-e authors are grateful to the Foundation for Science and
Technology (FCT, Portugal) for financial support by national
funds FCT/MCTES to CIMO (UIDB/00690/2020),
CEB (UIDB/04469/2020), REQUIMTE-LAQV (UIDB/50006/2020) units, and the Associate Laboratories for Green
Chemistry-LAQV (UIDB/50006/2020) and SusTEC (LA/P/0007/2020), as well as to BioTecNorte operation (NORTE-
01-0145-FEDER-000004) funded by the European Regional
Development Fund under the scope of Norte2020—Programa
Operacional Regional do Norte. ´Itala M.G. Marx also
acknowledges the PhD research grant (SFRH/BD/137283/2018) provided by FCT. Nuno Rodrigues likes to thank
national funding by FCT—Foundation for Science and
Technology, P.I., through the institutional scientific employment
program contract.
Oils from cv. Arbequina were industrially extracted together with olive leaves of cv. Arbequina or Santulhana (1%, w/w), and their
olfactory and volatile profiles were compared to those extracted without leaves addition (control). -e leaves incorporation
resulted in green fruity oils with fresh herbs and cabbage olfactory notes, while control oils showed a ripe fruity sensation with
banana, apple, and dry hay grass notes. In all oils, total volatile contents varied from 57.5 to 65.5 mg/kg (internal standard
equivalents), being aldehydes followed by esters, hydrocarbons, and alcohols the most abundant classes. No differences in the
number of volatiles were observed. -e incorporation of cv. Arbequina or Santulhana leaves significantly reduced the total content
of alcohols and esters (minus 37–56% and 10–13%, respectively). Contrary, cv. Arbequina leaves did not influence the total content
of aldehydes or hydrocarbons, while cv. Santulhana leaves promoted a significant increase (plus 49 and 10%, respectively). -us, a
leaf-cultivar dependency was observed, tentatively attributed to enzymatic differences related to the lipoxygenase pathway.
Olfactory or volatile profiles allowed the successful unsupervised differentiation of the three types of studied cv. Arbequina oils.
Finally, a lab-made electronic nose was applied to allow the nondestructive discrimination of cv. Arbequina oils extracted with or
without the incorporation of olive leaves (100% and 99 ± 5% of correct classifications for leave-one-out and repeated K-fold crossvalidation
variants), being a practical tool for ensuring the label correctness if future commercialization is envisaged. Moreover,
this finding also strengthened that olive oils extracted with or without olive leaves incorporation possessed quite different olfactory
patterns, which also depended on the cultivar of the olive leaves.
