monitoring the thin layer drying kinetics of rhubarb during ultrasound-osmotic dehydration process

in this research, the effect of ultrasound-osmotic dehydration process in different conditions on the drying kinetics parameters of rhubarb was investigated. before dying process, rhubarb samples were placed in contact of ultrasound-osmotic pretreatment and then dried by convection hot air dryer equipped with circulated fan. the results showed that using osmotic pretreatment at 40% sucrose solution along with 30 min sonication could the drying rate to reach maximum. after optimization and determination the best pretreatment for final drying, drying behavior of rhubarb in optimal conditions by ten empirical models such as parabolic, midli-kucuk, silva et alii, peleg and suchlike was fitted. the modelling results showed that, midli-kucuk model due to the highest r2 and the lowest χ2 and rmse were selected as goodness model to predict drying curve of rhubarb. the values of these parameters were estimated equal to 0.9957, 0.0032 and 0.0256, respectively.