FoodNet

Domestic science, principles and application

1914

Page 22

Presented as published in 1914. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
Test for Starch. — Iodine turns starch a deep blue. (Demonstrate.) CARBOHYDRA TE^—PO TA TOES 39 Use. — Starch in the prepared form is used to thicken liquids and sauces. Starch Experiments. — 1. Put a tsp. of starch in a glass containing 3^ c. of water. Watch it. What happens? 2. Mix 1 tsp. of starch with 3^ c. cold water to form a paste. Add 3^ c. boiling water. See what happens. 3. Pour }/2 c. boiling water over 1 tsp. of starch, with- out first mixing cold water. What happens? Break one of the lumps. 4. Mix starch grains with melted butter; add boiling water. 5 . Mix starch with granulated sugar ; add boiling water. Compare results of experiments and draw conclusions. Fig. 6. Effect of cooking on starch: a, cells of a raw potato, showing starch grains and framework; b, cells of a partially cooked potato; c, cells of a thor- oughly boiled potato. (Hutchison.) The Cooking of Starch. — Heat and moisture are needed to soften starch. Starch grains must be separated in some way before boiling water is added. Starch needs long, thorough cooking and a high tem- perature to make it easier to digest. 40 DOMESTIC SCIENCE POTATOES (Irish, or White) A potato is an enlargement of an underground stem. It is a storehouse of starch, which furnishes food for the young plants. Composition. — Potatoes contain — Water, about ^ their weight. For this reason they may be baked, since they contain enough water to soften the starch. Starch, about 1/5 their weight. Protein, about 2.5 per cent. Cellulose, which forms the walls of the cells. Mineral matter, which is mainly potash salts. What food principle is wholly lacking? Which is defi- cient in amount? Structure. — The potato is made up of cells with thin walls of fiber, and these cells contain starch grains and water. Surrounding the mass of starch cells and just beneath the skin is a layer of nutritious mineral matter and protein material. This is wasted if the potato is peeled too thickly. Manner of Growth. — Potatoes are grown from cuttings, each cutting planted producing several tubers beneath the soil. They are best when fully matured; those immature are soggy when cooked. Large potatoes are likely to be hollow at the center. Care in Storage. — Potatoes should be kept in a cool, dark, dry place. Do not let potatoes sprout. The sprouts use moisture and starch from the potato, and thus decrease its value for the table. Food Value. — Owing to their large content of starch, potatoes are excellent as heat and energy producers. Pota- toes are healthful and are easily and thoroughly digested. They furnish 12.5 per cent of the average American diet. CARBOHYDRATE^^— POTATOES 41 Rules for Paring Potatoes. — 1. Always pare potatoes thinly. 2. Remove sprouts and eyes with the point of a knife. 3. Drop potatoes in cold water as soon as they are peeled, but allow them to soak as little as possible. Explain why. 4. Soak old potatoes in cold water an hour before cooking, to restore part of their freshness. Points on Cooking Potatoes. — 1. Drop potatoes into boiling water to cook, not into cold water. Why? 2. Too vigorous boiling tears the outside of the pota- toes before the inside is cooked. 3. Pour off all the water when the potatoes are tender and let them stand uncovered. Why?