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…

A predictive model of spatial Eca variability in the vineyard to support the monitoring of plant status

[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"...

Towards adaptation to climate change in Rioja: Quality evaluation of wines obtained from Grenache x Tempranillo selections

The wine sector is of great relevance and tradition in Mediterranean countries, however, it may be most susceptible to climate change. In recent years, wine production is facing changes worldwide, both at environmental as well as commercial levels, due to global warming and the shift in consumers’ preferences. Wine growers and wine makers are in search of solutions that allow to face these new challenges. One of the most promising initiatives in the long term is the introduction of new plant materials, specifically intraspecific hybridizations between premium varieties that may improve traditional germplasm in its adaptation to climate change. These inter-varietal crosses have the potential to generate quality wines, whilst maintaining the regional typicity, and constitute an attractive alternative for the consumer due to their sensory attributes. In this study, we have evaluated wines from 29 intraspecific Garnacha x Tempranillo hybrids in two different locations, with the aim to assess their oenological potential and sensory attributes. Thirteen of the selections were white and 16 were red. Microvinifications were conducted with two or three replications depending on grape availability. Conventional oenological parameters were determined for all wines. The sensory evaluation and hedonic scores were given by five experts. Red selections obtained higher quality scores than white ones. Among the white selections with higher quality scores, GT-41 Varea and GT-159 Varea outstand, due to their high total acidity and high malic acid content. Regarding red selections, GT-57 Varea and GT-57 UR were perceived as higher in quality, highlighted for their moderate alcoholic and high anthocyanin content. Our results indicate that intraspecific hybridization may be a powerful tool for adapting traditional cultivars to climate change in Rioja.

Late season canopy management practices to reduce sugar loading and improve color profile of Cabernet-Sauvignon grapes and wines in the high irradiance and hot conditions of California Central Valley

Global warming is accelerating grape ripening, leading to unbalanced wines from fruit with high sugar content but poor aroma and colour development. Reducing the size of the photosynthetic apparatus after veraison has been shown to delay technological ripeness in cool climates, but methods have not been tested in areas with high irradiance and temperature where fruit exposure could have disastrous effects on berry composition. In this Cabernet-Sauvignon trial, we compared the application of an antitranspirant (pinolene), to severe canopy topping and above bunch zone leaf removal, all performed at mid-ripening, with an untouched control. We monitored the vines weekly by measuring stem water potential, gas exchange, fruit zone light exposure. We sampled berries to measure berry weight, total soluble solids, pH, titratable acidity, and the anthocyanin profile. At harvest, we assessed yield components, measured carbon isotope discrimination, rated sunburn on clusters, and produced experimental wines. We submitted harvest samples to metabolomic profiling through PFP-Q Exactive MS/MS and wines to sensory analysis. Application of the antitranspirant significantly reduced stomatal conductance and assimilation rate but did not affect the stem water potential. Inversely, leaf removal and topping increased water potential but did not affect leaf gas exchange. The late topping was the only treatment able to decrease sugar content (up to 2Bx), increase titratable acidity and pH, and improve anthocyanin content because of lower degradation of di-hydroxylated forms. Late leaf removal above the bunch zone increased lightning conditions in the canopy and produced the most significant damage on fruits. Yield components were not affected. This work suggests that late-season canopy management can effectively control ripening speeds and improve grapes and wines. Still, the effect on grape exposure in a critical time must be well balanced to avoid problems with the appropriate technique.

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

Spatial determination of areas in the Western Balkans region favorable for organic production

In problematic conditions for production of grapes and wine caused by the COVID-19 pandemic and the resulting occurrence of wine surpluses, producers are increasingly turning to the innovative viticulture and winemaking of products that are more appealing to the market and the consumers. On the other hand, consumption of the food safety or organic products, and therefore of organic grapes and wine, is increasingly common in the world, in particular in Europe. The Regional Rural Development Standing Working Group (SWG RRD), as a regional intergovernmental organization gathers actors in the viticulture and winemaking sector from states and territories of the Western Balkans (South-East Europe) in the Expert Working Group for Wine, with the aim of improving viticulture and winemaking in this region through joint activities. In accordance with the aforementioned, the SWG RRD is working on advancing organic production of grapes and wine, and on recognition of specificities of the terroir of wine-growing areas in Western Balkans. In addition, as part of the project “Facilitation of Exchange and Advice on Wine Regulations in Western Balkan Countries” helmed by the German Federal Ministry of Food and Agriculture, in addition to harmonization of relevant legislation with EU regulations, efforts are being invested towards recognition of organic wines. Within activities and project implemented by this organization, expert analyses and scientific research of the terroir of Western Balkans were carried out, and some of the results are presented in this paper.