Human Foods and Their Nutritive Value by Harry Snyder (dark academia books to read .TXT) ๐
CHAPTER XXI
LABORATORY PRACTICE 299
Object of Laboratory Practice; Laboratory Note-book and Suggestions for Laboratory Practice; List of Apparatus Used; Photograph of Apparatus Used; Directions for Weighing; Directions for Measuring; Use of Microscope; Water in Flour; Water in Butter; Ash in Flour; Nitric Acid Test for Nitrogenous Organic Matter; Acidity of Lemons; Influence of Heat on Potato Starch Grains; Influence of Yeast on Starch Grains; Mechanical Composition of Potatoes; Pectose from Apples; Lemon Extract; Vanilla Extract; Testing Olive Oil for Cotton Seed Oil; Testing for Coal Tar Dyes; Determining the Per Cent of Skin in Beans; Extraction of Fat from Peanuts; Microscopic Examination of Milk; Formaldehyde in Cream or Milk; Gelatine in Cream or Milk; Testing for Oleomargarine; Testing for Watering or Skimming of Milk; Boric Acid in Meat; Microscopic Examination of Cereal Starch Grains; Identification
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87. Use of Beans in the Dietary.โThere is no vegetable food capable of furnishing so much protein at such low cost as beans; from a pound costing five cents about one fifth of a pound of protein and three fifths of a pound of carbohydrates are obtained. Beans can, to a great extent, take the place of meats in the dietary. There is more protein in beans than in beef. Four ounces of uncooked beans or six ounces of baked beans are as much as can conveniently be combined in the dietary, and these will furnish a quarter of the protein of the ration. In the case of active out-of-door laborers over a pound of baked beans per day is often consumed with impunity.
Fig. 20.โBeans, Raw and Cooked. Skins, Wet and Dry.
88. String Beans.โString beansโgreen beans with podโcontain a large amount of water, 85 to 88 per cent. The dry matter is rich in protein, nearly 20 per cent, although in the green beans as eaten, containing 85 per cent water, there is less than 2ยฝ per cent. Lima beans are richer in protein than string beans, as the green pod is not included. String beans are valuable both for the nutrients they contain and for the favorable influence they exert upon the digestibility of other foods.
89. Peas.โIn general composition and digestibility, peas are quite similar to beans. They belong to the same family, Leguminosรฆ, and the protein of each is similar in quantity and general properties. The statements made in regard to the composition, digestibility, and use of beans in the dietary apply with minor modifications to peas. When used in the preparation of soups, they add appreciable amounts of nutrients.
Fig. 21.โPea Starch Granules.
90. Canned Peas.โIn order to impart a rich green color, copper sulphate has been used in the canning of peas. Physiologists differ as to its effect upon health. While a little may not be particularly injurious, much interferes with normal digestion of the food and forms insoluble copper proteids. In some countries a small amount of copper sulphate is tolerated, while in others it is prohibited.
91. Peanuts.โPeanuts differ from peas and beans in containing more fat. They should be considered a food, for at ordinary prices they furnish a large amount of protein and fat. Like the other members of the legume family, the peanut is rather slow of digestion and requires considerable intestinal work for completion of the process.
NUTS92. General Composition.โNuts should be regarded as food, for they contribute to a ration appreciable amounts of nutrients. The edible portion of nearly all is rich in fat; pecans, for example, contain as high as 70 per cent. In protein content nuts range from 3 per cent in cocoanuts to 30 per cent in peanuts. The carbohydrate content is usually comparatively low, less than 5 per cent in hickory nuts, although there is nearly 40 per cent in chestnuts. On account of high fat content, nuts supply a large amount of heat and energy.[33]
93. Chestnuts are characterized by containing less fat and protein and much more carbohydrate material, especially starch, than is found in other nuts. In southern Europe chestnuts are widely used as food; the skins are removed, and the nuts are steamed, boiled, or roasted, and sometimes they are dried and ground into flour. Chestnuts are less concentrated in protein and fat, and form a better balanced food used alone than do other nuts.
94. The Hickory Nut, which is a characteristically American nut, contains in the edible portion about 15 per cent protein, 65 per cent fat, and 12 per cent carbohydrates.
95. The Almonds used in the United States come chiefly from southern Europe, although they are successfully raised in California. They contain about 55 per cent fat and 22 per cent protein. The flavor of almonds is due to a small amount of hydrocyanic acid.
96. Pistachio.โSome nuts are used for imparting color and flavor to food products, as the pistachio nut, the kernel of which is greenish in color and imparts a flavor suggestive of almonds. The pistachio has high food value, as it is rich in both fat and protein. It is employed in the manufacture of confectionery and in ice cream for imparting flavor and color.
97. Cocoanuts grow luxuriantly in many tropical countries, and have a high food value. They are characteristically rich in fat, one half of the edible portion being composed of this nutrient. For tropical countries they supply the fat of a ration at less expense than any other food. When used in large amounts they should be supplemented with foods rich in carbohydrates, as rice, and in proteids, as beans. Cocoanut milk is proportionally richer in carbohydrates and poorer in fat and protein than the meat of the cocoanut. In discussing the cocoanut, Woods states:[34]
"The small, green, and immature nuts are grated fine for medicinal use, and when mixed with the oil of the ripe nut it becomes a healing ointment. The jelly which lines the shell of the more mature nut furnishes a delicate and nutritious food. The milk in its center, when iced, is a most delicious luxury. Grated cocoanut forms a part of the world-renowned East India condiment, curry. Dried, shredded (desiccated) cocoanut is an important article of commerce. From the oil a butter is made, of a clear, whitish color, so rich in fat, that of water and foreign substances combined there are but O.0068. It is better adapted for cooking than for table use. At present it is chiefly used in hospitals, but it is rapidly finding its way to the tables of the poor, particularly as a substitute for oleomargarine."
98. Use of Nuts in the Dietary.โWhen nuts can be secured at a low price per pound, ten cents or less, they compare favorably in nutritive value with other staple foods. Digestion experiments with rations composed largely of nuts show that they are quite thoroughly digested. Professor Jaffa of the California Experiment Station, in discussing the nutritive value of nuts and fruits, says:[35]
"It is certainly an error to consider nuts merely as an accessory to an already heavy meal, and to regard fruit merely as something of value for its pleasant flavor, or for its hygienic or medicinal virtues. The agreement of one food or another with any person is more or less a personal idiosyncrasy, but it seems fair to say that those with whom nuts and fruits agree, can, if they desire, readily secure a considerable part of their nutritive material from such sources."
Average Composition of Nuts(From Fifteenth Annual Report, Maine Agricultural Experiment Station.)
Portion Edible Portion Value
per lb.[A] Water Prot. Fat Carb. Ash % % % % % % % Calories Almonds 64.8 35.2 1.7 7.3 19.3 6.2 0.7 1065 Almonds, kernels -- 100.0 4.8 21.0 54.9 17.3 2.0 3030 Brazil nuts 49.6 50.4 2.7 8.6 33.6 3.5 2.0 1545 Filberts 52.1 47.9 1.8 7.5 31.3 6.2 1.1 1575 Filberts, kernels -- 100.0 3.7 15.6 65.3 13.0 2.4 3290 Hickory nuts 62.2 37.8 1.4 5.8 25.5 4.3 0.8 1265 Pecans 49.7 50.3 1.4 5.2 35.6 7.2 0.8 1733 Pecans, kernels -- 100.0 2.9 10.3 70.8 14.3 1.7 3445 Walnuts 58.0 42.0 1.2 7.0 27.0 6.1 0.7 1385 Walnuts, kernels -- 100.0 2.8 16.7 64.4 14.8 1.3 3305 Chestnuts 16.1 83.9 31.0 5.7 6.7 39.0 1.5 1115 Acorns 35.6 64.4 2.6 5.2 24.1 30.9 1.6 1690 Beechnuts 40.8 59.2 2.3 13.0 34.0 7.8 2.1 1820 Butternuts 86.4 13.6 0.6 3.8 8.3 0.5 0.4 430 Litchi nuts 41.6 58.4 10.5 1.7 0.1 45.2 0.9 875 Piรฑon, P. edulis 40.6 59.4 2.0 8.7 36.8 10.2 1.7 1905 Piรฑon, P. monophylla 41.7 58.3 2.2 3.8 35.4 15.3 1.6 1850 Piรฑon, P. sabiniana 77.0 23.0 1.2 6.5 12.3 1.9 1.1 675 Pistachio, kernels -- 100.0 4.2 22.6 54.5 15.6 3.1 3010 Peanuts, raw 26.4 73.6 6.9 20.6 30.7 13.8 1.6 1935 Peanuts, kernels -- 100.0 9.3 27.9 42.0 18.7 2.1 2640 Roasted peanuts 32.6 67.4 1.1 20.6 33.1 10.9 1.7 1985 Shelled peanuts -- 100.0 1.6 30.5 49.2 16.2 2.5 2955 Peanut butter -- -- 2.0 29.3 46.6 17.1 [B]5.0 2830 Cocoanuts 48.8 51.2 7.2 2.9 25.9 14.3 0.9 1415 Cocoanuts, shredded -- -- 3.5 6.3 57.3 31.6 1.3 3125 Cocoanut milk -- -- 92.7 0.4 1.5 4.6 0.8 97
[A]Calculated from analyses.
[B]Including salt, 4.1.
CHAPTER VII MILK AND DAIRY PRODUCTS99. Importance in the Dietary.โThere is no article of food which enters so extensively into the dietary as milk, and it is one of the few foods which supply all the nutrients,โfats, carbohydrates, and proteids.[36] Milk alone is capable of sustaining life for comparatively long periods, and it is the chief article of food during many diseases. An exclusive milk diet for a healthy adult, however, would be unsatisfactory; in the case of young children, milk is essential, because the digestive tract has not become functionally developed for the digestion of other foods.
It is necessary to consider not only the composition and nutritive value of milk, but also its purity or sanitary condition.
100. General Composition.โAverage milk contains about 87 per cent water and 13 per cent dry matter. The dry matter is composed approximately of:
Fat is the most variable constituent of milk. Occasionally it is found as low as 2 per cent and as high as 6 per cent or more. The poorest and richest milks differ mainly in fat content, as the sugar, ash, casein, and albumin, or "solids of the milk serum," are fairly constant in amount and composition. Variations in the content of fat are due to differences in feed and in the breed and individuality of the animal.
Fig. 22.โMilk Fat Globules.
101. Digestibility.โMilk is one of the most completely digested of foods, about 95 per cent of the protein and fat and 97 per cent of the carbohydrates being absorbed and utilized by the body.
In a mixed ration, the
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