应用动态光散射和透射电镜研究热力学不相容条件下果胶与乳清蛋白混合体系的微观结构  

Study of Microstructure of Pectin and Whey Protein Isolate Mixtures under Incompatible Conditions Using Dynamic Light Scattering and Transmission Electron Microscopy

作　　者：冷小京[1] 柴智[2] 任发政[1] 张录达[2] Turgeon S L 

机构地区：[1]中国农业大学食品科学与营养工程学院,教育部-北京市功能乳品实验室,北京100083 [2]中国农业大学理学院,北京100094 [3]加拿大拉瓦尔大学农业与食品科学学院,乳品科技研究中心,加拿夫魁北克市G1K7P4

出　　处：《光谱学与光谱分析》2010年第8期2196-2200,共5页Spectroscopy and Spectral Analysis

基　　金：国家高技术研究发展计划(863计划)项目(2007AA10Z311);国家“十一五”科技支撑计划项目(2006BAD04A06);加拿大自然科学与工程理事会NSERC资助

摘　　要：应用动态光散射、透射电镜和粘度-剪切模型3种方法互相配合,研究了果胶与乳清分离蛋白的混合体系在热力学不相容条件下的微观结构。在90℃及pH7.4条件下,向5%蛋白浓度的乳清蛋白溶液中加入带有负电的果胶分子,可导致热变性乳清蛋白分子之间发生损耗聚集,并引发混合体系内的相分离现象。确切地说,当果胶与乳清蛋白的混合重量比小于0.08时,溶液内可观察到粒径小于300nm的聚集颗粒,体系呈现牛顿流体特征;而当混合重量比大于0.08时,体系粘度上升,切稀特征逐渐明显,聚集集团粒径接近700nm。The microstructure of the pectin/whey protein isolate mixtures under incompatible conditions was investigated using dynamic light scattering spectroscopy,transmission electron microscopy and shear-viscosity model.Under the condition of 90 ℃ and pH 7.4,the presence of negatively charged pectin could induce depletion aggregation in a 5% protein solution,and promote phase separation;precisely,when the mass ratio of pectin/whey protein isolate was lower than 0.08,the hydrodynamic size of the aggregates was less than 300 nm,and the system showed Newtonian properties;when the mass ratio was higher than 0.08,the viscosity of the solution increased rapidly,the shear thinning properties became obvious and the size of the aggregates was close to 700 nm.

关 键 词：乳清分离蛋白 果胶 粘度 剪切 相分离 

分 类 号：O657.3[理学—分析化学]