The microstructure and component distribution in spray-dried emulsion particles

Publication date: Available online 17 May 2016 Source:Food Structure Author(s): Marta Munoz-Ibanez, Marine Nuzzo, Christelle Turchiuli, Björn Bergenståhl, Elisabeth Dumoulin, Anna Millqvist-Fureby Microencapsulation by spray drying of oil-in-water (o/w) emulsions provides a means to encapsulate functional lipophilic ingredients. The active ingredient is dispersed in continuous solid phase providing protection. However, the encapsulation efficiency depends on the microstructure and morphology of the dry particles influenced by several mechanisms occurring during processing such as oil droplet breakup during atomization, ingredient diffusivity, interfacial adsorption of surface active ingredients, and drying kinetics. In this work, sunflower oil (model for lipophilic compounds) was encapsulated in solid particles composed of acacia gum and maltodextrin DE12. Three powders with different initial emulsion size (e.g. about 0.1 and 1μm) and atomized under high and low shear rate were analyzed for the morphology and distribution of oil droplets and matrix constituents within the solid particle (20 to 100μm). The microscopic (optical, SEM,LVSEM, confocal Raman), spectroscopic (XPS) and analytical (solvent extraction) techniques used were either qualitative or quantitative. Their combination made it possible to determine both the composition at the surface and inside the particle. The surface differs from the bulk in composition, confirming the constituent segregat...

Source: Food Structure - May 18, 2016 Category: Food Science Source Type: research