Osmo-air drying of aloe vera gel cubes

Aloe vera (Aloe barbadensis Miller) cubes of 12.5 × 12.5 × 12.5 mm thick were osmosed for 4 h in sugar syrup of 30, 40 and 50°Brix concentration and temperatures of 30 and 50°C at constant syrup to fruit ratio of 5:1. Osmosed and unosmosed aloe vera samples were hot air dried at 50, 60, 70 and 80°C with constant air velocity of 1.5 m/s. The water loss, solid gain and convective drying behaviour were recorded during experiments. It was observed that water loss and solid gain ranged from 39.2 to 71.3 and 2.7 to 6.3%, respectively during osmo-drying. The moisture diffusivity varied from 2.9 to 8.0 × 10−9 m²/s and 2.7 to 4.6 × 10−9 m²/s during air drying of osmosed and unosmosed aloe vera samples, respectively. Drying air temperature and osmosis as pre-treatment affected the water loss, solid gain, diffusivity at −p ≤ 0.0

Osmotic dehydration of peas .1. Influence of process variables on mass transfer

WOS: A1996UR98200001Osmotic dehydration of uniformly sized peas at 30C was studied using different solutions of sucrose, sodium citrate and sucrose+citrate mixture. The influence of various factors such as solution concentration and composition and the effect of agitation on the mass transfer mechanism was investigated. It was shown that the rate of water loss in the sample was increased by increasing concentration of osmosis solution and agitation. The most effective osmotic dehydration was obtained in sucrose+citrate mixed solutions of 60% total solids level for which a dehydration model was proposed. The apparent diffusion coefficient of water D-a was determined using the dehydration model. The values of D-a were found to be in the range 9.10 x 10(-11) - 7.63 x 10(-10) m(2)/s