Changes in biological value of cereal proteins due to heat treatment.

Abstract

This mixture should support normal growth provided the intake is sufficient and the quantity and quality of proteins contained in the cereal are adequate. The cereals thus tested were, (1) raw cracked whole wheat, (2) cracked whole wheat cooked with excess of water, (3) cracked whole wheat toasted, (4) baker's white bread, (5) baker's white bread toasted in 1/4-inch slices, (6) crumb of white bread, (7) crust of white bread, (8) puffed wheat, (9) shredded wheat, (10) cream of wheat, (11) puffed rice, (12) raw rice. From four to twelve animals were kept from eight to sixteen weeks on each of these diets, with accurate food intake records. Practically normal growth was obtained upon the raw wheat, water-cooked wheat, white bread, crumb of bread, shredded wheat, cream of wheat. Raw rice gave rather less than normal growth. Very much retarded growth was obtained upon the puffed wheat, puffed rice, toasted wheat, toasted bread and crust diets. There was some variation in food intake, but growth calculated in terms of gain per gram of food, or of protein eaten, indicates definite inferiority of the latter diets. For example, the average gains in grams of body weight per gram of protein eaten during the eight weeks of rapid growth, when the animals were four to twelve weeks of age, were as follows: toast, 1.3; bread, 1.5; cracked wheat, 1.8; puffed wheat, 0.9. No serious differences in protein content exist among these preparations. These figures are quite similar to those obtained by Osborne and Mendel in their comparable study of the nutritive value of cereal proteins.