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Food Values and Adulterations (II)

HUMAN NUTRITION-DIETARY STANDARDS-KINDS OF NUTRIENTS -PROBLEMS OF DIET-MEAT IN THE DIET-FISH AS FOOD- POULTRY AND DAIRY PRODUCTS SOURCES OF CARBOHYDRATES -FOOD ADULTERATIONS-CANNED VEGETABLES AND FRUITS -FLAVORING EXTRACTS AND CONDIMENTS-BAKING CHEMICALS -TEA AND COFFEE-DAIRY AND MEAT PRODUCTS The choice, preparation, service and care of food are topics of vital importance in every home. Until quite recently experience-as represented by the traditions of the best housekeepers-has been about the only source of information on these subjects. And such experience is still in many respects the best and safest guide. But of late a great many scientific investigations as to food values and adulterations have been made-notably under the direction of the United States Department of Agriculture-and very practical results have been secured. The most essential facts and principles are here condensed for ready reference.

In many respects the result of scientific study has been to confirm popular impressions derived from everyday experience. Yet it has been shown that certain very widespread beliefs are wholly groundless. All the conclusions here stated have been abundantly confirmed by practical experiments and may be accepted without hesitation. Such knowledge is valuable because it dispels doubt and uncertainty. It confirms good practices. It also draws attention to mistakes and shows how they may be corrected.

HUMAN NUTRITION The human body has often been likened to a steam engine in which as refuse. Some are of no value the food we eat takes the part of fuel. This comparison is partly true but is inadequate. A steam engine gradually wears out with use. Then the worn or broken parts must be replaced from some source without itself. The human body also wears away, but-unlike the steam engineit has the power of rebuilding its own parts from the fuel (food) which it consumes. It can also bring about certain chemical changes whereby its fuel (food) is converted into new forms either for immediate use for storage within the body against future needs. Hence the value of food depends in part upon its capacity to produce needed heat and energy, and in part upon its capacity to supply material for growth and repair of bodily waste. or Food Wastes. - The relation between the cost of food and its actual value to supply bodily needs is affected by at least three different kinds of wastes. These differ greatly in different kinds of food. They are among the things which should be most jealously watched and studied by the housewife. There is considerable loss between some kinds of foods as purchased and as cooked or served. Familiar examples are the shells of eggs, skins and seeds of fruit and vegetables, bones and offal of meat, bran of cereals and the like. These are commonly known FOOD VALUES AND ADULTERATIONS since they are wholly indigestible (for example egg shells). Others may be utilized in various ways as meat bones, which may be used for soup stock.

A second kind of waste is that caused by cooking. This is less important since, in most cases, it cannot be helped. But with some of the more expensive kinds of food, the choice among methods of cookery may be affected by the fact that economical are ways than others. some more A third waste is due to the fact that a part of the food actually eaten is not taken up into the lymph and blood channels but passes through the digestive tract and is excreted from the body. This is said not to be "available" to digestion.

The net product which finally gets into the blood is called nutritive material, or nutrients. Nutrients in Food.-Formerly a great many scientific terms were used in discussing the nutritive value of foods. This made the subject uninteresting to most persons because difficult to understand. With the increase of popular interest, efforts were made to simplify the language of science. It was found that all nutrients may be classed under five heads and referred to by means of terms, all but two of which are in every-day use. These unusual terms are "proteid" and "carbohydrate."

Of these the former is indispensable.

There is no other word which can take its place. It refers to that part of foods which contains (among other things) the element nitrogen.

These include, chiefly, the lean of meat; the gluten of wheat and other cereals; the curd (casein) of milk; and the white (albumen) of eggs.

The two words sugar and starch can be used in place of the term "carbohydrate" as the word refers chiefly to these two substances. These and other carbohydrates are so called because they contain the element hydrogen in the same proportions in which it occurs in water but combined with the element carbon; hence the name.

Good examples of carbohydrates are potato or corn starch, and cane, grape, or milk sugar. use.

The names of the other three classes of nutrients are in common These are water, fat and ash.