ISHS Acta Horticulturae 463: VIII International Symposium on Plant Bioregulation in Fruit Production
POLYAMINES EVOLUTION DURING POST-HARVEST OF ‘FORTUNE’ MANDARINS AT TWO DIFFERENT RIPENING STAGES |
| Authors: | D. Valero, M. Serrano, M.C. Martínez-Madrid, F. Riquelme |
| Abstract:
The evolution of free polyamines (putrescine, spermidine and spermine) was studied in the peel (flavedo plus albedo) of ‘Fortune’ mandarins at two ripening stages: stage 1 (unripe) and stage 2 (ripe) after harvesting and storage at 20°C for 72 hours. Also the acidity and total soluble solids were examined in the juice. Ratio between total soluble solids, expressed as °Brix, and acidity, expressed as g of citric acid per 100 g of fresh weight (F.W.), in recently harvested fruits was 4.48 for stage 1 and 5.96 for stage 2, indicating the different maturity stage for both fruits. No changes were found in soluble solids and acidity ratio during the three days of storage. However, we have found differences in the polyamine evolution of the peel between the two ripening stages. For the stage 1 fruits, putrescine levels decreased from 496.22 to 84.91 nmol g-1 F.W. during the first 24 hours after harvested, and then a slight increase was observed (176.47 nmol g-1 F.W.). For the stage 2 mandarins, initial putrescine levels (416.67 nmol g-1 F.W.) increased within 24 hours until 647.29 nmol g-1 F.W. and tended to decrease until the end of the experiment (513.64 nmol g-1 F.W.). Spermine levels in the stage 1 fruits were higher than those in the stage 2 fruits, and decreased during the storage at 20°C, while in stage 2 fruits spermine levels increased. Finally, spermidine levels remained unchanged for both ripening stages fruits and postharvest storage at 20°C. Results show that there are not modifications in the ripening stage of mandarins during the three days following to harvesting. However, important variations were found in peel polyamine evolution during this time, which were different depending on the ripening stage of mandarins. | |
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