How the management of ph during winemaking affects acetaldehyde evolution and the formation of polymeric phenolics over the red wine aging

With the steady rise in wildfire occurrence in wine regions around the world, there are quality issues beginning to face the wine industry. These fires produce clouds of smoke which have the ability to carry organic molecules across vast distances that can be absorbed by grapes. When these compounds make their way into the final wine, unpleasant smokey and burnt flavors are present, along with a lasting ashy finish. Along with the volatile compounds carried by smoke, once incorporated into the fruit these compounds become bound to sugars, forming glycosidic compounds.

Although the ripening process of grapevine berries is well-documented at the vineyard level, pinpointing distinct developmental stages remains challenging. The asynchronous development of berries results in dynamic biases and metabolic chimerism. It is thus crucial to consider individual berries separately and resynchronize their internal clock for deciphering physiological changes throughout development. Given the importance of grape composition in wine quality, we aimed at measuring developmental changes in the metabolome of Syrah single berries from anthesis to over-ripening, without a priori preconceived.

Stomata are microscopic pores mainly located in leaf epidermis, allowing gas exchanges between plants and atmosphere. Stomatal initiation relies on the transcription factor SPEECHLESS which is mainly regulated by the MAP kinase cascade, in turn controlled by small signaling peptides, the Epidermal Patterning Factors (EPF and EPF-Like), namely EPF1, EPF2 and EPFL9. While EPF1 and EPF2 induce the inhibition of SPEECHLESS, their antagonist, EPFL9, stabilizes it, leading to stomatal formation. In grapevine, there are two paralogs for EPFL9, VviEPFL9-1 and VviEPFL9-2. Despite their structural similarity, it remains unclear whether they are differentially regulated and have distinct roles.

Cette communication sera basée sur les résultats d’une étude auprès des consommateurs réalisée par la société G3 pour l’I.N.A.O. sur les attitudes des consommateurs vis à vis des produits de terroir et des A.O.C. et sur un mémoire de DEA soutenu par Monsieur J-C. DURIEUX à l’Université de Paris X Nanterre, consacré aux variables explicatives du comportement d’achat des vins A.O.C.

Clonal evaluation of winegrapes in California has not been extensive. Early selection work by Alley (1977), Olmo (unpublished data) and Goheen (personal communication) resulted in the current collection