Research on variable-temperature drying process of Zhaotong Gastrodia elata Bl. f. glauca S. Chow
(2.Kunming Key Laboratory of Sustainable Development and Utilization of Famous-Region Drug, Kunming, China 650500)
(3.Institute of Medicinal Plants, Yunnan Academy of Agriculture Science, Kunming, China 650231)
(4.Yiliang County Xiaocaoba Wild Gastrodiaelata Development Co., Ltd., Zhaotong, China 657000)
【Abstract】Objective To put an end to the overproof events of sulfur content in Zhaotong G. elata Bl. f. glauca S. Chow (ZGE) and to improve the drying efficiency. Methods The effects of steaming time and drying parameters on appearance and internal quality characteristics of ZGE were investigated. The drying process of ZGE adapted to modern process equipment was explored. Results The optimal steaming time for second-grade fresh ZGE was 4 min at 95 °C. The suitable drying process parameters were as follows: ZGE was naturally cooled at room temperature for 12 h after steaming. ZGE was dried at 30 °C for 1 d, and then the temperature was raised with a speed of 2 °C/12 h to 40 °C. Then with the speed of 5 °C/12 h until to 60 °C, all the work was stopped until the ZGE was dried completely. It totally took about 6 d. Then the ZGE was light brown and had less deformation, and the folds were shallow, without hollow. The content of gastrodin was 0.93%, the content of soluble extract was 20.1%, and the content of total ash was 2.65%. All quality indexes met the requirements in Chinese Pharmacopoeia (2010 Edition). Conclusion The drying process of ZGE was applied to the modern processing equipment. It could not only guarantee the appearance but also internal qualities of ZGE. Meanwhile, it could improve the production efficiency and was suited to be promoted and applied in Zhaotong region.
【Keywords】 Gastrodia elata Bl.; steaming; variable-temperature drying; gastrodin; quality control;
 Chinese Pharmacopoeia [S]. Volume I. (2010) (in Chinese).
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