Colletotrichum gloesporioides inhibition using chitosan-Ruta graveolens L essential oil coatings: Studies in vitro and in situ on Carica papaya fruit

• Published in: International journal of food microbiology 2020-08, Vol.326, p.108649-108649, Article 108649
• Main Authors: Peralta-Ruiz, Yeimmy, Grande Tovar, Carlos, Sinning-Mangonez, Angie, Bermont, Daniel, Pérez Cordero, Alexander, Paparella, Antonello, Chaves-López, Clemencia
• Format: Article
• Language: English
• Subjects: Acetic acid; Anthracnose; Antifungal activity; Antifungal agents; Carica papaya; Chitosan; Coatings; Conidia; Decay index; Edible coating; Emulsions; Essential oils; Fruits; Fungicides; Germination; Hyphae; Maturation fruit; Microbiota; Microscopic analysis; Molds; Morphological alterations; Morphology; Mycelia; Oils & fats; Organoleptic properties; Papayas; Physicochemical analysis; Postharvest pathogen; Reduction; Ripening; Ruta graveolens
• ISSN: 0168-1605; 1879-3460
• DOI: 10.1016/j.ijfoodmicro.2020.108649

In this study we assessed the efficacy of chitosan (CHI) (2%) emulsion added with Ruta graveolens L. essential oil (REO) at different concentrations (0.5%, 1.0% and 1.5%) to control C. gloesporioides grows both “in situ” and “in vitro” in papaya Maradol (Carica papaya L.). In vitro studies showed a decrease on fungal growth (mycelia diameter) with the increase of REO concentration, while 0.5% of REO induce a reduction of 56.42%, REO at 1.0% and 1.5% induced a reduction of 97%. Microscopic analysis showed irreversible deleterious morphological and ultrastructural alterations as well as changes in conidia morphology, and conidia germination inhibition up to 90%. Among the most abundant REO constituents, 2-Nonanol showed strong antifungal activity followed by 2-Undecanone, Benzyl acetate, 2-Nonanone, 2-Tridecanone and 2-Dodecanone. Studies “in situ” on papaya fruit during 12 days at 20 °C, showed a reduction of the C. gloesporioides lesion expansion by 50% using CHI-REO 0.5% emulsions and by 100% with treatments of CHI-REO 1.0 and 1.5%, in addition the emulsions were efficacious to reduce the fruit surface microbiota. On the other hand, physicochemical analysis of the papaya fruits demonstrated that CHI-REO emulsions treatment delayed papaya ripening without affecting the organoleptic characteristics. All these results demonstrated for the first time the application of coatings CHI-REO as a postharvest treatment for the control of anthracnose on papaya fruit. [Display omitted] •Chitosan-Ruta graveolens EO emulsions inhibit Colletotrichum gloeosporioides growth.•CHI-REO reduces Anthracnose severity and lesion expansion in papaya fruit.•Sublethal concentration of CHI-REO emulsions induced abnormalities in fungal mycelia.•The emulsions extend the shelf-life of papaya•The CHI-REO did not lead negative impact on sensorial attributes of papaya fruit.