Improvement of the Quality and the Shelf Life of Figs (Ficus carica) Using an Alginate–Chitosan Edible Film

Abstract

The consumption of fresh figs (Ficus carica) has long been associated with longevity and health benefits. However, fresh figs are highly perishable. An alternative to extend the shelf life of this fruit might be the application of an edible film. Thus, in this study, fig fruits collected at two maturity stages (referred as stages III and IV) were coated with an alginate–chitosan bilayer edible (A–Ch BE) film and the main physiological and quality attributes were evaluated during storage at low temperature (6 °C) at 0, 3, 6, 9, 12, and 15 days of storage. Ethylene and CO2 productions were considered as physiological parameters, while firmness, color changes, weight loss, and visual infection were the quality attributes evaluated. The application of the film reduced CO2 production and increased ethylene emission, regardless of the maturity stage of the figs. Firmness for uncoated figs underwent a significant decrease during storage, exhibiting values lower than 1.0 N. On the contrary, for coated figs, firmness was not only maintained but also even increased up to 3 N, for figs of stage III, and up to 2.5 N for the more mature figs (stage IV). Furthermore, coated figs exhibited better external color retention (ΔE < 2), lower weight loss (∼8 %), and also lower visual fungal contamination (<5 %) than uncoated fruits during the 15 days of storage at 6 °C, regardless the maturity stage. Therefore, the results indicate that application of an A–Ch BE film not only can improve the overall quality of figs (F. carica var. Mission) stored at 6 °C but is also able to extend their shelf life.