Comparison of Antioxidant Activities of the Enzymatic Hydrolysate Fractions derived from Oilseed Meals

The objective of this study was to compare the hydrolytic and antioxidant characteristics of oilseed meals (soybean meal, perilla seed meal, and distillers dried grains with solubles (DDGS)). The oilseed meal samples were homogenized in distilled water at a concentration of 20% (w/v) and enzymatically hydrolyzed with applied enzymes (Alcalase and trypsin) at an enzyme-to-substrate ratio (E:S) of 1:100 (w/w) for 2 h. The optimal hydrolysis conditions of the applied enzymes were pH 8.0/50°C and pH 8.0/37°C, respectively. After inactivation, the resulting protein hydrolysates were fractionated by ultrafiltration, obtaining fractions below 5 kDa, and the filtrate was freeze-dried and powdered. 1,1-Diphenyl-2-picrylhydrazyl (DPPH) radical scavenging activity, 2,2-azino-bis-3-ethylbenzthiazoline -6-sulphonic acid (ABTS) radical scavenging activity, reducing power and total polyphenol content of the obtained oilseed meal protein hydrolysate fractions (5 < kDa) were measured. The lowest degree of hydrolysis was observed for perilla seed meal (p<0.05), which was likely due to the lower protein solubility of perilla seed meal compared to soybean meal and DDGS. The DPPH and ABTS radical scavenging activities were significantly higher in the hydrolysate fraction from perilla seed meal, along with the highest total polyphenol content (p<0.05). In conclusion, the results of this study suggest the potential utilization of perilla seed meal hydrolysate fractions as an alternative to manufacturing bioactive peptides from soybean meal. A further study to isolate and identify the antioxidant peptides from the hydrolysate fraction from perilla seed meal would be warranted.