THIN-LAYER DRYING OF BAY LAUREL LEAVES (LAURUS NOBILIS L.)

Abstract

In this work, bay laurel leaves were dried using pilot-scale, cabinet-type, convective dryer. Drying experiments were conducted using constant air velocity of 2 m/s and air temperatures of 50, 60 and 70C. Drying rate increased with increase in air temperature and thus reduced the drying time. The experimental drying data were applied to 14 thin-layer drying models. Nonlinear regression analysis was performed to relate the parameters of the model with the drying conditions. The performance of these models is evaluated by comparing R-2, chi(2) and RMSE between the observed and predicted moisture ratios. Among all the models, Midilli et al.'s model was found to be the best for explaining the drying characteristics of bay laurel leaves. The effective moisture diffusivity ranged from 9.38 x 10(-12) to 2.07 x 10(-11) m(2)/s over this temperature range studied, with activation energy of 36.48 kJ/mol for bay laurel leaves.