Résumé
Ethanol is the major constituent of the head-space of alcoholised beverages and generate a strong signal on the sensor arrays used in electronic noses, impairing aroma discrimination. Head-space de-alcoholisation strongly improved the aroma sensing ability of a MOS-based Enose. However, discrimination was still affected by the original alcohol content, because ethanol decreased the aroma compound volatility. This effect was quantified by gas chromatographic analysis in the 0–12% (v/v) ethanol concentration range, further demonstrated on reference samples using a electronic nose coupled with a de-alcoholisation system and illustrated during a discrimination study between spirits, beers and wines. The amplitude of ethanol effect could not be quantitatively predicted from usual physico-chemical characteristic of aroma compounds.
Therefore, ethanol effects seem to have been strongly underestimated in the past. When no head-space pre-treatment can be achieved, experimental procedures should be revisited to avoid erroneous discriminations.