Food Colloids and Processing Group, School of Food Science and Nutrition, University of Leeds, LS2 9JT, UK.
Soft Matter. 2016 Apr 21;12(15):3558-69. doi: 10.1039/c5sm02998h.
Emulsions stabilized by soft whey protein microgel particles have gained research interest due to their combined advantages of biocompatibility and a high degree of resistance to coalescence. We designed Pickering oil-in-water emulsions using whey protein microgels by a facile route of heat-set gel formation followed by mechanical shear and studied the influence of heat treatment on emulsions stabilized by these particles. The aim of this study was to compare the barrier properties of the microgel particles and heat-treated fused microgel particles at the oil-water interface in delaying the digestion of the emulsified lipids using an in vitro digestion model. A combination of transmission electron microscopy and surface coverage measurements revealed an increased coverage of heat-treated microgel particles at the interface. The heat-induced microgel particle aggregation and, therefore, a fused network at the oil-water interface were more beneficial to delay the rate of digestion in the presence of pure lipase and bile salts compared to intact whey protein microgel particles, as shown by the measurements of zeta potential and free fatty acid release, plus theoretical calculations. However, simulated gastric digestion with pepsin impacted significantly on such barrier effects, due to the proteolysis of the particle network at the interface irrespective of the heat treatment, as visualized using sodium dodecyl sulfate polyacryl amide gel electrophoresis measurements.
由于具有生物相容性和高度抗聚结的双重优势，由软乳清蛋白微凝胶颗粒稳定的乳液引起了研究兴趣。我们通过简便的热凝胶形成后机械剪切的方法使用乳清蛋白微凝胶设计了 Pickering 水包油乳液，并研究了热处理对这些颗粒稳定的乳液的影响。本研究的目的是比较微凝胶颗粒和热处理融合微凝胶颗粒在油-水界面处的阻隔性能，以延迟使用体外消化模型乳化脂质的消化。透射电子显微镜和表面覆盖测量的组合揭示了界面处热处理微凝胶颗粒覆盖度的增加。与完整的乳清蛋白微凝胶颗粒相比，热诱导的微凝胶颗粒聚集，因此在油-水界面处形成融合网络，更有利于在存在纯脂肪酶和胆汁盐的情况下延迟消化速率，这可以通过测量动电电位和游离脂肪酸释放以及理论计算来证明。然而，由于界面处的颗粒网络的蛋白水解作用，模拟胃消化用胃蛋白酶的消化显著影响了这种阻隔效果，这一点可以通过十二烷基硫酸钠聚丙烯酰胺凝胶电泳测量来可视化。
