Abstract
Single or combined heat pump technologies are generally used to dry fruits and vegetables, with combined heat pump technologies offering superior performance. This review summarizes the applications of single and combined heat pump drying technologies for fruits and vegetables in China and globally, discusses their current advantages and disadvantages, and outlines future development directions for heat pump-based drying methods. Future research should focus on improving combined heat pump technologies and enhancing the performance of single heat pump drying systems to enhance the effectiveness and feasibility of these technologies for drying fruits and vegetables. Improved technologies would also help meet the increasing demand for high-quality food and social development. Moreover, changes in the mechanisms of key indicators, such as mechanical and thermodynamic properties, should be continuously monitored while drying various fruits and vegetables. Future research into combined heat pump technologies should focus on determining the conversion methods between pairs of drying technologies and identifying the most effective drying technology combinations. Future research into single heat pump technologies should focus on improving the performance levels of core components, such as compressors and drying media.