The effect of salivary amylase on changes in gastric protein hydrolysis was studied. The study was carried out in vitro, saliva, gastric juice, solutions of starch, casein, albumin and hemoglobin were used in the work. It was concluded that the use of starch-protein mixtures helps to reduce protein hydrolysis by gastric juice, due to the formation of starch-protein complexes that prevent protein hydrolysis, and reduce the access of gastric proteases to proteins in the starch-protein complex. An increase in the ratio of starch and protein in the direction of increasing starch contributes to an additional decrease in protein hydrolysis, which may be an additional decrease in the access of gastric proteases to proteins, in addition to an obstacle to proteins in the starch-protein complex. In addition, salivary amylase helps to improve the digestibility of proteins by gastric juice, both due to a decrease in starch-protein complexes, and to increase the access of proteases to proteins by reducing the concentration of starch as a result of its digestion by salivary amylase.