Kano Hiroshi, Shiraki Kentaro
Research Institute for Creating the Future, Fuji Oil Holdings INC, 1 Sumiyoshi-cho, Izumisano-shi, Osaka 598-8540, Japan.
Faculty of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573, Japan.
Food Chem X. 2023 Jan 7;17:100567. doi: 10.1016/j.fochx.2023.100567. eCollection 2023 Mar 30.
This study aimed to improve the emulsifying properties of commercial soy protein isolates (CSPIs). CSPIs were thermally denatured without additives (CSPI_H) and with arginine (CSPI_A), urea (CSPI_U), and guanidine hydrochloride (CSPI_G), which improve protein solubility to prevent aggregation. These additives were removed by dialysis, and the samples were lyophilized. CSPI_A resulted in high emulsifying properties. FT-IR analysis showed that the β-sheet content in CSPI_A was reduced compared to that of untreated CSPI (CSPI_F). Fluorescence analysis showed that the tryptophan-derived emission peak of CSPI_A shifted between CSPI_F and CSPI_H which was exposed to hydrophobic amino acid chains with aggregation. As a result, the structure of CSPI_A became moderately unfolded and exposed the hydrophobic amino acid chains without aggregation. The CSPI_A solution had a more reduced oil-water interface tension than other CSPIs. These results support that CSPI_A attaches efficiently to the oil-water interface and produces small, less flocculated emulsions.
本研究旨在改善商业大豆分离蛋白（CSPIs）的乳化性能。商业大豆分离蛋白在无添加剂（CSPI_H）以及添加精氨酸（CSPI_A）、尿素（CSPI_U）和盐酸胍（CSPI_G）的情况下进行热变性处理，这些添加剂可提高蛋白质溶解度以防止聚集。通过透析去除这些添加剂，然后将样品冻干。CSPI_A具有较高的乳化性能。傅里叶变换红外光谱（FT-IR）分析表明，与未处理的商业大豆分离蛋白（CSPI_F）相比，CSPI_A中的β-折叠含量降低。荧光分析表明，CSPI_A中色氨酸衍生的发射峰在CSPI_F和暴露于聚集的疏水氨基酸链的CSPI_H之间移动。结果，CSPI_A的结构适度展开，暴露了疏水氨基酸链且未发生聚集。CSPI_A溶液的油水界面张力比其他商业大豆分离蛋白更低。这些结果表明，CSPI_A能有效地附着于油水界面，并产生小的、絮凝较少的乳液。
