Title : Studies on Osmotic Dehydration and Air-Drying Characteristics of Aloe Vera (Aloe Barbadensis) Gel

In this study the effect osmotic dehydration followed by drying on the physicochemical properties of aloe vera (Aloe barbadensis) gel was evaluated. The aloe vera gel cubes were osmotically dehydrated in sucrose of concentration 40-60B at room temperature and at 40C. The osmotically dehydrated aloe vera gel cubes were then air dried and the quality characteristics of the dried gel cubes were studied. The osmotic dehydration kinetics revealed that the logarithmic model represented the mass transfer kinetics of the aloe vera gel cubes both. It was also observed that the increase in sucrose concentration and osmosis temperature increased the solid gain and water loss ratio in aloe vera gel cubes. The air-drying characteristics of the aloe gel cubes revealed that the osmosis time increased the drying rate irrespective of the sucrose concentration and osmosis temperature. Further, the osmosis time, temperature and solute concentration reduced the water activity of the aloe vera gel cubes after air drying. However, the rehydration ratio of osmo-air dried sample decreased significantly with the increase in sucrose concentration, time and temperature.