A Study on Anti-oxidative Activity of Soybean Peptides with Linoleic Acid Peroxidation Systems1

Soybean bioactive peptides (SBPs) were prepared from the isolated soybean protein by proteolysis with an alkaline protease, alcalase, at 50 °C and pH =8.0. The dependence of hydrolysis time on hydrolysis degree and molecular weight distribution were examined. The hydrolysate was fractionated on a Sephadex G-25 column and the anti-oxidative activities of the fractions were detected by the method of pyrogallol auto-oxidation. The average chain length of soybean peptides that have anti-oxidative activity was estimated to be about 7. The anti-oxidative properties of the soybean peptide were also studied by using linoleic acid peroxidation systems. The optimal condition of the peroxidation system was set up, Vc/Cu 2+ as the inducer at pH = 7.4 and 25 °C. In addition, soybean peptides show higher anti-oxidative activity compared with GSH.