Effect of gamma irradiation on storability of apples (Malus domestica L.)

The aim of this study was to investigate the effect of gamma irradiation on storability of the two main apple varieties, Golden Delicious and Starking, in Syria. The experiments were performed in 1995 and 1996. Fruits were irradiated with 0, 0.5, 1.0 and 1.5 KGy. Irradiated and unirradiated fruits were stored at 1 to 2 °C and under a relative humidity of 80 to 90%. Weight loss and spoilage due to physiological disorders and fungal diseases were evaluated throughout the different storage periods. Firmness, coloration and pH values were estimated immediately after irradiation. The results showed that, in both varieties, gamma irradiation increased the weight loss after 45 days of storage in apples gathered in 1995 but not in the 1996 season. After 180 days of storage, gamma irradiation had different effects on weight loss depending on the growing year and variety, and increased fungal spoilage. Application of gamma irradiation prevented the growth of Aspergillus niger and the formation of skin scald in Golden Delicious fruits. Immediately after treatment, gamma irradiation increased the softening of fruits, changed their color from green to yellow and decreased the pH value of the juice.