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IVES 9 IVES Conference Series 9 Rapid measurement of phenolic quality as a useful tool for viticultural zoning

Rapid measurement of phenolic quality as a useful tool for viticultural zoning

Abstract

Un des principaux objectifs du zonage viticole est l’individuation des zones plus indiquées à la production de vins de haute qualité en relation aux cépages. Ceperrlant depuis beaucqup d’années, entre les paramètres de qualité du raisin, on n’a pas considéré les substances phénoliques par effet de l!l difficulté d’analyse en temps rapides.
En considérant l’importance des polyphénols sur la qualité du raisin, en particulier le raisin rouge, un nouveau système d’évaluation en temps réel d’un indice de qualité phénolique du raisin rouge a été réalisé.
En utilisant un système d’analyse de la couleur particulier dans le spectrum de réflexion, il est possible d’analyser le raisin pendant la maturation ou de classer le raisin au moment de la livraison à la cave. Il s’agit d’un système d’analyse a posteriori, donc il est possible de réaliser un panorama indicatif de la potentialité phénolique des raisins déjà cultivés en différentes zones viticoles et pour chaque cépage.
Les données du présent travail expérimental sont relatives à des évaluations réalisées en Italie, Espagne et Australie au cours des dernières vendanges dans des domaines intéressées par l’évaluation des polyphénols comme paramètre supplémentaire pour la classification des raisins rouges à la livraison.
Les expériences réalisées ont permis de vérifier qu’il n’y a pas des corrélations significatives entre les polyphénols et les sucres à la récolte, en outre l’indice de qualité phénolique qu’on obtient en temps réel sur un échantillon représentatif est un résultat intéressant pour suivre l’évolution de la maturation en vigne.
La conséquence est que de grands projets de caractérisation des zones viticoles seraient peu significatifs si on néglige le patrimoine phénolique comme indice de qualité.
On peut donc affirmer que le système d’analyse rapide utilisé pourrait devenir un instrument efficace à introduire dans les programmes de zonage pour renouveler les données afin de définir la meilleure combinaison terroir x cépage pour la production de raisin avec un potentiel œnologique élevé.

One of the main aims of viticultural zoning is to identify the areas most suited to the production of high-quality wine in relation to each cultivar. In recent years, however, phenolic content as a parameter for assessing grape quality has often been neglected as it is not easy to measure quickly.
In view of the enormous importance of polyphenols in defining grape quality, in particularly black grapes, a new real-time evaluation system has been devised providing a phenolic quality index for black grapes.
Thanks to a special colorimetric system for assessing the reflectance spectrum, the grapes can be analysed during ripening or classified when delivered to the winery. Since this is a grape quality analysis system, it is possible to obtain an indication of the phenolic potential of the grapes already present in the various vine-growing areas and for each cultivar.
The data provided by this study refer to experiments performed in Italy, Spain and Australia in very recent grape harvests at wineries interested in analysis of polyphenols as an additional parameter for classification of black grapes at delivery, prior to start the winemaking process.
Tests showed that there is no significant correlation between the polyphenols and the sugar level at grape harvest, furthermore, the phenolic quality index obtainable in real time on a representative sample is useful for monitoring ripening in the vineyard. This means that wide­-ranging projects for the characterisation of vine-growing areas would have very little significance if the phenolic content were neglected as an index of grape quality.
In the light of these results, the rapid analysis system used could become a valid tool in zoning programs for updating the existing data in order to identify the area x cultivar combination best suited to the production of grapes with a high enological potential.

 

 

 

DOI:

Publication date: February 15, 2022

Issue: Terroir 2002

Type: Article

Authors

E. CELOTTI, G. CARCERERI DE PRATI, F. BATTISTUTTA and R. ZIRONI

Dipartimento di Scienze degli Alimenti, Università degli Studi di Udine, Via Marangoni 97 -33100 Udine/Italie

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Keywords

Zonage, Raisin, Qualité Phénolique, Couleur, Polyphénoles
Zoning, Grape, Phenolic Quality, Colour, Polyphenols

Tags

IVES Conference Series | Terroir 2002

Citation

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