College of Food Science, Northeast Agricultural University, Harbin 150030, China.
College of Food Science, Northeast Agricultural University, Harbin 150030, China; Key Laboratory of Soybean Biology of Chinese Education Ministry, Harbin 150030, China; HeilongjiangBeidahuang Green Health Food Co. LTD, Heilongjiang, Jiamusi 154000, China.
Food Chem. 2022 Aug 1;384:132507. doi: 10.1016/j.foodchem.2022.132507. Epub 2022 Feb 19.
Understanding the molecular mechanism behind protein-polyphenol interactions is critical for the application of protein-polyphenol compounds in foods. The purpose of this research was to investigate the non-covalent interaction mechanism between soy protein isolate (SPI) and catechin and its effect on protein conformation. We observed that particle size, ζ-potential, and polyphenol bound equivalents of SPI increased significantly after non-covalent modification with catechin. These changes caused SPI to aggregate and form a network-like structure. Fourier transform infrared spectroscopy (FTIR) indicated that increased catechin concentrations caused SPI to become looser and more disordered as its α-helix and β-sheet transformed into β-turn and random coil. Furthermore, internal structure of SPI was opened and its hydrophobic groups were exposed to a polar environment, which was demonstrated by decreased surface hydrophobicity. Thermodynamic analysis and molecular docking results showed that the main forces present between SPI and catechin were hydrophobic interactions and hydrogen bonds.
了解蛋白质-多酚相互作用的分子机制对于蛋白质-多酚化合物在食品中的应用至关重要。本研究旨在探讨大豆分离蛋白（SPI）与儿茶素之间的非共价相互作用机制及其对蛋白质构象的影响。我们观察到，SPI 经儿茶素非共价修饰后，粒径、ζ-电位和多酚结合当量显著增加。这些变化导致 SPI 聚集并形成网状结构。傅里叶变换红外光谱（FTIR）表明，随着儿茶素浓度的增加，SPI 的α-螺旋和β-折叠结构逐渐转化为β-转角和无规卷曲，变得更加松散无序。此外，SPI 的内部结构被打开，疏水性基团暴露在极性环境中，表面疏水性降低证明了这一点。热力学分析和分子对接结果表明，SPI 和儿茶素之间的主要相互作用力为疏水相互作用和氢键。
