Terroir 2004 banner
IVES 9 IVES Conference Series 9 The effect of terroir zoning on pomological, chemical and aromatic composition of Muscat d’Alexandrie grapevine variety cultivated in Tunisia

The effect of terroir zoning on pomological, chemical and aromatic composition of Muscat d’Alexandrie grapevine variety cultivated in Tunisia

Abstract

[English version below]

La composition du raisin de la variété Muscat d’Alexandrie a été étudiée dans trois terroirs différents au Nord-Est de la Tunisie (RafRaf, Baddar et Kelibia).
Des échantillons de raisins ont été récoltés à maturité industrielle durant les saisons 2001 et 2002 dans les trois régions citées. Les paramètres pomologiques (poids moyen de la grappe et de la baie) et physico-chimiques (acidité totale, pH, densité, degré Brix et indice des polyphénols totaux) ont été immédiatement mesurés. Les composés libres et liés de l’arôme ont été analysés par chromatographie en phase gazeuse (C.P.G.) équipée d’un Détecteur à Flamme d’Ionisation (FID).
Les caractéristiques pomologiques et physico-chimiques n’ont pas subi une modification importante dans les différentes régions étudiées. Cependant, l’effet significatif du terroir se reflète essentiellement sur la composition de la baie en arôme. Bien que la somme des trois monoterpénols (MT; linalol+nérol+géraniol) a toujours été comprise dans le seuil de perception de la note muscatée, une nette différence au niveau de leur distribution a été constatée. Linalol et geraniol sont les composés d’arôme les plus sensibles aux changements des conditions du milieu.
Selon l’année (2001 et 2002) et le terroir, la fraction liée des composés d’arôme est de 4 à 6 fois plus importante que la fraction libre.

The effect of terroir zoning on the pomological, chemical and aromatic composition has been studied on the Muscat d’Alexandrie grapevine variety over two years 2001 and 2002. This variety was cultivated in three terroirs (RafRaf, Baddar and Kelibia) in the North-East of Tunisia.
Muscat d’Alexandrie from each terroir was randomly harvested at commercial maturity, in 2001 and 2002. Pomological parameters (bunch and berry mean weights) and chemical characteristics (total acidity, pH, density, Brix degree and total polyphenol index) have been immediately measured. The aroma free and bound fractions were analyzed using CPG equipped by FID detector.
The results showed that the pomological and chemical parameters were the less affected by the terroir zoning. Nevertheless, zoning affected mainly the aromatic composition of the berry. Although, the global value MT of the free monoterpenols (linalool+nerol+geraniol) was included in the Muscat aroma perception interval, the distribution of the concentration of each changed from region to another. Indeed, linalool and geraniol compounds were the most sensitive to environmental changes and consequently terroirs.
During 2001 and 2002 and according to the terroir, the glycosidically bound fraction has been increased 4 to 6 times.

DOI:

Publication date: January 12, 2022

Issue: Terroir 2004

Type: Article

Authors

Souid I. (1), Zemni H. (1), Ben Salem A. (1) , Fathalli N. (1) , Mliki A. (1), Hammami M. (2), Hellali R. (3) and A. Ghorbel(1)

(1) Laboratoire de Physiologie Moléculaire de la Vigne. Institut National de Recherche Scientifique et Technique. BP 95. Hammam Lif 2050. Tunisia
(2) Laboratoire de Spectrométrie de Masse. Faculté de Médecine de Monastir 5019
(3) Laboratoire d’Arboriculture Fruitière. Institut National Agronomique de Tunis. 43 Av. Charles Nicolle. 1082 Cité Mahrajène. Tunis

Contact the author

Keywords

Muscat d’Alexandrie, jus de raisin, arôme, terroir, Tunisie

Tags

IVES Conference Series | Terroir 2004

Citation

Related articles…

Phenological characterization of a wide range of Vitis Vinifera varieties

In order to study the impact of climate change on Bordeaux grape varieties and to assess the adaptation capacities of candidates to the grape varieties of this wine region to the new climatic conditions, an experimental block design composed of 52 grape varieties was set up in 2009 at the INRAE Bordeaux Aquitaine center. Among the many parameters studied, the three main phenological stages of the vine (budburst, flowering and veraison) have been closely monitored since 2012. Observations for each year, stage and variety were carried out on four independent replicates. Precocity indices have been calculated from the data obtained over the 2012-2021 period (Barbeau et al. 1998). This work allowed to group the phenological behaviour of the grapevine varieties, not only based on the timing of the subsequent developmental stages, but also on the overall precocity of the cycle and the total length of the cycle between budburst and veraison. Results regarding the variability observed among the different grape varieties for these phenological stages are presented as heat maps.

Impact of climate change on the viticultural climate of the Protected Designation of Origin “Jumilla” (SE Spain)

Protected Designation of Origin “Jumilla” (PDO Jumilla) is located in the Spanish provinces of Albacete and Murcia, in the South-eastern part of the Iberian Peninsula, where most of the models predict a severe impact of climate change in next decades. PDO Jumilla covers an area of 247,054 hectares, of which more than 22,000 hectares

Effects of organic mulches on the soil environment and yield of grapevine

Farming management practices aiming at conserving soil moisture have been developed in arid and semiarid-areas facing water scarcity problems. Organic mulching is an effective method to manipulate the crop-growing microclimate increasing crop yield by controlling soil temperature, and retaining soil moisture by reducing soil evaporation. In this sense, the effectiveness of different organic mulching materials (straw mulch and grapevine pruning debris) applied within the row of a vineyard was evaluated on the soil and on the vine in a Tempranillo vineyard located in La Rioja (Spain). Organic mulches were compared with a traditional bare soil management technique (based on the use of herbicides to avoid weed incidence). Mulching coverages favourably influenced the soil water retention throughout all the grapevine vegetative cycle. However, the soil-moisture variation was not the same under different mulching materials, being the straw mulch (SM) the one that retained more water in comparison with grapevine pruning debris (GPD) based-cover. The changes of soil moisture in the upper surface layer (0–10 cm) were highly dynamic, probably due to water vapour fluxes across the soil-atmospheric interface. However, both, SM and GPD reduced these fluctuations as compared with bare soils. A similar trend occurred with soil temperature. Both organic mulches altered soil temperature in comparison with bare soil by reducing soil temperature in summer and raising it in winter. Moreover, the same buffering effect for the temperature on the covered soil also remains in the deeper layers. To conclude, we could see that organic mulching had a positive impact on soil-moisture storage and soil temperature and the extent of this effect depends on the type of mulching materials. These changes led to higher rates of photosynthesis and stomatal conductivity compared to bare soils, also favouring crop growth and grape yields.

Grapevine sugar concentration model in the Douro Superior, Portugal

Increasingly warm and dry climate conditions are challenging the viticulture and winemaking sector. Digital technologies and crop modelling bear the promise to provide practical answers to those challenges. As viticultural activities strongly depend on harvest date, its early prediction is particularly important, since the success of winemaking practices largely depends upon this key event, which should be based on an accurate and advanced plan of the annual cycle. Herein, we demonstrate the creation of modelling tools to assess grape ripeness, through sugar concentration monitoring. The study area, the Portuguese Côa valley wine region, represents an important terroir in the “Douro Superior” subregion. Two varieties (cv. Touriga Nacional and Touriga Franca) grown in five locations across the Côa Region were considered. Sugar accumulation in grapes, with concentrations between 170 and 230 g l-1, was used from 2014 to 2020 as an indicator of technological maturity conditioned by meteorological factors. The climatic time series were retrieved from the EU Copernicus Service, while sugar data were collected by a non-profit organization, ADVID, and by Sogrape, a leading wine company. The software for calibrating and validating this model framework was the Phenology Modeling Platform (PMP), version 5.5, using Sigmoid and growing degree-day (GDD) models for predictions. The performance was assessed through two metrics: Roots Mean Square Error (RMSE) and efficiency coefficient (EFF), while validation was undertaken using leave-one-out cross-validation. Our findings demonstrate that sugar content is mainly dependent on temperature and air humidity. The models achieved a performance of 0.65

Climate change projections to support the transition to climate-smart viticulture

The Earth’s system is undergoing major changes through a wide range of spatial and temporal scales as a response to growing anthropogenic radiative forcing, which is pushing the whole system far beyond its natural variability. Sources of greenhouse gases largely exceed their sinks, thus leading to a strengthened greenhouse effect. More energy is thereby being supplied to the system, with inevitable shifts in climatic patterns and weather regimes. Over the last decades, these modifications have been manifested in the full statistical distributions of the atmospheric variables, with dramatic changes in the frequency and intensity of extremes. Natural hazards, such as severe droughts, floods, forest fires, or heatwaves, are being triggered by extreme atmospheric events worldwide, thus threatening human activities. Viticultculture is not only exposed to changing climates but is also highly vulnerable, as grapevine phenology and physiological development are strongly controlled by atmospheric conditions. Therefore, the assessment of climate change projections for a given region is critical for climate change adaptation and risk reduction in viticulture. By adopting timely and suitable measures, the future sustainability and resiliency of the sector can be fostered. Climate-grapevine chain modelling is an essential tool for better planning and management. However, the accuracy of the resulting projections is limited by many uncertainties that must be duly taken into account when transferring knowledge to stakeholders and decision-makers. Climate-smart viticulture will comprise ensembles of locally tuned strategies, envisioning both adaptation and mitigation, assisted by emerging technologies and decision-support systems.