Background: This study was carried out to determine the physicochemical components of Rehmannia glutinosa (RG) fermented with Rhizopus delemar. Methods and Results: Physicochemical components such as changes in moisture content, pH value, total acidity, amount of reducing sugars as well as quantity of free sugars, free amino acids, and catalpol were investigated. Result showed that, the moisture content ranged from 64.26 to 65.51%. The pH and total acidity of the fermented RG decreased significantly during fermentation. The reducing sugar content ranged from 0.10 to 1.34%. The most abundant main free sugars were identified as raffinose, xylose, glucose, fructose, and sucrose. The sucrose content in 80% ethanol and in water extracts increased during RG fermentation. In total, 26 free amino acids were detected, including seven essential amino acids. In addition, the quantity of free amino acids decreased significantly during fermentation. Finally, the catalpol content of the fermented RG was highest on the 2nd day of fermentation at 2,028.67㎎/ 100 g. Conclusions: These results indicated that fermentation of Rhizopus delemar could be used to enhance biological activity, and that fermented RG could be used as a functional material and as an edible resource in food and functional materials industries.

This study carried out to determine the physicochemical components of Cynanchi wilfordii Radix (CWR) fermented with Rhizopus delemar. The physicochemical components such as changes on moisture content, pH, total acidity, reducing sugars, and the contents of free sugars, free amino acid, cynandione A were investigated. The moisture content of fermented CWR was increased after 4 days of fermentation. The pH value of fermented CWR was decreased after 4 days of fermentation. The reducing sugars contents were in the range of 1.42-1.69%. The major free sugars were identified as rhamnose, glucose, fructose and sucrose. The content of free sugars was decreased during fermentation process of CWR while the glucose contents in 80% ethanol and water extracts were increased. In addition, the free amino acid increased significantly during fermentation. Finally, The content of cynandion A of the fermented CWR was highest at the level of 14.09 mg/g on the 8th day. These results are indicated that fermentation with Rhizopus strains could be used to increase the bioactivity of CWR and the fermented CWR can be used as a functional material and edible resource in the food industry.