Delayed cooling (conditioning) was evaluated for effectiveness in avoiding chilling injuries of Maciel peaches harvested at two ripeness stages, mature-green or tree-ripe, and immediately thereafter placed in cold rooms at 0ºC (controls) or maintained for 2 days (tree-ripe) or 3 days (mature-green) at 20ºC before transfer to cold storage at 0ºC. After 7, 14, 21 or 28 days, samples were retrieved from storage and kept for 3 more days to complete ripening at 20ºC. Delayed cooling mature-green (DCMG) peaches had higher weight losses compared to control mature-green fruit at retrieval from storage and more reduced fresh weight losses after ripening. Peaches harvested at the tree-ripe stage did not differ significantly in weight loss. DCMG peaches were less firm than control mature-green peaches after retrieval from storage. Delayed cooling tree-ripe fruits (CTR) were firmer than controls. No woolliness symptoms were observed in any of the treatments. Flesh browning was determined in all conditioned peaches after 21 or 28 days at 0ºC. Leatheriness was observed in all the peaches transferred to air after 21 or 28 days at 0ºC. Conditioning of Maciel peaches is not an efficient postharvest procedure to avoid chilling injuries and, therefore, should not be recommended for this cultivar.
stone fruits; chilling injuries; ripeness stage
