二步加热对豆腐物性的影响

Method of two step-heating on tofu's physical properties

蛋白质的热变性是制作豆腐形成凝胶的前提。大豆中的蛋白质主要是7S和11S。采用分步加热的方法,使大豆中的蛋白质分步变性,即研究将豆浆分别在75℃和95℃下加热。通过对比一步加热的加工方法发现,采用二次加热法制得的豆腐的质构特性及保水性、得率均明显高于一步加热法,并且随着豆浆浓度的增加时,二步加热法对于豆腐的保水性和得率的增强要明显地高于一步加热法。但是大豆原料的蛋白质含量与豆腐的保水性和得率之间并无明显的联系。

Thermal denaturation of soy proteins is a pre-requisite for tofu-gel formation, The two main proteins in soy proteins are glycinin of which denaturation temperature is 92℃ and β-conglycinin of which denaturation temperature is 71℃, Soymilk was heated at 75℃ and 95℃ for different time（5min, 7min, 10min）, Comparing to one step heating, selective thermal denaturation has promoted some textural parameters, syneresis and yield, Meanwhile, the effects of tofu＇s syneresis and yield which are under the method of two-step heating are much better than those of one-step heating. However, there are not direct relationships on tofu＇s quality with protein content of different samples and the heating methods