Degradation and O-methylation of phenols among volatile flavor components of dried bonito (katsuobushi) by Aspergillus species.

Abstract

Eleven strains of Aspergillus species, isolated from dried bonito (Katsuobushi), were grown in a liquid medium containing the individual phenolic compounds, in order to determine the fate of phenols during the molding process in Katsuobushi production. Of the 10 phenols studied, guaiacol, creosol and 2, 6-dimethoxyphenol were O-methylated by 5 strains of Aspergillus species, and the others were degraded by some strains studied. Similar changes in the phenols were presumed to occur also during the molding process in Katsuobushi production. It was concluded that the pungent smoky flavor became milder mainly through biological degradation or O-methylation of phenols during the molding process.