Pomegranate (Punica granatum L.) Fruit Storability Improvement Using Pre-storage Chitosan Coating Technique

Abstract

Application of edible coatings to enhance storage life of fresh fruit has recently been under considerable attention. This experiment was conducted in order to explore the effect of chitosan coating and storage temperature on the postharvest life of pomegranate (Punica granatum L.) fruit. Therefore, pomegranate fruits ‘Rabbab-e-Neyriz’ were dipped in 0, 1 and 2% aqueous chitosan solutions, air dried and then stored at 2 and 5°C with 90% relative humidity for up to 135 days. The application of chitosan coating retarded the respiration rate and weight loss of the fruit regardless of temperature during storage period; however, the retention was higher at 2 than 5°C. After 135 days of storage, the highest (18.19%) and lowest (9.33%) weight losses were recorded in the control fruit stored at 5°C and 2% chitosan-treated fruit stored at 2°C, respectively. The results revealed that postharvest weight losses in pomegranate fruit mainly related to weight losses in the fruit peel and 4-8% reduction in peel weight percentage (of whole fruit) was recorded in the treated fruit. A slight decline in Soluble Solids Content (SSC) and Titratable Acidity (TA) was found during storage in all treatments, while pH and maturity index increased slowly. Scanning electron microscopy of the treated fruit demonstrated that chitosan covered whole pericarp surface and pores of the coated fruit, and revealed more shrivelling symptoms on the peel of the non-coated fruit during storage. Keywords: Maturity index, Postharvest storage, Scanning electron microscopy, Storage period, Weight loss.