Page:Foods and their adulteration; origin, manufacture, and composition of food products; description of common adulterations, food standards, and national food laws and regulations (IA foodstheiradulte02wile).pdf/355

 hilum is, as a rule, clearly distinguished. The microscopic appearance of the grains of cassava starch is shown in Fig. 47.

Adulteration of Tapioca.—The true tapioca should only be made from starch of the cassava. Any starch, derived from any source whatever, if taken in the moist state may be subjected to the same process of heating, and forms an imitation tapioca which possesses many of the physical and probably all of the edible properties of the genuine article. The substitution, however, of any of the other starches for that of the cassava is at least an imitation, if not an adulteration, of the genuine article.

(× 200).—(Courtesy Bureau of Chemistry.)

Food Starches Derived from Cereals.—The starches which are derived from the common cereals are also extensively used as food products, especially the maize starch in the United States. It is commonly sold as "corn" starch, and is largely used for the purpose already mentioned. It may be in its natural state or it may be previously submitted to the action of heat while still moist, so that it takes on the character of tapioca or sago. In the United States the Indian corn is practically the only cereal which furnishes the food starch in very large quantities, although rye starch is extensively used for this purpose in other countries.

The starches of certain of the legumes, such as peas and beans, have also been separated and used for food purposes. They are not, however, used