The Effect of Desiccation upon the Nutritive Properties of Egg-white

Abstract

A diet of crude egg-white, boiled, and supplemented with wheat starch, cotton-seed oil, cod-liver oil, lemon juice, yeast extract, salts and water, supports young rats in growth and health. If, however, the egg-white is previously dried, the diet is inadequate and young rats fed upon it develop a train of symptoms[long dash]cessation of growth, loss of hair, dermatitis and spastic gait[long dash]which terminate in death. This condition is not developed if raw potato, potato starch, arrowroot, dried yeast, fresh egg-white, egg-yolk, milk, commercial caseinogen, crude lactalbumin, spinach and cabbage leaves, or banana are added, and the presence of a protective factor X in these substances is postulated. This factor shows a similar distribution in many ways to that of the water-soluble vitamins, but it is not identical with either the anti-neuritic factor or Gold-berger''s pellagra-preventive. Its resistance to heat and desiccation varies according to the substance in which it is found. The resistance shown by rats to the ill-effects of the dried egg-white diet depends chiefly upon the body-weight of the animal at the beginning of the experiment, also on the maternal diet during pregnancy and lactation. It seems probable therefore that rats can store reserves of the protective factor X. The change induced by drying egg-white is independent of the reaction of the solution; it is not a process of oxidation, nor the work of a thermolabile enzyme. It does not take place if the egg-white is coagulated by heat before desiccation. The crude proteins of horse-serum and milk do not suffer a similar change during desiccation.