The reaction engineering approach to modelling drying of thin layer of pulped Kiwifruit flesh under conditions of small Biot numbers

Drying is a subject of extensive research in the last three decades due to its importance in manufacturing many types of products. It has been modelled by adopting the drying characteristic curve method, the comprehensive transport phenomena approach or the entirely empirical correlation. Following the approach by Chen and Xie, this paper describes a mechanistic model of drying of thin layer material (Biot numbers for both heat and mass transfer are small) using a reaction engineering approach, This method considers drying as a competitive process between 'evaporation reaction' and 'condensation reaction'. Here, the drying kinetics parameters have been established through the experiments performed on pulped Kiwifruit flesh spread onto a shallow metal tray (forming a layer) to simulate the process of making fruit leather. The small Plot number conditions have been employed. The activation energy has been obtained and correlated to the residue water content and the equilibrium sorption isotherm. This approach may offer an alternative for food drying modelling. (C) 2001 Elsevier Science B.V. All rights reserved.