| The effects of in vitro digestibility and ultrafiltration on the antioxidant activity and antibacterial activity of glycosylated soybean protein(GSPI) were studied. Under certain enzymatic conditions of pepsin or trypsin, the corresponding degree of hydrolysis were 4.9% and 6.4%, and the soluble protein contents of hydolysates were 13.6 mg/mL and 15.0 mg/mL, respectively. Two fractions from the pepsin hydrolysates and trypsin hydrolysates with relative molecular weight lower than 5 000 were obtained with the ultrafiltration treatment. Soluble protein contents of the two fractions were 9.65 mg/mL and 10.65 mg/mL respectively. The results showed that in vitro digestion had no significant effect on the antibacterial activity of GSPI and resulted in a decrease in antioxidant activity of GSPI. Subsequent ultrafiltration treatment could obtain the fractions with significant increase in the bioactivity. Fe2+-chelating capacity of the ultrafiltration fraction from pepsin hydrolysates increased about one fold, the reducing power and hydroxyl radical scavenging activity of the ultrafiltration fraction from trypsin hydrolysates was significantly improved. At the same time, ultrafiltration fraction from pepsin hydrolysates exhibited the antibacterial activity on E. coli, and the ultrafiltration fraction from trypsin hydrolysates showed a strong inhibitory effect on E. coli. Combining in vitro digestion with subsequent ultrafiltration treatment could significantly improve the bioactivity of GSPI. |
