FEASIBILITY STUDY ON THE PASSITO WINES DISCRIMINATION BY AN E-TONGUE

The passito wines are a cultural and territorial heritage of Calabria (South of Italy). Here, three passito wine are produced from dried grapes of autochthonous vine: Greco di Bianco PDO, Mantonico IGT and Moscato di Saracena. Wine sensory attributes, closely tied not only to aromatic volatile compounds but also to the chemical composition (pH, total and volatile acidity, polyphenolic compounds), are crucial to determine consumer approval. The acidity in wine is an important component in the quality and taste. The amount of total acidity, refers to all acids, in wine tasting, refers to the fresh and sour attributes which are evaluated in relation to the sweetness and bitter components of the wine (i.e. phenolics). The electronic tongue is based on similar principles to the human tongue. It is able to discriminate the five different tastes - sweet, salty, bitter, acidic and umami (savoury) - and it is sensitive to multiple substances that determine taste and flavour of wine. The final aim of this research line was the optimization of the device to detect passito wine fraud. In this work was tested potentiality of the e-tongue for passito wine quality classification. The analyses were performed with the α-Astree electronic tongue (Alpha MOS company), that consisted of seven different liquid cross-selective potentiometric sensors and an Ag/AgCl reference electrode. The sensor responses were evaluated using discriminant function analysis (DFA). The e-tongue data were validated by means of conventional chemical methods for the determination of the main wine chemical parameters. The electronic tongue was able of distinguishing the passito wines from different geographical areas as well as the passito wines produced at different vintage. Thus, the instrument can be used for fast identification of passito wines.