Spray drying behaviour and functionality of emulsions with β-lactoglobulin/pectin interfacial complexes

Aim of the present study was to investigate the impact of atomization and drying on the functionality of emulsions with a bilayered oil-water interface consisting of a globular protein (beta-lactoglobulin, bLG) and anionic polysaccharides (pectins with varying degree of methoxylation). With regard to the atomization process, the emulsion spray droplet size generally decreased with increasing atomization energy. The spray droplet size distribution was narrower with rotary atomization compared to two-fluid nozzle atomization. The single droplet drying behaviour of the differently stabilized emulsions was similar as examined by acoustic levitation. With more than 95%, microencapsulation efficiency was high in all spray-dried particles. However, a shift in oil droplet size upon reconstitution indicated that oil droplet coalescence occurred within the process which was less pronounced in bilayer emulsions compared to the bLG-stabilised single layer emulsion. Data from interfacial viscoelasticity measurements showed distinct differences, which may explain oil droplet coalescence. The oxidative stability of encapsulated oil was influenced by both the physical state of the emulsions and the different constituents at the o/w-interface with bLG and low methoxylated pectin giving the best protection of the oil. (C) 2012 Elsevier Ltd. All rights reserved.