High internal phase emulsions (HIPE) prepared using whey protein microgels (WPMs) as a surfactant were demonstrated to have substantially higher stability than HIPEs prepared using similar loadings of non-gelled whey protein isolate (WPI) or Tween 20. Microgel colloids were prepared from WPI solutions by heat treatment at 85 °C in a narrow pH range (5.8–6.0) to particle sizes of approximately 90, 160 and 350 nm in diameter. ζ-potentials of the WPM increased in negativity with decreasing particle size from −7.4 ± 2.5 down to −21.1 ± 0.9 at 90 nm. All WPMs conferred high stability to corn oil based HIPE when used as an emulsifier. Light microscopy and cryo-scanning electron microscopy showed that both increasing WPM concentration and decreasing WPM particle size produced increasingly smaller and more hexagonally shaped corn oil emulsion droplets; WPI and Tween 20 based HIPE droplets were generally smaller and spherical in shape. The HIPE (75% w/w corn oil) produced with 1% (w/w) WPM as an emulsifier showed stability through 6 months storage at 4 °C at all WPM sizes tested, while the HIPE prepared with 1% (w/w) WPI or Tween 20 exhibited significant creaming. WPM and WPI based HIPE both showed thermal stability at 70 °C and 95 °C while the heating of Tween 20 based HIPE resulted in droplet coalescence and oil-phase separation. HIPE production with WPMs significantly improved the viscoelastic properties of the HIPE, imparting drastic increases in yield stress, critical stress, complex modulus and elastic modulus over HIPE prepared with WPI or Tween 20. The more rigid rheology of the WPM HIPE indicated by these data is likely the primary mechanism driving the improved stability of these emulsions.

中文翻译：

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通过包含乳清蛋白微凝胶形成货架稳定的Pickering高内相乳液（HIPE）†

已证明，使用乳清蛋白微凝胶（WPM）作为表面活性剂制备的高内相乳液（HIPE）具有比使用类似量的非凝胶化乳清蛋白分离物（WPI）或吐温20制备的HIPE更高的稳定性。通过在85°C的狭窄pH范围（5.8–6.0）中进行热处理，可将WPI解决方案制成直径约为90、160和350 nm的粒径。WPM的ζ电位呈负电性，且粒径从90纳米处的-7.4±2.5降低至-21.1±0.9。当用作乳化剂时，所有WPM均赋予玉米油基HIPE高稳定性。光学显微镜和低温扫描电子显微镜显示，增加的WPM浓度和减小的WPM粒度都会产生越来越小的，更六角形的玉米油乳状液液滴。基于WPI和Tween 20的HIPE小滴通常较小，呈球形。以1％（w / w）WPM作为乳化剂生产的HIPE（75％w / w玉米油）在所有测试的WPM尺寸下于4°C储存6个月均显示出稳定性，而HIPE以1％（w / w）的乳化剂制备w）WPI或Tween 20表现出显着的乳脂状。基于WPM和WPI的HIPE在70°C和95°C时均显示出热稳定性，而基于Tween 20的HIPE的加热导致液滴聚结和油相分离。与WPI或Tween 20制备的HIPE相比，使用WPM生产HIPE可以显着改善HIPE的粘弹性，从而大幅提高屈服应力，临界应力，复数模量和弹性模量。