Preparation and release mechanism of lavender oil microcapsules with different combinations of coating materials

The aim of the work was to control morphology and release of lavender oil (LO) microcapsules produced using spray drying through different combination of coating materials (gum acacia, sodium caseinate, gelatin, chitosan, beta-cyclodextrin and polyvinyl alcohol). In addition, the properties of LO microcapsules including encapsulating efficiency (EE), loading capacity, mean particle size and morphology were characterized. Results displayed that the ternary formulations showed higher EE than the pure and binary mixtures; meantime, employment of pure gum acacia indicated the worse encapsulation efficiency. Images from scanning electron microscopy (SEM) showed that morphology of microcapsules has better sphericity because of the presence of polyvinyl alcohol, which illustrated that polyvinyl alcohol might be contributed to surface modification of particles. Furthermore, the release mechanism was described as two stages: burst release and diffusion. And four release models were mainly used to reveal the release mechanism of microcapsules in diffusion process. In most cases, the release of LO microcapsules was dominant by Fickian diffusion except particles prepared from gum acacia-polyvinyl alcohol and gum acacia-sodium caseinate-polyvinyl alcohol.