Student's textbook of hygiene / [William James Wilson].

  • Wilson, William James.
Date:
[1915]
Catalogue details

Licence: Public Domain Mark

Credit: Student's textbook of hygiene / [William James Wilson]. Source: Wellcome Collection.

    136/316 (page 106)
    Cheese consists of coagulated casein, with amounts of fat which vary according to whether it has been prepared from whole or skim milk, or from milk to which extra cream has been added. Good cheese usually contains twice as much nitrogen and three times as much fat as the same weight of meat. On an average, cheese contains 20 to 35 per cent. of water, and 3 to 6 per cent. of salts. The remainder consists mainly of casein and fat, and the proportion of fat to casein should not be less than 1 to 2. Vegetable Foods.—The general characters of these foods are— (1) Richness in carbohydrates. The amount present in most cereals is 70 per cent. (2) Deficiency in fat. Exceptions to this rule are furnished by nuts, almonds, olives, etc. Oats contain 5 per cent. of fat. (8) Protein present in the form of globulins and albumoses—e.g., glutin, legumin—which are formed from globulin and albumose by the action of water. (4) Richness in salts and organic acids. (5) The possession by the vegetable cells of membranes composed of cellulose, a substance which is indigestible, but which promotes intestinal peristalsis. The Cereals—wheat, rye, barley, oats—contain on an average 10 to 12 per cent. of protein, and 65 to 75 per cent. of carbo- hydrates. The percentage of fat and mineral matter seldom exceeds two in each case. The grain of wheat consists of—(1) the germ, or embryo plant; (2) the kernel, or endosperm, repre- senting 85 per cent. of the grain, and consisting of starch and protein; (8) the bran, or outer envelope, consisting mainly of cellulose. In the old method of stone-grinding, the bran was removed and the germ was left attached to the endosperm. In modern roller-milling, the endosperm and germ are separated. The germ is rich in nitrogenous matter and fat, so that its removal lessens the nutritive value of the flour. The retention of the germ is liable to lead to the spoiling of the flour through its oil becoming rancid, and the bread baked from such flour becomes dark in colour through the action upon the starch of ferments contained in the soluble proteins of the germ. Treatment of the germ with superheated steam prevents these objectionable results by sterilizing the oil and destroying the ferments. The germ so treated is ground to a fine meal, and