Efeito de quitosana adicionado de óleos essenciais de orégano (Origanum vulgare) e tomilho (Thymus vulgaris) na inibição de Pectobacterium carotovorum subsp. carotovorum inoculado em tomate (Solanum lycopersicum)

Abstract

Despite technological advances in post-harvest conservation, biotic and abiotic factors still compromise the quality of fruits and vegetables, causing significant economic losses. Among the main agents involved is Pectobacterium carotovorum subsp. carotovorum (Pcc), a Gramnegative, facultatively anaerobic, and mesophilic phytopathogenic bacterium responsible for soft rot in various hosts, such as tomato, potato, carrot, and bell pepper, among others. In this context, there is growing interest in sustainable control alternatives, with special attention to edible coatings based on chitosan, a biopolymer obtained from the deacetylation of chitin with antimicrobial and antioxidant properties. These are often associated with essential oils rich in phenolic compounds, such as oregano (Origanum vulgare) and thyme (Thymus vulgaris). The present study evaluated the effect of chitosan-based edible coatings supplemented with essential oils on the inhibition of Pcc inoculated in tomatoes (Solanum lycopersicum) during 12 days of in natura storage. The experiment was conducted at the Federal University of Lavras (UFLA), using 216 'Gyottone' Italian variety fruits. These were subjected to three different treatments: T1-Control, T2-Chitosan, and T3-Chitosan + Essential Oils. Microbiological and physicochemical analyses were performed throughout the 12-day storage period. The obtained data were subjected to analysis of variance (ANOVA), and means were compared using Tukey's test (p < 0.05). The coatings significantly reduced pathogen activity compared to the control and preserved the measured quality attributes, notably showing less mass loss in the treated fruits. It is concluded that chitosan-based coatings, especially when combined with essential oils, exhibit a promising performance for extending the shelf life and mitigating post-harvest losses in tomatoes, with the potential for broader application in other fruits and vegetables.