Abstract:Oil-in-water emulsion was prepared from grape seed oil and rice hydrolyzed protein. The single factor test was carried out by selecting the addition amount of rice hydrolysate protein, oil phase proportion, pH value, high pressure homogenization time and high pressure homogenization pressure. On this basis, the Box-Behnken test design was adopted to carry out response surface analysis test with the emulsion particle size and emulsification stability as response values, and the optimal process parameters were determined as follows: The average grain size was (0.894±0.013) μm and emulsifying stability was (18 157.7±137) min when the addition amount of rice hydrolyzed protein was 2%, oil phase proportion was 10%, pH value was 7, homogenization time was 5 min, homogenization pressure 50 MPa. Under these conditions, the composite emulsion of grape seed oil/rice hydrolyzed protein was prepared, and the changes of emulsion particle size, emulsification index and microstructure were investigated at 1, 7, 15 d and 30 d, respectively, to evaluate the storage stability of the emulsion. The results showed that the emulsion was oil-in-water type, and the oil phase was evenly dispersed in the water phase. The emulsion appearance did not change significantly within 30 days of storage. The emulsion particle size increased slightly with the increase of the storage time, and the emulsification index decreases gradually.