超声耦合加热制备明胶稳定的水包油型乳液的研究

Study of preparation of gelatin-stabilized o/w emulsions by ultrasonic-assisted heating

热加工可导致水包油型乳液失稳,因此利用热加工制备乳液对拓展乳液在热加工领域的应用具有重要意义。该文主要通过对乳液粒径、乳析指数、显微结构、Zeta电位和界面蛋白负载量等指标的测定,研究热超声时间(0、20、40、60 min)对乳液稳定性的影响。研究结果表明,超声耦合加热可以形成对热稳定的明胶稳定的水包油型乳液。随着超声时间延长到40 min,乳析指数降低到82.40%、乳液稳定系数增加至62.60%;随着热超声时间进一步延长,乳析指数增加,乳液稳定系数下降。这些结果表明热超声40 min可形成热稳定的乳液,此时乳液体积平均粒径最低,为1.00μm,油滴微观大小与粒径结果相一致。进一步研究发现热超声40 min制备的乳液的界面蛋白负载量最高(7.35 mg/m^(2)),虽然此时Zeta电位的绝对值降低至16.69 mV,表明热超声40 min形成稳定乳液的关键因素是界面蛋白引起的空间位阻作用而非静电斥力。

Thermal processing can destabilize oil-in-water emulsions.Thus,it is of great significance to prepare emulsions by thermal processing to expand their application in food processing.In this research,the effect of thermo-ultrasound time(0 min,20 min,40 min,and 60 min)on the stability of emulsions was studied by evaluating changes in particle size,creaming stability,microstructure,Zeta potential,and surface protein load.Results suggested that heat-stable o/w emulsions stabilized by gelatin could be manufactured using ultrasonic-assisted heating.When thermo-ultrasound time increased to 40 min,the creaming stability decreased to 82.40%,and the emulsion stability increased to 62.60%.With the extension of thermo-ultrasound time,the creaming stability increased significantly,and the emulsion stability decreased significantly.These results implied that the heat-stable emulsion stabilized by gelatin could be prepared by thermo-ultrasound after 40 min,and the average particle size of the emulsion decreased to the lowest minimum of 1.00μm,which was also consistent with the results of the microstructure of oil droplets.Further investigation revealed that the emulsion prepared by thermo-ultrasound for 40 min had the highest surface protein load(7.35 mg/m^(2)),although the absolute Zeta potential value decreased to 16.69 mV,indicating that steric hindrance provided by the interfacial protein,rather than electrostatic repulsion,was the key factor in the formation of a stable emulsion prepared by thermo-ultrasound for 40 min.