Effect of ultrasound on physicochemical properties of emulsion stabilized by fish myofibrillar protein and xanthan gum

To investigate the effects ultrasound (20 kHz, 150–600 W) on physicochemical properties of emulsion stabilized by myofibrillar protein (MP) and xanthan gum (XG), the emulsions were characterized by Fourier transform infrared (FT-IR) spectroscopy, ζ-potential, particle size, rheology , surface tension, and confocal laser scanning microscopy (CLSM). FT-IR spectra confirmed the complexation of MP and XG, and ultrasound did not change the functional groups in the complexes. The emulsion treated at 300 W showed the best stability, with the lowest particle size, the lowest surface tension (26.7 mNm −1 ) and the largest ζ-potential absolute value (25.4 mV), that were confirmed in the CLSM photos. Ultrasound reduced the apparent viscosity of the MP-XG emulsions, and the changes of particle size were manifested in flow properties. Generally, ultrasound was successfully applied to improve the physical stability of MP-XG emulsion, which could be used as a novel delivery system for functional material.