Techniques for ethanol removal before discrimination of alcoholic drinks using electronic noses (a review)

The use of "electronic noses" to measure aromas of alcoholic drinks is limi ted by ethanol which masks other volatile signals. In the first part of thi s paper, studies dealing with alcoholic beverage measurements using electro nic noses are analysed. This literature survey shows an increasing awarenes s of the. influence of alcohol content in alcoholic drink discrimination. E xperiments carried out with aroma sensors composed of the three commerciali sed technologies (metal oxide, conducting polymers and quartz microbalance) show the difficulty in discriminating hydro-alcoholic solutions or wines c ontaining Various aromas at very low concentrations. Therefore, these measu rements require a previous sample treatment. Ethanol has to he completely o r partially removed from the sample and volatiles must also be concentrated . Consequently, in the second part of the paper, various methodologies whic h are able to be adapted to ethanol removal, are put forward. This literatu re review analyses their performance level in comparison with ethanol remov al efficiency. Promising methods, such as pervaporation and solvent or adso rbent extraction, are detailed. However, many potential technologies remain to be studied thoroughly, such as gas permeation, apolar resins and concen tration methods like "purge and trap".