Osmo-convective dehydration of perlette variety of grapes

The fruits of Perlette variety of grapes having total soluble solids more than 17°Brix were treated with different chemicals and then fumigated with sulphur. These treated grapes were then dried convectively and also osmo-convectively and were stored at room temperature in pet jars and high-density polyethylene (HDPE) bags of 300 gauges. The osmotic dehydration was done by dipping the treated grapes in sucrose syrup of 50° Brix. It was found that the raisins produced from grapes with treatment, 0.3% NaOH+0.4% olive oil for 2–3 seconds at 85° C, followed by sulphur fumigation @ 2.0g sulphur per Kg. of grapes for 105 minutes and osmo-convective dehydration at 50°C, were of good quality and had shelf life of more than one year at room temperature storage.