The fundamental role of pH in the anthocyanins chemical behavior and in their extractability during winemaking

Acetaldehyde is a common component of wine. It is already formed during the fermentation being an intermediate in the production of ethanol. Moreover, it can derive from the oxidation of ethanol during the wine production and aging. In wine, concentrations of acetaldehyde range from 30 to 130 mg/L. Acetaldehyde in wine can react with many compounds such as SO2, amino acids and

The rising trend of moderate wine consumption as a part of a healthy lifestyle promotes white wines with higher phenolic content because of their bioactive properties. Duration and temperature of the maceration process have a marked impact on the content and composition of wine phenolics. The aim of this study was to explore the effect of applying maceration processes of different durations and temperature on total phenolic content and flavan-3-ol compounds concentration of Malvazija istarska (Vitis vinifera L.) wines, an autochthonous Croatian white grape variety. Vinification took place at the Institute of Agriculture and Tourism (Poreč) where pre-fermentative two days cryomaceration treatment at 8 °C (CRYO), seven days maceration treatment at 16 °C (M7), and prolonged post-fermentative maceration treatments at 16 °C for 14 days (M14), 21 day (M21), and 42 days (M42) were studied and compared to non-maceration control treatment (C). Total phenolic content was determined by the Folin-Ciocalteu colorimetric method using a UV/VIS spectrophotometer and the results were expressed as gallic acid equivalents (mg/L GAE).

Climate changes are impacting viticultural regions throughout the world with temperature increases being most prevalent.1 These changes will not only impact the regions capable of growing grapes, but also
the grapes that can be grown.2 As temperatures rise the growing degree days increase and with it the sugar accumulation within the berries and subsequent alcohol levels in wine. Consequently, viticultural
practices need to be examined to decrease the levels of sugars.

Le territoire de Suzette se développe sur un grand coteau viticole et boisé situé au cœur du site naturel des Dentelles de Montmirail (40km au nord d’Avignon). Ce site est à la fois l’un des pôles d’attraction touristique du département et le lieu d’une production viticole renommée (Gigondas, Vacqueyras, Beaumes de Venise, … ). Cet ensemble remarquable de terrasses viticoles et de crêtes rocheuses et boisées, forme un des paysages emblématiques du Vaucluse. La commune est actuellement soumise à une importante pression foncière due à une forte demande résidentielle. Le paysage du coteau forme et possède de ce fait un patrimoine culturel de valeur et une image de marque importante pour la production viticole locale.

Climatic changes cause significant variations in the composition of grapes. for red grapes, a mismatch between phenolic and technological ripening is often observed. There is also often a marked increase in pH and a reduction in fixed acids, which affect the stability and evolution of the wine during ageing. These experiments will provide more information on the role of pH during the winemaking of red wines on the extraction and evolution of phenolic compounds.