Optimized Infrared Vacuum Drying of Bananas for High-Quality Products

Abstract

This paper proposes a combined drying method called infrared vacuum drying (IVD) to extend the shelf life of perishable items like fruits. The method combines infrared and vacuum drying methods, allowing for quick drying and efficient use of thermal energy. First, the material tray temperature distribution was analyzed before IVD. Second, a single-factor experiment was conducted to explore the impact of infrared heating power, banana thickness, banana ripeness, and drying time on the color and moisture content of dried samples via IVD. The moisture content of bananas was found to be influenced by the power of infrared heating, with higher infrared heating power leading to faster drying rates and lower moisture content. Green bananas showed the best color performance before drying, while brown bananas had the highest initial moisture and sugar content. Drying banana slices with a thickness of 5 mm took at least 90 min to reach a moisture content below 20%. Third, the Taguchi method was used to determine the optimum process based on seven performance indicators including sugar content, color, texture, moisture content, rehydration rate, sensory analysis, and energy consumption. Based on the findings, the process having green bananas, infrared heating power of 432 W, 3-mm thick banana slices, and a drying time of 90 min obtained the highest average score of 7.4 among all performance index scores. Fourth, the energy consumption of IVD and freeze vacuum drying (FVD) was also analyzed, finding that IVD is still more energy-efficient than FVD in terms of energy consumption.