Abstract: In this study, rapeseed protein solution (40 mg·mL-1) was pretreated with different heat (60, 80 and 100℃), ultrasonic power(200, 300 and 500 W), sodium triphosphate and succinic anhydride respectively before being hydrolyzed by alcalase for 3 hours. Peptide content and DPPH radical scavenging activity in hydrolysates were investigated. Results indicted that the best pretreatment alone was 60℃, 500 W, sodium triphosphate with an amount of three times of protein weight, and succinic anhydride in a dosage of 0.05 times of protein weight. Under these pretreatments, peptide contents were 35.00%±0.18%,41.48%±0.66%,39.27%±0.74% and 40.39%±0.34% respectively. The DPPH radical scavenging activities of the four modified protein hydrolysis solutions were all higher than the control．

Key words: enzymatic hydrolysis solution, protease, pretreatment, rapeseed protein, peptide content, DPPH radical scavenging activity