Studies on character impact odorants of coffee brews

Twenty-two compounds, which had been revealed by dilution experiments as potent odorants, were quantified by stable isotope dilution assays in brews prepared from roasted Arabica (Coffea arabica) and Robusta coffees (Coffea canephora var. Robusta). Calculation of odor activity values (OAVs; ratio of concentration to odor threshold) indicated 2-furfurylthiol, 3-mercapto-3-methylbutyl formate, methanethiol, beta-damascenone, methylpropanal, and 3-methylbutanal as the most potent odorants. However, the rankings of the OAVs were different in the two coffee brews. The extraction yields obtained during the preparation of the brews were determined for 17 odorants. Polar compounds (e.g. guaiacol, 4-hydroxy-2,5-dimethyl-3(2H)-furanone, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 2,3-butanedione) were extracted with higher yields (75-100%); nonpolar compounds (e.g. beta-damascenone, 2-isobutyl-3-methoxypyrazine) gave yields of only 10-25%. The overall odor of the models containing the odorants in the concentration levels that had been found in the two brews was clearly coffee-like. The models reproduce the differences in the odor profiles of the two brews.