Controlled atmosphere storage of pomegranate

Pomegranates cv. Mollar were stored for up to 8 weeks at 5 °C and above 95% relative humidity (RH) in air and in controlled atmospheres of 10% O₂ and 5% CO₂, 5% O₂ and 5% CO₂, 5% O₂ and 0% CO₂ and 5% O₂ and 0% CO₂ ethylene-free. Storage was followed by a shelf-life period of 6 days at 20 °C in air. Respiratory activity slightly declined during storage at 20 °C, from 12 to 8 ml CO₂ · kg^–1 · h^–1 and was around 4 ml CO₂ · kg^–1 · h^–1 at 5 °C showing a non-climacteric pattern. When compared with color at harvest, an increase in thea ^* value in the juice from pomegranates stored in 10% O₂ and 5% CO₂ was observed. This supports that view that juice red colour can increase in intensity during storage. Controlled atmosphere storage reduced weight loss, the risk of decay and the severity of husk scald (except at 10% O₂ and 5% CO₂). The relatively low control of husk scald at 5% O₂ disagrees with the level proposed previously for Wonderful cv.; Mollar cv. seems to be more sensitive to scald than other varieties. No symptoms of black spots or membranose and no off-flavours were detected at any time. However after a period of shelf-life storage, the controlled atmosphere caused a slight reduction (lower than in air-stored fruit) in titratable acidity, reducing sugars and vitamin C and an increase of the soluble solids content/titratable acidity (maturity index) without differences among the various gas compositions studied. The maturity index must be considered to be a good criterion of pomegranate maturity for sweet varieties.