OSMOTIC DEHYDRATION OF POMEGRANATE SEEDS (PUNICA GRANATUM L.): EFFECT OF FREEZING PRE-TREATMENT

摘要

The osmotic dehydration of pomegranate seeds was compared using freshnand frozen seeds. The process was carried out at 50C in a 55°Brix solution ofnsucrose. Freezing pomegranate seeds before osmotic dehydration involved annincrease of effective diffusivity and a reduction in dehydration time. The mostnsignificant changes of water loss (WL) (46 g/100 g of fresh seeds [FS]) andnsolids gain (SG) (7 g/100 g of FS) took place during the first 20 min for frozennseeds. After this period, seeds WL and SG ranged on average close to 43 andn8 g/100 g of FS, respectively. Osmotic dehydration was slower starting fromnfresh fruits but led to a higher rate of WL (62 g/100 g of FS) at the end of thenprocess. Both scanning electron microscopy and texture analysis showed andestruction of cell structure and seed texture during the pretreatment (freezing).nThe same techniques also revealed a texture/structure modificationninduced by the osmotic dehydration process.