Modification of emulsifying properties of mussel myofibrillar proteins by high-intensity ultrasonication treatment and the stability of O/W emulsion

The purpose of this research was to investigate the effects of high-intensity ultrasonication (HIUS) treatment at different ultrasonic powers (0, 150, 300, 450, 600 W) on the emulsifying properties of mussel myofibrillar protein (MMP). The changes in fourier infrared spectroscopy, fluorescence spectroscopy, free sulfhydryl groups and surface hydrophobicity, indicated that HIUS treatment changes the structure of MMP. HIUS treatment could significantly improve the emulsifying properties of MMP by affecting its physicochemical properties. HIUS treatment improved the emulsification activity index, emulsification stability index, adsorption protein percentage, creaming index, interfacial tension, rheology and other emulsifying properties of O/W emulsion. HIUS treatment at 600 W had the best effect on the solubility of MMP. Solubility, compared to control, increased from 11.1% to 33.4%; and the change in molecular structure of MMP was characterized by smaller particles (from 48.64 to 20.60 µm), lager absolute zeta potential (from 56.24 to 79.92 mV), and decreased turbidity (from 1.68 to 0.97). The emulsion stabilized by MMP ultrasonicated at 600 W showed the best storage stability, with the lowest particle size, the lowest surface tension (11.83 mN/m) and the largest absolute value of zeta potential (31.78 mV), which was confirmed in the microstructure photos. The results of this research provide theoretical basis for the application of ultrasonic modified MMP as functional protein ingredients to control emulsion-type seafood products or design of MMP-based emulsion delivery systems for functional material in the food industry.