Analysis of characteristic aroma of fungal fermented Fuzhuan brick-tea by gas chromatography/mass spectrophotometry

Fuzhuan brick-tea is a popular fermented Chinese dark tea because of its typical fungal aroma. Fungal growth during the production process is the key step in achieving the unique colour, aroma and taste of Fuzhuan brick-tea. To further understand the generation of the characteristic aroma, changes in the main volatile compounds of Fuzhuan brick-tea during the fungal growth stage were studied by gas chromatography/mass spectrophotometry. The results showed that the content of volatile compounds, especially aldehyde compounds with stale aroma such as (E)-2-pentenal, (E)-2-hexenal, 1-penten-3-ol, (E,E)-2,4-heptadienal and (E,Z)-2,4-heptadienal, increased significantly in fermented tea samples. The concentration of terpene alcohols with flower aroma also increased notably during the fermentation process. The compounds with stale and flower aromas in combination with some volatile components of the raw material contributed to the characteristic 'fungal/flower' aroma of Fuzhuan brick-tea. Microbial metabolism during the fermentation process probably played the key role in the generation of characteristic aromatic compounds of Fuzhuan brick-tea. (c) 2007 Society of Chemical Industry.