Reduction of Chilling Injury and Peroxide Hydrogen Accumulation in Thompson Grape (Vitis vinifera L.) Fruit by Proline and Ascorbic Acid During Storage

This experiment was carried out to determine the effects of proline and ascorbic acid on chilling injury, electrolyte leakage, lipid peroxidation, peroxide hydrogen and antioxidant enzymes activity of Thompson grape (Vitis vinifera L.) fruit. Grape fruits were treated by 0 (control), 250 and 500 µM proline and 0 (control), 2 and 4% ascorbic acid and their combinations, then stored at 1°C and 90-95 % relative humidity for 28 days. Grapes treated with 500 µM proline and its combination with 2 and 4% ascorbic acid had the lowest amount of lipid peroxidation and peroxide hydrogen and lower chilling injury and electrolyte leakage than non-treated fruits. Moreover, grapes treated with 500 µM proline and its combination with 2 and 4% ascorbic acid significantly increased ascorbate peroxidase, superoxide dismutase, catalase and peroxidase enzyme activity. The present study can be regarded as the first evidence that proline and ascorbic acid enhance grape fruit tolerance to cold stress and therefore fruit quality.