Viticulture and climate: from global to local

Tannin and polysaccharide concentration and composition is important in defining the texture of red wines, but can vary due to factors such as cultivar, region, grape ripeness, viticultural practices and winemaking techniques. However, the concentration and composition of these macromolecules is dependent not only on grape tannin and polysaccharide concentration and composition, but also their extractability and, in the case of polysaccharides, their formation by yeast. Through studies into the influence of grape maturity, winemaking and sensory impacts of red grape polysaccharides, seed and skin tannins, recent research in our laboratory has shown that the processes involved in the extraction of these macromolecules from grapes and their retention in wine are very complex.

The behaviour of cv. “Tinta Roriz” (Vitis vinifera L.), was studied when moderate drip irrigation was applied from veraison to harvest. Field studies were conducted during three growing seasons

AIM Astringency is described as a ‘dry puckering‐like sensation’ following consumption of tannins1 that affect consumer preference of foods and beverages, including red wine2. To improve the understanding of astringency, which is a complex interaction due to multiple mechanisms occurring simultaneously, further studies are needed. In this view, oral tribology is considered a useful technique for beverage study to evaluate the thin-film lubrication properties of saliva resulting in oral friction‐related sensations3. The aim of this study was to examine the film behavior of selected protein-based fluids under controlled friction conditions, to understand polyphenol-protein interactions involved in the sensation of astringency.

Previous work from our laboratory has shown that both a purified toasted oak powder and extracts made from unoaked and oaked red wines influenced physiological parameters, metabolism and hepatic gene expression in high-fat fed C57/BL6J male mice (Luo et al., 2020).  Impacted pathways included glucose metabolism, liver fat accumulation, markers of chronic inflammation, and expression of the Gsta1 mRNA.  

Botrytis cinerea is a necrotrophic pathogen that causes one of the most serious diseases of the grapevine (Vitis vinifera), grey mold or Botrytis bunch rot. In Champagne, the Botrytis cinerea disease leads to considerable economic losses for winemakers and wines exhibit organoleptic defaults.