Evaluation of chitosan coatings enriched with turmeric and green tea extracts on postharvest preservation of strawberries

Abstract

Strawberries are a widely consumed fruit that contains a variety of antioxidant metabolites. However, postharvest strawberries are highly perishable and susceptible to a variety of fungal pathogens. In this study, a chitosan-based coating containing turmeric (TU) and green tea (GT) extracts was developed and evaluated for the preservation of strawberries. Both TU and GT extracts contained high phenolic contents (>5.8 g kg−1 dry weight), but only TU extract showed strong antifungal activity. SEM observations revealed that high concentrations of extract (3–5% v/v) caused the formation of agglomerates within the films, reduced elongation at break and increased tensile strength. The postharvest treatment of strawberries with chitosan coating containing TU extract inhibited the proliferation of Botrytis cinerea during 7 d of storage at 20 °C, whereas the coating containing GT extract extended the antioxidant properties of postharvest strawberries from 4 to 8 d at 20 °C. Sensory analysis indicated that the coatings did not significantly affect flavor and taste. Overall, TU extract was used for the first time for food packaging purposes and proved to be a great complement to the antioxidant properties of GT to extend the shelf-life of postharvest strawberries.