Effects of hot water treatment on reducing chilling injury of pomegranate (Punica granatum) fruit during storage

In an initial experiment comparing hot water and chemical effects on chilling injury, 'Malas Yazdi' and 'Malas Saveh' pomegranates (Punica granatum) were dipped in hot water at 50 and 75 degrees C, imazalil (1 and 3 ml/L) and benzyladenine (80 and 100 mg/L) for 2 and 5 min. Distilled water at 25 degrees C was used as a control treatment. Treated fruit were stored at 1.5 degrees C and 85 +/- 3% RH for 4.5 months. Although water at 75 degrees C resulted in heat injury of fruit, hot water at 50 degrees C compared with the other treatments significantly reduced chilling injury. In a second experiment, 'Malas Yazdi' pomegranates were dipped in hot water at 25 (control), 35, 45, 55 and 65 degrees C for 2 and 5 min. Treated fruit were stored for 3 months under the same conditions as used in the first experiment. The results showed that increasing the water temperature to 45 degrees C significantly reduced chilling injury, electrolyte and K+ leakage but had no significant effect on total soluble solids, total acidity, ascorbic acid and pH of fruit after removal from storage.