Different stability regimes of oil-in-water emulsions in the presence of bile salts

In this work, we study the stability of emulsified olive oil-in-water emulsions at different bile salt (BS) concentrations. The effect of the interfacial properties of the emulsion is analyzed by using different emulsifiers (Epikuron 145V and Pluronic F68). Emulsion characteristics (electrophoretic mobility, average droplet size) are measured under the different conditions, and the stability of these systems is characterized by monitoring backscattering, using a Turbiscan. Adsorption of BSs at the emulsion interface would explain the higher stability at low bile salt concentrations as well as the more negative electrophoretic mobility when comparing with the emulsion in the absence of BS. The stability of the emulsion decreases above a critical BS concentration, which is higher when the emulsifier is Pluronic, and is much higher than the critical micelle concentration of the BS. Depletion flocculation induced by BS micelles is the destabilizing mechanism proposed at high BS concentrations.