Peng Ziqi, Liu Kunlun, Liao Ning
College of Food Science and Engineering, Henan University of Technology, Zhengzhou 450001, China.
Foods. 2025 Jun 18;14(12):2130. doi: 10.3390/foods14122130.
Soy isolate protein (SPI), as a high-quality plant protein source, is often processed into various soy products. In this study, the physicochemical properties of SPI treated with transglutaminase (TGase) were investigated in correlation with emulsification characteristics and rheological behavior. The polyacrylamide gel electrophoresis with sodium dodecyl sulfate (SDS-PAGE) and Fourier-transform infrared spectroscopy (FTIR) and endogenous fluorescence spectrum analysis results showed that TGase was able to promote the covalent binding of lysine and glutamine residues in SPI. The moderate pre-crosslinking treatment of TGase (5-7.5 U/g TGase pre-crosslinked for 2 h or 5 U/g TGase pre-crosslinked for 2-3 h) improved the emulsification and gel properties to varying degrees: the nanoparticle and emulsification performance increased by 24.35% and the storage modulus of the gel increased by 288%. Furthermore, the surface charge of SPI increased due to the crosslinking impact of TGase, indicating a considerable rise in the surface electrostatic potential. Simultaneously, the protein surface exhibited a substantial increase in hydrophobicity, while the level of free sulfhydryl groups reduced. These changes indicate that TGase enzymatic crosslinking could significantly improve the structural stability of nanoparticles by enhancing the generation efficiency of covalent bonds between protein molecules.
大豆分离蛋白（SPI）作为一种优质的植物蛋白来源，常被加工成各种豆制品。在本研究中，研究了经转谷氨酰胺酶（TGase）处理的SPI的物理化学性质与乳化特性和流变行为的相关性。十二烷基硫酸钠聚丙烯酰胺凝胶电泳（SDS-PAGE）、傅里叶变换红外光谱（FTIR）和内源荧光光谱分析结果表明，TGase能够促进SPI中赖氨酸和谷氨酰胺残基的共价结合。TGase的适度预交联处理（5 - 7.5 U/g TGase预交联2 h或5 U/g TGase预交联2 - 3 h）不同程度地改善了乳化和凝胶性能：纳米颗粒和乳化性能提高了24.35%，凝胶的储能模量提高了288%。此外，由于TGase的交联作用，SPI的表面电荷增加，表明表面静电势显著上升。同时，蛋白质表面的疏水性大幅增加，而游离巯基水平降低。这些变化表明，TGase酶促交联可通过提高蛋白质分子间共价键的生成效率，显著改善纳米颗粒的结构稳定性。
