Evaluation of mannoprotein formation by different yeast strains by enzymatic analysis of mannose and tribological estimation of astringency

Most oxidation reactions in wine require iron as a catalyst. The iron content of wine has decreased greatly in recent decades due to the use of low or no release cellar materials; however, in some cases it is still necessary to adopt winemaking practices to remove excess iron from wine, prevent its oxidation, and be able to reduce the addition of sulfur dioxide and other antioxidants.

In a collective marketing strategy, the Protected Designation of Origin (PDO) can be used as a quality indicator. To highlight terroir specificities, it is useful to know how the wines are positioned on the local, national or international market from a sensory point of view. This is especially true for a comparison of varietal wines (e.g. Sauvignon blanc). We focus on the case of two closed Loire Valley PDO (France): Quincy and Reuilly. Three distinct tastings were organized. Firstly, at the local level comparing the 2 PDO (11 and 9 wines, 17 professional assessors); secondly at a regional level adding 3 closed PDO: Menetou-Salon, Sancerre and Pouilly-Fumé (3 wines per PDO, 16 assessors) and thirdly at an international level comparing these 5 PDO with Sauvignon Blanc wines coming from South Africa, New Zealand and Chile (1 to 3 wines per PDO, 19 assessors). All the wines were from the 2019 vintage and were considered to have a traditional elaboration process without contact with oak. A sensory descriptive analysis was performed using an aroma wheel allowing to combine a Check-All-That-Apply methodology, often used in sensory benchmarking, with a hierarchical structuration of the attributes. The aim is to facilitate data acquisition in a professional context without common training, to consider the hierarchical relationships among the attributes during the data analysis and to be able to characterize wines with a large range of sensorial variability. We use univariate, multivariate and clustering analyses. Similarities and differences between Quincy and Reuilly PDO wines and other Sauvignon blanc wines were identified. Specific attributes can distinguish the two PDO and different proximities exist with other local PDO, while clear differences were observed compared to international wines. Our study contributes to propose and discuss a method to do a wine sensory benchmarking highlighting sensory specificities linked to origin.

In the course of the present work, which is the first part of a study on the “characterization of Barbera dell’Oltrepo Pavese D.O.C.” 30 wines Barbera from 1993 vintage have been compared only regarding their sensory characteristics. An unstructured scale card, composed by 15 descriptors have been used.

The effect of cover crop on the water relations, yield and grape composition of Pinot noir vines was investigated during two seasons (2003 and 2004) in a gravely soil located in Tarragona (Spain). Seventeen-year-old vines, grafted onto R110 and trained onto a Ballerina training system, were used.

In this study, stationary and time-resolved fluorescence signatures were statistically and chemometrically analyzed among three typologies of Chardonnay wines with the objectives to evaluate their sensitivity to acidic and polyphenolic changes.