Using an e-tongue based on voltammetric electrodes to discriminate among red wines aged in oak barrels or aged using alternative methods: Correlation between electrochemical signals and analytical parameters

An electronic tongue based on voltammetric sensors has been used to discriminate between red wines aged in oak barrels and red wines matured in steel tanks in contact with oak wood chips. The quality of wines has also been analyzed by means of conventional chemical methods. Principal component analysis has demonstrated that both methods allow discriminating wines according to the type of ageing. Moreover, partial least squares (PLS) regression has demonstrated that measurements carried out with the electronic system allow establishing prediction models that are capable to infer the methodology used to age wines. Good correlations have been found between the signals obtained with the electronic tongue and the chemical parameters. Moreover, the electrochemical signals have been successfully employed to estimate chemical parameters related to the polyphenolic content or the pH such as the tannins content. Both the calibration and the validation values obtained by using partial least squares (PLS2) regression method, indicate a good-quality model performance (slope near 1, off set near 0 and large correlation between sensors and categorized variables).