INTENSIFICATION OF APPLE DRYING USING CONVECTIVE AND COMBINED METHODS OF DEHYDRATION

Abstract

The paper examines the intensification of drying apple slices to low residual moisture content. It is proposed to use an energy-efficient multi-stage mode of convective drying at 80/60 °C and a combined multi-stage mode with IR radiation and IR convective heating (100 W) + 60 °C / 60 °C. The paper presents the temperature and kinetic curves and changes in drying speed for the studied dehydration regimes. A formula was obtained for determining the total duration of the process of drying apple slices using a combined method, and a dependence of the Rebinder number for the studied dehydration modes was constructed. Based on the experimental data analysis and generalization of research results, a method of determining the drying intensity based on the average moisture exchange and the average temperature of material heating per minute, at the first stage of drying and during the entire drying time, was proposed for the first time. The efficacy of the proposed modes is confirmed by a reduction in drying duration 1.9 times compared to the stationary mode at a coolant temperature of 60 °C. The obtained dried product is characterized by high recoverability (78–80%) and appropriate organoleptic properties.