Osmotic dehydration of aloe vera cubes and selection of suitable drying model

In the present study, the effect of pretreatments (i.e. osmotic dehydration in 30, 40 and 50ºBrix sugar solution at 30°C syrup temperature) and drying air temperature (50, 60, 70 and 80°C) on drying behaviour of aloe vera cubes were investigated. The aloe vera cubes were dried in a laboratory model tray dryer. Drying of aloe vera occurred in falling rate period. Five thin-layer drying models (Exponential, Page, Henderson and Pabis, Logarithmic and Power law) were fitted to the moisture ratio data. Among the drying models investigated, the Page model satisfactory described the drying behavior of aloe vera cubes. During convective dehydration, the average effective moisture diffusivity of un-osmosed and osmosed samples at drying air temperatures ranging from 50 to 80 ºC varied between 2.69 to 4.59 ×10^-09 m²/s between 2.93 to 7.99×10^-09 m²/s respectively.