CHARACTERIZATION OF THE VOLATILE COMPOUNDS PROFILE OF COMMERCIAL GRAPPAS OBTAINED FROM THE POMACE OF AMARONE WINES

Abstract

Grappa is a traditional Italian alcoholic beverage, with an alcohol content generally between 40-60% vol., obtained from the distillation of grape pomace used for the production of wine. Grappa are often aged in wooden barrels. There are various types of grappa: young, aromatic, aged, extra-aged depending on whether the distillate comes from aromatic vines or is aged in wooden barrels for shorter or longer periods. There is also flavored grappa if herbs, fruit or roots are added. All this makes it an extremely heterogeneous product both from an organoleptic and compositional point of view. There is therefore the need to deepen the characterization of the different types in order to optimize the production processes and improve the products by enhancing their distinctive characteristics.

This work aims to characterize the volatile compounds profile of the Grappa obtained from the pomace of Amarone, a red wine from the province of Verona (northern Italy) produced from withered grapes of the Corvina and Corvinone varieties. For this study, the volatile profiles of 19 samples of Amarone grappa were compared with those of 7 grappas not obtained from Amarone pomace but from other vines. The aromatic profiles were obtained by SPE extraction of the volatile molecules followed by GC-MS analy-sis. A total of 62 compounds belonging to various chemical classes (alcohols, C6, terpenoids, sesquiterpeneoids, norisoprenoids, benzenoids, fatty acid esters) were identified and quantified in the samples. Through non-parametric statistical analysis (Kruskal Wallis) the compounds characterizing the Amarone grappas were identified, including: hexanoic acid, ethyl octanoate, 1,4-cineole, β-damascenone, β-ionone, TPB, 2,2 dihydrofarnesol and α-farnesol. Furthermore, the Amarone grappa was more characterized by compounds linked to the aging of the distillate in wood such as: syringaldehyde, vanillin, 2-methoxyphenol, whiskey lactone. In conclusion, these results allow us to better understand which compounds could be characterizing Amarone grappa, in order to study their behavior more thoroughly during the various production phases in order to manage the aromatic potential of these products.