Abstract
Oak barrels typically used to age whiskey are known to contain various biologically active materials including ferulic acid. Ferulic acid is the precursor of vanillin and vanillic acid and is known for its anti-inflammatory effects in the human body. However, there currently are no established methods for extracting ferulic acid from oak barrels. In this study, we focused on ferulic acid esterase, which is found in Japanese rice wine (sake) as a possible factor that may promote the extraction of ferulic acid from oak barrels. By putting sake inside oak barrels, we were able to obtain sake with a rich content of ferulic acid, vanillin, and vanillic acid.
