Predictive Breeding: Impact of véraison (onset of ripening) on wine quality

PAs are compartmentalised within the grape berry, and differ in their composition and degree of extractability. Within each compartment, the CWM limits PA extraction firstly by its degree of permeability and secondly its ability to complex with PA molecules.

Volatile thiols are impact aroma compounds, well-known in the literature for imparting tropical fruit aromas such as passion fruit, guava, grapefruit, and citrus in white wines [1]. More recent evidence suggests that tropical fruit aromas are also caused by other aroma compounds besides thiols, such as fermentation esters, or the interaction between these volatile families. Therefore, the objective of this study was to investigate the effects of combining esters and/or thiols to determine their impact on the fruitiness aroma perception of white wines. Pinot gris wine was produced at the OSU research winery and was dearomatized using Lichrolut® EN. Combinations of fermentation volatile compounds were added to the wine, forming the aroma base. Treatment wines were composed of additions of different concentrations and combinations of thiols and/or esters. Samples were subjected to sensory analysis where forty-six white wine consumers evaluated the orthonasal aroma of the wines and participated in Check-All-That-Apply (CATA).

The phenolic profiles of little known red grape cultivars, namely Garnacho, Moribel and Tinto Fragoso, which are autochthonous from the Spanish region of La Mancha (ca. 600,000 ha of vineyards) have been studied over the consecutive seasons of years 2013 and 2014. The study was separately performed over the skins, the pulp and the seeds, and comprised the following phenolic types: anthocyanins, flavonols, hydroxycinnamic acid derivatives (HCADs), total proanthocyanidins (PAs) and their structural features. The selected grape cultivars belong to the Vine Germplasm Bank created in this region in order to preserve the great diversity of genotypes grown in La Mancha.

Vegetative growth and yield are reported to affect grape and wine quality. They can be controlled through different techniques linked to vine management. The objective of this research was to determine the effect of vine vigour and number of clusters per vine on physicochemical composition and phenolic profile of red wines. The experiment was carried out during two vegetative cycles, with cv. Cabernet Sauvignon grafted onto Paulsen 1103. Three vine vigour were defined, according to shoot weight at previous harvests, being low, medium and high. Five treatments of number of clusters were used for each vigour, with 15, 22, 29, 36, and 45 clusters per vine. Grapes from all treatments were harvested in the same day from Brix and total acidity criteria. Thirty days after bottling, classical analyzes and phenolic compounds were performed. As results, different responses were obtained from each vintage. In 2020, a dry season from veraison to harvest, grapes and wines obtained from low vigour treatment and 45 clusters per vine was the highest in sugar and alcohol content respectively, while grapes and wines from high vigour and 15 clusters presented the lowest sugar and alcohol content. Total anthocyanins were higher in treatment with low vigour and 15 clusters, while the lowest amounts were found in low vigour with 45 clusters, as well as medium and high vigour with 36 clusters per vine. Total tannins were higher in high vigour with 22 clusters and medium vigour with 29 clusters, while were lower in low vigour with 36 clusters. In 2021, a wet season at harvest, responses were different, and great variations were observed between treatments. As conclusions, yield and vine vigour had strong influence on grape and wine quality, promoting different enological potentials on which can be indicated/used for aging strategies of red and even rosé wines.

In several cultivars, such as Gewürztraminer and Riesling, grape and wine aromas are determined by volatile terpenoids.