Search results for "Vinification"

Construction of a genetically modified wine yeast strain expressing the Aspergillus aculeatus rhaA gene, encoding an -L-Rhamnosidase of enological in…

2003

Monoterpenes such as geraniol, linalool, and -terpineol present in grapes determine the varietal flavor properties of young quality wines made from Muscat varieties (for reviews, see references 19 and 21). Geraniol and linalool are considered to be the most important of the monoterpene alcohols, as they are present in greater concentrations and have lower flavor thresholds than other major wine monoterpenes. In particular, linalool is thought to be responsible for the grapelike aroma of wines produced from the Muscat variety. A large proportion of

Mitotic Recombination and Genetic Changes in Saccharomyces cerevisiae during Wine Fermentation

2000

Natural strains of Saccharomyces cerevisiae are prototrophic homothallic yeasts that sporulate poorly, are often heterozygous, and may be aneuploid. This genomic constitution may confer selective advantages in some environments. Different mechanisms of recombination, such as meiosis or mitotic rearrangement of chromosomes, have been proposed for wine strains. We studied the stability of the URA3 locus of a URA3/ura3 wine yeast in consecutive grape must fermentations. ura3/ura3 homozygotes were detected at a rate of 1 x 10(-5) to 3 x 10(-5) per generation, and mitotic rearrangements for chromosomes VIII and XII appeared after 30 mitotic divisions. We used the karyotype as a meiotic marker an…

Diversité des Brettanomyces et de leur résistance au SO2. Les nouvelles avancées vers une meilleure gestion du SO2 en vinification.

2019

International audience; Des recherches ont été menées par le Groupe National « Lutte contre Brettanomyces » et plus particulièrement sur la relation SO2 et Brettanomyces bruxellensis afin d’approfondir les connaissances sur le comportement de la levure et d’apporter des données essentielles à une bonne gestion du risque.Une grande diversité de la levure Brettanomyces a été mise en évidence (identification de différents groupes génétiques) ainsi que des comportements différents vis-à-vis du SO2 : sensibles, tolérants ou résistant. Grâce à la mise au point d’un outil prédictif (TYP \ Brett), les professionnels pourront connaître le groupe génétique pour mieux intervenir.Ces travaux ont égalem…

Pratiques et évolution de la vinification dans un cellier bourguignon à la fin du Moyen Âge : le cas de la collégiale Notre-Dame de Beaune (fin XIVe-…

2014

The accounts of the cellar of the collegiate church of Notre-Dame of Beaune are almost continuously preserved from the end of the 14th century to the French Revolution of 1789. Until the year 1507 the canons themselves exploited a part of their domain, located mainly in the territory of the city of Beaune. This enables us to describe precisely the current practices of this cellar, and thus the winemaking process of the " vin de Beaune " at the end of the Middle Ages. This article explores the different techniques in use, in both their materiality and in their specificities. We also try to point out the evolution of the practices from ca. 1380 to 1500, respecting the point of view of the med…

Wine-making with protection of must against oxidation in a warm, semi-arid terroir

2016

In order to defend varietal aromas from oxidation before alcoholic fermentation, two musts were prepared from white grapes pre-cooled and added with ascorbic acid and solid CO2 (trial ACO2) or SO2 (trial BSO2). Experiments were performed with grapes of a white grape variety indigenous to western Sicily, the wines from which, obtained by vinification of musts protected from oxidation and poor in copper, as previously proven, have aroma descriptors ascribed to passion fruit and grapefruit skin. The smaller content in flavanols in the ACO2 trial, demonstrated that the use of solid CO2, instead of SO2, reduced the extraction of such polyphenols from grape solids. The higher content in hydroxyci…

Effects of traditional and light pruning on viticultural and oenological performance of bobal and tempranillo vineyards

2015

<p style="text-align: justify;"><strong>Aim</strong>: Light pruning may improve vine yield and quality although vineyard responses are variable. We assessed the effects of traditional manual pruning and mechanical light pruning on the viticultural and oenological performance of <em>Vitis vinifera </em>cv. Bobal and cv. Tempranillo.</p><p style="text-align: justify;"><strong>Methods and results</strong>: During 2008-2011, Bobal and Tempranillo vineyards underwent traditional pruning or light pruning. The effects of both pruning techniques were determined in vine vigour and yield, and grape and wine characteristics. Both cultivars responde…

La vinification du vin de Beaune aux XIVe et XVe siècles. Théorie et pratique du savoir "oenologique" à la fin du Moyen Âge

2013

Molecular Characterization of a Chromosomal Rearrangement Involved in the Adaptive Evolution of Yeast Strains

2002

Wine yeast strains show a high level of chromosome length polymorphism. This polymorphism is mainly generated by illegitimate recombination mediated by Ty transposons or subtelomeric repeated sequences. We have found, however, that the SSU1-R allele, which confers sulfite resistance to yeast cells, is the product of a reciprocal translocation between chromosomes VIII and XVI due to unequal crossing-over mediated by microhomology between very short sequences on the 5' upstream regions of the SSU1 and ECM34 genes. We also show that this translocation is only present in wine yeast strains, suggesting that the use for millennia of sulfite as a preservative in wine production could have favored …