FACTORS AFFECTING PROTEIN DIGESTIBILITY IN SOYBEAN FOODS

Factors affecting protein digestibility in soybean foods were studied. There was no significant correlation between protein digestibility of the soybean foods examined and their levels of inhibitory activity against trypsin and alpha-chymotrypsin. On the other hand, a variation in protein digestibility among soybean foods examined was noted: the protein of yuba (soy protein-lipid film) was more digestible by protease, but the protein of kinako (roasted soy meal) was less digestible. Kinetic analysis revealed a difference in susceptibility of proteins to proteolytic action between yuba and kinako. The present stydy concludes that the chemical form of proteins of soybean foods may be an important factor in their protein digestibility.