Effects of Different Drying Methods on Quality of Codonopsis Radix

OBJECTIVE To compare the effects of different drying methods on the quality of Codonopsis Radix， and screen out the suitable drying process. METHODS  Fresh roots of Codonopsis pilosula collected from Pingshun， Shanxi were processed by traditional and modern drying methods， separately. The contents of lobetyolin， atractylactone Ⅲ， syringol， polysaccharide and appearance traits of medicinal materials were used as evaluation indicators to assess the effects of different drying methods on the quality of Codonopsis Radix. Meanwhile， the best drying method of Codonopsis Radix was optimized by comprehensive evaluation of different drying methods combining with dry time and energy consumption. RESULTS Different drying methods and conditions caused significant differences in the contents of functional substances which were stable at low temperature and decreased at excessively high temperature in Codonopsis Radix. The infrared drying method was preferred when the contents of lobethal， atractyloside Ⅲ and glycosides as indexes. Taking the total polysaccharide content as an index， infrared， hot air and microwave were suitable drying methods for Codonopsis Radix. Considering the functional substance content， sample appearance， drying time and energy consumption together， the optimal drying method for Codonopsis Radix was infrared or hot air drying at 60 ℃. CONCLUSION The quality of Codonopsis Radix processed by different drying methods varied greatly. The precise regulation and control of Codonopsis Radix processing can be achieved by monitoring the drying method through multiple indicators， which provided a reference for improving the quality of Codonopsis Radix medicinal materials in production.