DRYING OF THYME (THYMUS VULGARIS L.) AND SELECTION OF A SUITABLE THIN-LAYER DRYING MODEL

摘要

The air drying characteristics of thyme was investigated at a temperature range ofn40–60C and at an air velocity of 2.0 m/s.The drying time varied from120 to 495 min.nIncrease in air temperature significantly reduced the drying time of the thyme. Effectivenmoisture diffusivity was estimated using the analytical solution of Fick’s law ofndiffusion. It was found to be in the range of 1.097–5.991 ￥ 10-9 m2/s in the temperaturenrange. The temperature dependence of the effective moisture diffusivity wasndescribed by the Arrhenius relationship with activation energy of 73.84 kJ/mol.nTwelve mathematical models were evaluated by using the coefficient of determinationn(R2), mean relative percent error (P), reduced chi-square (c2) and root meannsquare error. The drying characteristics of thyme were well predicted by the Midillinet al. modelwithin the limits of the experiment.Rehydration behaviorswere affectednby the drying temperature and were found to increase with drying temperature.