Abstract The role of salt in oil-in-water emulsion is not widely studied, but relevant to food processing, formulation and sensory properties. The interaction between the emulsifier and salt could impart an important effect on the emulsion stability and rheology. This present study aimed to determine the interfacial rheology of oil-in-water emulsions that were stabilized by different salts and affected by the different emulsifiers that promote the interfacial layer. In addition, this study intended to investigate whether the droplet size and zeta potential functioned as contributing parameters. Two salts (sodium chloride-NaCl and calcium chloride-CaCl2) and three emulsifiers (lecithin, mono-diglycerides, sodium steoryl-2-lactylate) were chosen to select appropriate combinations for oil-in-water emulsions. The relationship between the interfacial properties and the O/W emulsion stability in the presence of salt was assessed by both optical microscopy and visual observation of phase separation throughout the storage. As a result, it was found that the interfacial storage (Gi’) and loss modulus (Gi’’) values were dependent on the frequency. This result suggested that the oil/water interfaces support the conformational reconstruction of emulsifier changes to take advantage of improved hydrophobicity which results from the frequency dependence of the surface modules. The stability of emulsions prepared with the presence of CaCl2 was found to be higher than the emulsions prepared with NaCl which can be attributed to the counter ions effects of the CaCl2. The steady, dynamic and interfacial rheological measurements were consistent with ζ-potential, creaming and morphological observations. The results of this study also demonstrated that the interfacial rheology data might be predictive of emulsion stability and CaCl2 salt will increase the stability of the product with the different emulsifiers in the food formulations.

中文翻译：

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盐对油/水界面O/W乳液形态、乳化和界面流变特性之间相互关系的影响

摘要 盐在水包油乳液中的作用尚未得到广泛研究，但与食品加工、配方和感官特性有关。乳化剂和盐之间的相互作用会对乳液稳定性和流变学产生重要影响。本研究旨在确定由不同盐类稳定并受促进界面层的不同乳化剂影响的水包油乳液的界面流变学。此外，本研究旨在调查液滴尺寸和 zeta 电位是否作为贡献参数起作用。选择了两种盐（氯化钠-NaCl 和氯化钙-CaCl2）和三种乳化剂（卵磷脂、单甘油二酯、硬脂酰-2-乳酸钠）来选择合适的水包油乳液组合。在存在盐的情况下，界面性质与 O/W 乳液稳定性之间的关系通过光学显微镜和整个储存过程中相分离的目视观察来评估。结果，发现界面储能 (Gi') 和损耗模量 (Gi'') 值取决于频率。该结果表明油/水界面支持乳化剂变化的构象重建，以利用由表面模块的频率依赖性引起的改进的疏水性。发现存在 CaCl 2 制备的乳液的稳定性高于使用 NaCl 制备的乳液，这可归因于 CaCl 2 的反离子效应。稳态、动态和界面流变测量与 ζ-电位一致，乳状液和形态观察。这项研究的结果还表明，界面流变学数据可能可以预测乳液稳定性，而 CaCl2 盐会增加食品配方中不同乳化剂的产品稳定性。