Background : Dioscorea bulbifera (DB) contain steroidal saponin which has anticancer and anti-inflammatory. DB is a health-functional material used as edible and medical materials. However, DB has not been studied in detail as industrial purposes of fermentation.
Methods and Results : D. bulbifera (DB) was fermented by Rhizopus oryzae CN105 for 3 days. Samples were prepared by adding 10% honey to the D. bulbifera (DBH) and honey free D. bulbifera (DB). The pH, total acidity (%) and reducing sugar (%) were investigated. The free sugar and color values related to taste components were analyzed. The pH level decreased while total acidity increased during fermentation. The free sugar and color values related to taste components were analyzed. The content of free sugar in the DB was the highest after 3 days of fermentation. In case DBH, only glucose was the highest after 3 days of fermentation. The content of fructose, sucrose and lactose were decrease during fermentation. Total polyphenol content of DB and DBH was measured by the Folin-Denis method. Total flavonoid content was measured by the Moreno method. Total polyphenol content and flavonoid content was the highest after 1 days of fermentation in both DB and DBH.
Conclusion : The results showed that physicochemical components improved during fermentation in DB. But antioxidant activity was the highest after 1 days of fermentation in DB and DBH. These results are indicated that fermented DB can be used as a functional food.