The Deff values obtained in the present study have a magnitude close to values published for food products particularly leaf material, e.g. 1.14 × 10−11–2.98 × 10−11m2/s for drying of black tea leaves (Panchariya et al., 2002) and 6.3 × 10−11–2.19 × 10−10m2/s for drying of coriander leaves (Sarimeseli, 2011).