Antioxidant performances of corn gluten meal and DDGS protein hydrolysates in food, pet food, and feed systems

Protein hydrolysates from corn gluten meal (CGM) and distillers’- dried grains with solubles (DDGS) were prepared with Neutrase and Alcalase, and the antioxidant activity of those hydrolysates in bulk oils, ground pork, canine pet food, and pig feed were evaluated by measuring oxidation stability based on peroxide value (PV) and thiobarbituric reactive substances (TBARS) value. Alcalase-hydrolyzed CGM (CPH-A) and Neutrase-hydrolyzed CGM (CPH–N) had stronger 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity than Alcalase-hydrolyzed DDGS (DPH-A) and Neutrase-hydrolyzed DDGS (DPH-N). The CPH-N showed better prevention on lipid oxidation in both corn oil and fish oil compared with other corn antioxidants. The best oxidation prevention in ground meat was observed with 2 g/kg of CPH-N. Lipid oxidation in pet food containing 2% DPH-A was efficiently retarded by 37.8% reduction at the end of the incubation, and TBARS value of pig feed containing 2% CPH-N was reduced the most compared with other treatments. However, there was no significant difference in growth performance and plasma antioxidant concentration between broilers fed with DDGS or Alcalase-treated DDGS. Overall, CGM and DDGS protein hydrolysates could potentially be used as naturally derived antioxidant in food, pet food, and feed systems with good protection efficiency for lipid oxidation to improve product storage stability.