Fabrication and immediate release characterization of UV responded oregano essential oil loaded microcapsules by chitosan-decorated titanium dioxide

In the present study, in order to establish a triggerable system of core-shell structure, oregano essential oil (OEO) loaded microcapsules by chitosan-decorated titanium dioxide (TiO2) were prepared and characterized to explore their immediate triggered release abilities by UV-mediated triggers. The surface modification of chitosan composite shells could improve encapsulation yield and loose bulk density. Microcapsules loaded TiO2 were more conducive to release after UV irradiation and the mechanism involved in the release process was followed a classical Fickian diffusion. The microcapsules had higher thermal stability compared to free OEO but UV irradiation reduced the thermal stability of microcapsules with TiO2. Furthermore, the analysis of FTIR and XPS showed that the damaged shell structures were observed, especially glycosidic bonds, and were advantageous to the overflow of OEO. Therefore, loading TiO2 in core-shell system was a promising strategy for controlling the release by UV irradiation according to the needs.