Use of the soils information system for detailed vineyard soil surveys and as a component of precision viticulture

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.

Cabernet Sauvignon is one of the most important winegrape varieties in Chile. However, temperature raise and decreased rainfall due to climate change can lead to grape quality decrease in certain areas. Amino acids are essential as nitrogen source for yeast but also directly affect grape quality serving as precursors of certain volatile compounds that enhance the wine bouquet. Besides, glutathione is an important tripeptide acting as antioxidant, preventing the appearance of browning pigments in must and exerts a protective effect in volatile compounds.

The AOC Gaillac area is divided into three main terroirs : « The left bank terraces », « The right bank coteaux » and
« The plateau Cordais ». This division is valid at a regional scale, but it suffers of a number of local-scale exceptions. This spatial variability of the pedologic-geologic characteristics at the plot scale has been derived mainly from the main late-Würmian solifluxion phase occurring at the transition between the peri-glacial climate and the Holocene temperate conditions (13,000-10,000 yrs BP).

Under current climate change pressures, obtaining grapes with adequate acidity at harvest is one of the main challenges for growers, especially if the goal is producing sparkling wines. This issue arises from two main occurrences: i) higher temperatures enhance degradation of malic acid; ii) grape maturity may occur under suboptimal climatic conditions due to an advanced phenology.

Astringency sensation decreases slowly during the aging of red wine. Complex reactions of condensation and precipitation of wine polyphenols are involved in this phenomenon. Wine composition and conditions of aging, such as temperature and oxygen availability, strongly influence evolution of the phenol matrix. Recently, a Post-Fermentative cold Maceration (PFM) technique was tested with the aim of accelerating reactions leading to the reduction of astringency and exploiting chemical compounds not extracted from the solid parts of grapes during the previous traditional maceration phase. To this purpose, an innovative maceration system was engineered and used to perform PFM trials on marc derived from vinification of different varieties of red grapes.