Antioxidant Activities of Rapeseed Protein Hydrolysates

Rapeseed protein hydrolysates (RPH) were obtained by enzymatic hydrolysis of rapeseed protein using Alcalase 2.4 L FG. The degree of hydrolysis (DH) of RPH was about 25% using pH-stat method. The antioxidant activities of RPH were investigated by employing several in vitro assay, including the 1,1-diphenyl-2-picrylhydrazyl (DPPH)/superoxide/hydroxyl radical scavenging assays, and reducing power assay. RPH showed scavenging activity against free radicals such as DPPH, superoxide, and hydroxyl radicals. The radical scavenging effect was in a dose-dependent manner, and the EC50 values for DPPH, superoxide, and hydroxyl radicals were found to be 0.71, 1.05, and 4.92 mg/mL, respectively. In addition, the RPH also exhibited notable reducing power, which was 0.51 at 2.00 mg/mL. The data obtained by in vitro systems obviously established the antioxidant potency of RPH. Combined with the results of the amino acid profiles, RPH were believed to have high nutritive value in addition to antioxidant activities.