Effets de l’application d’acide gibbérellique (GA3) sur la qualité de raisins et de vins produits en climat tropical au Nord-Est du Brésil

Context and purpose of the study. The concept of terroir encompasses the investigation of the physical environment’s influence on grapevine physiology, grape composition, and wine quality, with an emphasis on employing viticultural zoning techniques to systematically characterize and analyze terroirs.

Through the years, extensive studies have been conducted on fungal biodiversity during the winemaking process: from the vineyard until aging.

The consequences of the global climate change in the vitiviniculture are revealed as a gap between phenolic and technological grape maturities, higher grape sugar concentration that leads to high wine alcohols levels, lower acidities and high pH values, among others. The unbalanced phenolic maturity caused in this scenario leads to harsh astringency and to instable colour of wines. Previous studies have reported that the addition of yeast mannoproteins (MPs) to wines may have positive effects on these two organoleptic properties due to their capability to interact with wine polyphenols [1]; however, studies about the effect of the pH on these interactions have not been carried out so far.

Nowadays there are many challenges facing both winegrowers and workers, in other agricultural practices, related to the growing demand for food products, the safety and quality of these products, and the preservation of the environment…

Malolactic fermentation (MLF) is a secondary wine fermentation conducted by lactic acid bacteria (LAB). This fermentation is important in winemaking as it deacidifies the wine, converting L-malic acid into L-lactic acid and carbon dioxide, and it contributes to microbial stability. Wine pH is highly selective, and at pH below 3.5 generally only strains of O. oeni can survive and express malolactic activity, while under more favorable growth conditions above pH 3.5, species of Lactobacillus and Pediococcus may conduct the MLF. Among the LAB species Lactiplantibacillus plantarum strains have shown most interesting results under hot climate conditions, not only for their capacity to induce MLF, but also for their homo-fermentative properties towards hexose sugars, which makes them suitable for induction of MLF in high pH and high alcohol wines, when inoculated at the beginning of alcoholic fermentation.