Effects of heat treatment and calcium on postharvest storage of atemoya fruits

The aim of the present study was to investigate the effect of postharvest warm dipping with calcium chloride (CaCl2) on atemoya fruit (Annona cherimola Mill x Annona squamosa L.) storage. Fruits were immersed in 6% CaCl2 solution at 20 and 40°C for 20 min followed by storage at room temperature. The effectiveness of the treatment was assessed in terms of its impact on peel and fl esh appearance, weight loss, total soluble solids (TSS), total titratable acidity (TTA), pH, ascorbic acid content, total phenolics, and enzyme activities of polyphenoloxidase (PPO) and peroxidase (POD). Treatment at 40°C preserved eatable conditions up to 6 days, although calcium affected the appearance of the peel as soon as 4 days. Flesh browning was detected only on the 8th day in untreated fruits, after an increase in PPO and POD activities and total phenolics, and a decrease in ascorbic acid content. The weight loss was continuous throughout the storage period, with no signifi cant difference between treatments. TTA and TSS contents increased and pH decreased during the experiment. Results suggest that CaCl2 dipping had a positive effect on fl esh browning, which was reduced, while heat treatment showed a synergic effect, which could be related broadly with a fall in PPO activity. The variations in ascorbic acid content during storage suggest that the warm dipping combined with CaCl2, contributed to the antioxidant capacity of the fruit