Mono and double-layer emulsions of chia oil produced with ultrasound mediation

The principle of layer by layer was used to produce mono and double-layer emulsions of encapsulated chia oil, stabilized by whey protein concentrate (WPC) and by WPC and pectin respectively. Sonication time varied from 2 to 15 min, power amplitudes were of 50%, 75% and 100% (60, 90 and 128 W for monolayer and 63, 95 and 132 W for double-layer emulsions) and the values for energy density (Ev) were later calculated. Emulsions were characterized according to kinetic stability, zeta potential, mean droplet diameter, microstructure and rheological behavior. Emulsions stable to phase separation had a droplet size smaller than 3.69 μm. Higher Ev did not necessarily improve emulsion's stability, since over-processing was observed when an Ev higher than 332 MJ/m3 was applied to WPC-stabilized emulsions. The process conditions for both mono and double-layer emulsions were set using 2-min at 100% and 75% of power amplitude (Ev: 58.7 MJ/m3 and 42.7 MJ/m3) respectively.