OC fermentation
The method of fermentation of OC described by Aoki H. et al. was utilized with some
modifications (Aoki et al., 2003). OC (Food Chemifa Co., Ltd.) was soaked in 0.2% sodium
citrate (Wako Pure Chemical Industries) at room temperature for 60 min, and then steamed
at 121°C for 20 min. The steamed OC was then cultured with R. oligosporus (Akita Konno
Co., Ltd.) at 30°C for 24 h under aerobic conditions. After incubation, the fermented
product, OT, was lyophilized.