Virgin olive oil odour notes: their relationships with volatile compounds from the lipoxygenase pathway and secoiridoid compounds

Fifty-one virgin olive oils of good quality, extracted with a laboratory mill in the same operative conditions from different unripe Italian, Greek and Spanish cultivars, were submitted to sensory evaluation, and to the determination of both polyphenols and the composition of volatile compounds produced through lipoxygenase (LOX) pathways. Univariate analysis was applied to the mentioned variables and some correlations were observed among them. Moreover, a Linear Regression Analysis (LRA) was carried out assuming, as dependent variable, each sensory attribute perceived by tasters and, as independent variables, all compounds derived, derived LOX pathways and polyphenols. The results obtained demonstrate the essential role played by hexanal in the formation of most attributes considered. The most relevant contributors among C6 compounds from linolenic acid were trans-2-hexenal, trans-2-hexen-1-ol and cis-3-hexenyl acetate. Polyphenols contributed to the characterization of walnut husk, bitter and pungent characters, whereas C5 compounds, especially 1-penten-3-one, strongly affected most attributes.