碱溶热处理对大豆分离蛋白溶解度、热聚集和流变性质的影响

Effects of alkaline-heating treatment on the solubility,thermal aggregation and rheological property of soybean protein isolate

以大豆低温脱脂豆粕为原料提取大豆分离蛋白(SPI),在传统碱溶酸沉法制备SPI的碱溶阶段采用不同程度的热处理(25、50、60、70、80℃),研究了碱溶热处理对SPI溶解度、热聚集和流变性质的影响。其结果表明,碱溶热处理破坏了SPI的溶解度,可溶性部分含有大量由二硫键结合的大分子聚集体。碱溶热处理能提高蛋白弹性模量的同时降低凝胶点温度。适当的碱溶热处理(60℃)不仅能保留较好的蛋白溶解度,还能获得最佳的凝胶弹性。

Soybean protein isolate（SPI） was prepared from low-heat defatted soy flour,and preheated during alkaline extraction. The effects of alkaline-heating treatment（25,50,60,70 and 80℃） on the solubility,thermal aggregation and rheological property of SPI were studied. The results showed that alkaline-heating treatment destroyed the protein solubility. The soluble portion of SPI samples contained a large number of aggregates which were mainly cross-linked by disulfide bonds. The alkaline-heating treatment could significantly improve the elastic modulus but decrease the gel point temperature of SPI samples. Alkaline-heating at 60℃ was proved to maintain a relatively fine solubility and exhibit the best elasticity of SPI.