Antioxidant activity of tryptic digests of hen egg yolk phosvitin

Abstract

BACKGROUND: Food protein-derived peptides with antioxidant activity have great potential for use as natural antioxidants in food products. However, neither the structure-activity relationship nor the antioxidant mechanism of peptides is fully understood. Egg yolk phosvitin has been acknowledged to have strongly antioxidant protein owing to its highly phosphorylated form. In this study the antioxidant activities of tryptic digests of hen egg yolk phosvitin (PPPs), which were prepared by partial dephosphorylation and subsequent hydrolysis by trypsin, were compared with that of intact phosvitin. RESULTS: Compared with intact phosvitin, PPPs exhibited distinctly stronger capability of inhibiting lipid oxidation in a linoleic acid system and more efficient radical-scavenging activity on 2,2-diphenyl-1-picrylhydrazyl (DPPH) free radicals. However, the chelating capability of PPPs on iron(II) was weaker than that of intact phosvitin. The strong antioxidant activity of PPPs can be mainly attributed to the amino acid composition rather than to the content of phosphorylserine ligands. Histidine, methionine and tyrosine are the amino acids most likely to be responsible for the strong antioxidant activity of phosvitin peptides. CONCLUSION: The present study indicated that PPPs could be used in foods as natural antioxidants with strong antioxidant activity. © 2007 Society of Chemical Industry.