Effect of pumping and atomisation on the stability of oil/water emulsions

Abstract

This work evaluated the effects of a peristaltic pump and a two-fluid pneumatic nozzle on the stability parameters of oil/water emulsions. Droplet size (DS), polydispersity index (PDI), Turbiscan® stability index (TSI), and wall material thicknesses were measured in emulsions with three different initial stabilities (most stable or ME, intermediate stable or IE, and less stable or LE) at different stages during their transport to the atomisation nozzle. Results indicated that pumping and atomisation gave place to more homogeneous emulsions in respect to the original one, having smaller sizes (0.98–1.29 μm), thicker shells (0.21–0.29 μm), and better stability as indicated by TSI (1.20–2.40), which kinetics were successfully fitted to a two-parameter kinetic model (R 2 = 0.99; RMSE <0.245). LE emulsion increased the most its stability because of its passage through the pump and nozzle due to greater instability differences in TSI. It was noted that, for all emulsions after their passage through the pump and nozzle, changes in stability were driven by coalescence. This study can contribute to determining operating conditions for encapsulating by spray drying. • Pumping and atomisation gave place to emulsions with smaller sizes, thicker shells, and improved stability. • Turbiscan stability index kinetics were well fitted to a two-parameter model. • The less stable emulsion increased the most its stability with pumping and atomisation. • Emulsion particles with higher stability had thicker shells.