Cooking improves cereals in many ways. For the average person, proper cooking has almost as much to do with the nutriment finally obtained as the proportions of nutrients originally present. Flavor and appearance are improved, with the gain in digestibility that comes from appetizing foods which stimulate the flow of digestive juices. Cooking to convert nutrients ' into more digestible forms, is very important in the case of cereals which contain so much starch; and since the starch in these foods is surrounded by cell-walls of crude fiber (largely cellulose) upon which the digestive juices are unable to act, these walls must be broken down. Part of this disintegration may be accomplished in milling, and part by thorough mastication but complete digestion of the starch is assured only by thorough cooking.

Parching is one of the simplest methods of cooking grains. The invisible moisture in the cells is expanded by the heat, and the cell walls burst. Some of the starch is also made soluble or changed to dextrin by this process. The digestibility of protein seems to be lessened by cooking at high temperatures, but the starch can be made almost perfectly digestible.

The softening of cellulose is more perfectly accomplished by cooking for a long time in the presence of a large amount of moisture, as in steaming, or cooking with water or milk in a double boiler. The glutinous material which surrounds the starch grains and prevents their digestion is disintegrated so that the digestive juices can act. In general, the more crude fiber a cereal contains, the longer it should be cooked. Reference to the table (p. 234) shows that oats requires more cooking than rice; whole or partially crushed grains than finely ground ones. There is danger in undercooked cereals, not only of loss of valuable nutriment through failure of digestion, but in irritation of the alimentary tract. This should be especially remembered in preparing partially cooked breakfast foods.

When cereals are cooked in water some of it is absorbed, and soluble substances in the food pass into the remaining water. If this is thrown away, as when rice is boiled in a large quantity of water and subsequently drained dry, a considerable part of the nutriment is lost. Rice water frequently contains enough dissolved starch to form a jelly on cooling. For this reason steaming is a preferable method. Practical application of the fact that certain nutrients in cereals are soluble is made in the preparation of all kinds of cereal waters and starchy jellies. (See Eecipes, pp. 124-244).

Gruels are thin porridges made from flour or other finely ground grain products, with either water or milk. They are cooked for a long time to insure the starch being changed to soluble starch, or even partially dextrinized. Time for cooking should therefore be conscientiously kept by the clock.

By passing the material through a cheese-cloth or sieve, the coarser, undissolved portions are removed, and the smooth product does not irritate weakened digestive organs; hence this method is desirable for invalids and young children.

In cooking all cereal products, the following points should be observed:

Use a double boiler.

Observe carefully the correct proportions of cereal, water and salt.

Cook at boiling temperature (212° F.).

Watch the time by the clock, and always cook the full time prescribed, preferably longer.

Serve attractively.

Improper cooking and poor serving are largely responsible for unpopularity of cereal foods.

Digestibility

The digestibility of cereals is greatly influenced by the mode of preparation and the thoroughness of insalivation. For the normal healthy person cereal foods are very wholesome. In general, about 90 per cent. or more of the organic matter is assimilated. The carbohydrates are most completely digested; the protein shows a wide variation, but is less perfectly assimilated than the other nutrients, owing partly to the fact that it is often hardened in cooking and partly that it is intimately bound up with cellulose in the bran coats. For this reason white flour shows a higher degree of digestibility for protein, than do whole wheat preparations.

Among cereal breakfast foods, rolled wheat ranks first in digestibility, rolled oats next, and corn preperations among the lowest. The partially digested or ready-to-eat cereals supply more digestible material than the plain grains when well cooked.

Nutritive Value

Cereals supply actual digestible nutriments to the body more cheaply than any other class of foods except the dried legumes. All animal foods, especially meats, are more expensive, even as sources of protein, than cereals. A glance at their composition shows that they are chiefly fuel foods, because of their high carbohydrate content. Their cost varies with the cost of labor and fuel in preparing the food. The comparatively expensive ready-to-eat breakfast foods do not yield any extra nutritive value. Their only advantages are pleasant flavor and ease of serving. Cereal products yield on the average between 1600 and 1700 calories per pound. Thus:

1 lb. flour furnishes 1665 calories.

1 lb. entire wheat flour furnishes 1675 calories.

1 lb. corn meal furnishes 1655 calories.

1 lb. cornstarch furnishes 1675 calories.

1 lb. wheatlet furnishes 1685 calories.

1 lb. hominy furnishes 1650 calories.

1 lb. granulated corn meal furnishes 1665 calories.

1 lb. wheat germ furnishes 1695 calories.

1 lb. tapioca furnishes 1650 calories.

Care Of Cereals

Cereals must be kept in a cool, dry place; warmth will favor the development of the maggot eggs; and moisture, when absorbed, makes them musty.