基于酸浆量变化的豆腐蛋白沉淀机理研究  

Mechanism of Tofu Protein Precipitation Based on Acid-Pulp Content Change

作　　者：张志衡 陈振家[1] 王晓闻[1] 李玉娥[1] 张雪冰 ZHANG Zhi-heng;CHEN Zhen-jia;WANG Xiao-wen;LI Yu-e;ZHANG Xue-bing(College of Food Science and Engineering,Shanxi Agricultural University,Jinzhong 030800,China)

机构地区：[1]山西农业大学食品科学与工程学院,山西晋中030800

出　　处：《大豆科学》2022年第3期345-351,共7页Soybean Science

基　　金：山西省重点研发计划(201903D221035);山西农业大学博士科研启动资金(2016ZZ06)。

摘　　要：为探究酸浆豆腐凝固过程中蛋白沉淀过程的机理,以实现对豆乳凝固过程的有效监测,本研究添加不同含量酸浆制备豆腐,建立凝固曲线,采用SDS-PAGE电泳分析蛋白亚基含量变化,进行粒径分布和Zeta电位分析,采用紫外扫描方法分析蛋白空间结构变化,并利用激光共聚焦分析凝胶微观结构变化,研究豆腐凝固过程中蛋白亚基的含量变化和聚集情况。结果表明:蛋白质沉淀量随酸浆添加量的增加而逐渐增大,在20%时达到最大值并趋于稳定;豆乳凝固过程中蛋白质亚基组成发生了较大变化,2%酸浆添加量是诱导蛋白质凝固和豆乳中蛋白质亚基组成改变的重要拐点,A;和β亚基最早参与凝胶形成,α和α′亚基表现出明显的聚集延迟;豆乳中蛋白质粒径和电位绝对值随酸浆添加量的增加而逐渐减小,体系的稳定性遭到破坏;随着酸浆添加量的增加,豆乳中色氨酸、酪氨酸、苯丙氨酸残基逐渐暴露,豆乳疏水性增强;酸浆添加量对凝胶微观结构的影响显著,添加量低于20%时,凝胶网络结构随着酸浆添加量的增加而逐渐变得细腻。综合上述研究结果表明,在一定的酸浆添加量范围内,随着酸化速率的增大,豆乳聚集过程加快,在此过程中豆乳稳定性、豆乳中蛋白质分子结构以及形成凝胶的微观结构均发生显著变化。In order to explore the mechanism of protein precipitation in soybean-curd solidification, as well as to effectively monitor the process of soybean-milk solidification, this study used different contents of acid-pulp and established a solidification curve. We analyzed the protein subunit content change by SDS-PAGE electrophoresis, the particle-size distribution and zeta potential, the protein spatial structure change by UV scanning, and the gel microstructure change by laser confocal scanning, and studied the protein subunit content change and aggregation in the process of soybean-curd solidification. The results showed that the precipitation amount of protein gradually increased with increased amount of acid pulp and reached the maximum at 20% before stabilizing. Great changes occurred in the protein-subunit composition during soybean-milk solidification. The addition of 2% acid pulp was an important inflection point to induce protein solidification and changed the protein-subunit composition in soybean milk. The A;subunit and the β subunit participated in gel formation at the earliest, as well as the α and α′ subunits, showed obvious aggregation delay. The absolute value of particle size and potential of protein in soybean milk gradually decreased with increased acid-pulp addition, and the stability of the system was destroyed. With increased amount of acid pulp, the tryptophan, tyrosine, and phenylalanine residues in soybean milk were gradually exposed, and the hydrophobicity of soybean milk was enhanced. The amount of acid pulp significantly affected the gel microstructure. When the amount of acid pulp was less than 20%, the gel-network structure gradually became fine with increased acid pulp. These results showed that within a certain amount of added acid pulp, with the increase of acidification rate, the soy milk aggregation process was accelerated, within which the stability of soybean milk, the molecular structure of protein in soybean milk, and the microstructure of gel formed significantly changed.

关 键 词：豆腐 酸浆 添加量 凝固 蛋白性状 凝胶微观结构 

分 类 号：TS214.2[轻工技术与工程—粮食、油脂及植物蛋白工程]