Characterization by gas chromatography-olfactometry of the most odour-active compounds in Italian balsamic vinegars with geographical indication.

Odour-active compounds in three traditional balsamic vinegars from Modena (TB) and seven balsamic vinegars from Modena (PGI) were determined by gas chromatography-olfactometry (GC-O) using frequency of detection methodology (modified frequency, MF, %). The main odour compounds (mean MF > 60%) were 2,3-butanedione (75%), acetic acid (70%), furan-2-carbaldehyde (62%), 1-(furan-2-yl)ethanone (62%), 2-methylpropanoic acid (66%), butanoic acid (78%), 3-methylbutanoic acid (83%), 2-phenylethyl acetate (65%), 2-hydroxy-3-methylcyclopent-2-en-1-one (61%), 2-phenylethan-1-ol (84%), 3-hydroxy-2-methylpyran-4-one (60%), (5-formylfuran-2-yl)methyl acetate (68%), 2-phenylacetic acid (69%) and 4-hydroxy-3-methoxybenzaldehyde (86%). All odour impact compounds were grouped into 7 categories according to their aromatic character: cheesy-butter-lactic, sweet, flower, empyreumatic, fruity, chemical and miscellaneous. Balsamic vinegars from Modena showed lower values for the sweet category whereas for the miscellaneous and chemical categories they exhibited higher values than those found in traditional balsamic vinegars from Modena. A principal component analysis showed that both types of vinegars from Modena could be clearly differentiated based on olfactometric data.