Food Chemistry and Technology Department, Teagasc Food Research Centre, Moorepark, Fermoy, Co. Cork P61 C996, Ireland; Technische Universität Berlin, Department of Food Technology and Food Material Science, Königin-Luise-Str. 22, 14195 Berlin, Germany.
Technische Universität Berlin, Department of Food Technology and Food Material Science, Königin-Luise-Str. 22, 14195 Berlin, Germany.
Food Res Int. 2022 Oct;160:111674. doi: 10.1016/j.foodres.2022.111674. Epub 2022 Jul 14.
High shear rheometry was used to investigate the rheological behavior of high internal phase emulsions (HIPEs) stabilized by whey protein isolate (WPI). The physical stability of HIPEs was tested at extremely high shear rates generated by decreasing the gap height between parallel plates. Viscosity and yield stress, at narrow gaps, increased with protein concentration due to tighter packing of smaller droplets. Structural breakdown and recovery of HIPEs were affected by protein concentration and pH. The hysteresis behavior of HIPEs was either thixotropic or anti-thixotropic and was determined by protein concentration, whereas pH affected the magnitude of anti-thixotropy. At pH 3, emulsions showed greater stability against extreme shear and creaming due to higher deformability of oil droplets and increased interdroplet interaction compared to neutral pH. Challenging the physical integrity of concentrated emulsions under high shear is an effective way to characterize microstructural changes and stability of HIPEs in foods.
高剪切流变仪用于研究乳清蛋白分离物（WPI）稳定的高内相比乳液（HIPE）的流变行为。通过减小平行板之间的间隙高度来产生极高的剪切速率，从而测试 HIPE 的物理稳定性。在较窄的间隙下，由于较小液滴的紧密堆积，粘度和屈服应力随蛋白质浓度的增加而增加。HIPE 的结构破坏和恢复受蛋白质浓度和 pH 值的影响。HIPE 的滞后行为是触变或反触变，取决于蛋白质浓度，而 pH 值影响反触变的幅度。在 pH 值为 3 时，由于油滴的变形性更高以及与中性 pH 值相比，相间相互作用增加，乳液在极端剪切和乳状液分层下表现出更高的稳定性。在高剪切下挑战浓缩乳液的物理完整性是一种有效的方法，可以用于表征食品中 HIPE 的微观结构变化和稳定性。
