β-葡聚糖对大豆分离蛋白酸致混合凝胶流变性的影响

Effect of β-Glucans on Rheology of Soybean Protein Isolate Acid-Set Mixed Gels

采用乳酸菌对大豆分离蛋白（SPI）/β-葡聚糖混合体系进行发酵制备酸致凝胶，研究β-葡聚糖浓度（0.4~1.6%，w/v）和分子量（OGL80~OGL360）对SPI（4%、6%、8%，w/v）酸致混合凝胶流变性的影响。结果表明：在SPI中添加β-葡聚糖不会改变大豆蛋白的变性温度，但会使表面疏水性由81.97降低至71.83。一定浓度β-葡聚糖会使SPI酸致凝胶的起点由1 Pa降至0.01~0.1 Pa，甚至降低凝胶终点G′至10 Pa以下不能形成凝胶。而高分子量β-葡聚糖通过增加体系粘度而减少分层现象并保持体系稳定，从而降低或消除β-葡聚糖对SPI酸致混合凝胶的弱化作用，甚至会改善混合体系凝胶强度。

Soybean protein isolate （SPI）/[3 -glucans acid -set mixed gels were prepared by fermentation using lactobacillus. The effect of concentration （0.4 - 1.6mg/100 mL） and molecular weight （ OGL80 - OGL360） of β- glucans on rheology and microstructure of SPI （4,6,8 mg/100 mL） acid - set mixed gels were researched. Results showed that additions of β - glucan into SPI have no affect on the denaturation temperatures of soybean protein, while it reduced surface hydrophobicity from 81.97 to 71.83. A certain concentration of β- glucans could reduce the start- ing point of SPI acid -set gel from 1 Pa to 0.01-0.1 Pa. And it even reduced the end point G＇ of gel below 10 Pa, which could not form gels. However, high molecular weight β- glucans reduced stratification and keeped the system stable by increasing the viscosity of system, which reduced or eliminated the weakening effect of the β - glucans on SPI acid- set mixed gels, and even improved gel strength of mixed system.