Antioxidative hydrolysates from corn gluten meal may effectively reduce lipid oxidation and inhibit HepG2 cancer cell growth

Peptides hydrolyzed from food proteins are potentially healthy antioxidants for food applications. In this study, corn gluten meal (CGM) was hydrolyzed by different enzymes to obtain antioxidative hydrolysates. The CGM hydrolysates using Neutrase was further fractionated through membrane ultrafiltration, and the medium sized fraction (F3, 3-5 kDa) exhibited promising antioxidant capacities as measured by 1,1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity, ABTS scavenging activity, and metal ion (Fe2+) chelating activity. Addition of the F3 fraction into an oil-in-water emulsion system greatly reduced the formation of primary and secondary oxidation products during 15 days incubation, with an average reduction of 82.17 and 90.71%, respectively. The F3 fraction also resulted in 49.17% reduction of lipid oxidation when added to ground pork at 1000 mg/kg. Peptide composition of the F3 fraction was further identified through RP-HPLC followed by MALDI-TOF/TOF MS analysis. The toxicity and anticancer performance of the F3 fraction was evaluated in a human hepatocarcinoma HepG2 cell line at 50 and 200 mu g/mL for 6 days, resulting a significant growth inhibition by 64.2 and 71.6%, respectively. However, cell viability remained the same, indicating that the F3 peptides are not toxic for food applications as antioxidant additives. This study demonstrated that the corn gluten meal hydrolysates could be effective as antioxidants in delaying lipid oxidation and inhibiting cancel cell growth.