Estimation of potato moisture diffusivity from convective drying kinetics with correction for shrinkage

The aim of this paper is to report potato moisture diffusivity data determined from experimental convective drying kinetics. Two different methods have been applied to evaluate this coefficient. The first one was based on the analytical solution of a fickian diffusive model which enabled diffusivity determination by simple linear regression over experimental data. The regression was done using the real sample thickness in order to account for shrinkage. The second one was based on a numerical solution of solid mass balance equation and moisture transfer diffusion/convection equation, these equations being coupled by the solid phase velocity due to shrinkage. At each time step of the simulation, the diffusivity was adjusted to minimize the difference between calculated and measured sample mean moisture content. Due to several simplifying hypothesis the first method could only provide approximate results, while the second could be considered as reference. Predictive correlations for moisture diffusivity as function of temperature and moisture content are presented.