REDWINE project: use of Chlorella vulgaris to prevent biotic and abiotic stress in Palmela’s region, Portugal, vineyards

Mannoproteins (MPs) constitute one of the most abundant classes of wine polysaccharides. They are proteoglycans located in the yeast cell wall that are composed by a major polysaccharide moiety (formed mainly by mannose) linked to a minor protein part.

Nowadays, the rapid growth of vineyards with organic practices and the use of copper as the only fun-gicide against downy mildew raises again the question of the effect of copper on varietal thiols in wine, especially 3-sulfanylhexan-1-ol (3SH) and its acetate (3SHA). A few decades ago, several works indicated that the use of copper in the vineyard had a negative effect on the content of varietal thiols in Sauvignon blanc wines [1, 2]. However, these studies only considered the concentration of the reduced form (RSH) of varietal thiols, without quantifying the oxidised ones. For this purpose, we proposed to monitor both reduced and oxidised forms of varietal thiols in wine under copper stress during alcoholic fermentation to have a more complete picture of the biological and chemical mechanisms.

The aim was to study the impact of structural features in the polysaccharide moiety of mannoproteins on their interaction with polyphenols and the formation of colloidal aggregates.

Acidity is often touted as a predictor of wine ageability, though surprisingly few studies have systematically investigated the chemical basis for this claim.

Dimethyl sulfide (DMS) is a volatile sulfur compound with a complex role in wine aroma, contributing both desirable and undesirable sensory characteristics depending on its concentration (1).