Effect of grape polysaccharides on the volatile composition and aromatic profile of Viura wines

Il a été souvent démontré (Seguin, 1970), que les meilleurs terroirs sont ceux qui présentent pendant la période de maturation du raisin, une régulation et une limitation de l’alimentation hydrique de la vigne. Si on s’intéresse aux facteurs influençant ce régime hydrique, on constate le rôle prépondérant du taux d’éléments grossiers non poreux qui limitent la réserve utile du sol en diminuant le taux de terre fine. De plus, ces éléments grossiers jouent également un rôle au niveau du pédo-climat thermique car leur conductivité thermique et leur chaleur spécifique sont plus élevées que celles de la terre fine. Ainsi le sol se réchauffera et se refroidira plus rapidement (Saini et McLean, 1967), (Gras, 1994).

The need to rationalize agricultural inputs has recently increased interest in assessing vineyard variability in order to implement variable rate input applications, so-called ‘precision viticulture’. In many viticultural areas globally, precision viticulture is already widely used such as for selective harvesting and variable rate application (VRA) of inputs such as irrigation and/or fertilizer. Robust VRA relies on having a geostatistically accurate map (of one or more vineyard attributes) requiring high sampling densities, which can be cost- and time-prohibitive to obtain. Previous work on spatial interpolation using kriging have upscaled ground-based measurements, but such upscaling strategies are applicable only when vineyard conditions are spatially continuous and satisfies the assumption of second-order stationary processes. Alternatively, mixed models that combine kriging and auxiliary information, such as the regression kriging (RK) method, are more instructive for spatial predictions. In order to improve prediction accuracies, it is therefore necessary to incorporate additional information to achieve accurate spatial patterns with low error.

In red wines the post-MLF SO2 addition is an essential event. It is also the case for the “mutage” during the elaboration of the “liquoreux”. At these moments SO2 plays an antimicrobial action and an antioxidant effect. But at current pH of wines, ensuring a powerful molecular SO2 has become very difficult. Recent work on Brettanomyces strains have also shown that some strains are resistant up to 1.2 mg / L of molecular SO2. It’s also the case of the some Saccharomuces or Zygosaccharomyces strains suitable to re-ferment “liquoreux” wines after the “mutage”.

The landscape is defined by the European convention of the landscape (Florence, October 20, 2000) like part of the territory as perceived by the populations, whose character results from the action of natural and/or human factors and their interrelationships. This convention is based on the contribution cultural, ecological, environmental, social of the landscapes and aims at a reinforcement of the tools of protection and valorization in particular in the agricultural policies, of regional planning and town planning. Moreover, it encourages a step of identification and qualification of the landscapes and underlines the need for developing the sensitizing and the training of the actors concerned.

During winemaking, some byproducts are obtained, such as grape pomace, which represent 13% of winery byproducts.