(e) What foodstuff has passed off in the form of vapor during evaporation?
(f) As mentioned above, milk also contains vitamines.
LESSON XLVII
MILK WITH COCOA AND CHOCOLATE
EXPERIMENT 46: SCALDING MILK.—Fill the lower part of a double boiler one third full of boiling water. Put 1/2 cupful of milk in the top of the double boiler, cover, and heat over the boiling water. In a few minutes examine. Carefully note the appearance of the surface of the milk. Explain why it is that dishes that have contained milk should be soaked in cold water, and then washed in warm water.
Insert a thermometer in the milk and record temperature. Is it possible to boil milk over hot water? Explain your answer. (Use this scalded milk to make cocoa and chocolate.)
The taste of milk is changed by heating it above 158 degrees F. Less change, however, is produced by scalding than by boiling. Milk is also apt to scorch if cooked at boiling temperature. It is sometimes necessary to boil milk to sterilize it.
COCOA AND CHOCOLATE as found at market are prepared from cacao beans. The latter grow in pods,—the fruit of the tropical cacao trees (see Figure 41). The beans are taken from the pods, allowed to ferment, dried, and roasted. The husks loosened by roasting are then removed from the beans.
Cacao beans are ground, molded, and sold as bitter or baker's chocolate. In the preparation of sweet chocolate sugar is added to the powdered chocolate before molding. Cocoa differs from chocolate in that some of the fat is removed.
Cocoa and chocolate contain protein, fat, and carbohydrates. These materials, in addition to the milk and sugar used in preparing the beverages, make the cocoa and chocolate beverages high in food value. But in addition to the materials mentioned above, there is present in cocoa and chocolate some tannin and stimulating materials. The large percentage of fat existing in chocolate may produce distressing effects when taken in addition to a full meal. If, however, the use of these beverages causes no ill effects, they may be classed among the nutritious foods and are much preferable to tea and coffee especially for girls and boys.