High Milk-Protein Bread

The protein content of bread was increased from 13.96 to 18.04% on a dry basis, or nearly 30%, by including 25 parts of nonfat dry milk per 100 of flour in the bread formula.The loaves had excellent flavor and good toasting quality; symmetry and crust color were substandard; crumb color, texture and grain, and cell structure good.The biological value of the protein was nearly doubled in comparison with the protein in bread containing only four parts nonfat dry milk per 100 of flour and, at the same time, the bread had good consumer acceptability in limited, preliminary trials.The use of nonfat dry milk (NFDM) in bread has become an established practice in the United States.In 1957, the baking industry utilized 332.5 million pounds ( 6) at an estimated level of 3 to 4%, based on the flour used.This amount imparts obvious advantages in improved crust color, grain, texture, and toasting quality.Less readily observed advantages are improved dough uniformity, machinability, and water absorption and, finally, improved nutritive value o'f the bread is perhaps the most significant of all.Despite these advantages, the per capita consumption of bread has decreased annually in recent years.This decrease can be attributed partly to current ideas of diet.It is, however, of considerable interest that Jack and Haynes (5), in a carefully controlled study, showed that young boys ate increasing amounts of bread containing increased amounts of NFDM.Levels of 6, 10, and 14% NFDM caused increased consumption of 4, 8, and 13%, respectively.A detailed consideration of the nutritional advantages of supplementing wheat proteins which are deficient in L-lysine, with milk proteins that are rich in L-]ysine, is not a simple matter.Bender (1) has recently given evidence that deficiencies of threonine and methionine exist in cereal proteins, so that L-lysine almle does not suffice for complete supplementation.The differences in amino acid requirements between experimental animals and man, and varying requirements of humans with age, sex, and physical activity, all make any exact interpretation of nutritional tests difficult.Nevertheless, the consensus of nutritionists, that milk furnishes an excellent supplementation for cereal proteins, is wellfounded and supported by a large body of evidence.The present investigation was undertaken to determine how high the level of NFDM could be raised in white bread formulas, and still produce satisfactory bread, without radically modifying production methods.Powers (7), in 1936, carried out a similar study and patented production methods based on mixing the dough two to five times as long as the optimum mixing time for bread dough without milk.The results of his study and those reported herein are, on the whole, in excellent agreement.