基于色差变化研究大豆蛋白/葡聚糖溶液共混体系溶胶-凝胶转变特性

Sol - gel Transition Properties of Soy Protein -dextran Blend Based on Color Dynamic Monitoring

摘要:

提出了一种基于色差动态变化分析大豆分离蛋白（SPI）/葡聚糖（DEXT）溶液共混体系GDL诱导溶胶-凝胶转变过程凝胶起始时间、凝胶完成时间和凝胶速度的定量化新方法。建立了色差亮度值（L*）随冷致凝胶时间（t）变化关系的Boltzmann函数数学模型：L*=L*2+（L*1-L*2）/{1+exp[（t-tg）/dt]}，该模型的参数具明确物理意义。应用此模型研究大豆分离蛋白-葡聚糖共价复合物（SPI-g-DEXT）对SPI/DEXT溶液共混体系溶胶-凝胶转变过程特性影响发现：与对照相比，添加0.20%（m/m）SPI-g-DEXT，凝胶起始点时间被迟滞1.07±0.21 min，溶胶-凝胶转变过程完成时间延长了1.34±0.16 min，平均凝胶速度降低幅度达10.5%。当SPI-g- DEXT添加量为0.30%~0.50%（m/m），与未添加共价复合物对照相比，凝胶起始点被提前，凝胶完成时间显著降低，平均凝胶速度因相分离作用显著增加，主因共价复合物空间位阻优于增容效应所致，且上述三参数变化趋势随SPI-g-DEXT添加量增加而加剧。

Abstract:

A novel method to quantitatively analyze initial gelation time, whole gelation time and gelation velocity of GDL induced soy protein isolate (SPI)/dextran (DEXT) blends solution sol-gel transition process was proposed with dynamic luminance determination. A Boltzmann function model depending on blends luminance (L*) - gelation time(t) was established as L*=L*2+（L*1-L*2）/{1+exp[（t-tg）/dt]}，which had a clear physical meaning for parameters of this equation. The effect of -SPI-g-DEXT amount (0-0.50%) on sol-gel transition properties of SPI/DEXT was investigated with the above equation. Compared to the control sample，incorporation of 0.20% (m/m) SPI-g-DEXT led to the delay of the initial gelation point by 1.07±0.21 min and extend the time threshold of sol-gel transition process to1.34±0.16 min, while reduce the average gelation velocity amplitude about 10.5%. Further increase in the SPI-g-DEXT amount to 0.30%~0.50% (m/m) shorted the initial gelation point and the time threshold of sol-gel transition process, but increased the average gelation speed, which was mainly due to space steric hindrance beyond compatibilizing effect produced by relatively higher SPI-g-DEXT amount. In addition, the trends of the above three parameters could be exacerbated with the SPI-g-DEXT amount increase.