Osmo-convective dehydration of plum (Prunus salicina L)

Plums, which have a high water content level, are highly perishable and it is necessary to find alternatives to minimize product deterioration. Osmotic dehydration is one of these effective alternatives. Besides water removal from the product, the process also promotes solid gain due to high concentration of solute. In this study, the effect of different osmotic agents (sugar and sugar-glycerol) was reported. The Magee model could satisfactorily describe the solid gain and water loss during osmosis. Drying was conducted at 45, 55 and 65°C. Osmotic dehydration followed by air drying reduces the drying period. Osmotic dehydration resulted in a decrease in total convective dehydration time. The osmotic dehydration in sugar and sugar-glycerol solution reduced approximately 240 and 120 minutes as compared to the osmo-convective dehydration time of lye-treated plums at 65°C. The drying rate curves contained no constant rate period and showed a linear falling rate throughout the drying process.