Cotton-seed oil has no especially bad flavor, but it is unpleasant and indigestible when used raw as in sardines and salads. The after taste which it leaves reminds one too forcibly of castor-oil.
Olive-oil of the best quality is almost absolutely without flavor. It is prepared in several grades: the first pressing from the fruit is the best, the second is fair, the third inferior, and there is sometimes a fourth known as refuse oil. For deep fat frying nothing is so good as olive-oil, but its costliness in this country excludes it from common use.
The fat of the sheep and ox, after it has been rendered, and deprived of all membrane and fibers, is called tallow. The term is also applied to the fat of other animals, and to that of some plants, as bayberry-tallow, piny tallow, and others. The uncooked fat of any animal is called suet, but the name has come to be applied to the less easily melted kinds, which surround the kidneys or are in other parts of the loin. The fat which falls in drops from meat in roasting is called dripping.
THE CARBOHYDRATES
Starch. Starch is a substance found in wheat, corn, oats, and in fact in all grains, in potatoes, in the roots and stems of many plants, and in some fruits. In a pure state it is a white powder such as is seen in arrowroot and corn-starch. Examined by a microscope this powder is found to be made up of tiny grains of different shapes and sizes, some rounded or oval, others irregular. Those of potato-starch are ovoid, with an outside covering which appears to be folded or ridged, and looks somewhat like the outside of an oyster-shell, although its similarity extends no further than appearance, as the little ridges are true folds, and not overlapping edges.
Size of Starch Grains. Starch grains vary in size according to the source from which the starch is obtained. Those of ground rice are very small, being about 1 3000 of an inch in diameter; those of wheat are 1 1000 of an inch, and those of potato 1 300 of an inch.
Starch is a carbohydrate, being composed of six parts of carbon, ten of hydrogen, and five of oxygen. Its symbol is C6H10O5. It is insoluble in water, but when the water is heated, the grains seem to absorb it; they increase in size, the ridges or folds disappear, and when the temperature reaches 140° Fahr. or a little over, they burst, and the contents mingle with the liquid forming the well-known paste.
Test for Starch. Mix a teaspoon of starch with a cup of cold water and boil them together for a few minutes until a paste is formed; then set it aside to cool. Meanwhile make a solution of iodine by putting a few flakes into alcohol, or use that which is already prepared, and which may be obtained at any pharmacy. Add a drop of this solution to the paste mixture; it will immediately color the whole a rich dark blue. This is known as the "iodine test," and is a very valuable one to the chemist, for by means of it the slightest trace of starch can be detected.
Exp. with Arrowroot. Make a thin paste by boiling a little arrowroot and water together. When cool test it with a drop of the iodine solution. The characteristic blue color will be very strong, showing that arrowroot is rich in starch.