酸诱导大豆蛋白凝胶动态变化与流变特性

Dynamic Behavior of Acid-induced Soybean Protein Gels and Their Rheological Properties

利用小变形震荡流变(SAOS)分析大豆蛋白酸诱导过程中的流变性质,考察GDL浓度、大豆蛋白浓度、温度对大豆蛋白冷凝胶形成过程中储能模量(G′)和损耗模量(G″)的影响,同时用色差亮度变化表征凝胶过程的动态变化。试验结果表明:室温(25℃)下,随GDL含量(0.5%~3%)的增加,8%的蛋白质聚集体溶液p H值迅速下降,G′和G″迅速增加,凝胶强度增大,耗散因子(tanδ)在0.2左右,形成弱凝胶体系;蛋白质含量(1%~7%)和冷却过程(95~25℃)显著影响凝胶强度,且蛋白质浓度越高,形成凝胶的G′值越大,强度越高。冷却过程中氢键和范德华力的形成进一步增强了凝胶强度。在凝胶过程中,浊度增大,用色差仪准确测量其亮度值,从光学角度研究酸诱导凝胶的动态变化行为。

The rheological properties of acid-induced soybean protein gels were tested by the small deformation oscillatory rheology. The effects of GDL concentration, soybean protein concentration and temperature on SPI cold-set gels＇ storage modulus and loss modulus were researched. At the same time we use luminance fluctuation to characterize the gel process. Results indicate that while increasing the GDL concentration, the p H value of 8% soluble aggregates decreased rapidly, the storage modulus（G′） and loss modulus（G″） increased sharply, the strength of the gel increased gradually at room temperature（25 ℃）. The damping factor tan delta was about 0.2, forming a weak gel system. Protein concentration（1%~7%） and cooling processes（95~25 ℃） significantly affect the gel strength. The higher the concentration of the protein, the formation of the gels＇ G′ values were greater, indicating higher strength. Forming in the cooling process of the hydrogen bonds and Van der Waals＇ forces further enhance the gel strength. The turbidity increased during gel process. We use the colorimeter to measure luminance value changing exactly. From the angle of optical analysis, we studied the dynamic behavior of acid-induced gel.