Study on Optimal Conditions of Alcalase Enzymatic Hydrolysis of Soybean Protein Isolate

Soybean protein isolate was hydrolyzed to obtain soybean polypeptide solution using Alcalase as hydrolase. Degree of hydrolysis and the recovery rate of protein were used to characterize the soybean protein hydrolysis reaction result. Influence factors of soybean protein hydrolysis reaction including the substrate concentration, temperature, pH, enzyme concentration characterized by E/S (ratio of Enzyme and Substrate) and hydrolysis time were systematically studied with single factor and multi-level experimental. The optimal reaction conditions of soybean protein isolate hydrolyzed by Alcalase were that the substrate concentration was 8%; E/S was 3.6 AU/100 g substrate; pH was 8.0; temperature was 60°C and hydrolysis time was 2 h. The study also showed that the hydrolytic activity of the Alcalase to soybean protein isolate was stronger in the front 1 h; the hydrolytic activity of Alcalase weakened gradually with time when reaction time was longer than 2 h.