Terroir 2004 banner
IVES 9 IVES Conference Series 9 Flanan-3-ol compositional changes in red grape berries (Vitis vinifera L. cv Cabernet franc) from two terroirs of the Loire Valley (France)

Flanan-3-ol compositional changes in red grape berries (Vitis vinifera L. cv Cabernet franc) from two terroirs of the Loire Valley (France)

Abstract

[English version below]

La quantité et la qualité des flavonoïdes sont des éléments importants de la qualité de la baie. En particulier, les tannins contribuent de manière essentielle aux propriétés spécifiques des vins rouges telles que la couleur, l’astringence et l’amertume. Cependant, leur synthèse et leurs propriétés sont encore mal connues. Ainsi, la compréhension des relations qui existent entre, d’une part, le milieu et d’autre part la mise en place de ce pool tannique jusqu’à la vendange est insuffisante. La composition en tannins des pellicules est suivie depuis le milieu de la phase de croissance herbacée (30 jours après le début floraison) et jusqu’à une maturité normale, sur deux parcelles. L’étude considère un stade donné de développement et non pas la valeur moyenne des paramètres à la parcelle. Ainsi, l’apport d’une relation plus fonctionnelle entre composition et stade physiologique du raisin constitue un levier puissant d’interprétation. La composition en flavan-3-ols et en proanthocyanidines des pellicules est déterminée par HPLC-phase inverse et par histochimie. Le couplage de ces deux techniques permet d’associer des informations quantitatives et spatiales. Cette approche originale permet de mettre en évidence l’importance de la période pré-maturation, en relation avec l’avancement de la maturation mais également d’autres facteurs, comme le nombre de pépins. Qualitativement et quantitativement, les teneurs évoluent peu après véraison. Il est suggéré que le pool tannique est acquis avant véraison. D’autre part, il est montré une relation entre le nombre de pépins des baies et leur qualité.

The quantity and the quality of flavonoïds are important parts of the global quality of the grape berries. Especially, the tannins are responsible of some majors flavour properties of the red wines including colour, bitterness and astringency. Nevertheless, their synthesis and properties are still misunderstood. Thus, the comprehension of the relations between environment and setting of this tannic pool, up to the harvest of the grapes, is not sufficient. The tannin composition was monitored since the middle of the first growth period (30 days after the onset of flowering) to the average maturity, for two plots. The study the stage of the berries, and not the average value of the parameters. Thus, the contribution of a more functional relation between composition and physiological stage of the grape constitutes a powerful lever for interpretation. The composition in flavan-3-ols and in proanthocyanidins of skins were determined by HPLC reversed phase and by histochemistry. The linking of these two analytical techniques allowed the association of quantitative and spatial data. This original approach pointed out the importance of the period previous maturation in relation with the stage of maturation but also others factors, such as the number of seeds. There was little evolution of the tannins after veraison. It is suggested that the tannic pool is set before veraison. More, a relation between the number of seeds and the quality of the berries was shown.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

Y. Cadot (1), M.T. Miňana (1), R. Champenois (1), M. Chevalier (2) and G. Barbeau (1)

(1) Unité Vigne et Vin, Institut National de la Recherche Agronomique, Centre de Recherches d’Angers, 42 rue Georges Morel, 49071 Beaucouzé Cedex, France
(2) Unité Mixte de Recherche Génétique et Horticulture (GenHort), Institut National de la Recherche Agronomique, Centre de Recherches d’Angers, 42 rue Georges Morel, 49071 Beaucouzé Cedex, France

Contact the author

Keywords

Tannins, maturation, Vitis vinifera var. cabernet franc, skin, seed, histochemistry

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Climate ethnography and wine environmental futures

Globalisation and climate change have radically transformed world wine production upsetting the established order of wine ecologies. Ecological risks and the future of traditional agricultural systems are widely debated in anthropology, but very little is understood of the particular challenges posed by climate change to viticulture which is seen by many as the canary in the coalmine of global agriculture. Moreover, wine as a globalised embedded commodity provides a particularly telling example for the study of climate change having already attracted early scientific attention. Studies of climate change in viticulture have focused primarily on the production of systematic models of adaptation and vulnerability, while the human and cultural factors, which are key to adaptation and sustainable futures, are largely missing. Climate experts have been unanimous in recognising the urgent need for a better understanding of the complex dynamics that shape how climate change is experienced and responded to by human systems. Yet this call has not yet been addressed. Climate ethnography, coined by the anthropologist Susan Crate (2011), aims to bridge this growing disjuncture between climate science and everyday life through the exploration of the social meaning of climate change. It seeks to investigate the confrontation of its social salience in different locations and under different environmental guises (Goodman 2018: 340). By understanding how wine producers make sense of the world (and the environment) and act in it, it proposes to focus on the co-production of interdisciplinary knowledge by identifying and foreshadowing problems (Goodman 2018: 342; Goodman & Marshall 2018). It seeks to offer an original, transformative and contrasted perspective to climate change scenarios by investigating human agency -individual or collective- in all its social, political and cultural diversity. An anthropological approach founded on detailed ethnographies of wine production is ideally placed to address economic, social and cultural disruptions caused by the emergence of these new environmental challenges. Indeed, the community of experts in environmental change have recently called for research that will encompass the human dimension and for more broad-based, integrated through interdisciplinarity, useful knowledge (Castree & al 2014). My paper seeks to engage with climate ethnography and discuss what it brings to the study of wine environmental futures while exploring the limitations of the anthropological environmental approach.

Differential responses of red and white grape cultivars trained to a single trellis system – the VSP

Commercial grape production relies on training grapevine cultivars onto a variety of trellis systems. Training allows for well-lit leaves and clusters, maximizing fruit quality in addition to facilitating cultivation, harvesting, and diseases control. Although grapevines can be trained onto an infinite variety of trellis systems, most red and white cultivars are trained to the standard VSP (Vertical Shoot Positioning) system. However, red and white cultivars respond differently to VSP in fruit composition and growth characteristics, which are yet to be fully understood. Therefore, the objective of this study was to examine the influence of the VSP trellis system on fruit composition of three red, Cabernet Sauvignon, Merlot and Syrah, and three white, Chardonnay, Riesling, and Gewurztraminer cultivars grown under uniform growing conditions in the same vineyard. All cultivars were monitored for maturity and harvested at their physiologically maximum possible sugar concentration to compare various fruit quality attributes such as Brix, pH, TA, malic and tartaric acids, glucose and fructose, potassium, YAN, and phenolic compounds including total anthocyanins, anthocyanin profile, and tannins. A distinct pattern in fruit composition was observed in each cultivar. In regards to growth characteristics, Syrah grew vigorously with the highest cluster weight. Although all cultivars developed pyriform seeds, the seed size and weight varied among all cultivars. Also varied were mesocarp cell viability, brush morphology, and cane structure. This knowledge of the canopy architectural characteristics assessed by the widely employed fruit compositional attributes and growth characteristics will aid the growers in better management of the vines in varied situations.

The plantation frame as a measure of adaptation to climate change

The mechanization of vineyard work originally led to a reduction in planting densities due to the lack of machinery adapted to the vineyard. The current availability of specific machinery makes it possible to establish higher planting densities. In this work, three planting densities (1.40×0.80 m, 1.80×1 m and 2.20×1.20 m, corresponding to 8928, 5555 and 3787 plants/ha respectively) were studied with four varieties autochthonous of Galicia (northwestern Spain): Albariño and Treixadura (white), Sousón and Mencía (red). The vines were trained in a vertical shoot positioning system using a single Royat cordon, and pruned to spurs with two buds each. Agronomic data (yield, pruning wood weight, Ravaz index) and oenological data in must were collected. The higher planting density (1.40×0.80 m) had no significant effect on grape yield per vine in white varieties, although production per hectare was much higher due to the greater number of plants. In red varieties, this planting density resulted in a significantly lower production per vine, compensated by the greater number of plants. In addition, it significantly reduced the Brix degree in the must of the Albariño, Treixadura and Sousón varieties, and increased the total acidity in the latter two and Mencía. It also caused an increase in extractable and total anthocyanins and IPT in red grapes. The effects of high planting density on grapes are of great interest for the adaptation of varieties in the context of climate change. In the future, it could be advisable to modify the limits imposed by the appellations of origin on the planting density of these varieties in order to obtain more balanced wines.

Modulation of berry composition by different vineyard management practices

High concentration of sugars in grapes and alcohol in wines is one of the consequences of climate change on viticulture production in several wine-growing regions. In order to investigate the possibilities of adaptation of vineyard management practices aimed to reduce the accumulation of sugar during the maturation phase without reducing the accumulation of anthocyanins in grapes, a study with severe shoot trimming, shoot thinning, cluster thinning and date of harvest was conducted on Merlot variety in Istria region (Croatia), under the Mediterranean climate. Four factors which may affect grape maturation and its composition at harvest were investigated in a two-years experiment; severe shoot trimming applied at veraison when >80% of berries changed colour (in comparison to untreated control), shoot thinning (0 and 30%), cluster thinning (0 and 30%), and the date of harvest (early and standard harvest dates). Shoot thinning had no significant impact on berry composition, despite the obtained reduction in yield per vine. Lower Brix in grapes were obtained with earlier harvest date and if no cluster thinning was applied, although at the same time a reduction in the concentration of anthocyanins in berries was observed in these treatments. On the other hand, if severe shoot trimming was applied when >80% of berries changed colour, a reduction of Brix was obtained without a negative impact on berry anthocyanins concentration. We conclude that in cases when undesirably high sugar concentrations at harvest are expected, severe shoot trimming at 80% veraison may effectively be used in order to obtain moderate sugar concentration in berries together with the adequate phenolic composition.

Mapping and tracking canopy size with VitiCanopy

Understanding vineyard variability to target management strategies, apply inputs efficiently and deliver consistent grape quality to the winery is essential. However, despite inherent vineyard variability, the majority are managed as if they are uniform. VitiCanopy is a simple, grower-friendly tool for precision/digital viticulture that allows users to collect and interpret objective spatial information about vineyard performance. After four years of field and market research, an upgraded VitiCanopy has been created to achieve a more streamlined, technology-assisted vine monitoring tool that provides users with a set of superior new features, which could significantly improve the way users monitor their grapevines. These new features include:
• New user interface
• User authentication
• Batch analysis of multiple images
• Ease the learning curve through enhanced help features
• Reporting via the creation of colour maps that will allow users to assess the spatial differences in canopies within a vineyard.
Use-case examples are presented to demonstrate the quantification and mapping of vineyard variability through objective canopy measurements, ground-truthing of remotely sensed measurements, monitoring of crop conditions, implementation of disease and water management decisions as well as creating a history of each site to forecast quality. This intelligent tool allows users to manage grapevines and make informed management choices to achieve the desired production targets and remain profitable.