Volatile compounds isolated from rice beers brewed with three medicinal plants

摘要

The volatile compounds and physicochemical properties of rice beers brewed with three medicinal plants, namely Acanthopanax senticosus (Siberian ginseng), Scutellaria baicalensis (baikal skullcap) and Cornus officinalis (Japanese cornel) were analysed. The rice beers were produced and fermented from unhulled ground rice, malt, and medicinal plant extracts. The medicinal plant extracts, used at 5 and 10 % (v/v) were blended with wort before fermentation. Compared with a draft beer fermented without rice, the rice beers had lower levels of pH, acidity, amino acid content and reducing sugars. Of the rice beers, the beer with the addition of 10% Japanese cornel had the highest colour value and foam stability. The volatile compounds of the rice beers were extracted using a solvent-assisted flavour evaporation apparatus and analysed by gas chromatography-mass spectrometry. The rice beer with 10% Siberian ginseng showed the most diverse volatile profile, in that 54 kinds of volatile compounds were detected. The rice beer with 10% Japanese cornel had the highest relative amount of volatile chemicals of all of the rice beers. Lactones such as γ-hexalactone, γ-nonalactone and γ-decalactone were detected in all of the rice beers.