茶多酚对大豆分离蛋白乳液性质及界面蛋白胆盐置换的影响

Effect of Tea Polyphenols on Soy Protein Isolate-Stabilized Emulsions and Interfacial Protein Displacement by Bile Salts

通过添加不同含量的茶多酚提取物修饰大豆分离蛋白制备水包油乳液,考察大豆分离蛋白乳液的界面张力、蛋白吸附比例、乳液粒径以及Zeta电位等性质变化,探究茶多酚对大豆分离蛋白乳液性质和界面蛋白置换的影响。实验结果表明:添加茶多酚后,大豆分离蛋白的界面张力升高;大豆分离蛋白溶液(1%,质量分数)按照9∶1(质量比)与大豆油混合后,经过高速剪切和超声制备成水包油乳液,添加茶多酚制备的乳液稳定性提高,与空白对照组相比,当茶多酚添加量为0.04%时,乳液平均粒径从1.702μm显著下降至1.203μm(P<0.05),乳液的蛋白吸附比例从9.22%显著上升至20.68%(P<0.05),Zeta电位绝对值从25.7 mV显著上升至27.1 mV(P<0.05);大豆分离蛋白在油-水界面上具有抗胆盐置换的特性,由茶多酚修饰的大豆分离蛋白更加难以被胆盐置换,这可能是添加茶多酚后大豆分离蛋白具有较强的静电相互作用以及较厚的界面层导致的。肠道中的脂质消化是界面过程,探究脂滴界面上蛋白与胆盐的置换反应对研究脂质代谢和食品精准设计具有指导作用。

The soy protein isolate was modified by adding different concentrations of tea polyphenols extract to prepare the oil-in-water(O/W)emulsion.The interfacial tension,interfacial protein adsorption fraction,emulsion particle size and zeta potential were investigated to explore the effect of tea polyphenols on the properties of soy protein isolate emulsion and interfacial protein displacement.The results show that the interfacial tension of soy protein isolate is increased after the addition of tea polyphenols.When soy protein isolate(1%,mass concentration)and soy oil are prepared into O/W emulsion with 9∶1 mass ratio by high-speed shear and ultrasound,tea polyphenols addition can improve the emulsion stability.Compared to the blank control group,when the amount of tea polyphenols added is 0.04%,the particle size of emulsion decreases significantly from 1.702μm to 1.203μm(P<0.05),the protein adsorption fraction increases significantly from 9.22%to 20.68%(P<0.05),and the zeta potential increases significantly from 25.7 mV to 27.1 mV(P<0.05),respectively.Soy protein isolate shows resistance to bile salts displacement at the oil-water interface.In addition,the soy protein isolate modified by tea polyphenols is more difficult to be displaced by bile salts because of the strong electrostatic interaction and the thicker interface layer.Lipid digestion in intestine is an interfacial process.Exploring the interfacial displacement between protein and bile salts is beneficial to the study of lipid metabolism and food precise design.