Antifungal potential of clove and white thyme essential oils encapsulated in electrosprayed starch-OSA against Penicillium digitatum

Estefania Júlia Dierings de Souza, Dianini Hüttner Kringel, Tatiane Jéssica Siebeneichler, César Valmor Rombaldi, Eliezer Avila Gandra, Alvaro Renato Guerra Dias, Elessandra da Rosa Zavareze

The objective of this study was to develop microcapsules based on starch modified by octenyl succinic anhydride (OSA) containing clove essential oil (CEO) and white thyme essential oil (WTEO) in different concentrations. Two key components can be highlighted: (1) starch, a polysaccharide from natural and renewable sources, and (2) essential oils, due to their bioactive potential. The microcapsules were produced by electrospraying and evaluated for morphology, particle size distribution, loading capacity, thermal properties, functional groups, and antifungal activity against Penicillium digitatum, evaluated by microatmosphere and agar diffusion. The microcapsules presented a spherical and uniform shape. The loading capacity of the microcapsules ranged from 69 to 83%, with the capsule with 4% CEO presenting the highest loading potential. The analysis of functional groups suggested a molecular interaction between the EOs and the wall material. Thermogravimetric properties demonstrated that starch-OSA was able to protect the volatile compounds of EOs and delay their thermal degradation, suggesting that starch-OSA was efficient as a wall material to encapsulate EOs. The starch-OSA microcapsules added with 4% CEO and 4% WTEO stood out for presenting the most extensive halos of inhibition of P. digitatum mycelial growth. The results demonstrate the potential application of microcapsules with both EOs as an antifungal agent against the fungus P. digitatum.

https://doi.org/10.1016/j.eurpolymj.2024.113192