Comparison between the volatile chemical profile of two different blends for the enhancement of  “Valpolicella Superiore”

Abstract

Valpolicella is a famous wine producing region in the province of Verona owing its fame above all to the production of two Protected Designation of Origins (PDOs) withered wines: Amarone and Recioto. In recent years, however, the wineries have been interested in the enhancement and qualitative increase of another PDO, Valpolicella Superiore. All the Valpolicella PDOs wines are produced with a unique grape blend, mainly Corvina, Corvinone, Rondinella and a range of other minor varieties.

From 2019 Valpolicella product regulation has changed the grape proportion of the blend allowing new composition parameters of wines. For this reason, studying the volatile chemical profiles to support wine makers in the effort to produce high quality wines represents a field of great interest.

The study aimed to evaluate the volatile chemical and sensory composition of two different blends, one “traditional” (70% Corvina, 30% Rondinella) and an “experimental” (60% Corvinone, 20% Corvina, 20% Rondinella).

The grapes were supplied by six wineries in Valpolicella, four of which provided both blends, whereas two companies provided only traditional modality.

Winemaking was performed under standardized conditions . Free volatile compounds as well as those obtained through hydrolysis of glycosidic precursors were analysed with gas chromatography mass spectrometry (GC-MS) coupled with SPE and SPME extractions.

Fermentation kinetics were found to be influenced by the different composition of the blends.

Differences between different blends were attributable both to varietal as well as fermentative compounds.

Interesting differences were found between the various classes of volatile compounds in relation to the two different blends, confirming how by changing the two different blends we can define two very different styles of wines. Traditional-blends wines have been found to be richer in free terpenes and C6 alcohols, while experimental-blends wines have been found richer in free norisoprenoids (in particular TDN, -ionone and β-damascenone), benzenoids and alcohols. Traditional-blends wines have been also found richer in almost all bound compounds (especially ethyl esters, terpens and benzenoids).

In conclusion, this study highlighted the different  blends’ potential studied to produce wines with specific and different aromatic profiles.