Abstract:In this study, infrared-assisted spouted bed drying (IRSBD) of Chinese yam was carried out using constant temperature drying (40, 50, 60 ℃ and 70 ℃) and variable temperature drying (staged rising temperature and staged falling temperature) processes to investigate the effects on drying kinetics, uniformity, and quality properties (texture, rehydration, total phenolic content, microstructure, and shrinkage). The mathematical modeling results of the Chinese yam IRSBD drying curve showed that the Midilli model had the best fit, with the maximum R2 value (0.99989) and the minimum RMSE and χ2 values (0.00319 and 1.69872×10-5, respectively), indicating that it was most suitable for describing the IRSBD kinetics of Chinese yam. In the comparative analysis of different drying processes, it was found that increasing the drying temperature under constant-temperature drying conditions was beneficial for shortening the drying time and reducing energy consumption. Staged rising temperature drying had energy consumption only slightly higher than that of constant-temperature drying at 70 ℃, but it exhibited the best drying uniformity, the highest total phenolic content [(85.25±7.41) mg GAE/100 g DW], and the lowest shrinkage and hardness [(74.3±3.96)% and (24.95±7.41) N], respectively, as well as a desirable color. The staged falling drying process produced samples with higher equilibrium rehydration ratio and crispness, but it did not show significant advantages over the staged rising temperature process in terms of drying time, energy consumption, uniformity, hardness, shrinkage ratio, and total phenolic content. Therefore, it can be concluded that staged rising temperature drying is a more ideal drying process for Chinese yam using IRSBD. This study provides data reference and theoretical support for the application of IRSBD technology in agricultural product processing and industrial production.