Principles of cooking

Recipe for Boiled Onions. — Wash and peel about eight medium-sized onions. Place them in a stewpan, cover with boiling water, and boil until soft, about 40 minutes. If the onions have a strong odor, the water may be changed once or twice during cooking. When the onions are soft, drain the water off and serve with White Sauce. Calculate cost. At what meal would you serve boiled onions ? Onions contain :—_ Water Carbohydrate Cellulose Protein Fat Mineral Matter 87.6% 9.90% .8% .93% 1.69% 1 This cellulose is included in the carbohydrate. The carbohydrate in onions is mainly in the form of cellulose and sugar. (Test may be made for starch.) Onions contain a volatile oil which gives to them their distinctive flavor. The oil is also soluble in water; much of it is dissolved in the water during cooking as well as evaporated with the steam. If the dish in which the onions are cooking is left uncovered, much of the oil passes off gradually in the steam, and the odor of boiled onions is not as noticeable as when the dish is kept covered and the cover removed occasionally. 1. Heat and moisture soften cellulose. 2. Volatile oil is soluble in water. Recipe for White Sauce. — Melt two tablespoons of butter, add two tablespoons of flour, and rub them together thoroughly. Add one cup of milk and cook until it thickens, stirring constantly. Add one fourth teaspoon of salt and a speck of pepper. (Thin white sauce is made by using one tablespoon of flour instead of two. Thick white sauce is made by using from three to four tablespoons of flour.) When boiling water or milk is poured over starch, the starch grains expand and gelatinize or thicken, and tend to stick together and become lumpy. Some substance should be mixed with the starch to separate or surround the particles so that they will have room to expand when boiling water or milk is added later, or when cold liquid is added and the mixture is boiled. Melted fat may be used for this purpose, and the starch and fat should be rubbed together thoroughly so that the fat will surround the starch. As starch is not soluble in cold water, a little cold water or cold milk may be used to separate the starch grains. If the liquid is used, mix the liquid and starch ‘thoroughly until there are no lumps left, before adding the boiling liquid. In pudding sauces, sugar may be mixed with the starch for the same purpose. (As flour contains so much starch it is often used instead of cornstarch as the thickening agent.) Heat and moisture cause starch grains to swell and burst the walls of cellulose that inclose them, hence starch is used as a thickening agent. Recipe for Stewed Apples. — Wash and peel about eight apples. Cut into quarters and remove the cores. Place the apples in a stewpan, add a small quantity of water, about one fourth cup, simmer slowly until the apples are soft. If the apples are tart, it will take 10-15 minutes. When the apples are soft, add sugar, a speck of pepper or cinnamon, and one teaspoon of butter. Some apples contain more water and sugar than others, so the exact amount of water and sugar to use cannot be given. Sugar is added after the apples are cooked because, if it were added sooner, the acid in the apples would change or invert the sugar to glucose, and some of the sweetening power would be destroyed. Glucose is about three fifths as sweet as cane sugar. This reduction in sweetness does not impair the food value of the sugar, however, for cane sugar is changed to glucose in the normal digestive processes. 1. Heat softens cellulose. 2. Acid softens cellulose. 3. Acid inverts or changes cane sugar to glucose.