Abstract：
The objective of this paper was to investigate the interactions between (-)-Epigallocatechin-3-gallate (EGCG) and whey protein isolate (WPI) by covalent and non-covalent combinations and the effects of the interactions on the conformational and functional changes of whey protein. Conformational changes in the secondary structure of whey protein with various concentrations of EGCG were studied using FTIR spectra. EGCG was more likely to form covalent bonds than non-covalent bonds when it interacted with whey proteins. The addition of EGCG altered the conformation of whey protein. The content of β-sheet decreased, while that of β-turn increased, however, the random coil remained unchanged. An reduction in surface hydrophobicity was observed in all the WPI-EGCG complexes, suggesting that modification in secondary structure of WPI were induced by EGCG. Additionally, the emulsifying and foaming attributes of WPI were enhanced after interaction with EGCG. This study confirms that EGCG can enhance the functional properties of WPI. It is also a pointer to the possible application of WPI-EGCG complexes in the dairy industry.
摘要：
本文的目的是通过共价和非共价组合研究（-）-表没食子儿茶素-3-没食子酸酯（EGCG）与乳清分离蛋白（WPI）之间的相互作用，以及相互作用对构象和功能变化的影响。乳清蛋白。使用FTIR光谱研究了各种EGCG浓度下乳清蛋白二级结构的构象变化。当与乳清蛋白相互作用时，EGCG与非共价键更可能形成共价键。EGCG的加入改变了乳清蛋白的构象。β-折叠的含量下降，而β转角增加，然而,随机线圈保持不变。在所有WPI-EGCG复合物中观察到表面疏水性的降低,提示EGCG诱导了WPI二级结构的修饰。此外,与EGCG相互作用后，WPI的乳化和起泡特性得到增强。本研讨证实EGCG可以增进WPI的机能性质。这也是WPI-EGCG复合物在乳制品行业中可能应用的指针。
