Nutritional evaluation of dry-roasted navy bean flour and mixtures with cereal proteins

A navy bean flour prepared by dry roasting in a salt bed as a medium of heat exchange was found to have a higher PER than beans which had been autoclaved in the conventional manner. This difference was attributed to a small but significant improvement in the digestibility of the protein. The PER of the roasted beans was higher than the autoclaved beans even in the presence of supplemental methionine. When various proportions of roasted beans and corn were fed at a level of 8.3% protein in the diet, a mixture in which 40% to 60% of the protein was provided by either beans or corn had a PER essentially the same as casein. Diets containing roasted beans and various cereal grains (oats, barely, buckwheat, wheat germ, and rice) were formulated in proportions calculated to give the highest chemical scores. In most cases the PER' were not significantly different from that of casein, and, in the case of rice, the PER was higher than that of casein. Supplementation of such diets with their first limiting amino acid failed to produce a further enhancement of the PER.