Monitoring of the ageing of red wines in oak barrels by means of an hybrid electronic tongue

A novel hybrid sensor array based on voltammetric electrodes has been successfully applied to monitor the ageing of red wines and to discriminate wine samples aged in oak barrels of different characteristics (wood origin and the toasting level). The hybrid sensor array is formed by three families of chemically modified electrodes, including polypyrrole sensors doped with a range of counterions, carbon paste electrodes modified with metallophthalocyanine complexes and finally, carbon paste electrodes modified with perylene imide derivatives. The diversity of the sensing materials has allowed obtaining a high cross-selectivity in the responses of the sensors forming the array. This voltammetric signals provided by the sensors have been used as data source for a principal component analysis (PCA) and soft independent modelling of class analogy (SIMCA) to confirm the high capability of discrimination and classification of the e-tongue.The array of voltammetric sensors has been able to follow the changes experienced by red wines aged in oak barrels after 3 and 6 months of ageing. In addition, the differences caused by oak barrels of different origins (French, Lithuanian and American) and toasting levels have also been discriminated.