Abstract: In this experiment, soy protein isolate (SPI) and walnut oil were used as the main raw materials. By adding different concentrations of small-molecule surfactants Tween 20, and preparing the oil-in-water (O/W) emulsion with high-pressure homogenization technology, the effects of emulsifiers containing protein and small-molecule surfactants on interfacial characteristics, physical and oxidative stability of emulsions were investigated. The results show that when the concentration of Tween 20 increases from 0 to 10 g/L, the particle size of the emulsion tends to be concentrated and gradually decreases, and the microstructure of the emulsion also obtains the same results; the Zeta potential and the surface tension decrease; During this period, the tryptophan fluorescence intensity of protein decreases, and the value of hydroperoxide and TBARS increase. The above results indicate that the increase of Tween 20 concentration in the emulsion improves the physical stability of the emulsion; however, the replacement of SPI at the interface by Tween 20 weakens the emulsion oxidation stability. This study of the effects of interfacial composition on the physical and oxidative stability of emulsions containing mixed emulsifiers provides a reference for the application of protein emulsion containing small molecule surfactants in food processing.
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