Studies on the physicochemical properties on 3 types of Rehmannia glutinosa

Rehmannia glutinosa (RG) is a widely cultivated medicinal crop in Asia. Its rhizomes are widely used for food or traditional medicine in raw, dried or steamed state depending on their purpose. This study was performed to compare physicochemical properties of 3 types of RG. For this study, the korean domestic cultivar ‘Dagang’ was used. To prepare the 3 types of RG, drying and steaming process were conducted. For dried root, raw root was dried at 60℃ in hot air dryer for 48hours. For steamed root, dried root was steamed and dried repeatedly for 9 times. As a result, the color value of lightness was highest in raw root and lowest in steamed root. Each value was 86.83 and 38.49. The value of redness and yellowness was lowest in steamed root. Dried root has the highest value in hardness but lowest in adhesiveness. The content of catalpol was highest in dried root and the next was in raw root. Each value was 29.47 mg / g and 27.57 mg / g. It didn’t detect in steamed root. The aucubin content was highest in steamed root. The value was 0.95 mg / g. A value of 0.55 mg / g of aucubin was in dried root and 0.46 mg / g in raw root. The results show that physicochemical properties of RG was significantly different depending on the types of RG. It may work differently in drug and using proper types of RG would be important factor. Therefore, further study on pharmacological activities related these properties is needed.