Influence of packaging system and long term storage on physiological attributes, biochemical quality, volatile composition and antioxidant properties of pomegranate fruit

Commercially ripe pomegranate fruit were packed in ventilatedcarton with polyliner (referred to as passive modified atmosphere packaging, MAP), individual shrink wrap and open top carton (control) andstored under 7 ± 0.5 °C and 92 ± 2% RH for 4 months. Incidence of physiological disorders and changes in biochemical properties, phenolic compounds, total phenolics, total flavonoids, total tannins, total anthocyanins, antioxidant activity and vitamin C were analysed monthly. The results showed that fruit stored under polyliner and individual shrink wrapped significantly minimized weight loss compared to control. Significantly higher fruit decay incidence was observed after 3 months, irrespective of package type. TSS content, citric acid, and L-malic concentrations decreased considerably in all packaging systems with increasing storage time. Fructose and glucose concentrations fluctuated during storage with the lowest value observed at the end of storage infruit packed under polyliner and shrink wrapped packaging. Amongst phenolic compounds identified, catechin and rutin increased by 65.43% and 139.39%, respectively, in fruit packed inside polyliners and individual shrink wrap after 4 months of cold storage. Total phenolic and total tannin concentrations declined by 23.86 and 65.89% in fruit stored under polyliner and individual shrink wrap packaging after 3 months of storage, respectively. Furthermore, total anthocyanin concentration was significantly higher in fruit packed in MAP (103.59 g L⁻¹ of cyanidin-3-glucoside of pomegranate) than individual shrink wrap (84.78 g L⁻¹) after4 months of storage. Volatiles organic compounds including ethanol, alpha-pinene and beta-pine accumulation increased significantly with prolonged storage regardless of packaging material used.