Enhancing Microwave Freeze Drying: Exploring Maximum Drying Temperature and Power Input for Improved Energy Efficiency and Uniformity

Abstract The pursuit of energy-efficient and uniform processing drives ongoing research in microwave-assisted freeze drying (MWFD). While microwave application is acknowledged for its potential to reduce energy consumption of freeze drying applications, it introduces new challenges to gentle processing, particularly in achieving uniformity of processing due to the inherent uneven microwave field distribution in the drying chamber. This study investigates the impact of maximum drying temperature (T max ) and microwave power input on energy consumption and uniformity in temperature-controlled MWFD. Experimental results reveal that shorter equilibration times associated with higher T max significantly amplify the inhomogeneity of temperature distribution. Further, higher T max was associated with a significant reduction in total energy demand of MWFD. Despite noticeable trends, microwave power input did not yield statistically significant differences in energy consumption or uniformity. The limited range of explored values, combined with the temperature-controlled nature of the process, may have rendered a potential influence of microwave power input negligible. This research elucidates the extent of inhomogeneity in MWFD, with implications for achieving uniform, gentle drying. It highlights the critical role of temperature control in MWFD. The study contributes to advancing the understanding of optimal processing in temperature-controlled MWFD.