Computational Modeling and Simulation of Heat, Mass Transfer, and Quality Kinetics in Convective Drying of Kiwi Slices

Abstract

　Convective drying (CD) is widely used in the food industry, which causes quality deterioration, including discoloration, nutrient degradation, and crust formation. Understanding the physical effects of CD on heat and mass transfer, geometry deformation and quality degradation is necessary for accurate process prediction and optimization. This study developed a theoretical model to predict moisture, temperature profile, and quality kinetics degradation during kiwi fruit drying. The model coupled the heat and mass transfer equations with geometry deformation and a partial differential equation for chemical reactions during drying. COMSOL Multiphysics software was used for simulation, and predictions were validated against experimental data. Simulated results showed strong agreement with the experimental data. The Root Mean Square Error (RMSE) and coefficient of determination (R²) for temperature predictions ranged from 0.3205 to 1.9606 and 0.9384 to 0.9967, respectively. RMSE and R² values for moisture gradients were between 0.0194 to 0.0593 and 0.9484 to 0.9945. Quality degradation was assessed based on the total color change, antioxidant and phenolic content. The outcomes of the model indicated an RMSE of 0.8454 to 5.3441 and R² of 0.8715 to 0.9967. This model can optimize drying processes for complex geometries and fluctuating conditions, enhancing quality kinetics, minimizing energy consumption, and avoiding expensive pilot-scale tests.