糖基化大豆蛋白体外消化产物的生物活性研究

为了分析体外消化作用及超滤处理对糖基化大豆蛋白抗氧化活性及抑菌活性的影响,分别利用胃蛋白酶及胰蛋白酶酶解糖基化大豆蛋白,在一定的条件下水解度分别达到了4.9%和6.4%,此时可溶性蛋白质含量分别为13.6、15.0 mg/m L;再经过超滤处理得到相对分子质量低于5 000的组分,两种超滤组分的可溶性蛋白质含量分别为9.65、10.65 mg/m L。糖基化大豆蛋白体外消化产物的抑菌活性没有发生显著变化,但是抗氧化活性下降;进一步的超滤处理能够获得具有较高生物活性的组分:胃蛋白酶消化产物超滤组分的亚铁离子螯合率提高了约1倍;胰蛋白酶消化产物超滤组分的还原力及羟基自由基清除率显著提高;同时,胃蛋白酶消化产物超滤组分对大肠杆菌具有抑制活性,而胰蛋白酶消化产物超滤组分则具有较强的抑制作用。结果表明,结合体外消化作用及超滤处理能够显著改善糖基化大豆蛋白的生物活性。

Bioactivities of in vitro digestible products from glycosylated soybean protein

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.