Anthocyanin accumulation and extractability during the maturation of the grapes of three varieties

Abstract In this work the effects of early leaf removal performed manually at preflowering phenological stage, on the volatile composition of Tempranillo (Vitis vinifera L.) wines were studied. From 2009-2011 vintages 34 wine volatile compounds were identified and quantified by gas chromatography-mass spectrometry (GC-MS) where early leaf removal only modified 25 of them. The total C6 compounds, acetates and volatiles acids (with exception of isobutyric acid) were affected by defoliation, whereas alcohols and esters showed a minor effect. Furthermore the vintage effect also was shown.

The aromatic complexity of a wine results from the perception of the association of volatile molecules and each aroma can be categorized into different families. The “green” aromas family in red wines has retained our attention by its close link with the fruity perception. In that study, the “green” olfactory concept of red wines was considered through a strategy combining both sensory analysis and hyphenated chromatographic techniques including HPLC and MDGC (Multidimensional Gas Chromatography). The aromatic space of this concept was specified by lexical generation through a free association task on 22 selected wines by a panel of wine experts. Then, 70 French red wines were scored on the basis of the intensity of their “green” and “fruity” attributes.

Many parameters affect the organoleptic characteristics of wine: internal parameters like the chemical composition or polyphenol content and external as for example storage conditions or the type of obturator. The aim of this study was to characterize sensorally the impacts of several type of obturator on a white wine: Chasselas. To determine the organoleptic characteristics of this wine, a quantitative descriptive analysis could be used. But rapid sensory methods were preferred in this project. Indeed these methods are an appropriate alternative to conventional descriptive methods for quickly assessing sensory product discrimination.

The present study was performed in a traditional winery located in the viticultural area of Brunello di Montalcino, Siena, Italy, in the vintage 2015. Actually, in this winery Sangiovese grape musts are fermented in large oak barrels by a single strain of Saccharomyces cerevisiae previously isolated in the same winery. Pumping over operations are carried out once or twice a day until the end of alcoholic fermentations. The aim of this work was to investigate on the oenological properties of Sangiovese wine produced with the traditional winemaking process adopted by the winery under study obtained from the fermentation of whole berries compared to that from crushed grape must. In particular, two lots of 65q of Sangiovese grapes from the same 3ha vineyard were vinified in 150hL oak barrels.

Must oxidation is a complex process involving multiple enzymatic transformations, including the oxidation of phenolics containing an ortho-diphenol function. The latter process has a primary influence on wine aroma characteristics and stability, due to the central role of ortho-diphenols in the non-enzymatic oxidative reactions taking place during winemaking and in finished wine. Although oxidation of must is traditionally avoided, in recent years its contribution to wine quality has been revisited, and in some cases improvements to wine aroma have been observed with the application of controlled must oxidation. Nowadays there is a great interest in the wine industry towards the identification of specific markers or patterns to characterize and classify the response of grape must to oxidation.