Use of hyperspectral data for assessing vineyard biophysical and quality parameters in northern Italy

The blend of grapes used in the production of the four Valpolicella PDOs red wines, namely Valpolicella, Valpolicella Classico Superiore, Recioto della Valpolicella and Amarone della Valpolicella is quite unique, and includes two main varieties Corvina and Corvinone, and other minor varieties. To a very large extent all these grapes are only grown in the province of Verona. One of the main characteristics of Valpolicella is the use of grapes that are submitted to post-harvest withering. The aim of this study was therefore to evaluate the evolution of the free and glycosidically-bound volatile compounds in Corvina and Corvinone grapes under real production conditions.

Chardonnay is the world’s most planted white grape variety and has met a great commercial success for decades.

All along the red winemaking process, many microorganisms develop in wine, some being beneficial and essential, others being feared spoilers. One of the most feared microbial enemy of wine all around the world is Brettanomyces bruxellensis. Indeed, in red wines, this yeast produces volatile phenols, molecules associated with a flavor described as “horse sweat”, “burnt plastic” or “leather”. To produce significant and detectable concentrations of these undesired molecules, the yeasts should first grow and become numerous enough. Even if the genetic group of the strain present and the cellar temperature may modulate the yeast growth rate¹ and thus the risk of spoilage, the main factor seems to be the wines themselves, some being much more permissive to B. bruxellensis development than others.

ine nitrogen deficiency can negatively influence the aroma profile and ageing potential of white wines. Canopy management can alter vine microclimate, affect the nitrogen availability and influence the response of leaf senescence. Increasing the nitrogen availability to vines can increase the Yeast Assimilable Nitrogen (YAN) levels in harvested fruit and wine. Studies show that foliar nitrogen and sulphur applications at véraison, on low YAN Sauvignon blanc grapes have an effect on the level of amino acids (Jreij et al. 2009) and on S-containing compounds such as glutathione and thiols (Lacroux et al. 2008), which in turn can influence the formation of major volatiles and the aroma profile of the wine.

Controlling the speed of alcoholic (AF) and malolactic (MLF) fermentations in wine can be an important challenge for the production of certain short rotation wines for entry-level market segments. Immobilization techniques for Saccharomyces cerevisiae and Œnococcus œni, the microorganisms responsible for these fermentations, are widely studied for industrial applications. Indeed, these processes allow to accumulate biomass and thus to increase cell densities inducing high fermentation velocities. Recent works have shown the performance of MLF carried out with biofilms of O. œni, immobilized on various supports in a rich medium (MRSm: modified MRS broth with malic acid and fructose).