Analytical study of cyclic temperature drying: Effect on drying kinetics and product quality

Abstract

An analytical model has been formulated to determine the temperature and moisture distributions during the drying of an agricultural product when different cyclic air temperature variations were employed. The variations in these distributions, with respect to space and time, are presented graphically. Evaluation of the model predictions with drying data obtained from square-wave temperature variations showed good agreement between the model and the experimental data within 8.4%. The advantages of employing cyclic heating/cooling schemes on the drying kinetics and product quality are demonstrated. Analytical results illustrated the importance of product tempering, continuous heat flux reversals within the product and reducing the product surface temperature to minimise the ascorbic acid loss and product colour change due to non-enzymatic browning. © 2001 Elsevier Science Ltd. All rights reserved.