Modeling of thin-layer kinetics and color changes of apple slices during far-infrared vacuum drying

Abstract

In this study far infrared vacuum drying kinetics and change of color quality parameters of apple slices were analyzed. The experimental data set of drying kinetics was obtained on the experimental set-up designed to imitate an industrial far infrared vacuum dryer. For approximation of the experimental data with regard to the moisture ratio four well known thin-layers drying models from scientific and engineering literature and new developed model of Mitrevski et al., were used. The performed statistical analyzes show that the model of Mitrevski et al., has the best statistical performance than well-known thin-layer drying models. The estimated values of moisture diffusivity of apple obtained from this study are within the range from 2.80?10?11 to 1.70?10?10 m2/s. A negative effect on the total color change of far infrared vacuum dried apple slices was observed with in-creasing of temperature of infrared heaters and vacuum pressure.