Thin Layer drying study of acorns(<i>Quercus ilex</i> L.) -new mathematical modelling approach

Abstract

The thin layer drying behaviour of acorns was investigated at three oven temperatures (60, 70 and 80 °C). The drying kinetic was fitted and modelled using different mathematical drying models. The use of First Order (FO) and Pseudo First Order (PFO) was proposed and estimated for describe the moisture content evoluntion of acorns as a function of time. According the coefficient of determination R² ), the root mean square error ( RMSE ) and the sum mean of square error (χ² ), t he best fit was given by the Logarithmic model. A good fit R² > 0.9942; RMSE < 2.238 and χ² < 6.014) was shown by FO and PFO indicating their aptitude to describe the thin layer drying kinetic o f acorns. Effective moisture diffusivity increased from 4.016 x 10^-8 to 1.244 x 10^-7 m² s^-1 with the rice of drying tem perature. The elimination of water from the acorns requires an activation energy of about 55 kJ mol^-1.