Mechanisms of Gelation for Heat-induced and Spontaneous Gels of Proteins

根据动态粘弹测试得到的参数，（凝胶化的临界浓度和形成连接区的片段数）和计算蛋白质分散体的特性粘度，静态粘弹测量参数之间的相关性通过显微镜研究了凝胶的活化能、自由体积分数和微观结构，探讨了热-水凝胶的成胶机理。诱导和自发蛋白质凝胶。结果发现，（1）疏水作用对热诱导凝胶连接区的形成有很大影响，（2）蛋白质分子在形成凝胶时具有较大的占据体积，（3）蛋白质凝胶的连接区由3-4个片段组成;（4）SS/SH相互作用和氢键对蛋白质凝胶连接区的形成起着重要作用。诱导凝胶和自发凝胶本质上具有相同的胶凝机理，即，胶凝机理可以表示为蛋白质周围的水结构如何改变。在自发凝胶化的情况下，蛋白质分子周围的水结构可能被尿素破坏，在热诱导凝胶化的情况下，可能被加热破坏。

On the basis of the parameters obtained by dynamic viscoelastic measurement (the critical concentration of gelation and the number of segments for forming the junction zone) and calculating the intrinsic viscosity of protein dispersions, and the correlation between the parameters obtained by static viscoelastic measurement (activation energies and fractional free volumes) and microstructure of gels by microscopy were investigated the geling mechanism of heat-induced and spontaneous protein gels. It was found that; (1)formation of junction zone for heat-induced gels were largely influenced by hydrophobic interactions, (2)protein molecules possessed the large occupied volume when gels were formed, (3)junction zone of protein gels were formed by 3-4 segments and (4) SS/SH interactions and hydrogen bondings played an important role for forming the junction zone of protein gels.It was concluded that both heat-induced and spontaneous gels intrinsically possessed the same gelling mechanism, i.e., the gelling mechanism can be expressed how the water structure surrounding the proteins were changed. The water structure surrounding the protein molecules might be broken by urea in the case of spontaneous gelation and by heating in the case of heat-induced gelation.