Effects of different drying methods on quality of Gastrodiae Rhizoma

Different drying methods, including drying in the sun, sulphur fumigation, hot air drying, microwave drying, infrared drying and various coupling techniques,were used to dry fresh Gastrodiae Rhizoma. Characteristics, extracts and the contents of active components of all samples were compared to investigate the effects of different drying methods on quality of Gastrodiae Rhizoma. The results showed that the characteristics of the samples would be better with use of sulphur fumigation, hot air drying, and hot air-microwave drying. Different drying methods had little effects on extracts. Among them, the extract content was higher after hot air drying. The stilbene glycosides would transformation and the contents of Gastrodiae Rhizoma polysaccharides would decline with use of sulphur fumigation, microwave drying and infrared drying. In the comprehensive analysis of characteristics, content of active components, production cost and other factors, hot air drying or hot air-microwave drying was recommended as the first choice.