Multivariate Optimization for the Production of OSA-Starch Microcapsules Containing Clove and White Thyme Essential Oils: Antifungal Potential Against Penicillium digitatum

The objective of this study was to optimize the conditions for the production of microcapsules based on OSA-starch and clove (CEO) and white thyme (WTEO) essential oils (EOs) obtained by electrospraying. The antifungal activity against the fungus Penicillium digitatum was assessed using both the well diffusion method and volatile release action. The microcapsules were characterized by morphology, loading capacity (LC) presence of functional groups (FTIR), and thermal properties (TGA). Spherical microcapsules were formed in all treatments evaluated, with an average diameter ranging from 0.803 to 1.500 mu m. The morphology of the materials was not affected by the variation of the solution parameters (ethanol: 20% and 30%, OSA-starch: 40% and 50%, CEO and WTEO, and EO concentration: 0.2% and 0.4%). The LC ranged from 30.6% to 97.9%, and TGA and FTIR analyses for all treatments confirmed the interaction of EOs with OSA-starch. Microcapsules from OSA-starch with CEO showed greater efficiency in reducing the mycelial growth of P. digitatum through the release of volatiles. These results serve as a basis for future studies to evaluate the technological applicability of these capsules in a food matrix or packaging material for controlling the fungal growth of P. digitatum.