OSMOTIC DEHYDRATION IN APPLE - INFLUENCE OF VARIETY, LOCATION AND TREATMENT ON MASS-TRANSFER AND QUALITY OF DRIED RINGS

Golden Delicious and Red Gold varieties grown at three different agroc limatic locations, with or without pretreatments were evaluated for ma ss transfer behaviour upto 4.5 h of osmotic dip and the effect of the dip on the quality of osmo-vac dried rings was compared with conventio nally dried rings. Data for mass reduction (MR), water loss (WL) and s olid gain (SG) during osmotic dip and for chemical constituents and ov erall acceptability of dried rings were recorded, which differed signi ficantly. Apple rings made out of wet temperate and high hills (L-2) l ocation exhibited higher MR and WL. In general, Golden Delicious varie ty, irrespective of any location, yielded good quality osmo-vac dried rings. However, the rings from high hills and cold desert (L-3) locati on were the most acceptable, owing to crunchy texture, good taste/flav our with higher ascorbic acid retention and less browning. Treatment o f prepared rings with potassium metabisulphite/ascorbic acid proved es sential in checking oxidation during handling and drying, whereas blan ching resulted in undesirable penetration of sugars into the rings.