【作者】 宋艳；

【导师】 张培新； 刘剑洪；

【作者基本信息】 广西大学 ， 化学工艺， 2004， 硕士

【摘要】 本文采用粘度法对酪蛋白溶液粘度的浓度依赖性、时间依赖性、温度依赖性及Cu²⁺对酪蛋白溶液粘度的影响进行了系统的研究。通过动态激光光散射仪（DLS）及凝胶渗透色谱仪（GPO）研究了酪蛋白分子的构象。并且利用芘作为荧光探针，研究了酪蛋白及接枝酪蛋白水溶液的疏水微区极性。 结果表明：当酪蛋白溶液浓度小于动态接触浓度时，酪蛋白分子在溶液中主要以孤立链形式存在，溶液粘度较小。当浓度大于临界交叠浓度时，由于分子链间发生缠结，溶液粘度急剧增大。随着放置时间的延长，酪蛋白分子亚单元逐渐分离，溶液粘度下降。当酪蛋白溶液浓度小于临界交叠浓度时，Cu²⁺主要作用于单个酪蛋白分子内部，使单个分子链内缠结加剧；当溶液浓度大于临界交叠浓度时，Cu²⁺主要作用在不同酪蛋白分子之间，酪蛋白分子链间缠结加剧。温度升高会使酪蛋白溶液的粘度降低。动态激光光散射和凝胶色谱研究进一步证实了酪蛋白分子亚单元分离。利用芘作为荧光探针可对酪蛋白溶液中的疏水微区进行有效的分析，在不同pH值下，疏水微区的极性不同，与MMA接枝聚合后，酪蛋白溶液中的疏水微区增大，极性显著降低，疏水性增加，表明酪蛋白与MMA接枝聚合发生在酪蛋白疏水微区中。更多还原

【Abstract】 The effect of concentration, time, temperature and Cu2+ on the viscosity of the casein molecule was investigated systematically by viscosity method. The conformation of casein was studied by DLS and GPC. And the polarity of hydrophobic microdomain of casein and grafted casein in solution was studied using pyrene as fluorescence probe.The results indicated that viscosity of casein solution is lower and the casein is separated when the concentration of casein solution is lower than Cs. The viscosity of solution increases sharply because the chains of molecule tangle each other when the concentration of solution is higher than C*. Along with the time goes the sub-units of casein apart step by step and viscosity decrease. Cu2+ act mainly on inner of separated casein molecule and make the tangle in it more acute when the concentration ofsolution is lower than C*. Cu act mainly between the chains of casein molecule and make the tangle between them more acute when the concentration of solution is higher than C*. The viscosity of casein solution decreased with increasing the temperature. The separation of sub-unit of casein molecule is approved by DLS and GPC. Pyrene was aneffective fluorescence probe for detecting the hydrophobic microdomain of casein in solution. The hydrophobic microdomain of casein solution exhibited different polarity at different pH values. After the graft-copolymerization of methyl methacrylate (MMA) onto casein, the hydrophobic microdomain increased and the polarity decreased, indicating that the graft-copolymerization took place in the hydrophobic microdomain.更多还原