Preparation of Low-bitter Peanut Peptides

Peanut protein isolate was used as raw material to study the optimal conditions for the preparation of low-bitter peanut peptide by hydrolysis by complex enzymes and its antioxidative activity in vitro. According to the results of single factor experiments,the optimal hydrolysis conditions of low-bitter peanut peptides were screened,and their antioxidant activities were evaluated by measuring the ability to scavenge DPPH and ABTS⁺ free radicals. The results showed that the optimal reaction conditions for enzymatic hydrolysis of peanut protein isolated by complex enzymes were:Peanut protein isolate was hydrolysed by alcalase(pH8.5,temperature 55℃,time 4 h),protease P(pH7.0,temperature 50℃,time 3 h)and flavourzyme(pH7.0,temperature 50℃,time 2 h)step by step with the dosage of three enzymes 0.8%,0.4%,and 0.2%,respectively. Under this process,the enzymatic hydrolysate had a bitterness value of 1.3,the polypeptide yield was 86.75%,and the polypeptide contents of the enzymatic hydrolysate with a molecular weight lower than 1 kDa was 85.93%. When the concentration of enzymatic hydrolysate was 4 mg/mL,the DPPH radicals and ABTS⁺ radical scavenging rates were 80.70% and 87.92%,respectively,which indicated that the peanut peptides had good antioxidant activity.