Aromatic characterization of Moscato Giallo by GC-MS/MS and stable isotopic ratio analysis of the major volatile compounds

Among the Moscato grapes, Moscato Giallo is a winegrape variety characterized by a highcontent of free and glycosylated monoterpenoids, which gives very aromatic wines. Thearomatic bouquet of Moscato Giallo is strongly influenced by the high concentration of linalool, geraniol, linalool oxides, limonene, α-terpineol, citronellol, HO-trienol, HO-diols, 8-Hydroxylinalool, geranic acid and β-myrcene, that give citrus, rose, and peach notes. Except the quali-quantitative analysis, no investigations regarding the isotopic values of the target volatile compounds are documented in literature. Stable isotope ratio analysis represents a modern and powerful tool used by the laboratories responsible for official consumer protection, for the food quality and genuineness assessment. In this study, samples of Moscato Giallo were collected during the harvest season in 2019 from two Italian regions:Trentino – Alto Adige and Veneto, known lands for the cultivation of this aromatic variety. The flavor compounds were extracted from grapes and wines, after alcoholic fermentation of grape juice, and analysed by GC-MS/MS. The results confirmed the presence of typical terpenoids both in free and glycosylated form, responsible for the characteristic aroma of Moscato Giallo variety. The aromatic compounds were also analysed by GC-C\Py-IRMS for a preliminary investigation. The compound-specific isotope ratio analysis allowed to determine the carbon (δ13C) and hydrogen (δ2H) isotopic signatures of the major volatile compounds for the first time.