Influence of homogenisation conditions and drying method on physicochemical properties of dehydrated emulsions containing different solid components

Dehydrated o/w emulsions containing sodium caseinate and lactose (sample 1), and gelatine, sucrose and maltodextrin (DE 10) (sample 2) were used to study the influence of homogenisation conditions – homogenisation pressure (15 and 70 MPa) and number of passes (1 and 2) – and the drying method – spray‐drying vs. freeze‐drying – on physicochemical parameters, including oil microencapsulation efficiency (ME), oil droplet size in reconstituted emulsions, water activity, glass transition temperature, powder bulk density and time for emulsion reconstitution in water. Results showed that small and uniform oil droplets attained with increased homogenisation pressure were not sufficient for high oil encapsulation. The permeability of the solid wall to the extraction solvent appeared to be the dominant factor, and this may increase with homogenisation pressure. With the exception of oil droplet size in sample 1 and ME in sample 2, the drying method exerted larger changes in the physicochemical parameters studied than the homogenisation pressure. For sample 2, significant changes in the ME were not observed between the freeze‐dried and spray‐dried samples, even though a great emulsion destabilisation was observed in the reconstituted emulsion of the latter.