Abstract: Highly pure peptides with strong antioxidant activity in terms of 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging capacity, reducing power and oxygen radical absorbance capacity (ORAC) were obtained from the enzymatic hydrolysates of heads and shells of Penaeus vannamei by sequential ultrafiltration, gel filtration chromatography and preparative liquid chromatography. Furthermore, Caenorhabditis elegans were used to determine the antioxidant activity in vivo of the obtained antioxidant peptides. The results showed that the ultrafiltration fraction with molecular mass of 3–10 kDa exhibited the highest antioxidant activity. Further purification by gel filtration chromatography and preparative liquid chromatography could obtain a mixture of antioxidant peptides with a purity of 70%. The investigation of antioxidant activity in vivo showed that Caenorhabditis elegans fed with the purified antioxidant peptides laid more eggs and had higher survival rate under heat stress as well as significantly longer lifespan (P < 0.05), while the effect was not significantly different from that of VC (P > 0.05), indicating that the antioxidant peptides obtained in this study had protective effect against oxidative stress in Caenorhabditis elegans similar to that of VC and therefore could have potential application value.

Key words: Penaeus vannamei, proteins from shrimp heads and shells, antioxidant peptides, isolation and purification, Caenorhabditis elegans, antioxidant activity