Page:The Boston cooking-school cook book (1910).djvu/28

 acid or a ferment is changed to dextrose (C_{6}H_{12}O_{6}). Dextrose occurs in ripe fruit, honey, sweet wine, and as a manufactured product. When grain is allowed to germinate for malting purposes, starch is changed to dextrine and dextrose. In fermentation, dextrose is changed to alcohol (C_{2}H_{5}HO) and carbon dioxide (CO_{2}). Examples: bread making, vinegar, and distilled liquors.

Glycogen, animal starch, is found in many animal tissues and in some fungi. Examples: in liver of meat and oysters.

Raw starch is not digestible; consequently all foods containing starch should be subjected to boiling water or dry heat, and thoroughly cooked. Starch is manufactured from wheat, corn, and potatoes. Cornstarch is manufactured from Indian corn. Arrowroot, the purest form of starch, is obtained from two or three species of the Maranta plant, which grows in the West Indies and other tropical countries. Bermuda arrowroot is most highly esteemed. Tapioca is starch obtained from tuberous roots of the bitter cassava, native of South America. Sago is starch obtained from sago palms, native of India.

SUGAR (C_{12}H_{22}O_{11})

Sugar is a crystalline substance, differing from starch by its sweet taste and solubility in cold water. As food, its uses are the same as starch; all starch must be converted into sugar before it can be assimilated.

The principal kinds of sugar are: cane sugar or sucrose, grape sugar or glucose (C_{6}H_{12}O_{6}), milk sugar or lactose (C_{12}H_{22}O_{11}), and fruit sugar or levulose (C_{6}H_{12}O_{6}).

Cane sugar is obtained from sugar cane, beets, and the palm and sugar-maple trees. Sugar cane is a grass supposed to be native to Southern Asia, but now grown throughout the tropics, a large amount coming from Cuba and Louisiana; it is the commonest of all, and in all cases the manufacture is essentially the same. The products of manufacture are: molasses, syrup, brown sugar, loaf, cut, granulated, powdered, and confectioners' sugar. Brown sugar is cheapest, but is not so pure or sweet as white