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 r^2=98.21% was suitable for 10-mm diameter and henderson pabis model with r^2=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.