Evolution of grape aromatic composition in cv. Ugni blanc

Abstract

AIM: Cognac is a protected appellation of origin where world-famous brandies are produced. These brandies are obtained by the traditional double distillation of wines from Ugni blanc cultivar, which is the main variety planted. According to the Cognac Appellation, harvest can occur between 13 & 21 °Brix. To date the harvest is assessed by vine growers only by sugar & acidity ripeness without considering the evolution of the aromatic profile. Hence, the goal of this research is to study the behavior of the main volatile compounds of grapes in order to better conduct the harvest.

METHODS: Two vineyard plots during two consecutive vintages (2019, 2020) were used to collect different fractions of 30 whole bunches. The samples were collected every week from pea-size to over ripeness (>21 °Brix) and then were stored at – 40°C until further analysis. Berries were grounded according to the protocol as described in Poitou, 2016. Grape powder were obtained and then analyzed for free & total volatiles by SPME-GC/MS (Young et al. 2015 ; Poitou, 2016). Principal component analysis (PCA) was conducted on the means of all significantly different parameters to elucidate the differences between grapes according to the maturity stage (Agilent MassProfiler Pro).

RESULTS: The kinetics of the volatile compounds during maturation showed strong variations with multiple trends depending the stage. Linear increase (e.g β-damascenone) or decrease (e.g p-cymene) of volatiles and a peak for cis-3-hexenol at véraison were found. Similarly to previous studies (Poitou, 2016 ; Ferrari et al. 2012), aromatic compounds were found to exhibit the same pattern. According to Rosillo et al. 1999, Ugni blanc & Chardonnay presents similar aromatic properties with low concentration of monoterpenes. Finally, the analysis of total volatiles showed the presence of newly identified terpenes in Ugni blanc grapes.

CONCLUSION

These results gave new insights for Ugni blanc aromatic characterization. Identification of terpenes with the total volatile method concludes that they are in their glycosylated form in grapes. Thus, they may be released during fermentation or distillation and participate to the aromatic complexity of wine distillates. With climate change, sugar concentration is expected to increase and will decouple sugar/acidity balance and the aromatic maturity. Therefore, understanding the aromatic maturity of Ugni Blanc will help growers to adapt their harvest date.

DOI:

Publication date: September 2, 2021

Issue: Macrowine 2021

Type: Article

Authors

Amandine Bernier

Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France,Julia, GOUOT, Unité de recherche Œnologie, EA 4577, USC 1366 INRA, ISVV, Université de Bordeaux, F33882 Villenave d’Ornon, France  Adeline, BARREAU, Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France  Panagiotis, STAMATOPOULOS, Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France  Xavier POITOU, Jas Hennessy & Co, rue de la Richonne – CS20020, 16101 Cognac Cedex, France

Contact the author

Keywords

aromatic potential, berry composition, maturity, ugni blanc

Citation

Related articles…

First step in the preparation of a soil map of the Protected Designation of Origin Valdepeñas (Central, Spain)

This work is a first step to make a map of vineyard soils. The characterization of the soils of the Protected Designation of Origin (D.P.O.) Valdepeñas will allow to group the studied profiles according to their physico-chemical characteristics and the concentrations of most relevant chemical elements. 90 soil profiles were analysed throughout the territory and the soils were sampled and described according to FAO (2006) and classified according to and Soil Taxonomy (2014). All samples were air dried, sieved and some physico-chemical parameters were determined following standard protocols. Also, major and trace elements were analysed by X-ray fluorescence. The statistically study was made using the SPSS program. Trend maps were made using the ArcGIS program. The studied soils have the following average properties: pH, 8.3; electrical conductivity, 0,20 dS/m (low); clay, 18.8% (medium) and CaCO3, 17.1% (high). In the study for the major elements. The major elements of these soils are Si, followed by Ca and Al, with an average content of 203.7 g/kg, 105.5 g/kg and 74.0 g/kg respectively. On the other hand, 27 trace elements have been studied. Of all of them, it can be highlighted the average values of Ba (361.8 mg/kg), Sr (129.3 mg/kg), Rb (83.4 mg/kg), V (74.2 mg/kg) and Ce (70.6 mg/kg). Ba, V and Ce values are higher and the values of Sr and Rb are lower to those found in the literature. The discriminant analysis shows a percentage of grouping of 91%. The content of chemical elements together with the physico-chemical characteristics allows grouping the soils in 4 group according to their order in the classification to Soil Taxonomy; due to the importance of the Calcisols in Castilla-La Mancha, it has been decided to establish them as their own group even if they do not appear in Soil Taxonomy classification.

Local adaptation tools to ensure the viticultural sustainability in a changing climate

[lwp_divi_breadcrumbs home_text="IVES" use_before_icon="on" before_icon="||divi||400" module_id="publication-ariane" _builder_version="4.19.4" _module_preset="default" module_text_align="center" module_font_size="16px" text_orientation="center"...

Rapid damage assessment and grapevine recovery after fire

There is increasing scientific consensus that climate changeis the underlying cause of the prolonged dry and hot conditions that have increased the risk of extreme fire weather in many countries around the world. In December 2019, a bushfire event occurred in the Adelaide Hills, South Australia where 25,000 hectares were burnt and in vineyards and surrounding areas various degrees of scorching and infrastructure damage occurred. The ability to coordinate and plan recovery after a fire event relies on robust and timely data. The current practice for measuring the scale and distribution of fire damage is to walk or drive the vineyard and score individual vines based on visual observation. The process is time consuming, subjective, or semi-quantitative at best. After the December 2019 fires, it took many months to access properties and estimate the area of vineyard damaged. This study compares the rapid assessment and mapping of fire damage using high-resolution satellite imagery with more traditional ground based measures. Satellite imagery tracking vineyard recovery in the season following the bushfire is being correlated to field assessments of vineyard productivity such as canopy health and development, fertility and carbohydrate storage. Canopy health in the seasons following the fires correlated to the severity of the initial fire damage. Severely damaged vines had reduced canopy growth, were infertile or had very low fertility as well as lower carbohydrate levels in buds and canes during dormancy, which reduced productivity in the seasons following the bushfire event. In contrast, vines that received minor damage were able to recover within 1-2 years. Tools that rapidly and affordably capture the extent and severity of damage over large vineyard area will allow producers, government and industry bodies to manage decisions in relation to fire recovery planning, coordination and delivery, improving the efficiency and effectiveness of their response.

Adaptability of grapevines to climate change: characterization of phenology and sugar accumulation of 50 varieties, under hot climate conditions

Climate is the major factor influencing the dynamics of the vegetative cycle and can determine the timing of phenological periods. Knowledge of the phenology of varieties, their chronological duration, and thermal requirements, allows not only for the better management of interventions in the vineyard, but also to predict the varieties’ behaviour in a scenario of climate change, giving the wine producer the possibility of selecting the grape varieties that are best adapted to the climatic conditions of a certain terroir. In 2014, Symington Family Estates, Vinhos, established two grape variety libraries in two different places with distinctive climate conditions (Douro Superior, and Cima Corgo), with the commitment of contributing to a deeper agronomic and oenological understanding of some grape varieties, in hot climate conditions. In these research vineyards are represented local varieties that are important in the regional and national viticulture, but also others that have over time been forgotten — as well as five international reference cultivars. From 2017 to 2021, phenological observations have been made three times a week, following a defined protocol, to determine the average dates of budbreak, flowering and veraison. With the climate data of each location, the thermal requirements of each variety and the chronological duration of each phase have been calculated. During maturation, berry samples have been gathered weekly to study the dynamics of sugar accumulation, between other parameters. The data was analysed applying phenological and sugar accumulation models available in literature. The results obtained show significant differences between the varieties over several parameters, from the chronological duration and thermal requirements to complete the various stages of development, to the differences between the two locations, confirming the influence of the climate on phenology and the stages of maturation, in these specific conditions.

Upscaling the integrated terroir zoning through digital soil mapping: a case study in the Designation of Origin Campo de Borja

homogeneous zones by intersecting several partial zonings of major factors that influence vineyard growth. Each of them follows specific process from their corresponding disciplines. Soil zoning specifically refers to a Soil Resource Inventory map that has traditionally been generated by conventional soil mapping methods. These methods have shortcomings in reaching fine cartographic and categorical details and involve significant expenses, which undermines their applicability. A new framework named Digital Soil Mapping has introduced quantitative models by statistical techniques to establish soil-landscape relationships and is able to provide intensive scale cartography.

In the present study, a microzoning at 1:10.000 scale is generated from an initial zoning, where the conventional soil map with polytaxic map units is replaced by a new one from digital techniques that disaggregates them. The comparison between the zonings considers a quantitative evaluation of capability for each Homogeneous Terroir Unit by means of the Viticultural Quality Index and its categorization based on its distribution by map. The spatial intersection of both maps gives rise to a confusion matrix in which the flows of class variations after the substitution are assessed.

The results show a five-fold increase in the number of Homogeneous Terroir Units identified and a larger differentiation among them, evidenced by a wider range in the capability index distribution. Both elements are accompanied by an increase in the detection of areas of higher potential within previously undervalued uniform zones.These features are a direct effect of the improvements brought by Digital Soil Mapping techniques and would verify the advantages of their implementation in the Integrated Terroir zoning. Eventually, such new highly detailed terroir units would benefit precision viticulture and sustainable management practices.