Microencapsulation of extra virgin olive oil has been taken into consideration. Initially, emulsions were prepared using extra virgin olive oil and aqueous solutions of different proportions of maltodextrin (MD) having dextrose equivalent (DE) 19 and whey protein isolates (WPI), such as 100% MD, 100% WPI, 25% MD + 75% WPI, 50% MD + 50% WPI and 75% MD + 25% WPI. Subsequently, emulsions were used for dehydration by either spray-drying (SD) or freeze-drying (FD) to produce olive oil microcapsules. Emulsion stability, viscosity and droplet size influenced the characteristics of the microcapsules. The highest encapsulation efficiency was achieved using 50% MD + 50% WPI in the emulsions with subsequent SD. The moisture content of the microcapsules increased with increasing proportions of MD. The size of the microcapsules increased with increasing proportions of WPI. The bulk density and tapped density were reduced with higher proportions of MD in the microcapsules. Furthermore, microcapsules with a higher proportion of MD exhibited poor flowability and high cohesiveness. Microcapsules from the higher proportion MD emulsions, followed by SD were spherical with a smooth surface; however, microcapsules with dent structures were produced from 100% WPI in the emulsions with subsequent SD. Microcapsules, produced from emulsions with a higher proportion of WPI, followed by FD were flat flakes and had irregular surfaces.
Keywords: emulsion; freeze-drying; maltodextrin; microencapsulation of olive oil; spray-drying; whey protein isolate.