Research of antioxidant peptides produced from protein extracted from white shrimp head and shell

Protein extracted from white shrimp (Penaeus vannamei) head and shell was hydrolyzed using five proteolytic enzymes (pepsin, trypsin, alkaline protease, flavor protease, papain) to prepare antioxidant peptides. The hydrolysis conditions of the optimal protease were also optimized and the antioxidant activity of the hydrolysates obtained from the optimal conditions was investigated. The results show that flavor protease was the most suitable enzymatic proteinase. The optimal conditions of flavor protease for hydrolysis were as follows: temperature 54 ℃, time 10.5 h, pH 8, E/S 8 000 Ug-1. Under these conditions, the 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH) free radical scavenging activity of the resulted hydrolysates was 96.58%; reducing power was 0.77; DH was 15.62%; ORAC (oxygen radical absorbance capacity) was 15.50 molL-1. The DPPH radical scavenging activity of 5 mgmL-1 hydrolysates was 82.09%, equal to 90.50% activity of the same concentration of Vc; ORAC value of 0.5 mgmL-1 hydrolysates was 126.16 molL-1, equal to 79.73% activity of Vc.