应用流变模型分析乳清分离蛋白-果胶复配体的微观结构

Microstructural Analysis of Whey Protein Isolate-Pectin Mixture Using Rheological Models

通过对几种流变模型(剪切-黏度模型)的分析比较,配合使用透射电镜(TEM)的方法,在pH值中性并且不加入盐的条件下研究乳清分离蛋白(WPI)、果胶以及两者复合体的微观结构。流变模型主要为Cross模型、Carreau模型及其衍变形式。结果表明:在剪切速率为0.09～600s-1、温度80℃、溶液质量分数分别为WPI5%、果胶0.8%、5%WPI-0.8%果胶复合物的条件下,发现WPI和果胶溶液表现出牛顿流体特性,与Carreau衍变模型相符合,而它们的混合物表现出切稀特性,与Carreau模型相符合。

A comparative analysis of 2 rheological models such as the Cross model and the Carreau model as well as their separate modified expressions and transmission electron microscopic（TEM） examinations were carried out for elucidating the microstructures of pure whey protein isolate（WPI）,pure pectin and WPI/pectin mixture in aqueous solutions at pH 7 without added salts.The concentrations（m/m,%） employed for the solutions were：pure WPI,5%;pure pectin,0.8%,5%and WPI/0.8% pectin mixture（5%/0.8%）.Both the models were obtained from a shear strain-controlled rheometer over the shear rate range of 0.09s^-1 to 600 s^-1 and at 80 ℃.The pure WPI and the pure pectin solutions showed Newtonian behaviors,which could be well described by the modified Carreau model.The WPI/pectin mixture,on the other hand,showed shear thinning behaviors and the Carreau model provided a best fit.