Influence of climatic conditions on grape composition of Tempranillo in La Mancha DO (Spain)

Climate change is affecting wine production and inducing significant variability in wine composition between vintages.

Amarone is an Italian red wine with worldwide recognition and high added value. In Amarone wines, grapes undergo a withering process before vinification; this leads to a modification in the concentrations of sugars, acids, and secondary metabolites.

Trebbiano di Lugana (TdL) is a white variety of Vitis vinifera mainly cultivated in an Italian area located south near Garda lake (Verona, north of Italy). This grape cultivar, also known as “Turbiana,” is used for the production of TdL wine with recognized Protected Designation of Origin whose volatile profile was recently determined [1]. The presence of varietal thiols in TdL, namely 3-mercaptohexan-1-ol and its acetate form, conferring the tropical and citrus notes, has been documented. Winemaking strategies were also described with the purpose of protecting and maintain these desired aromas [2]. To the best of our knowledge, the varietal thiol precursors (VTPs) were not previously determined in TdL grape and must. This study aimed to quantify VTPs in both grape during the ripening and must during the pressing. Volatile C6 compounds were also measured in the must fractions.

The balance between the different flavours of a wine largely determines its perception and appreciation by the consumers. In white wines, sweetness and sourness are usually the two poles balancing the taste properties. The bitter flavour, on the other hand, is frequently associated with a loss of equilibrium and all white wines (dry and sweet, young and aged) are affected.
Several bitter compounds are already well-described in wines.

Typically, subjective, and visual methods are used by grape growers to assess harvest maturity. These methods may not accurately represent the maturity of an entire vineyard – especially if extensive and representative sampling was not used. New technologies have been investigated for improved harvest management decisions. Spectroscopy methods utilizing the near-infrared region of the light spectrum is one such technology investigated as an alternative to classic methods and particularly the application of hyperspectral imaging (HSI) has recently gained attention in research. HIS is a spectroscopic technique that obtains hundreds of images at different wavelengths collecting spectral data for each pixel in the sample i.e., providing both spectral and spatial data.