Drying kinetics of single layer Thompson seedless grapes under heated ambient air conditions

For determination of drying kinetics of Thompson seedless grapes a suitable experimental unit for online measurement was designed and fabricated. The drying characteristics of oil emulsion pretreated grapes were measured for all ranges of temperature (50 to 80 degrees C) and velocity (0.25 to 1.00 m /s) of the ambient air which may be used for drying purposes. Out of the th ree models considered (Page's, Single term and Two term exponential) Page's model was found to be the most suitable for describing the drying behaviou r of the grapes. The dependence of drying constant k of Page's model on pro cess variables (Temperature and Velocity of air) was analysed using Arrheni us and power law model. It was found that the Arrhenius model gives better values of k than the power law model. It is also found that the dependence of another drying constant N of the Page's model on the process variables c an not be described in terms of Arrhenius or power law model.