The equilibrium moisture content, Xe in Eq. (1) was calculated as 0.0007 kg/kg db according to GAB equation (Krokida et al., 2003). When Fourier number is greater than about 0.1, the terms higher than the first term can be ignored in Eq. (1). Taking the natural logarithm of both sides of Eq. (1), the following equation is obtained (McCabe et al., 1993): The effective diffusivity, Deff, was determined from the slope of the ln((X − Xe)/(X0− Xe)) versus time plot.