Review Questions

Chapter I

General Composition of Foods

1. To what extent is water present in foods? 2. What foods contain the most, and what foods the least water? 3. How does the water content of some foods vary with the hydroscopicity of the air? 4. How may changes in water content of foods affect their weight? 5. Why is it necessary to consider the water content of foods in assigning nutritive values? 6. How is the dry matter of a food determined? 7. Why is the determination of the water in a food often a difficult process? 8. What is the ash or mineral matter of a food? 9. How is it obtained? 10. What is its source? 11. Of what is the ash of plants composed? 12. What part in plant life do these ash elements take? 13. Name the ash elements essential for plant growth. 14. Which of the mineral elements take the most essential part in animal nutrition? 15. In what form are these elements usually considered most valuable? 16. Why is sodium chloride or common salt necessary for animal life? 17. How do food materials differ in ash content? 18. Define organic matter of foods. 19. How is it obtained? 20. Of what is it composed? 21. Into what is the organic matter converted when it is burned? 22. Give the two large classes of organic compounds found in food materials. 23. Name the various subdivisions of the non-nitrogenous compounds. 24. What are the carbohydrates? 25. Give their general composition. 26. What is cellulose? 27. Where is it found? 28. What is its function in plants? 29. What is its food value? 30. In what way may cellulose be of value in a ration? 31. In what way may it impart a negative value to a ration? 32. What is starch? 33. Where is it mainly found in plants? 34. Give the mechanical structure of the starch grain. 35. Why is starch insoluble in cold water? 36. How do starch grains from different sources differ in structure? 37. What effect does heat have upon starch? 38. Define hydration of starch. 39. Under what conditions does this change take place? 40. What value as a nutrient does starch possess? 41. What is sugar? 42. How does it resemble and how differ in composition from starch? 43. What are the pectose substances? 44. How are they affected by heat? 45. What food value do they possess? 46. What is nitrogen-free-extract? 47. How is it obtained? 48. How may the nitrogen-free-extract of one food differ from that of another? 49. What are the fats? 50. How do they differ in composition from the starches? 51. Why does fat when burned or digested produce more heat than starch or sugar? 52. Name the separate fats of which animal and vegetable foods are composed. 53. Give some of the physical characteristics of fat. 54. What is the iodine absorption number of a fat? 55. How does the specific gravity of fat compare with that of water? 56. Into what two constituents may all fats be separated? 57. What is ether extract? 58. How does the ether extract in fats vary in composition and nutritive value? 59. What are the organic acids? 60. Name those most commonly met with in foods. 61. What nutritive value do they possess? 62. What dietetic value? 63. What value are they to the growing plant? 64. What organic acids are found in animal foods? 65. What are the essential oils? 66. How do they differ from the fixed oils, or fats? 67. What property do the essential oils impart to foods? 68. What food value do they possess? 69. What dietetic value? 70. What are the mixed compounds? 71. How may a compound impart a negative value to a food? 72. What is the nutritive value of the non-nitrogenous compounds, taken as a class? 73. Why is it necessary that nitrogenous and non-nitrogenous compounds be blended in a ration? 74. What are the nitrogenous compounds? 75. How do they differ from the non-nitrogenous compounds? 76. Name the four subdivisions of the nitrogenous compounds. 77. What is protein? 78. What is characteristic as to its nitrogen content? 79. What are some of the derivative products that can be obtained from the protein molecule? 80. How does the protein content of animal bodies compare with that of plants? 81. Name the various subdivisions of the proteins. 82. What is albumin, and how may it be obtained from a food? 83. What is globulin, and how is it obtained from a food? 84. Give some examples of globulins. 85. What are the albuminates, and how are they affected by the action of acids and alkalies? 86. What are the peptones, and how do they differ from the albumins? 87. How are the peptones produced from other proteids? 88. What are the insoluble proteids? 89. Give an example. 90. Which of the proteids are found to the greatest extent in foods? 91. Why may proteids from different sources vary in their nutritive value? 92. What general change do the proteids undergo during digestion? 93. What is crude protein? 94. How is the crude protein content of a food calculated? 95. Why is the nitrogen content of a food more absolute than the crude protein content? 96. What food value do the proteins possess? 97. Why may proteins serve so many functions in the body? 98. Why is protein necessary as a nutrient? 99. What is the effect of an excess of protein in the ration? 100. What is the effect of a scant amount of protein in a ration? 101. What are the albuminoids? 102. Name borne materials that contain large amounts of albuminoids. 103. What food value do the albuminoids possess? 104. What are the amids? 105. How are they formed in plants? 106. What is their source in animals? 107. What general changes does the element nitrogen undergo in plant and animal bodies? 108. What is the food value of the amids? 109. What are the alkaloids? 110. What is their food value? 111. What effect do some alkaloids exert upon the animal body? 112. How may they be produced in animal foods? 113. What general relationship exists between the various nitrogenous compounds? 114. Why is it essential that the animal body be supplied with nitrogenous food in the form of proteids? 115. Name the cycle of changes through which the element nitrogen passes in plant and animal bodies.

Chapter II

Changes in Composition of Foods During Cooking and Preparation

116. How do raw and cooked foods compare in general composition? 117. In what ways are foods acted upon during cooking? 118. What causes chemical changes to take place during cooking? 119. What are the principal compounds that are changed during the process of cooking? 120. How does cooking affect the cellulose of foods? 121. What change does starch undergo during cooking? 122. When foods containing starch are baked, what change occurs? 123. How are the sugars acted upon when foods are cooked? 124. What effect does dry heat have upon sugar? 125. What change occurs to the fats during cooking? 126. How does this affect nutritive value? 127. What changes do the proteids undergo during cooking? 128. Why does the action of heat affect various proteids in different ways? 129. Why are chemical changes, as hydration, often desirable in the cooking and preparation of foods? 130. What physical changes do vegetable and animal tissues undergo when cooked? 131. How do foods change in weight during cooking? 132. Why is a prolonged high temperature unnecessary to secure the best results in cooking? 133. To what extent is the energy of fuels utilized for producing mechanical and chemical changes in foods during cooking? 134. What effect does cooking have upon the bacterial flora of foods? 135. In what ways do bacteria exert a favorable influence in the preparation of foods? 136. How may certain classes of bacteria exert unfavorable changes in the preparation of foods? 137. What are the insoluble ferments? 138. What are the soluble ferments? 139. What part do they take in animal and plant nutrition? 140. Define aerobic ferments. 141. Define anaërobic ferments. 142. What general relationship exists between the chemical, physical, and bacteriological changes that take place in foods? 143. Why should foods also possess an esthetic value? 144. What kinds of colors should be used in the preparation of foods? 145. What processes should be used for removal of coloring materials from foods?

Chapter III

Vegetable Foods

146. Give the general composition of vegetable foods as a class. 147. How do vegetable foods differ from animal foods? 148. Name some vegetables which contain the maximum, and some which contain the minimum percentage of protein. 149. Give the general composition of potatoes. 150. Of what is the dry matter mainly composed? 151. How much of the crude protein of potatoes is true protein? 152. What ratio exists between the nitrogenous and non-nitrogenous compounds in the potato? 153. Give the chemical composition of the potato. 154. What influence do different methods of boiling have upon the crude protein content of potatoes? 155. To what extent are the nutrients of potatoes digested and absorbed by the body? 156. What value do potatoes impart to the ration? 157. How do sweet potatoes differ in chemical composition and food value from white potatoes? 158. How do carrots differ in composition from potatoes? 159. What is characteristic of the dry matter of the carrot? 160. How do carrots and milk differ in composition? 161. To what is the color of the carrot due? 162. To what extent are the nutrients removed in the cooking of carrots? 163. What is the value of carrots in a ration? 164. Give the characteristics of the composition of parsnips. 165. How does the starch of parsnips differ from that of potatoes? 166. How does the mineral matter of parsnips differ from that of potatoes? 167. How does the cabbage differ in general composition from many vegetables? 168. To what extent are nutrients extracted in the boiling of cabbage? 169. Give the nutritive value of cabbage. 170. How does the cauliflower differ from cabbage? 171. Give the general composition of beets. 172. Give the general composition of cucumbers. 173. What nutritive value has lettuce? 174. Give the composition and dietetic value of onions. 175. How does the ratio of nitrogenous and non-nitrogenous compounds in spinach differ from that in many other vegetables? 176. Give the general composition and nutritive value of asparagus. 177. How much nutritive material do melons contain? 178. What are the principal compounds of tomatoes? 179. What nutrients do they supply to the ration? 180. In the canning of tomatoes, why is it desirable to conserve the juices? 181. How does sweet corn differ in composition from fully matured corn? 182. What nutritive value does the egg plant possess? 183. What are the principal nutrients of squash? 184. What nutritive material does celery contain? 185. To what does celery owe its dietetic value? 186. Why are vegetables necessary in a ration? 187. Why is it not possible to value many vegetable foods simply on the basis of percentage of nutrients present? 188. Name the miscellaneous compounds which many vegetables contain, and the characteristics which these may impart. 189. Why is it necessary to consider the sanitary conditions of vegetables? 190. How do canned vegetables differ in composition and food value from fresh vegetables? 191. What proportion of vegetables is refuse and non-edible parts? 192. Why is it necessary to consider the refuse of a food in determining its nutritive value?

Chapter IV

Fruits

193. To what extent do fruits contain water and dry matter? 194. Give the general composition of fruits. 195. What compounds impart taste and flavor? 196. How much nutrients do fruits add to a ration? 197. Why is it not right to determine the value of fruits entirely on the basis of nutrients? 198. Give the general composition of apples? 199. What compound is present to the greatest extent in the dry matter of apples? 200. How do apples differ in composition? 201. Give the general physical composition of oranges. 202. What nutrients are present to the greatest extent in oranges? 203. How do lemons differ in composition from oranges? 204. How does grape fruit resemble and how differ in chemical composition from oranges and lemons? 205. What are the main compounds in strawberries? 206. In what ways are strawberries valuable in a ration? 207. Of what is grape juice mainly composed? 208. What acid is in grapes, and what is its commercial value? 209. To what are the differences in flavor and taste due? 210. How do ripe olives differ in composition from green olives? 211. What is the food value of the olive? 212. What physiological property does olive oil have? 213. What is the principal nutrient in peaches? 214. What compounds give flavor to peaches? 215. Of what does the dry matter of plums mainly consist? 216. How do plums differ in composition from many other fruits? 217. What are prunes? What is their food value? 218. How do dried fruits differ in composition from fresh fruits? 219. What should be the stage of ripeness of fruit in order to secure the best results in canning? 220. How do canned fruits differ in composition and nutritive value from fresh fruits? 221. To what extent are metals dissolved by fruit juices? 222. Why should tin in which canned goods are preserved be of good quality? 223. What preservatives are sometimes used in the preparation of canned fruits? 224. What is the objection to their use? 225. Why are fruits necessary in the ration? 226. What change does heat bring about in the pectose substances of fruits?

Chapter V

Sugar, Molasses, Sirups, Honey, and Confections

227. What is sugar? 228. From what sources are sugars obtained? 229. Name the two divisions into which sugars are divided. 230. How are sugars graded commercially? 231. What per cent of purity has granulated sugar? 232. How is the coloring material of sugar removed? 233. How is sugar treated to make it whiter? 234. What value as a nutrient does sugar possess? 235. Why should sugar be combined with other nutrients? 236. What foods contain appreciable amounts of sugar? 237. Why is an excessive amount of sugar in a ration undesirable? 238. Does sugar possess more than condimental value? 239. What is the average quantity of sugar consumed in this country? 240. What is maple sugar? 241. How does it differ in composition from other sugar? 242. How is adulterated maple sugar detected? 243. To what extent is granulated sugar adulterated? 244. Why is it not easily adulterated? 245. What are the dextrose sugars? 246. How do they differ chemically from sucrose? 247. What is the inversion of sugar? 248. In what way does acid act upon sugar? 249. How are the acid products removed? 250. What is the food value of glucose? 251. What is molasses? 252. How is it obtained? 253. Of what is it composed? 254. What gives taste and flavor to molasses? 255. How may molasses act upon metalware? 256. What is the food value of molasses? 257. What is sirup? 258. Name three kinds of sirup, and mention materials from which they are prepared. 259. What is the polariscope, and how is it employed in sugar work? 260. What is honey? 261. How does it differ in composition from sugar? 262. How is strained honey adulterated? 263. What materials are used in the preparation of confections? 264. What changes take place in their manufacture? 265. What materials are used for imparting color? 266. What can you say in regard to the coal tar colors? 267. What should be the position of candy in the dietary? 268. What can you say of the comparative value of cane and beet sugar? 269. How do the commercial grades of sugar compare as to nutritive value? 270. What are some of the impurities in candy? 271. What is saccharine? 272. What are its properties?

Chapter VI

Legumes and Nuts

273. What nutrients do the legumes contain in comparatively large amounts? 274. How does the amount of this nutrient compare with that found in meats? 275. Why are legumes valuable crops in general farming and for the feeding of farm animals? 276. Give the general composition of beans. 277. How do beans compare in protein content with cereals? 278. How does the protein of beans differ from that of many other food materials? 279. To what extent are the nutrients of beans digested? 280. What influence does the combination of beans with other foods have upon digestibility? 281. What influence does removal of skins have upon digestibility? 282. In what part of the digestive tract are beans mainly digested? 283. How does the cost of the nutrients in beans compare with that of the nutrients in other foods? 284. How do string beans differ from green beans? 285. Give the general composition, digestibility, and nutritive value of peas. 286. What can you say of the use of copper sulphate in the preparation of canned peas? 287. What nutrients do peanuts contain in large amounts? 288. Give the general composition of nuts. 289. What are the characteristics of pistachio? 290. Give the general composition of the cocoanut. 291. What is cocoanut butter? 292. To what extent may nuts contribute to the nutritive value of a ration?

Chapter VII

Milk and Dairy Products

293. What can you say as to the importance of dairy products in the dietary? 294. Give the general composition of milk. 295. What compound in milk is most variable? 296. To what extent are the nutrients in milk digestible? 297. What influence does milk have upon the digestibility of other foods? 298. Why is cheese cured in cold storage? 299. How can the tendency of a milk diet to produce costiveness be overcome? 300. Why is it necessary to consider the sanitary condition of milk? 301. What factors influence the sanitary condition of milk? 302. What is certified milk? 303. What is pasteurized milk? 304. How can milk be pasteurized for family use? 305. What is tyrotoxicon? 306. What is its source in milk? 307. To what is the color of milk due? 308. To what extent is color associated with fat content? 309. What causes souring of milk? 310. What change occurs in the milk sugar? 311. What are the most favorable conditions for the souring of milk? 312. What are some of the preservatives used in milk. 313. What objection is urged against their use? 314. What is condensed milk? 315. What is buttermilk, and what dietetic value has it? 316. How does goats' milk differ from cows' milk? 317. What is koumiss, and how is it prepared? 318. What are the prepared milks? 319. How does human milk differ in composition from cows' milk? 320. Give the nutritive value of skim milk. 321. What content of fat should cream contain? 322. In what ways is milk adulterated? 323. How are these adulterations detected? 324. Give the general composition of butter. 325. What is the maximum amount of water that a butter may contain without being considered adulterated? 326. What can you say in regard to the digestibility of butter? 327. How is butter adulterated? 328. How does oleomargarine compare in digestibility and food value with butter? 329. What is the food value of butter? 330. How does cheese differ in composition from butter? 331. Give the general composition of cheese. 332. To what are the flavor and odor of cheese due? 333. Why is cheese ripened? 334. What chemical changes take place during ripening? 335. To what extent are the nutrients of cheese digested? 336. Why is cheese sometimes considered indigestible? 337. To what extent do the nutrients of different kinds of cheese vary in digestibility? 338. How does cheese compare in nutritive value and cost with meats? 339. What is cottage cheese? 340. What is Roquefort cheese? 341. Name four kinds of cheese, and say to what each owes its individuality. 342. How is cheese adulterated? 343. Why are dairy products in older agricultural regions generally cheaper than meats?

Chapter VIII

Meats and Animal Food Products

344. Give the general composition of meats. 345. How do meats differ in chemical composition from vegetable foods? 346. What is the principal non-nitrogenous compound of meats, and what of vegetables? 347. Name the different classes of proteins in meats. 348. Which class is present in largest amounts? 349. To what extent are amid compounds present in meats? 350. What characteristics do amids impart to meats? 351. How are alkaloids produced in meats? 352. In what ways does the lean meat of different kinds of animals vary chemically and physically? 353. Give the general composition of beef. 354. What relationship exists between the fat and water content of beef? 355. How much refuse have meats? 356. In what forms are the ash elements (mineral matter) present in meats? 357. How does veal differ in composition from beef? 358. What general changes in composition occur as animals mature? 359. How do these compare with the changes that take place when plants ripen and seeds are produced? 360. How does mutton vary in composition from beef? 361. How does it compare in food value with beef? 362. How do lamb and mutton differ in composition? 363. To what extent do the various cuts differ in composition? 364. How do the more expensive cuts of lamb compare in nutritive value with the less expensive cuts? 365. How does pork differ in composition from other meats? 366. Give the general composition of ham. 367. Give the composition and nutritive value of bacon. 368. How does bacon compare in food value with other meats? 369. How does the character of the fat influence the composition and taste of the meat? 370. What influences the texture or toughness of meats? 371. How do cooked meats compare in composition with raw meats? 372. To what extent are nutrients lost in the boiling of meats? 373. What influence does the temperature of the water in which the meat is placed for cooking have upon the amount of nutrients extracted? 374. To what is the shrinking of meats in cooking due? 375. Of what does meat extract mainly consist? 376. To what do beef extracts owe their flavor? 377. What is their food value? 378. What is their dietetic value? 379. What is lard? 380. How does it differ in composition from other fats? 381. What is imparted to meats during the smoking process? 382. Why is saltpeter used in the preservation of meats? 383. Do vegetable foods contain nitrates and nitrites? 384. How does poultry resemble and how differ in composition from other meat? 385. Give the characteristics of sound poultry. 386. Give the general composition of fish. 387. How does the flesh of different kinds of fish vary in composition? 388. What influence does salting and preservation have upon composition? 389. How do fish and meat compare in digestibility? 390. How does the mineral matter and phosphate content of fish compare with that of other foods? 391. What are the main nutrients in oysters? 392. Give the general food value of oysters. 393. What is meant by the fattening of oysters? 394. What effect does the character of the water used in fattening have upon the sanitary value? 395. Give the general composition of the egg. 396. How do different parts of the egg differ in composition? 397. How does the egg differ in composition from the potato? 398. Is color an index to the composition of the egg? 399. What effect does cooking have upon the composition of the egg? 400. What factors influence the flavor of eggs? 401. How do different ways of cooking affect the digestibility? 402. Under what conditions can eggs be used economically in the dietary? 403. Why should eggs be purchased and sold by weight? 404. How do canned meats differ in composition from fresh meats? 405. How do the nutrients of canned meats compare in cost with those of fresh meat? 406. What are the advantages of canned meats over fresh meats? 407. What are some of the materials used in the preservation of meats?

Chapter IX

Cereals

408. How are the cereals milled? 409. What are the cereals most commonly used for food purposes? 410. Give the general composition of cereals as a class. 411. What are the main nutrients in corn preparations? 412. What influence does the more complete removal of the bran and germ of corn have upon its digestibility? 413. How does the cost of nutrients in corn compare with other foods? 414. Why is corn alone not suitable for bread-making purposes? 415. Why should corn be combined in a ration with foods mediumly rich in protein? 416. What change takes place in corn meal from long storage? 417. Give the characteristics and composition of oat preparations. 418. How does removal of the oat hull affect the composition of the product? 419. To what extent do the various oat preparations on the market differ in composition and food value? 420. Do oats contain any special alkaloidal or stimulating principle? 421. Why should oatmeal receive longer and more-thorough cooking than many other foods? 422. To what extent are the nutrients in oatmeal digested? 423. How do wheat preparations differ in general composition from corn and oat preparations? 424. What influence upon the composition of the wheat breakfast foods has partial or complete removal of the bran? 425. What is the effect upon their digestibility and nutritive value? 426. What are the special diabetic flours, and how are they prepared? 427. What are the wheat middlings breakfast foods, and how do they compare in digestibility and food value with bread? 428. How do they differ mechanically? 429. How does barley differ from wheat in general composition? 430. What is barley water, and what nutritive material does it contain? 431. What cereal does rice resemble in composition? 432. With what food materials should rice be combined to make a balanced ration? 433. What can you say as to comparative ease and completeness of digestibility of rice? 434. Why are cereals valuable in the ration? 435. In what way do they take a mechanical part in digestion? 436. What are predigested breakfast foods? 437. How would you determine the general nutritive value of a breakfast food, knowing the kind of cereal from which it was prepared? 438. To what extent are cereals modified or changed in composition by cooking? 439. To what extent are the nutrients of cereal foods digested and absorbed by the body? 440. To what extent do the cereals supply the body with mineral matter? 441. How does the phosphate content of cereals compare with that of meats and milk?

Chapter X

Wheat Flour

442. Why is wheat flour especially adapted to bread-making purposes? 443. To what extent may wheat vary in protein content? 444. What are spring wheats? 445. What are winter wheats? 446. Give the general characteristics of each. 447. What are glutinous wheats? 448. What are starchy wheats? 449. Name the different proteids in wheat flour. 450. About how much starch does wheat flour contain? 451. What other carbohydrates are also present? 452. What is the roller process of flour milling? 453. What is meant by the first break? 454. How are the different products of the wheat kernel separated? 455. What is meant by middlings flour? 456. What is break flour? 457. What is patent flour? 458. Name the high grade flours. 459. Name the low grade flours. 460. How are the impurities removed from wheat flour? 461. What per cent of the wheat kernel is returned as flour? As offals? 462. What becomes of the wheat germ during milling? 463. What sized bolting cloths are used in milling? 464. What is graham flour? 465. How does it differ in mechanical and chemical composition from white flour? 466. What is entire wheat flour? 467. How does it differ in physical and chemical composition from white flour? 468. What effect has the refining of flour upon the ash content? 469. How do low and high grade flours differ in chemical composition? 470. How do the wheat offals differ in composition from the flour? 471. What are the factors which influence the composition of flours? 472. What effect does storage have upon the bread-making value of flour? 473. What change takes place when new wheat is stored in an elevator? 474. What is durum wheat flour, and how does it differ from other flour? 475. What gives flour its color? 476. Why is color an index of grade? 477. How is the color of a flour determined? 478. How do flours differ in granulation? 479. How does the granulation affect the physical properties of flour? 480. How is the granulation of flour approximately determined? 481. How is the absorptive capacity of a flour determined? 482. What factors cause a variation in the capacity of flours to absorb water? 483. Give the characteristics of a good gluten. 484. What causes unsound flours? 485. How is the bread-making value of a flour determined? 486. How are flours bleached? 487. How does bleaching affect the chemical composition of flour? 488. What influence does bleaching have upon bread-making value? 489. Traces of what compounds are formed during bleaching? 490. Are these compounds injurious to health? 491. What effect does bleaching have upon the color of fiber and débris particles in flour? 492. Is it possible to bleach low grade flours and cause them to resemble high grade flours? 493. Are flours usually adulterated? 494. Why? 495. How would mineral adulterants be detected? 496. How would the presence of other cereals be detected? 497. How does flour compare in nutritive value with other foods? 498. How does the cost of flour compare with that of other foods? 499. What causes flours to vary so in bread-making value? 500. Why may flours produced from the same type of wheat vary slightly in character from year to year? 501. What relationship exists between the nutritive and bread-making value of a flour?

Chapter XI

Bread and Bread Making

502. Define leavened and unleavened bread. 503. Why is yeast used in bread making? 504. Give the characteristics of a good loaf of bread. 505. Why is flour used for bread making purposes? 506. Name the eight chemical changes that take place during bread making. 507. To what extent do losses in dry matter occur during bread making? 508. What compounds suffer losses during bread making? 509. What is yeast? 510. What chemical changes does it produce? 511. What becomes of these products during bread making? 512. How is compressed yeast made? 513. What part does the alcohol take in bread making? 514. What temperature is reached in the interior of the loaf during bread making? 515. Through what chemical changes does starch pass during bread making? 516. To what extent are soluble carbohydrates formed? 517. In what way is starch acted upon mechanically? 518. Explain the structure of the starch grains in flour and in dough after they have been acted upon by the yeast ferments. 519. To what extent are acids produced in bread making? 520. What becomes of the acids formed? 521. How may the acids thus developed affect the properties of other chemical compounds? 522. To what extent are volatile carbon compounds, other than carbon dioxid and alcohol, liberated during bread making? 523. What changes occur to the various proteids during the process of bread making? 524. Why do flours vary in quality of gluten? 525. To what extent do losses of nitrogen occur during bread making? 526. How much of the total nitrogen of flour is present as proteids? 527. How is the fat of flour affected during the process of bread making? 528. What effect does the addition of 10 per cent of wheat starch to flour have upon the size of the loaf? 529. What effect does the addition of 10 per cent of wheat gluten to flour have upon the size of the loaf? 530. What relationship exists between gluten content and capacity of a flour to absorb water? 531. Give the general composition of bread. 532. What factors influence its composition? 533. What effect does the use of skim milk and lard in bread making have upon composition? 534. How does the temperature of the flour influence the bread-making process? 535. Why is it necessary to vary the process of bread making in order to get the best results with different kinds of flour? 536. To what extent are the nutrients of bread digested? 537. How does graham bread compare in digestibility with white bread? 538. How do graham and entire wheat breads compare in nutritive value with white bread? 539. What value do graham and entire wheat breads have in the dietary? 540. Why is white bread generally preferable in the dietary of the laboring man? 541. How do graham and entire wheat flours compare in chemical composition with white flour? 542. How do they compare in mechanical composition? 543. To what is the difference in digestibility supposed to be due? 544. Are graham and entire wheat breads necessary in a ration as a source of mineral elements? 545. What is the main difference in composition between old and new bread? 546. How do different kinds of bread made from the same flour compare in composition and nutritive value? 447. How does toast differ in composition from bread? 548. What influence does toasting have upon digestibility? 549. What is gained by toasting bread? 550. How does bread compare in nutritive value with other cereal foods? 551. How does bread compare in nutritive value with animal foods?

Chapter XII

Baking Powders

552. What is a baking powder? 553. What are the two kinds of materials which baking powders contain? 554. Name the different types of baking powders. 555. How does baking powder differ in its action from yeast? 556. What are the cream of tartar baking powders? 557. What is the nature of the residue which they leave? 558. What are the phosphate baking powders? 559. What is the nature of the residue which they leave? 560. Why is the mineral phosphate not considered equally valuable with that naturally present in foods? 561. What are the alum baking powders? 562. What residue is left from the alum powders? 563. Which of the three classes of baking powders is considered the least objectionable? 564. Why is a new baking powder preferable to one that has been kept a long time? 565. Why should baking powders be kept in tin cans, and not in paper? 566. Why are fillers used in the manufacture of baking powders? 567. How may a baking powder be prepared at home? 568. How does such a baking powder compare in cost and efficiency with those purchased in the market?

Chapter XIII

Vinegars, Spices, and Condiments

569. What is vinegar? 570. How is it made? 571. Give the three chemical changes that take place in its preparation. 572. Why is air necessary in the last stage of the process? 573. What ferments take part in the production of vinegar? 574. What is malt vinegar? 575. What materials other than apples can be used in the preparation of vinegar? 576. Give the characteristics of a good vinegar. 577. In what ways are vinegars adulterated? 578. What food value has vinegar? 579. Why should vinegars not be stored in metalware? 580. What dietetic value has vinegar? 581. To what materials do the spices owe their value? 582. What is pepper? 583. What is the difference between white and black pepper? 584. What compounds give pepper its characteristics? 585. How are peppers adulterated? 586. What is mustard? 587. Give its general composition. 588. How is it adulterated? 589. What is ginger? 590. How is it prepared for the market? 591. Give its general composition. 592. What is cinnamon? 593. What is cassia? 594. What gives these their taste and flavor? 595. What are cloves? 596. How are they prepared? 597. What is mace? 598. What is nutmeg? 599. Do the spices have any food value? 600. What is their dietetic value? 601. Why is excessive use of some of the spices objectionable?

Chapter XIV

Tea, Coffee, Chocolate, and Cocoa

602. What is tea? Name the two plants from which it is obtained, the countries where each grows best, and the number of flushes each yields. 603. Upon what does the quality and grade of tea depend? 604. Give differences in the preparation and composition of green and black teas. 605. The characteristic flavor of tea is imparted by what compound? 606. To what compound are its peculiar physiological properties due? 607. What can you say of the protein in tea as to amount and food value? 608. Why should tea—especially green tea—be infused for a very short time, never boiled? 609. What effect has tannin upon the digestion of proteids? 610. What three points are considered in judging a tea? 611. What is the most common form of tea adulteration? 612. Describe the coffee plant and fruit, and its method of preparation for market. 613. What is the difference in the chemical composition of tea and coffee? 614. Name the characteristic alkaloid of coffee. How does it compare with theme? 615. Why may coffee not be considered a food? 616. Tell different ways in which coffee may be adulterated. 617. Which is more commonly practiced, tea or coffee adulteration? Why? 618. How may real coffee be distinguished from chicory? Why? 619. Name the three kinds of coffee in general use. Give distinguishing features of each. Which is usually considered best? 620. From what are cocoa and chocolate obtained? 621. Give the two methods of preparing cocoa. 622. What alkaloid similar to the theme and caffeine of tea and coffee is present in cocoa and chocolate? 623. What is the difference in preparation of cocoa and chocolate? 624. What are cereal coffee-substitutes? 625. What nutritive value have they? 626. How do they differ in composition from coffee? 627. To what extent does cocoa add to the nutritive value of a ration? 628. What is plain chocolate? 629. Why do chocolate preparations vary so widely in composition? 630. What treatment is given to the cocoa bean in its preparation for commerce? 631. What treatment is sometimes given to prevent separation of the cocoa fat? 632. In what ways may cocoa and chocolate preparations be adulterated?

Chapter XV

Digestibility of Foods

633. Define the term nutrient. 634. Do all the nutrients of food have the same degree of digestibility? 635. What is a digestion coefficient? 636. How is the digestibility of a food determined? 637. What volatile products are formed during the digestion of food? 638. Define digestible protein; digestible carbohydrates, digestible fat. 639. What is the available energy of a ration? 640. How is it determined? 641. How do the nutrients, protein, fat, and carbohydrates, compare as to available energy? 642. Why is it necessary to consider the caloric value of a ration? 643. Is the protein molecule as completely oxidized in the body as starch or fat? 644. What residue is left from the digestion of protein? 645. What part do the soluble ferments take in digestion? 646. To what extent are the nutrients of animal foods digested? 647. Which nutrient, protein or fat, is the most completely digested? 648. How do vegetable foods compare in digestibility with animal foods? 649. What effect does cellulose have upon digestibility? 650. Which of the nutrients of vegetables, protein or carbohydrates, is more completely digested? 651. What mechanical value may cellulose have in a ration? 652. Why must bulk be considered in a ration, as well as nutrient content? 653. Name the eight most important factors influencing the digestibility of foods. 654. To what extent does the combination of foods affect the digestibility of the nutrients? 655. Why does a mixed ration give better results than when only a single food is used? 656. How does the amount consumed affect the completeness of the digestive process? 657. To what extent does the method of preparing food affect digestibility? 658. What is gained, so far as digestibility is concerned, by the cooking of foods? 659. To what extent does the mechanical condition of food affect its digestibility? 660. Why is it desirable to have some coarsely granulated foods in a ration? 661. Why should the ration not be composed exclusively of finely granulated foods? 662. Why is some coarsely granulated food more essential in the dietary of the sedentary than in the dietary of the laborer? 663. How does palatability affect the digestive process? 664. Do psychological processes in any way affect digestion? 665. What physiological properties do some foods possess? 666. To what are these physiological properties due? 667. To what extent is individuality a factor in digestion? 668. To what extent does digestibility differ with individuals? 669. Why do some foods affect individuals in different ways? 670. Why is it necessary that the quantity, quality, and character of the food should vary with different individuals? 671. In what different ways is the expression "digestibility of a food" used? 672. Why is it necessary to consider the digestibility of food, as well as its composition? 673. Does the digestibility of a food necessarily indicate the economic uses that will be made of it by the body? 674. How is it possible for one food containing 10 per cent of digestible protein, and other nutrients in like amounts, to be more valuable than another food with the same per cent of digestible protein and other nutrients? 675. How is it possible for one food to contain less total protein than another food and yet be more valuable from a nutritive point of view? 676. Why is it necessary to consider the mechanical condition of a food and its combination with other foods, as well as its chemical composition? 677. What effect does lack of a good supply of air have upon the completeness of the digestion process? 678. In what ways does the digestion of food resemble the combustion of fuel? 679. What is gained by a study of the digestibility of foods? 680. Why may two foods of the same general character give different results when used for nutritive purposes?

Chapter XVI

Comparative Cost and Value of Foods

681. To what extent do the nutritive value and the market price of foods vary? 682. How is the value of one food expressed in terms of another food? 683. How determine the amount of nutrients that can be procured in a food for a given sum of money? 684. How compare the amounts of nutrients that can be procured in two foods for a given sum of money? 685. How is it possible to determine approximately which of two foods is cheaper, when the price and composition of the foods are known? 686. To what nutrient is preference usually given in assigning a value to a food? 687. When the difference in this nutrient between two foods is small, then the preference is given to what nutrients? 688. At ordinary prices, what are the cheapest vegetable foods? 689. What are among the cheapest animal foods? 690. Why is it not possible to determine the value of a food absolutely from its composition and digestibility? 691. Why is it necessary to consider the physical as well as the chemical composition of foods? 692. What proportion of the income of the laboring man is usually expended for food? 693. What are the most expensive foods? 694. What foods furnish the largest amount of nutrients at the least cost?

Chapter XVII

Dietary Studies

695. What is a dietary study? 696. How is a dietary study made? 697. What is the value of the dietary study of a family? 698. To what extent does the protein in the dietary range? 699. Why is a scant amount of protein in a ration undesirable? 700. Why is an excess of protein in the ration undesirable? 701. What are dietary standards? 702. How are such standards obtained? 703. Why is it desirable in a ration to secure the protein and other nutrients from a variety rather than from a few foods? 704. Why is it necessary to consider the caloric value of a ration? 705. How is this determined? 706. What is a wide nutritive ratio? 707. What is a narrow nutritive ratio? 708. Why should the amount of nutrients consumed vary with the work performed? 709. How should the nutrients be apportioned among the meals? 710. What are some of the most common dietary errors? 711. What analogy exists between human and animal feeding? 712. What is gained by the rational feeding of both humans and animals? 713. What use can be made of the results of dietary studies for improvement of the dietary? 714. Why is it not possible for animal foods to compete in economy with cereal and vegetable foods? 715. Is a well-balanced ration and one containing an ample supply of nutrients necessarily an expensive ration? 716. Show how it is possible for one family to spend less money for food than another family, and yet secure more digestible nutrients and energy. 717. What are some of the most erroneous ideas as to food values? 718. Why is it necessary to consider previously acquired food habits in the selection of foods? 719. In general, what portion of the nutrients of a ration should be derived from vegetable foods, and what portion from meats? 720. To what extent may a ration vary from the dietary standards? 721. Why are some inexpensive foods often expensive when prepared for the table? 722. What are some of the ways in which the cost of a ration can be decreased without sacrificing nutritive value? 723. Why do different nationalities acquire distinct food habits? 724. Why is it not possible to make sudden and radical changes in the dietary? 725. Why is it not possible for a dietary which gives ample satisfaction for one class of people to be applied to another class with equal satisfaction? 726. What relationship exists between the dietary of a nation and its physical development? 727. What relationship exists between dietary habits and mental development and vigor? 728. Why is it unnecessary and undesirable to regulate absolutely the amount of nutrients consumed in the daily ration? 729. What is the general tendency as to quantity of food and amount of nutrients consumed? 730. Why do people of sedentary habits require a different dietary from those pursuing active, out-of-door occupations?

Chapter XVIII

Rational Feeding of Man

731. What is the object of the rational feeding of man? 732. On what is it based? 733. How does it compare with the rational feeding of animals? 734. What is a standard ration? 735. How is it determined? 736. To what extent may the nutrients of a ration vary from the standard? 737. How do you combine foods to form a balanced ration? 738. What foods are valuable for supplying protein? 739. What foods supply fats? 740. What foods are rich in carbohydrates? 741. What other requisites should a ration have in addition to supplying the necessary nutrients? 742. Why is it necessary to consider the calorie value of a ration? 743. If a ration contained an excess of carbohydrates and a scant amount of protein, how could it be improved? 744. How do you calculate the nutrients in a fraction of a pound of food? 745. Give the amounts of the common food materials, as potatoes, bread, butter, milk, and cheese, ordinarily combined to form a ration. 746. To what extent may foods differ in composition from the average analysis given? 747. What foods are subject to the greatest and what foods to the least variation?

Chapter XIX

Water

748. Why is water regarded as a food? 749. Does it enter chemically into the composition of plants? Of animals? 750. In addition to serving as a food, why is water necessary for life processes? 751. In what ways may water be improved? 752. What are the most common forms of impurities? 753. What are the mineral impurities of water? 754. What is their source? 755. What effect do some of these minerals have upon the value of the water? 756. What causes some waters to dissolve limestone? 757. What are permanently hard waters? 758. To what is temporary hardness in water due? 759. What is the best way to remove mineral matter from water? 760. What are the organic impurities of water? 761. What are the sources of the organic impurities? 762. What change does the organic matter of water undergo? 763. What becomes of the nitrogen of the organic matter? 764. What does the presence of nitrates in water indicate? Nitrites? 765. What is the total solid matter of a water, and how is it obtained? 766. Define the terms free ammonia; albuminoid ammonia. 767. What does the presence of chlorine in a surface well water indicate? 768. Explain natural purification of water. 769. Can natural purification always be relied upon? 770. Why does the character of the drinking water affect health? 771. What diseases are mainly caused by impure drinking water? 772. With what materials in water are the disease-producing organisms associated? 773. Why should a water of questionable purity be boiled? 774. State how the boiling should be done, to be effective. 775. Why should boiled water receive further care in its storage? 776. What effect does improvement of the water supply of a city have upon the death rate? 777. How may connections between cesspools and surface well waters be traced? 778. What impurities do rain waters contain? 779. Explain the workings of the Pasteur and Berkefeld water filters. 780. Why must special attention be given to cleaning the water filter? 781. Explain the processes employed for the removal of mechanical impurities of water by sedimentation and the use of chemicals. 782. Why should such purification be under the supervision of a chemist or bacteriologist? 783. What effect does freezing have upon the purity of water? 784. Why are precautions necessary in the use of ice for refrigeration? 785. What are mineral waters? 786. How are artificial mineral waters prepared? 787. What are the more common materials used in their preparation? 788. Why should mineral waters be extensively used only by the advice of a physician? 789. What are some of the materials used for softening water? 790. Which are the least objectionable of these materials? 791. Which are the most objectionable? 792. What can you say of the use of ammonia and ammonium carbonate for softening waters? 793. In washing clothing after contagious diseases, what materials may be used for disinfecting? 794. Why, in softening waters for household purposes, must caustic soda, potash, and bleaching powder be used with caution? 795. Why is it necessary to determine by trial the material most suitable for softening water? 796. What advantage, from a pecuniary point of view, results from the improvement of the water supply of a community?

Chapter XX

Food in its Relation to Household Sanitation and Storage

797. What are the compounds usually determined in a food analysis? 798. Does such an analysis necessarily indicate the presence of injurious compounds? 799. What are the sources of the injurious organic compounds in foods? 800. Why is it necessary to consider sanitary condition as well as chemical composition? 801. What are the sources of contamination of foods? 802. What is the object of the sanitary inspection of food? 803. How may flies carry germ diseases? 804. Why should food be protected from impure air and dust particles? 805. Why should places where vegetables are stored be well ventilated? 806. How may the dirt adhering to vegetables be the carrier of germ diseases? 807. Why should the cellar in which food is stored be in a sanitary condition? 808. What effect does the cleaning of streets and improvement of the sanitation of cities have upon the death rate? 809. Name the three natural disinfectants, and explain the action of each. 810. Why must dishes and utensils in which foods are placed be thoroughly cleaned? 811. Explain the principle of refrigeration. 812. What kind of ferment action may take place at a low temperature? 813. Why is some ventilation necessary in refrigeration? 814. What effect does refrigeration have upon the composition of food? 815. What relationship exists between unsanitary condition of soils about dwellings and contamination of the food? 816. Why should special attention be given to the sanitary disposal of kitchen refuse? 817. Name the ways in which this can be accomplished. 818. How may foods become contaminated through imperfect plumbing? 819. Mention the conditions necessary in order to keep foods sanitary.