Abstract The process stability of water-in-oil (W/O) Pickering emulsions (10 or 20 wt% water), co-stabilized by 0.14 wt% of polyphenol crystals (curcumin or quercetin) dispersed in a soybean oil phase, plus 2.0 wt% whey protein isolate (WPI) or 0.1–2.0 wt% whey protein microgel (WPM) particles present in the inner aqueous phase, was assessed by measuring the apparent viscosity (η), water droplet size (via light scattering) and microstructural changes (via confocal laser scanning microscopy, CLSM). Stability was measured as a function of temperature (25–50 °C), using a shear rate cycle between 0.1 and 100 s−1 to highlight shear- and time-dependent hysteresis of η. All the emulsions showed shear thinning to some extent, but those without added WPI or WPM particles in the aqueous phase exhibited coalescence at increasing shear rate, that was more pronounced at higher temperatures. Emulsions containing WPI in the dispersed phase were stable, whilst those containing WPM particles showed a decrease in mean droplet size (D4,3) on shearing due to the disruption of the aggregates of droplets, polyphenol crystals and/or WPM particles in the continuous oil phase, but with no droplet coalescence. The low shear rate (0.1 s−1) viscosity showed an increase with increasing WPM particle concentration. This increase, plus CLSM of the emulsions, suggested that the WPM particles increased W/O emulsion stability not only via their adsorption to the inner surface of the water droplets, but possibly also due to them promoting the formation of mixed weak flocs of polyphenol crystals + WPM particles + small water droplets in the oil phase attached to the surface of the main population of water droplets.

中文翻译：

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多酚晶体-蛋白质复合物共稳定的油包水乳液的稳定性作为剪切速率和温度的函数

摘要 油包水 (W/O) Pickering 乳液（10 或 20 wt% 水）的工艺稳定性，由 0.14 wt% 多酚晶体（姜黄素或槲皮素）分散在大豆油相中，加上 2.0通过测量表观粘度 (η)、水滴大小（通过光散射）和微观结构变化来评估存在于内部水相中的 wt% 乳清蛋白分离物 (WPI) 或 0.1–2.0 wt% 乳清蛋白微凝胶 (WPM) 颗粒（通过共聚焦激光扫描显微镜，CLSM）。稳定性作为温度（25–50 °C）的函数进行测量，使用 0.1 和 100 s-1 之间的剪切速率循环来突出 η 的剪切和时间相关滞后。所有乳液都显示出一定程度的剪切稀化，但那些在水相中未添加 WPI 或 WPM 颗粒的乳液在剪切速率增加时表现出聚结，这在较高温度下更为明显。分散相中含有 WPI 的乳液是稳定的，而那些含有 WPM 颗粒的乳液在剪切时表现出平均液滴尺寸 (D4,3) 的减小，这是由于连续油中液滴、多酚晶体和/或 WPM 颗粒的聚集体的破坏相，但没有液滴聚结。低剪切速率 (0.1 s-1) 粘度随着 WPM 颗粒浓度的增加而增加。这种增加，加上乳液的 CLSM，表明 WPM 颗粒不仅通过它们对水滴内表面的吸附来增加 W/O 乳液的稳定性，