Hierarchy of the interactions between physical and biological parameters intervening in the Pyrenean Gascon foothill vineyard

AIM: The objective of this work is to study the effect of the addition of polysaccharides extracted for grape pomace by-products and musts on sensory and chemical composition of white wines. Much of the waste obtained in the wine sector is not used, and they can have some valuable compounds, such as the polysaccharides (PS).

In this work we try to know the influence of two irrigation systems (Drip and Micro – jet ) with the same levels of water applied in an experimental vineyard in the region of Felgueiras.

Saccharomyces cerevisiae is the most commonly used yeast species in winemaking. The recent research showed that non-Saccharomyces yeasts as fermentation starters show numerous beneficial features and can be utilized to reduce wine alcoholic strength, regulate acidity, serve as bioprotectants, and finally improve wine aromatic complexity. The majority of published studies on this topic investigated the influence of sequential or co-inoculations of non-Saccharomyces and S. cerevisiae yeasts on the aroma of final wine.

The microbial diversity during spontaneous grape must fermentation has a determinant influence on the chemical composition and sensory properties of wine. Therefore, yeast diversity is an important target to better understand wine regionality. Hence, the aim of this study was to isolate, identify, and characterize the yeast core microbiota in grape must during the early stage of lab-scale spontaneous fermentation of withered grapes to produce Amarone della Valpolicella wine (Verona, Italy).

In the study of terroir, a separate analysis of its many component factors can be of great help in accurately identifying a vineyard’s natural elements that impact wine quality and typicity. This research used a dedicated pluri-disciplinary approach to investigate the ecological characteristics, including geology and geographical features, of 14 vineyards that produce Gewürztraminer and Sauvignon Blanc cultivars in the alpine Alto Adige DOC wine region. Both the geopedological method using Vineyards Geological Identity (VGI) and the new Solar Radiaton Identity (SRI) topoclimatic classification method were used to provide analytical measurements and qualitative/quantitative characterisations. In addition, wide-ranging targeted and untargeted oenological and chemical analyses were carried out on grapes, musts and wines to correlate the soils’ geomineral and physical conditions with the biochemical properties of their fruits and wines. The research identified strong correlations between vineyard geo-identity and wine biofingerprint, confirming a mineral traceability of strontium rubidium ratio and some minerals distinctive to the local geology, such as K, Ca, Ag, Ba and Mn.  The study also discovered that particular geomineral and physical soil conditions of the studied vineyards are related to the different amount of amino acids, primary varietal aromas and polyphenols found in grapes, musts and wines. The research confirmed that winemaking technologies support oenological quality, although in some cases, human practices can overpower certain characteristic elements in wine, erasing the typical imprint left by the vineyards’ natural terroir, which becomes less traceable. Terroir abiotic ecological factors and vineyard identity can be classified in detail using the new VGI and SRI analysis methods to discover interrelationships between geo-pedological and topoclimatic conditions that impact wine quality. These methods are also helpful in identifying which ecological elements are exclusive to a particular vineyard or wine sub-region.