Abstract
We attempted to enhance the production of diosgenin through the production of yam koji. Diosgenin was not detected in yam and yam koji itself. However, diosgenin was detected in the heat-processed yam koji at 55°C. To screen a suitable koji strain, we prepared 10 yam koji samples. After heat processing, diosgenin was detected in all yam koji, but no clear relationship was observed between the diosgenin content and the strains. While, a correlation was observed between β-glucosidase and α-rhamnosidase activities of yam koji and the diosgenin content in the heat-processed koji. These findings suggest that these enzymes contribute to the liberation of diosgenin. Three different heat processing were tested: 55°C, 75°C, and a sequential combination of 55°C followed by 75°C. The highest amount of diosgenin was obtained at 55°C. In conclusion, this study demonstrates that the potential contribution of yam koji to release of diosgenin.
