Mathematical modeling of combined far-infrared and vacuum drying banana slice

Combined far-infrared radiation (FIR) and vacuum drying has recently received more attention since the technique has proved effective in drying some types of fruits with the aim to produce fat-free fruit based snacks. However, most studies are of experimental nature. In this study a mathematical model, which allows prediction of the changes of moisture content and temperature of a model food material (banana) undergoing combined FIR and vacuum drying was developed. The predicted results were compared with the experimental results at the absolute pressures of the drying chamber of 5, 10, and 15 kPa and at the controlled banana center temperatures of banana of 50 degrees C, 55 degrees C, and 60 degrees C. Based on the comparison between the predicted results and the experimental results, it was found that the developed model performed adequately in predicting the changes of the moisture content. The simulated temperature at the center of a banana slice was higher than the experimental temperature during the first 50 min of drying but agreed well with each other afterwards. (C) 2008 Elsevier Ltd. All rights reserved.