Potentiometric sensor with lipid-polymer membranes for quality assessment of French red wines

The quality of wines resulting from vineyard management is important for consumers due to the taste and price of wines. In this work, the quality of red wines of three vintages has been investigated by potentiometric sensors with six all-solid-state electrodes. Two series of experiments were carried out. The first involved a qualitative analysis of wine of different vintages from freshly opened bottles. The second consisted of measurements on wine samples of different vintages that had been in contact with air for 15 min every day during 15 or 21 d. This sensor is characterized by good sensitivity to malic acid solutions of different concentrations. The polyphenol content and organoleptic acidity of red wines from different vintages have been established. The older the wine, the more polyphenol compounds it contains. The same sequence of polyphenol content can be observed in wine samples of different vintages that had been in contact with air for 15 min every day during 21 d. The samples of wine from freshly opened bottles from 2013 were more acidic than the wines between 2012 and 2014. The potentiometric results submitted to principal component analysis and cluster analysis have shown that wine samples from different vintages can be grouped according to their organoleptic acidity. The wine samples from freshly opened bottles and wine samples in contact with air belong to separate groups. It seems that the contact of wine with air influences its quality and plays the main role in wine grouping.