Varietal volatile patterns of Italian white wines

Abstract

Aroma diversity is one of the most important features in the expression of the varietal and geographic identity and sensory uniqueness of a wine. Italy has one of the largest ampelographic heritages of the world, with more than five hundred different varieties. Among them, many are used for the production of dry still white wines, many classified as Protected Designation of Origins and therefore produced in specific geographical areas with well-defined grape varieties. Chemical and sensory characteristics of the aroma of these wines have never been systematically studied, and the relative diversity has never been described and classified. During this study, which is part of the activities of the D-Wines research consortium, we considered 249 samples of different mono-varietal white wine types (Albana, Arneis, Cortese, Erbaluce, Garganega, Gewurztraminer, Greco di Tufo, Falanghina, Fiano, Lugana, Müller Thurgau, Nosiola, Pallagrello, Pinot Grigio, Ribolla Gialla, Verdicchio, Vermentino, Vernaccia di S. Gimignano) corresponding to major Italian PDOs. Volatile compounds primarily associated with varietal and geographical origin, namely terpenes, norisoprenoids, sulphur compounds and methyl-salicylate, have been analysed by means of different SPME-GC-MS techniques. Multivariate analysis and Hierarchical Cluster Analysis of volatile compounds showed a complex segmentation in which each wine type showed patterns of chemical compounds with similarities within the group but which at the same time partly overlapped with the patterns of other wine types. Despite this, almost all compounds showed significant differences according to wine type. We found that Vermentino was characterized by high concentrations of terpenes and in particular of linalool, whereas for other wine types either sulfur compounds, such as DMS, or norisoprenoids, such as β-damascenone, were found to be significantly discriminant. Similarities between wines from the same grape variety but different geographical origin were also detected, as in the case of Verdicchio and Lugana, both characterized by a higher methyl salicylate content.