Relación entre la Composición y la Actividad Antitríptica de Sueros de Soja y Tofu y Comportamiento Térmico de sus Proteínas Aisladas

Abstract

The differences in composition and antitryptic activity of soy whey and tofu whey, in relation to thermal behavior of its proteins, were studied. Soy whey was obtained from an aqueous extract of defatted soybean flour and tofu whey is a liquid industrial residue from the tofu production. Both byproducts contain carbohydrates as main components, proteins, non-protein nitrogen and salts. Tofu whey presented lower values of density, dry extract and proteins, while the antitryptic activity was three times lower than in soy whey. Differential scanning calorimetric studies of soy whey proteins showed the endotherms of lectin and antitryptic factors of Kunitz and Bowman-Birk, while the thermogram corresponding to tofu whey proteins showed only the last factor. The differences between wheys can be explained by the differences in the manufacturing processes.