Screening and evolution of volatile compounds during ripening of ‘Nebbiolo’, ‘Dolcetto’ and ‘Barbera’ (Vitis vinifera L.) neutral grapes by SBSE-GC/MS.

The evolution of pre-fermentative volatiles and of the global aroma potential in three Italian neutral varieties (‘Nebbiolo’, ‘Barbera’ and ‘Dolcetto’) was assessed from véraison to harvest by SBSE-GC/MS. C6 and C9 compounds, benzene derivatives, bound monoterpenes and sesquiterpenes showed differences among varieties in quantity and profiles during berry ripening. Quantitatively, the most of total monoterpenes, C-13 norisoprenoids and sesquiterpenes were detected after acid hydrolysis. Among pre-fermentative norisoprenoids, exclusively β-ionone was detected with different kinetics among varieties. Monoterpene accumulation started around véraison with the exception of (E)-geranylacetone, whose content was already high at véraison. (E)-geranylacetone, deriving from the degradation of carotenoids, could become a target molecule to study indirectly the accumulation of carotenoids. Data allowed to measure the global aroma potential and the pre-fermentative volatiles of grapes: result interpretation suggested a number of implications on biosynthetic processes that have been addressed.