| Abstract
| - This work focuses on flow-induced coalescence in highly concentrated emulsions stabilized by bovineβ-lactoglobulin. In these systems, flow-induced coalescence results in separation of oil. The amount of oilseparated increases with the intensity of the flow treatment and reaches a plateau value above a certainintensity of the flow treatment. In this work, the flow treatment was chosen to be sufficiently intense toreach this plateau value. The oil separation increased roughly linearly with the volume fraction of emulsiondroplets, starting at a critical volume fraction of approximately 0.90. Furthermore, at constant volumefraction, the oil separation increased with the time lapse during which the emulsion had been at thisvolume fraction. It reached a maximum value, which did not depend on the electrolyte concentration butwas higher for calcium ions than for sodium ions. The rate at which the oil separation reached this maximumvalue increased with the electrolyte concentration. These observations are explained on the basis of apreviously developed mechanism of flow-induced coalescence, in which the sensitivity to flow-inducedcoalescence is related to a slip−stick transition between the surfaces of the thin films between emulsiondroplets, caused by shear connections. It is shown that the same mechanism of coalescence is also relevantat volume fractions below 0.5 for systems in which the emulsion droplets are aggregated.
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