This section is from the book "Elements Of The Theory And Practice Of Cookery", by Mary E. Williams. Also available from Amazon: Elements Of The Theory And Practice Of Cookery; A Textbook Of Domestic Science For Use In Schools.
A. Put one heaping tablespoonful of cracked or rolled oats with about one cupful of cold water in a small bowl; rub the oatmeal between your thumb and fingers for a few minutes, and observe the effect on the water. Fill a small test-tube (a) with the water and set it aside.
C. Soak rolled wheat, corn-meal, tapioca, rice, or any preparation used for breakfast mush, as you did oatmeal in Exp. A; boil the water, and test it for starch. Is there any substance common to all these foods? What is it?
D. Test any or all of the following substances for starch:1 - 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 ?
1 Simply test with diluted tincture of iodine without adding water or heating.
All green plants contain more or less starch. They make it out of water and carbon and store it up in root, stem, or some other part, in the autumn, to nourish the young shoots in the spring. Plants obtain carbon from the carbon dioxide in the air. How do they obtain water?
Most of the starch we use is obtained from corn (maize), potatoes, wheat, and rice. It 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.