Abstract: This study compared the micromorphology and stability of O/W and W/O/W emulsions with different concentrations of rice bran protein, prepared by double emulsification using rice bran protein as an interfacial stabilizer, and explored the interfacial stability mechanism. The results showed that the stability of the W/O/W emulsion was significantly better than that of the O/W emulsion. The viscosity of the W/O/W emulsion was significantly improved compared with the O/W emulsion at the same protein level. When the concentration of rice bran protein was 0.4 g/100 mL, the stability of the W/O/W emulsion was twice higher than that of the O/W emulsion; besides, there were more W/O droplets inside the W/O/W emulsion, with larger particle size. The emulsion was more stable because it had greater electrostatic repulsion. The rate of protein adsorption to the O/W and W/O/W emulsions were higher than 78% when the concentration of rice bran protein was equal to or greater than 0.4 g/100 mL. This study provides a reference for the application of natural rice bran protein in food-grade emulsions and provides a new idea for the comprehensive utilization of grain by-products.

Key words: rice bran protein; W/O/W emulsion; O/W emulsion; interfacial property; emulsion stability