Effects of biopolymer-based active coatings on postharvest quality of okra pods in Tunisia

Introduction - Fresh okra represents an important source of nutrients for people in Tunisia. However, being climacteric, this crop fruit has a brief shelf life. The objective of this study was to assess the ability of sodium alginate (NaAlg)-based coatings incorporating bergamot or bitter orange essential oils (EO) to enhance the fruit quality and shelf life of okra (Abelmoschus esculentus) pods and retard fungal contamination caused by Cladosporium oxysporum. Materials and methods - The effects of the different treatments on physical characteristics of okra pods var. Marsaouia were measured over 12 days of cold storage in terms of weight loss, firmness and respiration rate of the fruit, while their efficacy in lowering fungal contamination was assessed over 8 days of storage at 25 degrees C. Likewise, sensory analysis was carried out to investigate the effect of the developed coatings on sensory attributes of fresh okra pods. Results and discussion - The applied coatings were able to lower respiration of okra pods and decrease weight and firmness losses by more than 36% and 18%, respectively, at the end of the storage period. The inclusion of citrus essential oil into NaAlg-based coating preserved the sensory attributes of okra pods, delayed the disease onset date and reduced by two-third the number of decayed pods compared with uncoated samples and those treated with neat NaAlg. Conclusion -NaAlg coatings amended with citrus oils show promising efficacy as substitutes to synthetic fungicides in the postharvest management of okra pods produced in Tunisia.