Low oxygen treatment prior to cold storage to maintain the quality of peaches

High value late season peach cultivars from the region of Aragon (NE, Spain) are appreciated for their delicate flavor, external uniform golden appearance, yellow pulp and chiefly to be free of chemicals as they are bagged from their last three months of growth until harvest. However, their shelf life under storage is very short due to several problems such as loss of firmness, appearance of chilling injuries, incidence of physiological alterations called vitrescent dark spot (VDS) or corky spot (CS) and fungal rots. The research team from Zaragoza has worked for years in the fight against calcium-related physiological disorders in apples by preharvest strategies of foliar calcium treatments. More recently, postharvest treatments with low oxygen at room temperature (LOT) have been successfully applied. However, no reports of these kinds of treatments have been previously reported in late season peaches. Therefore, immediately after harvest, 'Chato' peaches were stored for 2 days at 20 degrees C under low O-2 (1-2%) in Palliflex bags. Thereafter, fruits were cold-stored (0-2 degrees C) without bag for 40 days and changes were monitored in terms of fruit quality, chilling injuries, incidence of physiological alterations and respiration rates. After 40 days of cold storage, the firmness of treated fruits was the same as at the harvest day, about 41.9 N, meanwhile fruits untreated, decreased to 35.0 N. On the other hand, LOT treatment decreased both the incidence of VDS from 37.9 to 4.0% and chilling injury severity from 59.3 to 20.0%. Respiration rates were similar between treatments. Only statistical differences on ethanol production were found: higher in the treated fruits, probably due to the storage temperature the very first 2 days, although no odd flavors were found. In conclusion, the application of LOT treatments prior to cold storage may be a promising strategy to preserve fruit quality of late season peach cultivars and deserves further investigation.