The thin-layer drying characteristics of garlic slices

The thin-layer drying characteristics of garlic slices (2-4 mm) were investigated for a temperature range 50-90 degrees C, a relative humidity range 8-24%, and an airflow range 0.5-1 m/s. An analysis of variance (ANOVA) revealed that temperature and slice thickness significantly affected the drying rare while relative humidity and airflow rate were insignificant factors during drying. Effective diffusivity of water varied from 2 to 4.2 x 10(-10) m(2)/s over the temperature range investigated, with an energy of activation of 989 kJ/kg. Four mathematical models available in the literature were fitted to the experimental data, with the Page and the two-compartment models giving better predictions than the single-term exponential and Thompson's model. The temperature dependence of the diffusivity coefficients was described satisfactorily by a simple Arrhenius-type relationship. Copyright (C) 1996 Elsevier Science Limited.