Thin layer drying characteristics of hazelnuts during roasting were described for a temperature range of 100±160°C, using five semi-theoretical and two empirical thin layer models. The effective diffusivity varied from 2:301 10ÿ7 to 11:759 10ÿ7 m2/s over the temperature range. Temperature dependence of the diffusivity coefficient was described by Arrhenius-type relationship. The activation energy for moisture diffusion was found to be 1891.6 kJ/kg. Thin layer drying characteristics of hazelnut roasting were satisfactorily described by an empirical Thompson model with the linear temperature dependence. Ó 2000 Elsevier Science Ltd. All rights reserved.
1. Introduction