Study On The Interaction Between Natural Polyphenols Combined Active Ingredients And Whey Protein

Polyphenols are compounds that are widely present in plant foods and are beneficial to health,which makes them potential nutrients.Due to the excellent antioxidant properties of polyphenol compounds,foods rich in polyphenols will bring a variety of health benefits.When two or more polyphenols are administered together,they may have a synergistic effect.However,polyphenols are often instable due to their sensitivity to oxygen,light,pH and other factors.The co-encapsulation of multiple bioactive components in a carrier may produce synergistic effects and improve health benefits.Combined with the actual situation of our laboratory on the basis of literature review,various spectroscopic methods,isothermal titration calorimetry(ITC)and molecular docking were used to study the interactions between natural polyphenols andβ-lactoglobulin(β-LG)at different temperatures.The effects of the interaction on the antioxidant activity,stability and cytotoxicity of polyphenols were also discussed.This paper was divided into the following four parts:Part Ⅰ: The interactions of β-LG with epigallocatechin-3-gallate(EGCG)and/or piceatannol(PIC)were investigated by fluorescence spectroscopy,UV-vis absorption spectroscopy,isothermal titration calorimetry,circular dichroism spectroscopy,dynamic light scattering and molecular docking.The synergistic effect of EGCG and PIC was optimized by response surface methodology(RSM).The effects of β-LG in the binary and ternary systems on the antioxidant activity,stability and cytotoxicity of the polyphenols were also studied.Part Ⅱ: The interactions of EGCG and OXY alone or in combination with β-LG were studied by multispectroscopic techniques(fluorescence spectroscopy,UV-vis absorption spectroscopy circular dichroism spectroscopy and dynamic light scattering),isothermal titration calorimetry and molecular docking.The synergistic antioxidant effect of EGCG and OXY was studied,and the effect of β-LG on the antioxidant activity,stability and cytotoxicity of EGCG,OXY and EGCG + OXY was also studied.Part Ⅲ: The interactions of epicatechin gallate(ECG)and PIC alone or in combination with normal/heat treated β-LG were studied by fluorescence spectroscopy,UV-vis absorption spectroscopy,circular dichroism spectroscopy,dynamic light scattering and molecular docking.The synergistic antioxidant effect of ECG and PIC was studied,and the effect of β-LG on the antioxidant activity,stability and cytotoxicity of ECG,PIC and EGCG + PIC was also studied.The experimental results showed that the interaction of normal β-LG and heat-treated β-LG with polyphenols and the effect on the activity of polyphenols are significantly different.Part Ⅳ: The interactions of ECG and PIC alone or in combination with β-LG at different pHs were studied by multispectroscopic techniques(fluorescence spectroscopy,UV-vis absorption spectroscopy circular dichroism spectroscopy and dynamic light scattering).The synergistic effect of ECG and PIC at different pHs was optimized by RSM.Finally,the effect of β-LG on the antioxidant activity and stability of ECG,PIC and EGCG+ PIC at different pHs was also studied.