AIR drying kinetics of potato cylinders

An experimental air tunnel dryer was used to investigate the kinetics of moisture transport in potato cylinders (Solanum tuberosum). Accordingly, the experimental results, representing only falling-rate drying behaviour and hence, dehydration completely controlled by internal mass transfer, were interpreted on the basis of Fick's diffusional model for non-steady state radial diffusion. The effects of air velocity and temperature on the drying rate were studied with the temperature being the principal controlling factor. Analysis of the drying curves by the method of slopes resulted in a variable effective moisture diffusivity. Shrinkage as a function of moisture content under various drying conditions was investigated. The volumetric shrinkage of the samples was affected mainly by air velocity, whilst air temperature had a negligible effect. Good agreement was obtained between the experimental apparent density data and the predicted correlation.