All‐Vegetable Protein Mixtures for Human Feeding

SUMMARY Studies were carried out to determine the best combination of rice and cooked black beans when one partially replaced the other isonitrogenously. Experiments with young and with adult protein‐depleted rats indicate that the best combination was one in which about 60% of the protein of the diet is from rice and 40% from black beans. The range of values was from 70 to 50% rice and from 30 to 50% cooked black beans. The median figures correspond to 80 g of rice and 20 g of beans. On an isoproteic basis, rice protein is superior to black bean protein, and supplementation of either protein source with known limiting amino acids improved the protein value. Cooked black beans supplemented with methionine and valine still did not induce as good growth as rice supplemented with lysine and threonine. When rice‐black bean diets containing 50% protein from each source were supplemented stepwise with the limiting amino acids methionine, lysine, and leucine, the growth and feed and protein efficiencies of the rats improved; serum protein and liver fat tended to increase.