Soybean peptide preparation by enzymatic hydrolysis with and without ultrasound

Soybean protein powder and alkaline alcalase protease were taken as raw materials, and the effects of ultrasonic power, pH, substrate concentration, enzyme dosage, and temperature on soybean protein hydrolysis degree (DH) and DH increment percentage were studied with and without ultrasound in this paper. The results indicated that efficiency of ultrasound depended on its power. The ultrasound of 40kHz, 96W enhanced remarkably the enzymatic hydrolysis of soybean protein. Compared with those under no ultrasonic, the curve trend of relation between DH and pH, substrate concentration, enzyme dosage or temperature was not changed by ultrasound, and the optimal temperature, pH also kept the same, which was 55 degrees C, pH8.5 respectively, however, the DH increased evidently with ultrasound.