Modeling of Vacuum Drying of Licorice (Glycyrrhizia glabra) Roots

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.
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.
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.
The two term and Henderson Pabis models were assessed by comparing coefficients of determination and standard error between the monitored and forecasted moisture ratios.