Abstract:

Soybean peptides were prepared form enzymatic hydrolysis of soy protein isolate (SPI) by alcalase and then
made to react with sodium selenite to form Se-chelating peptides. A comparative analysis of antioxidant properties was
carried out on the soybean peptides and the Se-peptide complexes. The results of optimization using orthogonal array design
showed that the optimum chelating conditions were 1:2, 9.0, 80 ℃ and 2 h for 0.5 mol/mL sodium selenite/soybean peptides
ratio (V/V), pH, temperature and reaction time, respectively. Under these conditions, the chelating rate of selenite ion was
42.82%. The Se-peptide complexes possessed stronger scavenging activity against DPPH and hydroxyl radicals, iron (Ⅱ)
chelating ability and reducing power than the soybean peptides, which was increased in a concentration-dependent manner.

Key words: soybean peptide, selenium chelation, antioxidant activity