声流效应对大豆分离蛋白超声乳化效果研究

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

目的研究不同超声功率(0、28、47、69、88、109W)作用下声流效应对大豆分离蛋白乳化效果的影响。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,分别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,显著提高超声空化空间分布范围(P<0.05)。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乳化液平均粒径和粒径分布(P<0.05),提高乳化活性、乳化稳定性和表观粘度(P<0.05)。超声功率为88W时,乳化效果最佳。结论超声功率为88W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。

Objective To study the effects of acoustic flow phenomenon on the emulsification of soy protein isolate 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 explored the distribution characteristics of the ultrasonic cavitation field.The effects of ultrasonic cavitation by acoustic flow effect at different ultrasonic powers were verified by soy protein isolate ultrasonic emulsification experiments.The particle size,emulsification activity,emulsion stability,and apparent viscosity of soy protein isolate emulsions were measured by laser particle size analyzer,UV-visible spectrophotometer and rotational rheometer,respectively.Results Increasing the ultrasonic power could 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 improved the spatial distribution range of ultrasonic cavitation(P<0.05).Ultrasonic treatment of soy protein isolate emulsions under the action of acoustic flow could significantly reduced the mean particle size and particle size distribution of emulsions(P<0.05),as well as improved 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 soy protein isolate emulsions,which provides a feasible method for the optimization study of ultrasonic emulsification.