Modelling of drying and rehydration of carrots using Peleg’s model

Abstract

The drying and rehydration process of conventionally and organically cultivated carrots was studied and the resulting data were fitted to the Peleg’s model. Carrots were fluid-bed and halogen dried and after that soaked in water at room temperature. The Peleg’s model gave a good prediction of water removal and water uptake in all experiments (R>0,994). During the drying process the Peleg’s rate constant (K 1) was affected by temperature. K 1 values decreased with the increase of the drying temperature. This relation was linear for fluid-bed drying and exponential for halogen drying, which implied a higher impact of the drying temperature on the dehydration kinetics during halogen drying. The lower K 1 values for fluid-bed drying suggested higher initial drying rates in comparison with halogen drying at all drying temperatures. The temperature dependence of 1/K 1 followed an Arrhenius-type relationship. Both Peleg’s rehydration constants (K 1 and K 2) increased with the increase of the drying temperature. This implied regular decrease of initial rehydration rate and water uptake with the increase of the drying temperature.