Microwave Drying of Food Materials: Principles, Hybrid Techniques, Modeling Approaches, and Emerging Innovations

Microwave-assisted drying has gained increasing attention in the food industry due to its ability to improve drying efficiency, preserve nutritional and functional properties, and enhance the quality of final products compared to conventional thermal methods. Its capability for rapid, volumetric heating and reduced processing times positions microwave drying as a promising technology for modern food production. This review examines the fundamentals of electromagnetic and microwave energy, the design and operation of microwave ovens, and recent developments in microwave-based food drying techniques. Various standalone and hybrid methods, including microwave-hot air, microwave-infrared, microwave-vacuum, and solar-assisted microwave drying, are discussed. Additionally, chemical transformations during microwave drying, empirical and mechanistic modeling approaches, safety considerations, and nonthermal effects are addressed. Advances in solid-state microwave systems and the application of artificial intelligence for process optimization, monitoring, and automation are also reviewed. In conclusion, microwave drying technologies offer significant benefits in terms of energy efficiency, product quality retention, and process sustainability. However, challenges such as uneven heating and potential quality degradation remain. Future research should focus on intelligent control strategies, improved understanding of food properties, and scalable solutions to further enhance the reliability and industrial application of microwave-assisted drying.