Vineyard microclimate alterations induced by black mulch through transcriptome reshaped the flavoromics of Cabernet Sauvignon

Climate change is leading to an increase in average temperature and in the frequency and severity of heatwaves that is already significantly affecting grapevine phenology and berry composition (Webb et al., 2010). This is compounded by water stress, which is well known to increase the vulnerability of grapevines and berries to heatwaves. In hot climate regions like australia, grape production is only possible due to relatively secure supplies of water for irrigation. However, the upper temperature limits for berry survival of well-watered grapevines remains to be tested.

Amino acids are crucial nitrogen sources in yeast metabolism, influencing both biomass production and fermentation rate. The breakdown byproducts of amino acids contribute to the aroma of the wine and wine’s health benefit compounds. This study focused on the yeast’s extracellular metabolic profile of tryptophan, tyrosine, and phenylalanine belonging to the group of aromatic amino acids in experimental Maraština wines. Alcoholic fermentations were conducted on sterile grape Maraština must using seven autochthonous non-Saccharomyces yeasts in sequential fermentation with commercial Saccharomyces cerevisiae.

As elsewhere, southwestern France vineyards face more recurrent summer heat waves these last years. Among the possibilities of adaptation to this climate changing parameter, the use of net shading is a technique that allow for limiting canopy exposure to radiations. In this trial, we tested net shading installed on one face of the canopy, on a north-south row-oriented plot of cv. Gros Manseng trained on VSP system in the PDO Pacherenc-du-Vic-Bilh. The purpose was to characterize the effects on the ambient canopy temperatures and radiations during the season and to observe the consequences on the composition of grapes and wines. Two sorts of net were used with two levels of obstruction (50% and 75%) of the photosynthesis active radiation (PAR). They have been installed on the west side of the canopy and compared to a netless control. Temperature and PAR sensors registered hourly data during the season. On specific summer day (hot and sunny) manual measurements took also place on bunches (temperature) and in different spots of the canopy (PAR). The results showed that, on clear days, the radiation is lowered by the shade nets respecting the supplier criteria. The effects on the ambient canopy temperature were inconstant on this plot when we observed the data from the global period of shading between fruit set and harvest. However, during hot days (>30°C), the temperature in the canopy was reduced during afternoon and the temperature of the bunch surface was reduced as well comparing to the control. A decrease of the maturity parameters of the berries, sugar and acidity, was also observed. Concerning the wine aromatic potential, no differences clearly appeared.

Si on part de l’introduction que l’activité vitivinicole maintenant plus que jamais doit être une activité d’entreprenariat introduite de mieux en mieux sur le territoire et donc effectuée pour rendre maximal le Profit

Aging process is an essential stage in the improvement of wine quality. This process is usually performed by contact with oak wood whose compounds are released and transferred to wine, acquiring typical aging bouquet. Although the use of oak chips is a practice generally accepted as alternative to barrels to shorten aging process, the application of emerging technologies is being unfolded to accelerate this stage.