. Fig. 122. — Barley, X55. Surface view of epidermis with hairs. Fig. 123. — Barley, X125. Surface view of upper chaff layer. Fig. 124. — Barley Starch, X220. CEREALS. PLATE U. Fig. 125. — Buckwheat, Xno. Transverse section through part of pericarp, seed coat, and part of endosperm. Fig. 126. — Buckwheat, Xiio. Surface view of scutellum. Fig. 127. — Buckwheat, Xiio. Surface section. Aleurone or proteid layer. --^ o St ^^'6^ Fig. 128. — Buckwheat Starch, X220. Starch granules separated. PLATE III. CEREALS. **^ Fig. 129. — Buckwheat Starch, Xno. Starch grains in masses. Fig. 130. — Corn, Xno. Transverse section through pericarp, seed coat, proteid layer, and part of endosperm, showing starch cells. Fig. 131. — Corn, Xno. Surface view showing two layers of the mesocarp. Fig. 132. — Com, Xno. Surface section. Proteid layer. CEREALS. PLATE IV. ■■^'^•'■<^^ Pi^. Fig. i33._Com Starch, X220. Fig. 134. — Cornstarch, X22C. With polarized light. Fio. 135.— Oat, Xiio. Transverse section through chaff. Fig. 136.— Oat, Xiio. Surface section. Proteid layer with fragments of epidermis and hairs. PLATE V. Fig. 137.— Oat, Xiio. Surface view of upper chaff layer. Fig. 138.— Oat, X55. Surface view of epidermis and hairs. Fig. i39._Oat Starch, X220, Fia. 14c — Ri^e, X no Transverse section through seed coat and part of endospenn. CEREALS. PLATE VL Fig. 141. — Rice, Xiio. Surface section through starch cells. Fig. 142. — Rice, Xno. Surface view of upper chaff layer. -Ai \^ V ^ -Kf)^- J ^ Fig. 143. — Rice Starch, X220. Fig. 144. — Rye, X 18 Transverse section through the entire prain PLATE VII. CEREALS. Fig. 145. — Rye, Xiio. Fig. 146. — Rye, Xiio. Transverse section through pericarp, seed coat. Surface view of epidermis and underlying layers, aleurone layer, and starch cells of endosperm. Fig. 147. — Rye, Xiio. Surface view of epidermis and of seed eoat. _^». ;«He^e'niip<^^ P#1' Fig. 148. — Rye Starch, X220. PLATE VIII. CEREALS. Fig. 149.— Wheat, Xiio. Fig. 150.— Wheat, X no. Transverse section through pericarp, seed coat, Surface view of outer and inner epidermis Also proteid layer, and starch cells of endosperm. showing proteid layer. Fig. 151. — Wheat, Xiio. Surface view of epidermis, with hairs. Fig. 152. — Wheat Starch, X220. LEGUMES. PLATE IX. Fig. 153. — Bean, X no- Transverse section through starch cells. Fig. 154. — Bean Starch, X220. Fig. 155. — Bean, Xno. Transverse section through hull, showing palisade cells of epidermis, and underlying hypoderma. Fig. 156. — Lentil, Xno. Transverse section through hull and part of endo- sperm, showing some of the starch cells. PLATE X. LEGUMES. Fig. 157 — Lentil, Xiio. Surface view of epidermis. Fig. 158.— Pea, Xiio. Transverse section through hull and seed coat, showing outer palisade cells and underlying hypoderma. / Fig. 159. — Pea, Xiio. Surface section through base of palisade layer. Fig. 160. — Pea, Xiio. Powdered pea hulls. PLATE XI. LEGUMES. Fig. i6i. — Pea, Xiio. Surface view of palisade cells. Fig. 162. — ^Pea, Xiio. Transverse section through starch cells. r5^^* Fig. 163. — Pea, X30. Transverse section through starch cells. Fig. 164. — Pea Starch, X220. MISCELLANEOUS STARCHES. PLATE XII. Fig. 165. — Potato Starch, X220. Fig. 166. — Potato Starch, X220. With polarized light. ^X^' Fig. 167. — Arrowroot Starch, X220, Fig. 168. — Tapioca Starch, X220. (Cassava.) TURMERIC. SAGO. PLATE XIII. Fig. 169. — Turmeric, X 7°- Transverse section through rhizome. Fig. 170. — Turmeric, Xiio. Longitudinal section. Note spiral ducts through the center. Fig. 171. — Powdered Turmeric, Xno. Showing starch grains, fragments of cell tissue, coloring "natter, etc. Fig. 172. — Sago Starch, X220. PLATE XIV. COFFEE. Fig. 173.— Raw Coffee, Xiio. Fig. 174. — Roasted Coffee, X130, Transverse section of outer portion of endosperm. Transverse section through parenchyma of endo- sperm. Ftg. 17=5. — Coffee, Xno. Surface view of seed coat. L Fig. 176. — Coffee, Xnc. Roasted, ground coffee, showing fragments of endosperm parenchyma and of seed coat. PLATE XV. COFFEE. CHICORY. >f ■ Fig. 177. — Adulterated Coffee, X130. Dark masses of roasted pea starch are shown, with transparent fragments of the palisade cells of the pea-hull. Fig. 178. — Adulterated Coffee, X 130. The vascular ducts of chicory show most con- spicuously in this field. Fig. 179. — Chicory, X25. Transverse section through the root. Fig. 180. — Chicory, Xiio. Transverse section. PLATE XVI. CHICORY. COCOA. Fig. i8i. — Chicons Xno. Fig. 182. — Chicory, Xiio Tangential section, showing reticulated ducts and Radial section, showing bark parenchyma and wood parenchyma. milk ducts. j^' - a. ' fs ■ w ^ fifa. J^ Fig. 183.— Chicory, Xiio. FiG. 184.— Cocoa, Xiio. Roasted and ground, showing fragments of Transverse section through periphery of seed ducts and other tissues. seed coats, and cotyledon. * COCOA. PLATE XVII. t ^^^ R^~-:^^ >.^' ■- ■-■.-1 Fig. 185. — Powdered Cocoa, Xno. Fig. 186. — Adulterated Cocoa, Xiio Showing admixture of arrowroot with the cocoa powder. Fig 187. — Cocoa Shell, Xiio. Transverse section through epidermis, pulp, and mucilaginous layers of the pericarp and seed eoat. Fig. 188, — Cocoa Shell, X nc. Longitudinal section through shell PLATE XVIII. TEA. SPICES. Fig. 1S9. — Tea, X55- Transverse section through midrib of leaf. Note the paUsade layer below the upper epidermis, the inner wood vessels above the center, and the parenchyma of the pulp. Fig. 190. — Tea, >C no. Surface view of lower epidermis, \vith stomata and one of the hairs. Fig. 191. — Allspice, X9. Transverse section through the entire berry, show- ing the two cells, with kidney shaped seed in each. Fig. 192. — Allspice. X70- Transverse section through pericarp, showing oil spaces and stone cells. PLATE XIX. SPICES. Fig. 193. — Allspice Seed, Xno. Transverse section through seed shell and part of embryo, showing starch cells. Fig. 194. — Allspice Seed, Xno. Transverse section through the resinous portion of the seed coat, showing port wine colored lumps of gum or resin. tx Fig. 195. — Powdered Allspice, Xno. Fig. 196.— Adulterated Allspice, Xno. Showing stone cells, resinous lumps, and starch. Showing a large fragment of the seed skin of cayenne at the left. SPICES. PLATE XX. Fig. 197. — Cassia Bark, X45- Transverse section through the bark. Fig. 198. — Cassia Bark, X45. Longitudinal section. Fig. 199. — Cassia Bark, Xiio. Transverse section, showing cork cells, parenchy- ma, and stone cells. Fig. 200. — Cassia Bark, Xiio. Longitudinal section, showing bunches of bast fibers at the left, starch cells in the center, and stone cells at the right. SPICES. PLATE XXL I Fig. 20I. — Ccvi.in ( innamon Bark, Xiio. Fig. 202. — Ceylon CiiiMaiiiDn Hark, Xiio. Transverse section, slinwins; many bast fibers and Longitudinal section, showinc; bast fibers, stone starch cells. cells, and parenchyma. ^ Fig. 203. — Powdered Cassia, Xno. Showing stone cells, starch, and corky tissue. Fig. 2C4. — Powdered Cassia, Xiio. Showing bast fibers and starch. SPICES. PLATE XXII. Fig. 205. — Powdered Cassia, X no. Showing large bast fiber and starch grains. Fig. 206. — Adulterated Cassia, Xiio. A mass of foreign bark. Fig. 207. — Cayenne, Xiio. Transverse section through pericarp. Fig. 208. — Cayenne, Xiio. Transverse section through seed coat and part of endosperm. Collapsed parenchyma cells sepa- rate endosperm from long epidermal cells. SPICES. PLATE XXIII. Fig. 209. — Cayenne, Xiio. Surface view of fruit epidermis. Fig. 210. — Cayenne, Xiio. Surface view of two layers of seed coat. Fig. 211 . — Powdered Cayenne, X 1 10. A large mass of fruit epidermis. Fig. 212. — Powdered Cayenne, Xiio. Showing chiefly two of the seed coat layers. PLATE XXJV. SPICES. Fig. 213. — Adulterated Cayenne, X130. Fig. 214. — Adulterated Cayenne, X214. Com and wheat starch and cocoanut shells appear The central mass is ground red wood, surrounded chiefly. A bit of cayenne is shown at the right. by corn starch grains. Fig. 215.— Clove, X65. Fig. 216.— Clove, Xiio. Transverse section from the center outward to Transverse section near epidermis, showing large epidermis, showing parenchyma. oil cavities. 1 SPICES. PLATE XXV. >^-( Fig. 217. — Clove, X38. Longitudinal section through entire clove. Fig. 218. — Clove, X70. Central longitudinal section, showing duct bundles. Fig. 219. — Clove, Xiio. Surface view of epidermis. Fig. 220. — Powdered Cloves, X130. Dense, spongy tissue, with small oil drops. PLATE XXVI. SPICES. Fig. 221. — Clove Stem, X70. Fig. 222. — Clove Stem, X25. Transverse section through outer part of stem, Central longitudinal section through entire stem, showing bast fibers at the left, parenchyma in showing bast fibers in the center, and stone cells the center, and stone cells near the epidermis. at the right. Fig. 223. — Clove Stem, X 70. Longitudinal section, showing the stone cells. Fig. 224. — Powdered Clove Stems, Xiio. Showing fragments of tissues, stone cells, and bast fibers. SPICES. PLATE XXVII. Fig. 225. — ^Powdered Clove Stems, Xiio. Showing bundle of bast fibers. Fig. 226. — Adulterated Cloves, X130. Showing chiefly stone cells of cocoanut shells. A . ''■■"'■ -W-' v>E^ Fig. 227. — Adulterated Cloves, X130. Fig. 228. — Ginger, Xiio. With large admixture of cocoanut shells. Transverse section, showing starch cells with contents. PLATE XXViiI. SPICES. Fig. 229.— Ginger, Xno. Fk,. 230.— Ginger, ,> no. Transverse section, showing parenchyma, starch Longitudinal section, showing spiral ducts and grains, and duct vessels. pigment cells. Fig. 231. — Ginger Starch, X220. Fig. 232. — Adulterated Ginger, X 130. A mass of wheat bran tissue is most conspicuous. PLATE XXIX. SPICES. Fig. 233. — Adulterated Ginger, X 130. k d."'" '»► -i^^l qO -i^ ,A^^ Fig. 234. — Adulterated Ginger, X130. The central dark mass is a yellow fragment of Containing a large admixture of corn and wheat turmeric. starches. Fig. 235. — IVnantz: Mace, Xiio. FiG. 236. — Bombay or Wild Mace, Xiio. Transverse section through epidermis and oil cells, Transverse section through outer layers, showing showing also parenchyma with contents of yellow and red resinous lumps, amylodextrin. PLATE XXX. SPICES. f^f t: Fig. 237. — Nutmeg, Xiio. Transverse section through the exterior and in- terior teguments of the seed and part of the endosperm, showing starch cells. A^ Fig. 238. — Nutmeg, X25. Transverse section near exterior of seed. Fig 239. — Nutmeg, X no. Surface view of seed coat, showing also portions of underlying tissues. Fig. 240. — Powdered Nutmeg, Xiio. PLATE XXXI. SPICES. Fig. 241. — Wliite ^Tustard, Xiio Transverse section through mucilaginous epider- mis, sub-epidermal parenchyma layer (square cells), palisade cells, and broken parenchyma layer of the hull. Fig. 242. — White Mustard, Xno. Transverse section through the tissue of the radicle. Fig. 24^5. — White Mustard Xito Surface view of two layers of the hull or seed coat. Fig. 244. — \¥hite Mustard. Xno. Surface section through palisade cells and under- lying layer of the seed coat. PLATE XXXII. SPICES. Fig. 245.^l3lack Mustard, Xiio. FiG. 246. — Black Mustard, Xno. Transverse section, showing fragments of the epi- Surface view of two of the seed coat layers, dermis and dark colored palisade cells of the seed coat. Fig. 247. — Ground Mustard, X130. Ground without removal of the oil. Fig. 248. — Ground Mustard Hulls, Xiio. PLATE XXXIII. SPICES. ^•^\ \. Fig. 249. — Dakota Mustard Flour, Xiio. FiG. 250. — Adulterated Mustard Flour, X130. Dark spots show starch grains of foreign weed Showing masses of wheat starch, seed, stained with iodine. Xi^ Fig. 251. — Pepper, Xno. Transverse section through inner part of pericarp (including parenchyma and seed coat layers) and portion of perisperm, showing starch and oil cells. Fig. 252. — Pepper, Xno. Surface view of hypodermal layer. SPICES. PLATE XXXIV. Fig. 253. — Pepper, Xno. Transverse section through outer part of pericarp, showing epidermis, underlying stone cell layers, parenchyma, and seed coat. Fig. 254. — Pepper, Xiio. Surface section through stone cell layer #: '■'% ■\ ' , •* * • • >»-/^'{";<-.^ r'"- 9 / ? f \5 " * ^ / * . '^ . * Fig. 255. — Pepper Starch, X220. Starch granules separated. Fig. 256. — Pepper Starch, Xiio. Starch grains in masses. SPICES. PLATE XXXV. Fig. 257. — Ground Pepper Shells, Xno. Mainly sho\\ang stone cells. *•«*. -^ Fig. 258. — Adulterated Pepper, X130. Showing wheat and buckwheat starches. t ^'fU' '^' ^^ ' /** i^- *^ '. ^ ♦/ '1' Fig. 259. — Adulterated Pepper, X 130. Showing wheat, corn, and rice starches. Fig. 260. — Adulterated Pepper, X 130. The large, lower mass shows buckwheat starch, while the finer-grained mass near the top is of pepper. PLATE XXXVI. SPICES. SPICE ADULTERANTS. Fig. 261. — Adulterated Pepper, Xiio. Fig. 262. — Adulterated Pepper, X130. The central mass shows the sclerenchyma cells of Cayenne and wheat starch are the adulterants. olive stones. &■• >' --^klrra ., - -i.^ .- tf •<■■':■*, ■vie- - <^ ■ ^."^.^ \i ffm-ymf>:: "^'.4 Fig. 263. — Powdered Olive Stones, Xiio. Fig. 264. — Powdered Cocoanut Shells, X 1 10 PLATE XXXVII. SPICE ADULTERANTS. Fig. 265. — Powdered Elm Bark, Xno. Fig. 266. — Pine Sawdust, Xiio. Finely ground. m * m m - ^■'*^^J«^'^«••*;|- Fig. 267. — Pine Wood, Xno. Transverse section. ^4 Fig. 268. — ^Pine Wood, Xno. Radial and tangential sections. PLATE XXXVIll. EDIBLE FATS. Fig. 269. — Pure Butter, X25. With polarized light and selenite plate. Fig. 270. — Process or Renovated Butter, X25. With polarized light and selenite plate. Fig. 271. — Oleomargarine, X25. With polarized light and selenite plate. PLATE XXXIX. EDIBLE FATS. Fig. 272. — Lard Stearin, Xiio. Leaf lard, crystallized from ether. Fig. 273. — Lard Stearin, X220. Leaf lard, crystallized from ether. Fig. 274.- Lard :Dlearin, X220. " Back" lard, crystallized from ether. Fig. 275.— Lard Stearin, X480. "Back" lard, crystallized from ether. PLATE XL. EDIBLE FATS. Fig. 276. — Beef Stearin, >Cs5- Crystallized from ether. Fig. 277. — Beef Stearin, Xiio. Crystallized from ether. Fig. 278. — Beef Stearin, X220. Crystallized from ether. h3 X < S - er 2 c 9 OC t» o •* 05 ^ 4 h 1 / /l 1 f w / [ / si I I 1 II I ll 1 ■ o 1 / j / / d / I / ^' (5 1 1 ? ll ' II II i 1 1 ij j 1 i -y ' i — n 1 1 1 f \ y A/ // A y // 1 1 / r // 4 J- i ' / / / > 1 1 " ^ m B :;5 a 3 5 i! a -o 2 2 o o < « i-J atunioA -^q loqooiy