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Phenological, agronomical and enological characterization and sensory analysis of 26 autochthonous grape varieties in mountain areas

In each mountain area involved in the project the selection of minor wine grape cultivars, to be investigated from the pool of autochthonous grape varieties, was done following the criteria below listed:
- Grapevine varieties at present neglected (used to a minor extend) whose cultural and technological potential is unknown or hardly known.

- Grapevine varieties whose cultural and/or technological traits acquired so far can be considered of interest for development and exploitation.

- Grapevine varieties exempt from known growing faults.

- Grapevine varieties available (in a sufficient number of adults, yielding vines) in experimental or commercial vineyards located in suitable sites.

In this project was selected 36 wine grape cultivars, including several local major varieties as reference.

In each area test fields was accurately choose taking care of their dimension and their general situation. Data on climate and soil conditions of each one was taken.
Ampelographic (morphological) descriptions were carried out also in the second year for the selected varieties. The method used was in accord to primary and secondary descriptors priority list requested within the European Vitis Database (GENRES 081 project: Images of the major vine organs (shoot, adult leaf and bunch) were provided.

In both years of work, survey on phenological phases (bud burst, flowering, veraison and grape ripening), agronomical traits (fertility, vine vigour assessed by winter pruning weight, yield, tolerance or susceptibility to pests and diseases) and grape technological characteristics (bunch and berry weight and features, juice chemical composition) of each selected grapevine variety were carried out.

As to the progress in grape ripening, berry samples was collected weekly from 1-2 weeks after veraison to vintage and the obtained juice analysed. The results obtained in the two years were compared. When the grapes reach physiological ripening, detailed analyses were conducted on their composition, in order to guide the winemaking process completely.

The winemaking was done separately for every single grape variety. In general, a common methodology was agreed upon partners to obtain red and white wines (with only an exception for special wines). Whenever it is possible to compare scientifically the wines obtained from various working groups, standardized methods were adopted and identical additives used. A suitable wine-making flow-chart for red and white wines to be adopted by all participants (SME and RTD performers in each of the 6 mountain areas) was defined in light of already acquired experience.

Grape of each single cultivar was winemaking processed following standardized steps for red wine production: grape crushing and destemming, inoculation with active dry yeast, running-off at complete fermentation, addition of malo-lactic bacteria starter and tartrate stabilization and for white wines production: crushing, juice extraction with pressing, clarification of cooled must, inoculation with active dry yeast, running-off at complete fermentation, possible inoculation with malo-lactic bacteria and tartrate stabilization.

Besides routine chemical tests, that accompany the various phases of the working process, detailed analyses of the composition of finished wines was carried out, including phenolic and aromatic compounds.

Sensory evaluation of wines was performed according to two approach methods: the Quantitative Descriptive Analysis (QDA) and the Consumer Test. The QDA was performed during two years. According to ISO 6564 the 2003 wines were examined by three panels. Each panel examined all the wines and defined the sensory descriptors for each wine. A Quantitative Descriptive Card with these descriptors was then defined.

The wines produced in the first year of study were subjected to a Consumer test during the Turin wine exhibition “Salone del Vino”. For each sample were evaluated colour, odour and taste. An overall evaluation was also asked at the end of tasting. For each parameter a nine point hedonistic scale was used.

The Sensory Cards, defined in the first year of study, were used to evaluate all 2004 vintage wines, at the end of the experimental period. For this analysis the trained panels of each RTD were used. By mean of values computed for each descriptor among panellists and panels the sensory profiles were defined for each wine produced from single autochthonous grape varieties.

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