High-performance bioelectronic tongue for the simultaneous analysis of phenols, sugars and organic acids in wines.

Abstract

Electronic tongues have been widely used to analyze wines. However, due to the complexity of the matrix, the problem is not completely solved and further improvements are required. A high-performance potentiometric bio-electronic tongue (bio-ET) specifically devoted to the assessment of wine components is presented. The novelty of this system is due to two innovative approaches. First, the improved performance is obtained through the use of potentiometric biosensors based on carboxylated PVC membranes where enzymes specific to compounds of interest (glucose oxidase, tyrosinase, laccase and lyase) are linked covalently. Secondly, the performance is further enhanced by introducing in the PVC membrane electron mediators (AuNPs or CuPc) that facilitate the electron transfer process. Individual sensors exposed to target analytes (glucose, catechol, cysteine or tartaric acid) show a linear behavior with limits of detection in the range of 10-4 M for all the compounds analyzed, with excellent reproducibility (CV lower than 3%). Sensors combined to form a bio-ET, show excellent capabilities. Principal Component Analysis (PCA), can discriminate monovarietal white wines (PC1 77%; PC2 15%) and red wines (PC1 63%; PC2 30%). Using Partial Least Squares (PLS) the bio-ET can provide information about chemical parameters including Glucose, Total Polyphenols, Total Anthocyanins, Free SO2 , Total SO2 , Total acidity and pH with square correlation coefficients (R2 ) between 0.91 and 0.98 in calibration and between 0.89 and 0.98 in validation. This advanced instrument is able to assess the levels of seven parameters in a single measurement providing an advantageous method to the wine industry. This article is protected by copyright. All rights reserved.