An-Najah Staff

We explored the potential of packed bed premix emulsification for homogenizing coarse food grade W/O/W emulsions, prepared with sunflower oil. Using packed beds with different glass bead sizes (30–90 μm) at different applied pressures (200–600 kPa), emulsions with reasonably uniform droplet size (span ~ 0.75) were produced successfully at high fluxes (100–800 m³ m^− 2 h^− 1). Sodium chloride was used as a release marker: after five homogenization cycles, the produced emulsions were found to retain almost all of their initial content (99%). As was previously found for single emulsions, the packed bed system proved to be effective in breaking up the W/O/W emulsion droplets, with droplet to pore size ratios as low as 0.3. Results were analysed through the pore Reynolds number, Re_p, which characterizes the flow inside the packed bed, and were related back to the droplet break-up mechanisms occurring. At high Re_p, droplet break-up was expected to be governed by shear forces while at low Re_p, there is a shift from shear based to spontaneous droplet break-up.