Drying kinetics of plum (control, blanching and blanching in 1% KMS solution as pretreatments) in a tunnel dryer was studied at 55, 60 and 65 degrees C air temperatures. Drying of plum slices occurred in falling rate period. It was found that treated plum slices dried faster. Six thin layer drying models were fitted to the experimental moisture ratio data. Among the mathematical models investigated, the logarithmic model satisfactorily described the drying behaviour of plum slices with high r(2) values. The effective moisture diffusivity (D-eff) of plum increased as the drying air temperature increased. The Deff values were higher for treated samples than the control. (c) 2006 Elsevier Ltd. All rights reserved.