Preparation of enzymatic pretreated corn gluten meal hydrolysate and in vivo evaluation of its antioxidant activity

•Hydrolysate of corn gluten meal exhibiting high antioxidant activity was prepared.•Soaking with Na2CO3 solution, starch removal, and cooking are used as pretreatments.•Enzymatic catalysis by proteases at substrate protein concentration of 13.5% (w/w).•Molecular weight of the peptides in hydrolysate was 1200–250 Da.•It exhibited good antioxidant activity both in vitro and in vivo. Corn gluten meal (CGM) is a major by-product of corn wet milling. Pretreatments of CGM by Na2CO3, starch removal, and cooking reduced the total starch and fat by 93% and 78%, respectively. Higher antioxidant hydrolysate was prepared by using Alcalase, Protamex and Flavourzyme at a substrate concentration of 13.5% (w/w). The degree of hydrolysis reached 29.49% and 27.11%. The peptides in hydrolysate were in the range of 1200–250 Da. It increased the activities of superoxide dismutase, glutathione peroxidase, and reduced MDA equivalents of mice at a dose of 300 mg/kg. Therefore, corn gluten can be developed into an antioxidant supplement.