Towards adaptation to climate change in Rioja: Quality evaluation of wines obtained from Grenache x Tempranillo selections

The Ability of PVPP (Polyvinylpolypyrrolidone), PVP-DEGMA-TAIC (copolimerization of N-vinyl-2-pyrrolidinone with ethylene glycol dimethacrylate and triallyl isocyanurate) and PAEGDMA
(poly(acrylamide-co-ethylene glycol dimethacrylate)) polymers was tested as removal agents for Fumonisin B1 (FB1) and Fumonisin B2 (FB2) from model solutions and red wine. The polymers removal capacity was checked at three different resident times (2, 8 and 24 hours of contact time between the polymer and the sample), showing no differences in the percentage of FB1 and FB2 removal. Then, different polymer concentrations (1, 5 and 10 mg mL-1) were tested in model solution with and without phenolics (i.e. gallic acid and 4-methylcatechol).

The online monitoring of fermentative aromas provides a better understanding of the effect of temperature on the synthesis and the loss of these molecules. During fermentation, gas and liquid phase concentrations as well as losses and total productions of volatile compounds can be followed with an unprecedented acquisition frequency of about one measurement per hour. Access to instantaneous production rates and total production balances for the various volatile compounds makes it possible to distinguish the impact of temperature on yeast production (biological effect) from the loss of aromatic molecules due to a physical effect³.

Canopy-management practices are applied in viticulture to improve berries composition and quality, having a great impact on primary and secondary grape metabolism. Among these techniques, cluster zone leaf removal (defoliation) is widely used to manage air circulation, temperature and light radiation of grape bunches and close environment. Since volatiles are quantitatively and qualitatively influenced by the degree of fruit ripeness, the level of solar exposure, and the thermal environment in which grapes ripen, leaf removal has been shown to affect volatile composition of grape berries [1].

Yeast mannoproteins and derivates are polysaccharides produced from the cell walls of different yeast strains widely used in the winemaking and finning of wines to improve their overall stability and sensory properties.

The quality of wine is difficult to define. This is most certainly accredited to everyone´s different perception of quality. Some of the indicators of high-quality wines are complexity, balance, color and intensity. Color is one of the most crucial attributes of quality, not only for the obvious implications for their perception but also because they are indicators of other aspects related to its aroma and taste. Phenolic compounds are the main responsible for wine color, being anthocyanin and tannins the most determinant compounds in red wines. In addition to color, wine aroma is another important attribute linked with quality and consumer preferences.