Présentation d’une méthodologie de caractérisation des terroirs et valorisation par l’étude de l’effet terroir sur la typicité et l’originalité du produit vin dans la région des Côtes du Rhône

β-Damascenone is a key norisoprenoid in grape (Vitis vinifera L.) that imparts floral and fruity aromas to both fruits and wines. It is derived from carotenoid metabolism, with neoxanthin as a substrate.

Studying wine metabolome through multiple targeted methods is complicated and limitative; since grapes, yeasts, bacteria, oxygen, enological techniques and wine aging collaborate to deliver one of the richest metabolomic fingerprint.

The enzymatic browning of grape must is still a major problem in oenology today [1] being particularly serious when the grapes have been infected by grey rot [2]. Browning is an oxidation process that causes certain foods to turn brown, which often leads to them being rejected by consumers [3]. This is a particular problem in the case of wine, because grape must is very vulnerable to enzymatic browning [4].

Glutathione is a tripeptide (γ-Glu-Cys-Gly), which can occur in grapes, in must and in wine prevalently in the reduced form as well as in the oxidized form as glutathione disulfide. The importance of the reduced form of glutathione lies in its antioxidant activity. In must, it limits browning by reducing o-quinones produced by polyphenol oxidase activity on hydroxycinnamic acids; in wine, it exerts a protective effect on various aromatic compounds. Glutathione concentration in wine is lower than in grape juice and variable as it depends on several factors, ranging from the native content of grapes to winemaking technique.

Astringency is a crucial sensory attribute typically described as the drying and/or puckering sensation occurring after the consumption of tannin-rich foods and beverages. In this study, thirty-seven red wines from different varieties, origins and styles were evaluated, analyzing both chemical and sensory features. Principal Component Analysis was used for dimensionality-reduction and for correlating selected chemical parameters against astringency. The results showed that tannin content was the most important chemical parameter influencing overall astringency but more clearly the dryness sub-quality, followed by pH, titratable acidity and alcohol content.