Effects of drying methods on the quality of Hanyuan Zanthoxylum bungeanum based on physicochemical and functional metabolite analysis

Hanyuan Zanthoxylum bungeanum (HZB) is a well-known spice in China because of its unique taste and aroma. Fresh HZB needs to be dried immediately for preservation and long-term utilization; however, different drying processes may cause significant differences in the quality. In this study, the effects of sun drying (SD), hot-air drying at 50 and 60 °C (HAD-50 and HAD-60), and vacuum-freeze drying (VFD) on the color, total phenolic content (TPC), total flavonoid content (TFC), total alkylamide content (TAC), antioxidant activities, volatile organic compounds (VOCs), fatty acids (FAs), and the phenolics of HZB were evaluated. The results revealed that the SD-treated sample had the lowest antioxidant activities and total VOC content. In contrast, the highest total VOC content of dried HZB was obtained by HAD-50, but it decreased significantly (p < 0.05) with an increase in the drying temperature (HAD-60). The sample treated with VFD had the highest color (L*, a*, b*), TPC, TFC, TAC, antioxidant activities, total FAs content, four phenolics (epicatechin, rutin, hyperoside, and quercitrin) content. Overall, the results provided new insights into the effect of the drying method on the quality of HZB.