Comparison and Modeling of Different Drying Technologies for Zanthoxylum bungeanum Maxim.: Changes in Drying Kinetics, Color, Dehiscence Rate, Volatile Oil Content and Amide Content

This study systematically evaluated the drying kinetics of <i>Zanthoxylum bungeanum</i> Maxim. during microwave vacuum drying (MVD), pulsation vacuum drying (PVD) and hot-air drying (HAD) at different temperatures and analyzed the heating mechanism differences in the three technologies via numerical simulation. Drying kinetics indicated that MVD was the most efficient technique owing to its volumetric dielectric heating, whereas the PVD efficiency depended heavily on precise cyclic parameter control. As verified by simulations, a more uniform temperature field was formed in MVD, while PVD achieved focused core heating via infrared radiation. Quality analysis revealed that the dehiscence rate increased significantly with the temperature, and both MVD and PVD demonstrated superior color retention over HAD; however, MVD was the most effective for preserving volatile oils, while PVD excelled in amide preservation. It should be noted that the specific component retention advantages of PVD were balanced by its strict parameter requirements, which limits its potential for large-scale application. Comprehensive evaluation confirmed MVD's superiority in <i>Z. bungeanum</i> drying, effectively retaining thermosensitive components under a vacuum pressure of -90 kPa at 60 °C.