EFFECT OF PRE-STORAGE APPLICATION OF SPERMIDINE, CALCIUM CHLORIDE AND HOT WATER ON CHILLING INJURY OF COLD STORED POMEGRANATE

Pomegranate (Punica granatum L. ‘Malas Yazdi’) fruit are very susceptible to chilling injury during cold storage. A series of experiments were conducted to test the effect of polyamine, calcium and hot water on chilling injury of pomegranate. Fruit were dipped in 2 and 4% calcium chloride solution alone or in combination with 1 and 2 mM spermidine and/or hot water (45°C) for 4 min. The treated fruit were air-dried at 24±1°C and stored at 2°C with 85±5% RH for 4.5 months. The results showed that all treatments had ameliorative effect on chilling injury and keeping quality after shelf life. Moreover, 2% calcium chloride in combination with 2 mM spermidine significantly reduced chilling injury, browning, water loss, electrolyte and K+ leakage. Fruit dipped in cold and hot water had the highest TSS (16.63 and 16.46%, respectively) and the lowest total antioxidant activity (15.3 and 20.3%, respectively). Fruit treated with 2% calcium chloride in combination with 1 or 2 mM spermidine had the highest titratable acidity (1.71 and 1.67%, respectively). The results reported herein, showed that the effect of chemicals on chilling injury was more pronounced than that of heat treatment.