湿法糖基化改性对大豆分离蛋白功能性质的影响

大豆分离蛋白与葡萄糖按质量比4∶1溶解在重蒸水中配制成蛋白质质量浓度为8 g/100 mL的混合液，分别在70、80、90 ℃条件下反应0、1、2、3、4、5、6 h，得到不同反应温度和时间的糖基化产物。通过测定各糖基化产物的pH值、溶解性、乳化性和凝胶性质，研究糖基化对大豆分离蛋白功能性质的影响。结果表明：随着加热时间的延长，不同温度反应体系的颜色加深，pH值逐渐降低，溶解性、乳化活性和乳化稳定性显著提高，凝胶的弹性和硬度呈先上升后下降的趋势。其中90 ℃反应体系糖基化大豆分离蛋白的功能性质提高最为明显，从0 h到6 h，溶解性和乳化活性分别从17.37%、0.168提高到了38.7%、0.574，且效果显著（P＜0.05）；加热4 h制得的糖基化样品的乳化稳定性最强，其乳化稳定性为39.6；并且糖基化样品凝胶的硬度和弹性在反应3 h时最大，其硬度和弹性分别为81.3g和0.936。因此，糖基化修饰可有效提高大豆分离蛋白的功能性质。

Effect of Glycosylation under Wet-Heating Condition on Functional Properties of Soybean Protein Isolate

The effect of glycosylation under wet-heating conditions on functional properties of soybean protein isolate
(SPI) was investigated by determining the pH, solubility and gel properties of glycosylated products from the reaction between
8 g/100 mL of SPI and glucose with a weight ratio of 4:1 in double distilled water at 70, 80 and 90 ℃ for 0, 1, 2, 3, 4, 5 and 6 h,
respectively. The results showed that the color of the model system at each temperature became darker with extended heating
time, the pH was decreased, the sobubility, emulsifying activity and emulsion stability were significantly improved
(P ＜ 0.05), and the gel springiness and hardness tended to initially increase and then decrease. The most obvious
improvement was observed when the glycosylation reaction temperature was 90 ℃. The solubility and emulsifying activity
were increased from 17.37% and 0.168 at 0 h to 38.7% and 0.574 at 6 h, and the highest gel hardness and springiness, 81.3 g and 0.936
were obtained at 3 h. Hence, glycosylated modification can effectively improve functional properties of soy protein isolate.