Sensory study of the character impact aroma compounds of a coffee beverage

The more potent odorants in a sample of medium-roasted Arabica coffee and in the corresponding brew were quantified. Large amounts ( >75%) of acetaldehyde, 2,3-butanedione, 2,3-pentanedione, vanillin and some furanones were extracted from the coffee brew, whereas the yields of the more unpolar compounds, such as 3-isobutyl-2-methoxypyrazine, (E)-β-damascenone and the unstable 2-furfurylthiol were low (<25%). On the basis of quantitative data an aroma model was prepared for the brew. In triangle tests, models containing the complete set of 24 odorants were compared with a model missing one or more odorants. These experiments indicated that the aroma of the brew was mainly caused by some alkylpyrazines, furanones and phenols, and by 2-furfurylthiol, methional and 3-mercapto-3-methylbutyl formate. The higher impact of both methional and the formate on the aroma of the brew and the lower aroma activity of 4-vinylguaiacol were in contrast to results obtained in a previous study for ground coffee of the same provenance and roast degree. Received: 13 December 1999 / Revised version: 31 January 2000