Improvement of antioxidant activity of peptides with molecular weights ranging from 1 to 10 kDa by PEF technology

Abstract

Egg white protein powder was hydrolyzed with Alcalase to produce antioxidant peptides. Then, the peptides were fractionated with ultrafiltration membranes. The peptides (1–10kDa) were further treated by pulsed electric field (PEF) to investigate its effect on the antioxidant activity of the peptides. Antioxidant activity was evaluated using a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical inhibition assay. The results indicated that optimal electric field intensity and standing times of PEF can enhance the antioxidant activity of the peptides. Therefore, a Box-Behnken design (BBD) with three independent variables including concentration, electric field intensity and pulse frequency was used to establish the regression equation of second-order response surface. The optimal conditions were as follows: concentration 8mg/ml, electric field intensity 10kV/cm and pulse frequency 2400Hz. Under these conditions, the peptides antioxidant activity was 62.64%±0.98%. The present study demonstrated that the antioxidant activity of peptides (1–10kDa) could be improved using PEF.