Purification of wheat germ albumin hydrolysates by membrane separation and gel chromatography and evaluating their antioxidant activities

Wheat germ albumin (WGA) has potential as a high protein food ingredient which is rich in nutrients and contains a number of antioxidant polypeptides. In this paper, membrane separation and gel chromatography purification, which were already used as a powerful separation technique in the food industry, was used to improve the antioxidant activity of wheat germ albumin hydrolysates. After the wheat germ albumin was hydrolyzed by papain, the obtained hydrolyzed solution was separated by ultrafiltration to four fractions with molecular weight (3 KD, 3–5 KD, 5–10 KD, and >10 KD). The results showed that the antioxidant activity of wheat germ albumin polypeptide with molecular weight cutoff less than 3 kD was significantly greater than that of the other three fractions. The oxidation resistance of the fractions after gel chromatography was P3>P2>P1>P4 in descending order. In this paper, the results showed that microwave-assisted enzymatic hydrolysis could greatly shorten the enzymatic hydrolysis time, but the specific mechanism of microwave-assisted proteolysis and potential applications of purified peptides in food or pharmaceutical still needs further study.