Characterization of phenolics and VOCs in wines obtained from Malbec vineyards of the Uco Valley submitted to high-altitude solar UV-B and water restriction

Fungal chitosan is a polysaccharide made up of glucosamine and N-acetyl-glucosamine and derived from chitin-glucan of Aspergillus niger or Agaricus bisporus. Fungal chitosan has been authorized as an antiseptic agent in wine since 2009 (OIV) and in organic wine in 2018. At the maximum dose of 10g/hl, it was shown to eliminate Brettanomyces bruxellensis, the main spoilage agent in red wines. Fungal chitosan is highly renewable, biocompatible (ADI equivalent to sucrose) and non-allergenic. However, winemakers often prefer to use sulfites (SO2), though sulfites are classified as priority food allergens, than chitosan. Indeed, many conflicting reports exist regarding its efficiency and its side effects towards beneficial wine microorganisms or wine taste. These contradictions could be explained by the heterogeneity of the fungal chitosan lots traded, the diversity of the wines (chemical composition, winemaking process), but also, by the recently highlighted huge genetic diversity prevailing in wine microbial species.

AIM: Study the chemical and sensory parameters of fifty commercial white wines elaborated with different techniques (fermented in oak barrel and aged on lees (FB+AL); aged on lees (AL); and without aging (WA)) and different grape varieties (Verdejo, Sauvignon blanc and Godello).

The under-way zoning works of the Emilia viticulture have pointed out a huge variability of the features of the soils, which belong to this area.

Grapevine (Vitis vinifera) and its derived products, in terms of cultivated area and economic volume, constitute the most relevant fruit crop in the world (7.5 million cultivated hectares). In the current context of climate change, the wine sector faces unprecedented challenges to satisfy a growing demand for wines of greater quality through sustainable viticulture. Global warming threatens quality wine production in Mediterranean wine regions in particular. The increase in heatwaves and drought episodes accelerate the vine phenology and alter the ripening and composition of grapes and wine. Extreme abiotic stress episodes compromise grape production and plant survival, intensifying the pressure on the use of limited resources like water. Abscisic acid (ABA) is an important hormone in the ripening of certain fruits and in plant response to abiotic stress.

According to the last IPCC report, the scale of recent climate changes are unprecedented over many centuries. Each of the last four decades has been successively warmer than any decade since 1850. Projections for the future foresee that temperature could reach +3.3°C to +5.7°C under the most pessimistic scenario. It is also projected that every region will face more concurrent and multiple changes in climatic impact-drivers. The frequency of extreme climate events is also likely to increase, as well as the occurrence of indirect constraints. These evolving climatic conditions are alrealdy affecting and will continue to affect the suitability of traditional wine grape production areas, but also create opportunities in new locations.