Edible Coatings Based on Bacterial Nanocellulose and Its Functionalization Extend Postharvest Strawberry Conservation

Strawberry is a non-climacteric fruit with a short postharvest shelf life. Recently, edible coatings have attracted the attention of the food industry. Cellulose is the most abundant carbohydrate polymer on Earth, and is also a renewable natural material, biocompatible with food. This work aimed to evaluate the postharvest quality of strawberries coated with edible coatings based on hydroxypropylmethylcellulose (HPMC) and bacterial nanocellulose (BNC) and its functionalization, using vegetal extracts with reported antifungal activity. Five treatments were applied on postharvest strawberries: C (control, with no coating); Cel (HPMC:BNC in a 95:5 ratio); EPAC (cellulose + Persicaria acuminata extract); EO (cellulose + Pelargonium graveolens essential oil) and CBZ (cellulose + carbendazim). Weight, firmness, total soluble solids, titratable acidity, ripe index, respiration rate, ethylene production rate, and natural fungal incidence were measured. Furthermore, the C and Cel fruit surface was observed by SEM. Cel and EPAC treatments proved to be beneficial in maintaining the quality of the treated fruit during storage. Both coatings contributed to a lower weight loss and firmness. They also decreased the respiratory rate and the natural fungal incidence, delaying the senescence of the treated strawberries. These treatments can be alternatives to extend strawberry life postharvest.