Thermal postharvest treatments for improving pomegranate quality and shelf life

Sweet pomegranates (Punica granatum L. cv Mollar de Elche) were cold-stored for 90 days. Curing at 33 degrees C and 95% RH for 3 days before continuous storage at 2 or 5 degrees C and 95% RH was tested for reducing chilling injuries. Alternatively, cycles of intermittent warming (IW) of 1 day at 20 degrees C every 6 days at 2 or 5 degrees C were tested. Control fruits were conventionally stored at 2 or 5 degrees C and 95% RH, and a shelf life of 6 days at 15 degrees C and 75% RH was included in the trials. At the end of the storage and shelf life periods, IW fruits showed the highest anthocyanin concentrations and titratable acidity, and the best visual appearance. After shelf life, IW during 2 degrees C storage was the only treatment that resulted in fruit with flavor similar to that at harvest. Main losses were due to decay (Penicillium spp.) in treatments at 5 degrees C, with the least loss being in the IW2 degrees C treatment. Chilling injuries (pitting and husk scald) were strongly reduced by curing at 2 degrees C but only after cold storage. The lowest chilling injuries were found in the TW treatments. Severity of husk scald development was not directly related to low storage temperature. IW during 2 degrees C storage has proved to be the best treatment for minimizing chilling injuries and maintaining pomegranate fruit quality. (C) 2000 Elsevier Science B.V. All rights reserved.