Furthermore, the bulk physicochemical characteristics are also important for the formation and stability of the emulsion. For example, the density is decisive in the stability to sedimentation, the viscosity has influence in the droplets breakup and the mobility of droplets, and the oil polarity can affect the interfacial tension with the aqueous phase and the partitioning of the components at the interface. Besides, the chemical structure, such as fatty acids chain length, number of unsaturations, molecule configuration have also effect in the stability of the emulsion. Many studies use model systems with highly purified oils and with known chemical composition, but the behavior of those systems is different from the complex food-grade oils (McClements, 2005).
Thus, this study is aimed to evaluate the stability of W/O emulsions formulated with different types of oil and emulsifiers at two water:oil ratios. In order to understand the stability mechanisms, the interface of the systems was studied regarding the interfacial tension and the viscoelastic properties. Besides, the structure of the emulsions was analyzed microscopically through images and particle size distribution, and macroscopically, by the rheology of the emulsions