Optimization and Antioxidant Activity of Peptides from Rapeseed Cake Assisted by Superfine Grinding

To prepare bioactive peptides from rapeseed cake directly, the superfine grinding technology was used, and the resulting rapeseed cake superfine powder was used as the material. Single-factor experiments and response surface analysis were used to optimize the preparation extraction. The active peptides were purified by membrane separation and Sephadex G-15 membrane separation, and their antioxidant activity and structure were evaluated. The results showed that the optimal preparation conditions were as follows: grinding time 30 min, solid-to-liquid ratio 1:20(g/mL), pH2.94, enzyme dosage 6300 U/g, temperature 55 ℃, and enzymatic hydrolysis time 2.25 h. Under these conditions, the yield of peptides could reach 83.28%. The F-2 fraction from hydrolysates with molecular mass less than 1000 Da showed good antioxidant activity, with an ABTS⁺ free radical eliminating rate of 71.62% at a concentration of 1 mg/mL. Furthermore, five peptides were identified, namely PF, SF, TF, IAIPF, and PLDLL which were predicted to have much higher activity. Overall, the results of this study can provide a theoretical basis for the exploration of bioactive peptides directly from rapeseed cakes.