Preparation of culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.: Fr.) S.F. Gray (Aphyllophoromycetideae)-fermented wheat and its antioxidant properties.

The optimization of solid-state fermentation conditions for mycelial growth in wheat by culinary-medicinal maitake mushroom, Grifola frondosa (Dicks.: Fr.) S.F. Gray was studied. The results from the center of the design analysis showed that the recommended optimal conditions for carbon, nitrogen sources, and temperature were 19 mg lactose/g, 2.0 mg malt extract/g, and 30 degrees C, respectively. Under these conditions, the mycelial biomass of 533.1 mg/g was obtained in fermented wheat, comparable to that (545.7 mg/g) obtained using the one-factor-at-a-time method. Based on the results obtained, EC50 values of ethanolic and hot water extracts from fermented wheat were 1.13-15.27 mg/mL, indicating that fermented wheat was effective in antioxidant activity, reducing power, scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals, and chelating ability on ferrous ions. Total phenol contents of both extracts were 13.35 and 23.01 mg/g, respectively. Accordingly, the information obtained would be applicable for the cultivation and consumption of G. frondosa-fermented wheat to provide its beneficial health effects.