Comparison of potent odorants in a filtered coffee brew and in an instant coffee beverage by aroma extract dilution analysis (AEDA)

An overall sensory evaluation of a freshly prepared filtered coffee brew (FC) and an instant coffee beverage (IC) using a sensory panel revealed a clear difference in the aromas of both beverages, when smelled at 60 °C. Application of the aroma extract dilution analysis (AEDA) on an extract of FC indicated 40 odour-active compounds, of which (E)β-damascenone, methional, 3-mercapto-3-methylbutyl formate, 5-ethyl-3-hydroxy-4-methyl-2(5H)-furanone, 4-hydroxy-2,5-dimethyl-3(2H)-furanone and several phenols were detected as the most intense odorants. In IC, the same odorants were identified based on an evaluation by AEDA, but the flavour dilution (FD) factors of nearly every compound were much lower. The largest differences were determined for some sulfur-containing odorants (e.g., 2-methyl-3-furanthiol, 2-furfurylthiol, 3-mercapto-3-methylbutyl formate) as well as 2-methoxyphenol, 4-ethyl-2-methoxyphenol, 4-vinyl-2-methoxyphenol, vanillin and an unknown meaty smelling compound, which were much higher in FC. The lack of these, in combination with the unchanged odour activities of, in particular, the caramellike, seasoning-like smelling odorants is undoubtedly involved in the flavour differences between FC and IC.