Ferulic Acid Production in the Brewing of Rice Wine (Sake)

The traditional Japanese alcoholic beverage sake is produced by fermentation of rice by Saccharomyces cerevisiae and Aspergillus oryzae. A. oryzae releases ferulic acid. an antioxidant, from steamed rice during the fermentation process. The concentration of ferulic acid increased with time during fermentation and the production rate peaked 9-12 days post inoculation. Analysis of the fermentation cultures of Aspergillus oryzae, by high-performance liquid chromatography (HPLC), revealed that p-coumaric acid induced an 18.9-fold increase in the level of ferulic acid. Furthermore, SDS-PAGE analysis revealed an increase or decrease in the level of specific proteins after the addition of p-coumaric acid to fermentation Cultures of Aspergillus oryzae. Ferulate esterase (FAE) activity was observed in the fermented sake ten days following the start of the fermentation process. These results suggest that the level of ferulic acid is regulated by the enzymes synthesized by A. oryzae during the sake brewing process.