Efficacy of extracts of mango residues loaded in chitosan nanoparticles and their nanocoatings on in vitro and in vivo postharvest fungal

The antifungal efficacy of ethanolic extracts of peels and seeds of mango (cvs. Ataulfo, Manila, Kent and Creole) at concentrations of 2.5, 5, 7.5 and 10% w/v were assessed. Nanostructured coatings based on chitosan nanoparticles (CNPs), chitosan-peel extracts nanoparticles (CPNP) and chitosan-seed extracts nanoparticles (CSNP) were evaluated in the four mango cultivars. The volatile composition of the extract was measured by GC/ME. For the nanoparticles (NP), dynamic light scattering (DLS), Zeta potential and Fourier-transform infrared spectroscopy (FTIR) of CNP, CPNP and CSNP, and the in vitro and in situ effects of the nanocoatings on various postharvest phytopathogens were also tested. Of the 42 volatile found, 11 exhibited antimicrobial activity. Among these, alpha-pinene was present in all cvs and Creole. The average NP sizes were 5 +/- 2.76 nm for CNP, 4.123 +/- 1.23 nm for CPNP and 3.11 +/- 1.06 nm for CSNP with Zeta potentials of -1.94 mV, -2.26 mV and - 4.53 mV respectively. The peel extracts were more efficient at reducing mycelial growth. The most sensitive fungi were Colletotrichum asianum and Talaromyces variabilis. The CPNP completely inhibited the in vitro growth of C. asianum, Fusarium solani, Lasiodiplodia theobromae, Neofusicoccum oculatum, Pestalotiopsis mangiferae and T. variabilis. The lowest disease incidence was 20% for the cv. Manila with the nanocoating of CSNP, while in cv Kent, an infection reduction of 50% was achieved with the nanocoating of CPNP. Lower disease severity was with both nanocoatings in cv. Kent. The use of Nanocoatings from mango residues could be an excellent option as a natural antifungal agent.