FoodNet

Elements of the theory and practice of cookery

1901

Page 34

Presented as published in 1901. Historical recipes may not meet modern food-safety standards. Cook from the modern interpretation, not the original instructions.
D. Test any or all of the following substances for starch : ^ — flour, milk, fish, white of egg, cabbage, meat (in order to see the color, use cooked chicken, lamb, or veal), apple, turnip. Do any of the animal foods contain starch? Do all the vegetable foods contain starch ? Explain why flour is used to thicken white sauce. E. Pour off the water in test-tube a and dry the powder found at the bottom. Can you distinguish it in appearance and feeling from potato starch ? 122. Starch (oat, potato, or any other kind) is a fine white glistening powder, insoluble in cold water, but partially soluble in hot water, with which it forms a jellylike paste. It is turned intensely blue by iodine. Starch is formed and stored up by many growing plants as food for the young shoots, collecting in autumn to be used in spring. Laundry starch is made from corn. 1 Simply test with iodine without adding water or heating. FUEL FOODS: SOME STARCHY PLANTS 69 A Study of Starch 123. Starch under the microscope. — Under the micro- scope starch is seen to consist of irregularly shaped granules formed of layers folded around a central point. Starches from different plants differ from one another, granules of potato starch being larger than those of any other kind, and something like oyster shells in shape and marking, while rice starch granules are angu- lar and very small. When cooked the granules lose their distinctive appearance. A. Examine potato starch, rice starch, cornstarch, and other starches under the microscope. Do the different kinds of starch granules look aUke ? Are they all the same size? Which kind is largest? Which smallest? Make memory drawings of two or more kinds of starch granules as they appear under the microscope. B. Examine samples of starch paste under the microscope. Can you tell which is made from rice starch, which from potato starch, and so on ? 124. Experiments showing how to prevent starch from lumping while cooking. — A. Pour about two tablespoonf uls of boiling water upon one teaspoonful of dry cornstarch, stirring as you pour. What happens? Break open one of the lumps. What do you find inside ? Would pouring boiling water upon starch be a good way to cook it? Why not? When boiling water is poured upon dry starch, lumps form, because the starch first touched by the hot water swells suddenly, forming a sticky envelope around the rest, thus keeping it from swelling. B. Repeat Experiment A, mixing one-half tablespoonful of granulated sugar with the starch before stirring in water. Result? 70 THEORY AND PRACTICE OF COOKERY Explanation. — The grains of sugar, by separating the starch gran- ules, give the latter room to swell and thicken the liquid smoothly. C. Repeat Experiment A, mixing one-half tablespoonful of cold water with the starch. Note result and explain. D. Mix one-half tablespoonful of starch with one-half table- spoonful of butter or other fat, add two tablespoonfuls of cold water, and cook, stirring until the mixture thickens. Result ? 125. Starch used to thicken sauces. — Starch is used to thicken liquid in making sauces and gravies. In what three ways may lumping be avoided ? Which of these ways is used in making white sauce ?