Development and Evaluation of Chitosan-Based Food Coatings for Exotic Fruit Preservation.

Chitosan has gained agro-industrial interest due to its potential applications in food preservation. In this work, chitosan applications for exotic fruit coating, using feijoa as a case of study, were evaluated. For this, we synthetized and characterized chitosan from shrimp shells and tested its performance. Chemical formulations for coating preparation using chitosan were proposed and tested. Mechanical properties, porosity, permeability, and fungal and bactericidal characteristics were used to verify the potential application of the film in the protection of fruits. The results indicated that synthetized chitosan has comparable properties to commercial chitosan (deacetylation degree > 82%), and, for the case of feijoa, the chitosan coating achieved significant reduction of microorganisms and fungal growth (0 UFC/mL for sample 3). Further, membrane permeability allowed oxygen exchange suitable for fruit freshness and natural physiological weight loss, thus delaying oxidative degradation and prolonging shelf-life. Chitosan's characteristic of a permeable film proved to be a promising alternative for the protection and extension of the freshness of post-harvest exotic fruits.