| The extraction of peony seed protein isolate by salt solvent method was optimized by single factor experiment and response surface methodology, and the emulsifying properties of peony seed protein isolate under different pH were determined. The results showed that the optimal extraction conditions of peony seed protein isolate were obtained as follows: extraction time 69 min, extraction temperature 40?℃, ratio of material to liquid 1∶?20 and NaCl concentration 1.03 mol/L. Under these conditions, the yield of peony seed protein isolate was （23.49±1.21）%, and the purity was （90.75±0.87）%. When the pH was 8, the emulsifying capacity and the emulsion thermal stability were the highest, which were(85.27±1.23)% and(90.74±1.07)% respectively. When the emulsion pH was 2-5, Pickering emulsion was formed, the thermal stability and particle size of the emulsion increased remarkably, and the color of the emulsion changed. When the emulsion pH was 8-10, O/W emulsion was formed and the higher of the emulsion pH, the lower of the emulsifying capacity and emulsion thermal stability, the smaller of the particle size of emulsion, and the darker of the emulsion color. Under the neutral condition, the particle size of the emulsion was larger, while the thermal stability was lower. |
