Portal de Periódicos da CAPES

Determination of total polyphenol index in wines employing a voltammetric electronic tongue

2012; Elsevier BV; Volume: 732; Linguagem: Inglês

10.1016/j.aca.2012.02.026

1873-4324

Xavier Cetó, Juan Manuel Gutiérrez, Manuel Gutiérrez‐Capitán, Francisco Céspedes, Josefina Capdevila, Santiago Mínguez, Cecilia Jiménez‐Jorquera, Manel del Valle,

Analytical Chemistry and Chromatography

This work reports the application of a voltammetric electronic tongue system (ET) made from an array of modified graphite-epoxy composites plus a gold microelectrode in the qualitative and quantitative analysis of polyphenols found in wine. Wine samples were analyzed using cyclic voltammetry without any sample pretreatment. The obtained responses were preprocessed employing discrete wavelet transform (DWT) in order to compress and extract significant features from the voltammetric signals, and the obtained approximation coefficients fed a multivariate calibration method (artificial neural network-ANN-or partial least squares-PLS-) which accomplished the quantification of total polyphenol content. External test subset samples results were compared with the ones obtained with the Folin–Ciocalteu (FC) method and UV absorbance polyphenol index (I280) as reference values, with highly significant correlation coefficients of 0.979 and 0.963 in the range from 50 to 2400 mg L−1 gallic acid equivalents, respectively. In a separate experiment, qualitative discrimination of different polyphenols found in wine was also assessed by principal component analysis (PCA).