Abstract:

The antioxidant peptides derived from peanut meal hydrolysate prepared by bienzyme hydrolysis (first trypsin and then flavourzyme) were separated by ultra-filtration technology. The peanut meal hydrolysate was filtrated through 1μm microfiltration membrane prior to ultrafiltration. The effects of operating pressure, temperature, pH and concentration of filtrate on ultra-filtration flux of 3 kD MWCO membrane were investigated by single-factor method. Subsequently, an orthogonal array design involving 9 experiments of the four variables at three levels was employed for maximizing the ultra-filtration flux. A maximum ultra-filtration flux of 45.18 ml/m2·min was obtained by 20 min ultrafiltration at 0.08 MPa and 25 ℃ with the concentration of filtrate of 2%. The antioxidant effects of peanut peptides with different molecular weight were investigated. The peanut peptides with molecular weight below 3 kD exhibited stronger antioxidant activity than others. After 7 d storage, the POV of soybean oil with the 0.10% addition of 3 kD molecular-weight peanut peptide was 9.15 meq/kg, indicating the peptide has good antioxidant activity.

Key words: ultra-filtration, separation, peanut, antioxidant peptide, antioxidant activity