限制性酶解结合糖基化改性对大豆分离蛋白乳化性质的影响

目的：开发基于大豆分离蛋白（soybean protein isolate，SPI）的新型乳化剂。方法：采用限制性酶解结合糖基化处理对SPI进行结构修饰，研究协同改性对SPI乳化特性的影响。结果：SPI水解物（soybean protein isolate hydrolysate，SPIH）中的相对分子质量较大组分（F30）的乳化性最佳，且糖基化反应4 h的F30-葡聚糖轭合物乳化稳定性相对最好。相较于SPI，SPIH与F30，F30-葡聚糖轭合物稳定的乳液表现出最低的初始平均粒径，并且具有最佳的贮藏稳定性。当pH接近SPI等电点或体系处于高盐浓度时，所有乳液均出现不稳定聚集现象。与SPI相比，SPIH和F30稳定乳液的聚集程度更高，而F30-葡聚糖轭合物由于共价结合的葡聚糖提供了额外的空间位阻和亲水性，使得轭合物稳定的乳液能够耐受离子强度和温度的变化，在不利环境条件下表现出更高的抵抗力。结论：限制性酶解结合糖基化改性是开发SPI基乳化配料的潜在可靠途径。

Effects of limited enzymolysis and glycosylation on emulsifying properties of soybean protein isolates

Objective: This study aimed to develop novel soybean protein isolate （SPI）-based emulsifiers. Methods: The structure of SPI was modified by limited enzymolysis combined with glycosylation and the effects of this synergistic modification on the emulsification characteristics of SPI was studied. Results: Among the different components obtained from the SPI hydrolysate （SPIH）, the high molecular mass component （F30） exhibited the best emulsifying property. The emulsifying stability of F30-dextran conjugates obtained for 4 h was the best. Compared with SPI, SPIH and F30, the F30-dextran conjugates stabilized emulsions showed the lowest initial average particle size and the best storage stability. When the pH was close to the isoelectric point of SPI or the system was at a high salt concentration, all emulsions were unstable to cause aggregation. Compared with SPI, both SPIH and F30 stabilized emulsions had a higher aggregation degree. However, F30-dextran conjugates provided additional steric hindrance and hydrophilicity due to covalently bound dextran, which exhibited a higher resistance under adverse environmental conditions. Conclusion: Limited enzymolysis combined with glycosylation is a potential and reliable way to develop SPI-based emulsifying ingredients.