Free radical scavenging activity of porcine plasma protein hydrolysates determined by electron spin resonance spectrometer

A study was conducted to investigate the antioxidant capacity of porcine plasma protein before and after enzymatic hydrolysis. Porcine plasma protein was hydrolyzed by using Alcalase with degree of hydrolysis (DH) ranged from 0 to 17.8%. The free radical scavenging effects of porcine plasma protein hydrolysates (PPH) were evaluated by electron spin resonance (ESR) spectrometer. The reducing power of PPH increased with increasing of DH (P < 0.05). The 5-h PPH exhibited the strongest inhibition of lipid oxidation, as indicated by lowest thiobarbituric acid-reactive substance values in a liposome-oxidizing system, and the strongest free radical scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), hydroxyl (OH) and superoxide (O2-) radicals. The increase of protein concentration enhanced (P < 0.05) free radical scavenging effect of PPH. Although non-hydrolyzed plasma protein displayed an antioxidative effect, it was far less potent than PPH. The results indicated that the antioxidant capacity of porcine plasma protein could be enhanced by enzymatic hydrolysis of Alcalase.