FoodNet

A text-book of cooking

1915

Page 19

Presented as published in 1915. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
Cellulose. — Cellulose is a tough substance somewhat like the fiber of wood. The skins of vegetables and fruits and the covering of seeds contain much cellulose. Indeed it forms not only the outside covering of fruits, vegetables, and seeds, but their interior framework as well. The fibrous material found in rolled oats consists almost entirely of cellulose. Experiment 16: Separation of Cellulose and Starch. — Place a heaping teaspoonful of rolled oats in a cup and add just enough water to cover it. Allow it to stand for at least 15 minutes. Pour the mixture into a cheesecloth and press out the moisture and much of the starch, catching it in a saucepan. Rinse the starch out of the cloth as thoroughly as possible by holding it under running water. 38 THE COOKING OF POODS © O £* From Household Chemistry, by J. M. Blanchard. Examine the substance remaining in the cloth. Tear it into pieces. Is it tough ? Does it suggest any common material ? What is it ? Heat the contents of the saucepan. What is this substance ? The tiny grains of starch shown under the microscope (see Fig. 16) contain both starch and cellulose. The latter forms the outer covering of the microscopic grains. Starchy vegetables contain much cellu- lose : (a) in the outside cover- ing; (b) in the interior frame- work ; (c) in the covering of the starch grains. The cellulose of some plants in the raw condition can be eaten without distress by the normal person. However, the cellulose of many foods is very tough; it is necessary to soften it, if it is to be used as a food. This may be accomplished by cooking it. Cellulose contains practically no nourishment. Yet it is valuable in diet, for it furnishes bulk to foods and stimulates the flow of the digestive juices as it brushes against the walls of the di- gestive organs. Heat and moisture applied to starchy foods serve two important purposes : (a) They soften the cellulose. (6) They change the starch to a paste or make it semi- soluble. Fig. 1 6. — Grains of starch. a, potato starch ; b, corn starch. (Much magnified.) Foodstuffs Defined. — All the nutritious materials contained in foods can be grouped into five great classes. These classes of materials are called the foodstuffs (formerly called food principles). A few foods contain but one foodstuff, some contain several foodstuffs, many contain all the food- stuffs. CEREALS: STARCH AND CELLULOSE 39 Carbohydrate, a Foodstuff. — Because sugar, starch, and cellulose have somewhat the same composition and some properties in common, they are grouped into one class, viz. carbohydrate. Sugar, starch, and cellulose are all included in the term carbohydrate. Carbohydrate is one of the food- stuffs. Sugar is a food containing but one foodstuff. Cereals contain all of the foodstuffs. Cereals contain, however, a larger quantity of carbohydrate than any of the other food- stuffs, hence they are classed as carbohydrate foods. Cereals. — Cereals are cultivated grasses, the seeds of which are used for food. The most important are wheat, Indian corn or maize, rice, oats, rye, and barley. From these many different kinds of flours, meals, and breakfast foods are prepared. Cereals rank first in nutriment among the vegetable foods. Many of them contain about 75 per cent of starch. Because they are widely distributed in various climates, they have an important place in man's diet. Most of the cereals used as breakfast foods have a large quantity of cellulose. To make them palatable it is necessary to soften the cellulose and swell the large quantity of starch. This is accomplished by long cooking, the time of cooking de- pending upon the character of the cellulose and the method of preparation of the cereal for market.