Development of Nanostructured Chitosan Coating with Coffee Peels Extract for Preservation of Tomato Quality and Control Pre and Postharvest Disease Caused by <em>Rhizopus stolonifer</em>

The antifungal efficacy of coffee residues extracts (CRE) and chitosan nanoparticles (CNP) alone and with coffee residue extracts (CNP-CRE) were assessed on growth of Rhizopus stolonifer. Two nanostructured edible coatings, one based on chitosan nanoparticles (CCNP) another on coffee residue extracts encapsulated in chitosan nanoparticles (CCNP-CRE), were elaborated, characterised and applied on inoculated Naples tomatoes to evaluate their fungicidal activity and the effect on fruit quality. The tests consisted of evaluating physicochemical variables in tomato previously sprayed with CCNP and CCNP-CRE for 30 days preharvest and 14 days at 10°C postharvest. A CNP with a spherical shape and particle size of 2.4 ± 0.24 nm with a Z potential of −1.62 mV was observed, while CNP-CRE showed irregular and spherical shapes of 3.9 ± 0.55 nm with a Z potential of −0.89 mV. The FTIR spectrum showed the integration of CRE into the CCNP-CRE. A synergistic effect between CNP and 1 % CRE was observed since the greatest inhibition of mycelial growth (43%) was obtained. In the preharvest trials, the CCNP and CCNP-CRE showed differences with respect to the control in the variables of colour, total carotenoids and ethylene. In the postharvest test, both coatings showed differences in colour and CO2 production. The severity of the infection decreased 33% in tomatoes with coatings.