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(三+)随冷致凝胶时间(t)变化关系的Boltzmann函数数学模型:L*=L2+(L*2-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±0.21min,溶胶.凝胶转变过程完成时间延长了1.34±0.16min,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。
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*) - getation 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 to 1.34±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.