Characterization of edible coatings formulated with chitosan and Mentha essential oils and their use to preserve papaya (Carica papaya L.)

Abstract This study evaluated physicochemical and roughness surface characteristics of edible coatings formulated with chitosan (Chi, 5 g/L) and Mentha x villosa Huds (MVEO, 0.6 and 1.2 mL/L) or M. piperita L. essential oil (MPEO, 0.6 and 1.2 mL/L) and measured the effects of these coatings on quality parameters of papaya during cold storage. MVEO and MPEO affected positively coating thermal stability. Chi + MVEO or MPEO coatings had homogeneous surfaces. Papaya coated with Chi + MVEO or MPEO had decreased firmness, weight loss, total soluble solids and enzymatic activity, as well as delayed evolution of pulp and peel colour during storage when compared to uncoated papaya. Formulated coatings did not affect papaya sensory acceptability. These results indicate occurrence of interactions and molecular compatibility among Chi and MVEO or MPEO to form coatings. Application of Chi + MVEO or MPEO coatings caused delayed maturation without negative effects on papaya postharvest quality. Industrial relevance Papaya is a fruit with important market value and good acceptance by consumers, but with short shelf life due to a fast maturation process and susceptibility to phytopathogenic fungi, being necessary the use of effective strategies to preserve this fruit. Edible coatings formulated with antifungal additive or synergistic mixtures of Chi and MVEO or MPEO had satisfactory thermal stability, homogeneous surfaces and ability to form physical barriers on papaya, causing maintenance or improvements of physical, physicochemical and sensory characteristics of papaya during cold storage. Formulated edible coatings could be innovative strategies to preserve papaya with functionalities related to the control of fungal rot and parameters indicative of postharvest quality and more prolonged fruit storability.