Gas chromatography-olfactometry characterization of corvina and corvinone young and aged wines

Abstract

AIM AND METHODS: Corvina and Corvinone are the two main grape varieties used in the production of Valpolicella, Recioto and Amarone, top-quality red wines in north-eastern Italy. This work aimed at determining the aroma composition of Corvina and Corvinone experimental wines and identify the main aroma compounds contributing to the aroma characteristics of Corvina and Corvinone monovarietal wines. Five Corvina and five Corvinone wines were studied, the grapes coming from five different vineyards in Valpolicella. Volatile compounds were extracted by SPE and identified and quantified by gas chromatography-mass spectrometry (GC-MS), whereas their aroma impact was determined by gas chromatography- olfactometry (GC-O).

RESULTS: Based on the GC-MS-O analysis, 95 odor zones were detected, from which 68 compounds were successfully identified. Using the criterion of a value higher than 30% in modified frequency (MF %), 51 compounds were selected and grouped according to odor similarity. Compounds with values below 30% were discarded. Modified frequency percentage (MF %) was calculated using the frequency of citation and the intensity of each odor zone (Dravnieks, 1985). Fifteen groups were created with the following odor descriptors: vegetal, fruity, lactic, berry-like, balsamic, chemical, reductive, plastic, toasted-burnt, sweet, floral, rancid, herbaceous, sweet-spices and spicy. Diacetyl, ethyl butyrate, isoamyl acetate, isoamyl alcohol, 1-octen-3-one, methional, 2-/3-methylbutyric acid, methionol, beta-damascenone, 2-methoxyphenol (guaiacol), beta-phenethyl alcohol, 4- propylguaiacol, and eugenol, were found to be the most potent compounds. A number of other potent odor zones were detected but could not be identified, in particular associated with the odor descriptors such as balsamic, sweet-spices and toasted-burnt. Identification of the chemical compounds responsible for these odor zones is currently in progress.

CONCLUSIONS:

This work helps to shed more light on the aroma composition of some of the most representative red wines made in Italy and from which there is little information available to date.