Effect of controlled atmosphere storage on pomegranate quality investigated by two dimensional NMR correlation spectroscopy

Pomegranate fruit was studied by two dimensional NMR correlation spectroscopy during 25 weeks of controlled atmosphere (CA) storage. The proton T1-T2 correlation spectrum provided rich information on the characteristics of the environment of water in subcellular compartments. Three relaxation components were identified in the pomegranate arils, which could be assigned to the vacuole, cytoplasm, and cell wall. The results showed that water transferred out of the vacuole to other compartments during storage. Shrinkage of the vacuole was expected as a result of the significant loss of water. The soluble solids content and titratable acidity of the pomegranate decreased during the controlled atmosphere storage, but they were not the major contributor to the change in the relaxation rate of water in the subcellular compartments of the aril tissue. The change in the aril was gradual and not uniform across the tissue in response to CA storage. The variation in the response of the arils to CA diminished at longer storage time.