2015 Volume 31 Issue 1 Pages 11-17
Sendango is a traditional delicacy this is made by fermentation of sweet potato and is produced exclusively in Tsushima, Nagasaki, Japan. A noodle-type derivative of sendango, rokube, has a unique texture somewhat similar to that of konnyaku. A previous study has demonstrated that partial degradation of starch and fiber and especially a reduction in pectin levels is associated with this specific texture. In our preceding report we isolated Mucor sp. and Penicillium spp. with amylolytic and pectolytic activity. These organisms were present during the manufacturing process, regardless of the manufacturing farmer or the year, but it is not known whether they actually contribute to degradation within the sweet potato. Here, we attempted to reproduce sendango by fermentation with selected strains of Mucor sp. and Penicillium spp. Upon propagation of either Penicillium echinulatum 38-1 or Penicillium expansum 13-3 on sweet potato we observed partial degradation of starch and pectin. In addition, texture profiling showed that the simulated rokube made from the fermented sweet potato mix had physical properties similar to those of the original rokube form Tsushima. These results suggest that the unique texture of rokube is attributable to the action of specific strains of P. echinulatum and P. expansum.
