Journal of South China University of Technology(Natural Science Edition) ›› 2024, Vol. 52 ›› Issue (4): 26-32.doi: 10.12141/j.issn.1000-565X.230325

• Food Science & Technology • Previous Articles     Next Articles

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

GE Ge1,2 LIN Li1 ZHENG Jiabao2 SUN Weizheng2   

  1. 1.Beijing Institute of Food Inspection and Research (Beijing Municipal Center for Food Safety Monitoring and Risk Assessment),Beijing 100094,China
    2.School of Food Science and Engineering,South China University of Technology,Guangzhou 510640,Guangdong,China
  • Received:2023-05-15 Online:2024-04-25 Published:2023-07-12
  • Contact: 孙为正(1983-),男,博士,教授,主要从事蛋白质化学与营养研究。 E-mail:fewzhsun@scut.edu.cn
  • About author:葛鸽(1992-),女,博士,工程师,主要从事蛋白质化学与营养研究。E-mail:gege131700@163.com
  • Supported by:
    the General Program of the Natural Science Foundation of Guangdong Province(2021A1515010638)

Abstract:

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 1.702 μm to 1.203 μm (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.

Key words: tea polyphenols, soy protein isolate, emulsion, bile salts displacement, zeta potential

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