声流效应对大豆分离蛋白超声乳化效果研究

目的 研究不同超声功率（0、28、47、69、88、109 W）作用下声流效应对大豆分离蛋白(soy protein isolate, SPI)乳化效果的影响。方法 将声流效应形成机制与有限元方法相结合，对声场内的声流现象进行仿真计算，获取不同超声功率下的声流速度场分布，探究超声空化场分布特性。通过大豆分离蛋白超声乳化实验,对不同功率条件下声流效应产生的空化作用效果进行验证，利用激光粒度分析仪、紫外可见分光光度计、旋转流变仪测量大豆分离蛋白乳化液的粒径、乳化活性、乳化稳定性、表观粘度。结果 增大超声功率可使沿反应器轴向区域相同位置处声流速度值增大，声流效应增强，显著提高(P<0.05)超声空化空间分布范围。声流作用下，对大豆分离蛋白乳化液进行超声处理可显著降低(P<0.05)乳化液平均粒径和粒径分布，提高(P<0.05)乳化活性、乳化稳定性和表观粘度。超声功率为88 W时，乳化效果最佳。结论 超声功率为88 W所产生的声流效应对大豆分离蛋白乳化液的乳化效果影响最为显著，研究成果可为超声乳化的优化研究提供可行的方法。

Research on ultrasonic emulsification of soy protein isolate under the effect of acoustic flow

Objective To study the effect of acoustic flow phenomenon on the emulsification of soy protein isolate (SPI) under different ultrasonic powers (0, 28, 47, 69, 88, 109 W). Methods Combined the effect of acoustic flow formation mechanism and finite element method, we simulated the acoustic flow phenomena in the sound field, obtained the velocity field distributions of acoustic flow under different ultrasonic powers, and preliminarily explored the distribution characteristics of the ultrasonic cavitation field. The effect of ultrasonic cavitation by acoustic flow effect at different ultrasonic powers were verified by SPI ultrasonic emulsification experiments. The particle size, emulsification activity, emulsion stability, and apparent viscosity of SPI emulsions were measured using laser particle size analyzer, UV-visible spectrophotometer and rotational rheometer. Results Experimental results showed that increasing the ultrasonic power can increase the value of acoustic velocity at the same position along the axial region of the reactor, which enhanced the acoustic flow effect and significantly improves the spatial distribution range of ultrasonic cavitation(P<0.05). Ultrasonic treatment of SPI emulsions under the action of acoustic flow could significantly reduce the mean particle size and particle size distribution of emulsions(P<0.05), as well as improve emulsification activity, emulsion stability and apparent viscosity(P<0.05). The best emulsification effect was achieved when the ultrasonic power was 88 W. Conclusion The acoustic flow effect produced by the ultrasonic power of 88 W has the most significant effect on the emulsification effect of SPI emulsions. The results of the study may provide a feasible method for the optimization study of ultrasonic emulsification.