Application of pulsed vacuum drying technology in Cistanche deserticola: Effect on drying characteristics and quality

In the current study, a new drying method called pulsed vacuum drying (PVD) was utilized to dehydrate Cistanche deserticola, while the effects of drying temperature and pulsing ratio (PR) on drying behavior and physicochemical quality were explored. The related mechanism was revealed through microstructural changes and mathematical model establishment. The findings demonstrated that drying temperature and PR significantly influenced the drying time and quality properties of Cistanche deserticola. Appropriately extending the vacuum pressure holding time or shortening the ambient pressure time were beneficial to form microporous channels inside the material, thereby achieving superior drying rates and better rehydration performance. The Weibull model was capable of accurately characterizing the drying performance of Cistanche deserticola. The highest echinacoside and acteoside contents of dried Cistanche deserticola slices were achieved at 70 ℃ with PR of 5 min:4 min and 3 min:4 min, respectively. Compared to open-sun drying, PVD achieved better quality attributes by decreasing drying time, minimizing oxygen exposure, and altering the microstructure. PVD at 70 ℃ and PR of 3 min:4 min was deemed the appropriate drying set, as it yielded the maximum comprehensive score (0.71) when including both processing time and quality. These findings suggest that PVD is a promising drying technique for promoting the high-quality development of industrial processing of Cistanche deserticola.