THE FRUIT QUALITY BEHAVIOUR OF PEACH FRUIT CV. "SWELLING" DIPPING IN PUTRESCINE DURING COLD STORAGE

The present study entitled improvement in storability and quality of peach cv. Swelling with post-harvest application of putrescine at 0, 1, 2 or 3 mille Molar during 2018 and 2019. Following treatments, fruits were allowed to storage at 0 to 3.3°C and 85- 90 percentage (Relative humidity) for 28 days. Physico-chemical characteristics after 7, 14, 21 and 28 days of cold storage period were determined. The results showed that, the three putrescine treatments caused a significant decrease in fruit weight loss and the highest value of total soluble solids was obtained by (1 mM), in the first season, and obtained by (3 mM), in the second season. The three putrescine treatments maintained a significant increase in fruit firmness, acidity (%) and fruit vitamin C content compared to the control, except for the lowest concentration for acidity, in the second season only. The highest concentration caused a significant decrease in reducing sugars percentage compared to the control and the two lower concentrations of putrescine. The highest and lowest concentrations caused a significant decrease in fruit total sugars content compared to the control and the middle treatment, in the two experimental seasons. The two higher concentrations of putrescine caused a significant increase in fruit total phenols and decrease in both peroxidase and polyphenoloxidase activities compared to the control. During storage period, fruit weight loss, reducing sugars, total sugars and the two enzymes peroxidase and polyphenoloxidase activities content increased, while firmness, acidity, vitamin C and total phenols decreased by prolonging the storage period to 28 days.