Combined effects of controlled atmosphere and different postharvest treatment (salicylic acid, oxalic acid and putrescine) on bioactive compounds and quality of pomegranate cv. Hicaznar were investigated. Pomegranates were harvested at commercial harvest stage and transported immediately to postharvest physiology laboratory. Fruit were divided into four groups. 1 Control: Dipped into distilled water + 0.01% Tween-20 solution for 10 min. 2 Oxalic acid (OA): Dipped into 6 mM OA + Tween-20 solution for 10 min. 3 Salicylic acid (SA): Dipped into 2 mM SA + Tween-20 solution for 10 min. 4 Putrescine (PUT): Dipped into 2 mM PUT + Tween-20 solution for 10 min. After treatments, pomegranates were stored at 6 °C and 90 ± 5% relative humidity for 6 months in controlled atmosphere (5% O2 + 15% CO2). Weight loss, color, total soluble solids content, titretable acidity (TA), total phenolic content, vitamin C, antioxidant activity and sugar content (glucose and fructose) were determined at 0th, 2th, 4th and 6th month of cold storage. Generally, weight losses were minimized by treatments, especially PUT, compared to control. The level of ascorbic acid significantly tended to decrease throughout the storage in all treatments. Treated pomegranate exhibited higher titratable acidity, total phenolic contents and antioxidant activity compared to control samples. However, PUT was the best among all treatments. The results suggest that SA, OA and PUT have the potential to extend the storage life of pomegranate by delaying quality loss and maintaining some bioactive compound and antioxidant activity.
Keywords: Antioxidant activity; Ascorbic acid; Controlled atmosphere; Phenolic content; Punica granatum; Sugar.