Modeling of Vacuum Drying of Licorice (Glycyrrhizia glabra) Roots

Background and Objectives: Desiccation is a necessary procedure to eliminate moisture from foodstuffs in industries, especially pharmaceutical, food and tobacco industries. In the present study, a mathematical modeling was assessed for vacuum drying of the licorice roots. Materials and Methods: Fresh licorice roots were dried at 50 mbar. Temperatures included 22to 150°C and diameters of roots included 10 and 15 mm. A layer of licorice roots was transferred to a dish of balance on vacuum dryer and then changes in weight were recorded and moisture contents were calculated at various times. Results: Five mathematical models were adapted to empirical data. Curve expert has been used as statistical calculation. It was proved that the empirical two term’s model with high values of R2=98.21% was suitable for 10-mm diameter and Henderson Pabis model with R2=95.43% for 15-mm diameter roots. Conclusions: The two term and Henderson Pabis models were assessed by comparing coefficients of determination and standard error between the monitored and forecasted moisture ratios.