Osmotic dehydration combined with hot air convective drying of Aloe vera (Aloe barbadensis Miller) gel

Aloe vera gel is widely used as a functional ingredient in food processing. This gel is very unstable due to its high water activity. Drying process can be used to obtain shelf stable products. Response surface methodology was used to assess the effects of solution concentration (30-60% w/w), solution temperature (30-50°C) and immersion time (4-6h) at atmospheric pressure and constant solution to sample ratio (10:1) on water loss (WL), solid gain (SG), weight reduction (WR), vitamin C content (VCC) and the total phenolic content (TPC) of Aloe vera gel. The optimized conditions of osmotic dehydration combined with hot air drying were 60% (w/w) solution concentration, 30.2°C solution temperature and 349 min immersion time. Under these conditions water loss, solid gain and weight reduction found to be 72.67 (g/100g), 5.33(g/100g) and 67.34 (g/100g), respectively. The vitamin C and TPC of the osmo-air dried gel were 12.70 mg/100g DM and 11.33 mg GAE/100g DM, respectively