The effects of composite coatings containing chitosan and Mentha (piperita L. or x villosa Huds) essential oil on postharvest mold occurrence and quality of table grape cv. Isabella

• Coatings comprising chitosan and Mentha spp. essential oil inhibited mold occurrence.
• Test coatings delayed the appearance of postharvest mold infection in table grapes.
• Test coatings did not negatively affect the quality of table grapes.

The effects of coatings containing shrimp chitosan and the essential oil from Mentha piperita L. (MPEO) or M. villosa Huds (MVEO) to control common mold infections in table grape cv. Isabella (Vitis labrusca L.) that were caused by Aspergillus niger, Botrytis cinerea, Penicillium expansum and Rhizopus stolonifer were evaluated. The effects of the coatings on physicochemical and sensory characteristics of the grapes were also assessed. The coatings containing chitosan (4, 8 mg/mL) and MPEO or MVEO (1.25, 2.5, 5 μL/mL) delayed the mold growth and reduced the incidence of infections caused by all test fungi in grapes during storage at room and low temperatures. The coatings (chitosan 4 mg/mL; MPEO or MVEO 1.25, 2.5 μL/mL) did not negatively affect the physicochemical and sensory characteristics of grapes. From these results, coatings containing chitosan and MPEO or MVEO are potential postharvest treatments to control common mold infections in table grape cv. Isabella.Industrial relevanceIn table grapes, the reduction of losses resulting from fungal rot is a major goal of postharvest technology, which seeks to use effective methods to control the contamination and the growth of phytopathogenic fungi. However, the negative consumer perception of synthetic fungicides used for many years to solve the problem of mold infections in table grapes and the development of fungicide-resistant strains have impelled researchers to study the efficacy of natural compounds against postharvest pathogenic fungi. In this context, edible coatings composed of chitosan and essential oils have been considered as an environmentally friendly and added-value technology to control fungal postharvest decay in table grapes because of their biodegradability and lack of phytotoxicity. In this study, the authors evaluated composite coatings that contained shrimp chitosan and reduced amounts of Mentha (piperita L. or x vilosa Huds) essential oil as postharvest treatment to control the occurrence of mold infections caused by fungi in table grape cv. Isabella (Vitis labrusca L.), and their effects on the quality attributes of this fruit during storage. The tested composite coatings are presented as possible alternative technologies to control fungal infections and related post-harvest losses in table grape cv. Isabella.