Quality changes in pomegranates during ripening and cold storage

Abstract

The changes in the quality parameters of Spanish pomegranate fruit (cultivar Mollar) during ripening and during 7 weeks of cold storage at 5°C and 90–95% relative humidity were studied. The fruit and seed weights, as well as the surface colour increased with ripening. Total soluble solids (TSS), pH and titratable acidity (TA) did not show significant differences during the weeks studied (from the 26th to 32nd weeks after flowering), but the seeds' colour (“Lab” values) and juice colour (absorbance at 510 nm) showed an increase during this period with a maximum during the last 2 weeks. These results indicate that pomegranates should be harvested during the 31st to the 32nd after flowering, in order to get the best pigmentation without a decrease in other quality parameters. The anthocyanin profile changed during the different maturity stages, since the diglucoside derivatives were the prevailing pigments during the early ripening stages, whereas the monoglucoside derivatives were the main pigments in the latter stages. After cold storage of pomegranates harvested at two maturity stages, no differences in TSS, pH, TA and skin colour were observed. In addition, seeds' and juice colour did not decrease during storage. Hence, this study supports the theory that pomegranate is a nonclimacteric fruit and that pomegranates can be stored for at least 45 days without deterioration in the fruit quality.