Abstract:Hemp seed oil composite nano-emulsion was prepared from hemp seed oil, soybean protein isolate, lecithin and kaempferol. The effects of treatment under different ultrasonic powers (100, 200, 300 W and 400 W) for 10 min on the emulsion stability were studied, and the regularity of composite emulsion stability changing with the ultrasonic conditions was revealed. The particle size, Zeta-potential, intrinsic fluorescence spectra and surface hydrophobicity were measured. It was found that under 300 W, the system uniformly dispersed due to the cavitation effect of ultrasonic treatment, the hydrophobic residues inside the protein were exposed to the surface, the internal fluorescence spectra of emulsion were red-shifted, and both the fluorescence intensity and surface hydrophobicity increased. The measurement of emulsification, creaming index and oxidation stability of the samples showed that the emulsion had good physical stability and oxidative stability under 300 W. This indicated that proper ultrasonic treatment was beneficial to improve the stability of composite system. The research results could be used for reference to prolong the shelf life of hemp seed oil and to construct a composite emulsion system.