Relation between phenolic content, antioxidant capacity, oxygen consumption rate of diverse tannins

Some wood substances such as ellagitannins (vescalagin, castalagin, grandinin, roburins (A, B, C, D, E)…) can be extracted during wine ageing in oak barrels. The level of these hydrolysable tannins in wine depends of the species and origin of oak wood as well as its treatment during barrel realization.

The weather anomalies comparing the 1971-2000 time frame and the last years has showned a dramatic scenario when, in some months, average temperature in above 3ºC and the reduction in precipitation in more than 30%.

Not only vintner’s decisions in the vineyard, but also winemaker’s choices of technology approaches in the cellar play a significant role in the final wine style and quality. Whereas traditional technologies within chosen terroir are quite well explored and thus somehow predictable, there is no proper knowledge available on possible outcomes in case of implementing novel, alternative winemaking strategies. To reveal their effects on wine aroma compounds and sensory characteristics, two alternative strategies
(cryoextraction or addition of whole grape berries during last stages of fermentation) were compared to classical Vipava valley winemaking approach as normally used for an autochthonous variety Zelen. After separate vinification and bottling, all the experimental wines were subjected to semiquantitative metabolic profiling of volatile compounds (VOCs) by means of GC/MS and were then also sensorialy evaluated by pre-trained panel.

The presence of undesirable compounds in wines, such as OTA, biogenic amines and pesticides residues, affects wine quality and can cause health problems for the consumer. The main tool that a winemaker has to reduce their content in the wine is fining. However, some of the fining agents commonly used in the winery can cause allergies or even increase the protein content in the wine, increasing the turbidity. To avoid these problems, the use of plant fibers may be an alternative, such as those from grape pomace[1] or other plant origins.

Dans le but d’améliorer la qualité et la typicité des vins de l’Appellation d’0rigine Contrôlée CAHORS, une étude a été réalisée afin de mettre en évidence l’adéquation Cépage-Terroir- Qualité du vin.
Selon la méthodologie proposée par MORLAT et ASSELIN (1992), neuf unités terroirs ont été déterminées. Sur chacune, des parcelles de référence homogènes quant au matériel végétal Cot ou Malbec ( cépage principal de cette appellation greffé sur S04, et aux méthodes culturales, ont été suivies au niveau agronomique et œnologique (GARCIA et al., 1996).