Influence of provenance and roast degree on the composition of potent odorants in Arabica coffees

Twenty-eight potent odorants were quantified by stable isotope dilution assays of medium-roasted Arabica coffee blends from Colombia (Col), Brazil (Bra), El Salvador (El) and Kenya (Ken) as well as the varieties Tipica (Tip) from Colombia and Caturra from the regions Pinas (Cat-P) and Quevedo (Cat-Q) in Ecuador. The blends from Col and Bra were similar in their composition of odorants. Ken contained higher amounts of 3-mercapto-3-methylbutylformate than Col and Bra, while 2-furfurylthiol, guaiacol and bethylguaiacol were present in lower concentrations. El contained less 4-vinylguaiacol and 2-furfurylthiol, but more 3-methyl-2-buten-1-thiol. Tip, Cat-P and Cat-Q differed from Col, Bra and Ken in having lower amounts of 2,3-butanedione, 2,3-pentanedione and 4-hydroxy-2,5-dimethyl-3(2H)-furanone and higher contents of guaiacol, 3-mercapto-3-methylbutylformate and 3-methyl-2-buten-1-thiol. The largest amount of 2-furfurylthiol was found in Tip and Cat-P. The blends from Col and Ken and the variety Tip showed a significant increase of guaiacol, 4-ethylguaiacol and 3-methyl-2-buten-1-thiol when the roast degree was raised. 2-Furfurylthiol and 2(5)-ethyl-4-hydroxy-5(2)-methyl-3(2H)furanone increased only in Col and Ken, while in Tip the amounts of carbonyl compounds, 4-hydroxy-2,5-dimethyl-(2H)furanone, methional and (E)-beta-damascenone decreased during roasting from medium to dark.