Arii Yasuhiro, Nishizawa Kaho
Department of Food Science and Nutrition, School of Human Environmental Sciences, Mukogawa Women's University, Nishinomiya, Hyogo 663-8558, Japan.
Department of Dietary Life and Food Sciences, Junior College Division, Mukogawa Women's University, Nishinomiya, Hyogo 663-8558, Japan.
Heliyon. 2018 Sep 24;4(9):e00817. doi: 10.1016/j.heliyon.2018.e00817. eCollection 2018 Sep.
Different coagulant concentrations can induce urea-soluble precipitates (USPs) and urea-insoluble precipitates (UIPs) during tofu-like precipitate formation. In this study, MgCl concentration-dependent changes in USPs were quantified using a method based on urea solubility differences in order to investigate the factors affecting USP versus UIP formation. The addition of various Mg salts revealed that anions influence the solubility of proteins in both USPs and UIPs. Moreover, addition of MgCl/NaCl mixtures, in which the Cl concentration was held constant, demonstrated that Mg was essential for UIP formation but not for USP formation and that Cl was inconsequential for both USP and UIP formation. NaCl addition showed that the driving force for USP formation was salting-out due to the presence of cations. Overall, our data indicated that the Mg concentration determined the separation of USPs and UIPs. These results will help elucidate the molecular mechanisms mediating the separation of silken tofu and regular tofu.
在豆腐状沉淀形成过程中，不同的凝结剂浓度会诱导产生尿素可溶性沉淀（USP）和尿素不溶性沉淀（UIP）。在本研究中，基于尿素溶解度差异的方法对USP中MgCl浓度依赖性变化进行了量化，以研究影响USP与UIP形成的因素。添加各种镁盐表明，阴离子会影响USP和UIP中蛋白质的溶解度。此外，添加Cl浓度保持恒定的MgCl/NaCl混合物表明，Mg对于UIP的形成至关重要，但对USP的形成并非如此，并且Cl对USP和UIP的形成均无关紧要。添加NaCl表明，USP形成的驱动力是由于阳离子的存在导致的盐析作用。总体而言，我们的数据表明Mg浓度决定了USP和UIP的分离。这些结果将有助于阐明介导绢豆腐和普通豆腐分离的分子机制。
