CONTRIBUTION TO STALE FLAVOR OF 2-FURFURYL ETHYL ETHER AND ITS FORMATION MECHANISM IN BEER

The effect of storing beer on the generation of stale flavor was investigated by a sensory evaluation and quantitative determination of the volatile components. The results of the sensory evaluation revealed 2-furfuryl ethyl ether (2-FEE) to be an important component responsible for the astringent stale flavor, and (E)-2-nonenal (E2N) for the cardboard-like stable flavor. However, the stale flavor could not be reproduced by adding 2-FEE or E2N alone to fresh beer, but was closely reproduced when 2-FEE and E2N were added together. The results of experiments on adding furfuryl acetate (FAC) and furfuryl alcohol (FAL) to a 5% ethanol solution or beer indicate that 2-FEE was generated by the reaction between ethanol and FAL, which was formed by the hydrolysis of FAC, during the storage of beer.