The solubility of peanut protein was enhanced by four physical modification methods, including heat treatment, microwave treatment, high speed stirring and ultrasound treatment, and the composite use of the last two methods was found to be more effective. Through single factor experiment and orthogonal experiment, the optimal conditions of high speed stirring were obtained as follows: stirring rate 22 000 r/min, operation time 66 s, ratio of solid to liquid 1∶?7, and the optimal conditions of ultrasound treatment were obtained as follows∶? ultrasonic power 210 W, ultrasonic time 420 s, ratio of solid to liquid 1∶?10. Under their respectively optimal conditions, these two methods applied in turn were confirmed to increase the nitrogen solubility index of peanut protein to 78.2%. |