Supervisors info:
Μαγιάτης Προκόπιος Επίκ. Καθηγητής ΕΚΠΑ (επιβλέπων), Ρούσσης Βασίλειος Καθηγητής ΕΚΠΑ, Αληγιάννης Νεκτάριος Επίκ. Καθηγητής ΕΚΠΑ
Summary:
In the present study, a new method of direct measurement of four secoiridoids
in extra virgin olive oil (EVOO) with quantitative NMR was developed.
EVOO was treated with liquid- liquid extraction using c-Hexane/ Acetonitrile.
Four secoiridoids were isolated from the ACN fraction, oleocanthal, oleacein,
aldehydic form of oleuropein aglycon and aldehydic form of ligstroside aglycon.
Both aglycons isolated as an inseparable mixture of the two isomeric forms (5S,
8R, 9S) and (5S, 8S, 9S). The ratio between the two isomers for both aglycons
changed significantly during the chromatographic procedure, and was very
different from the original ratio in the olive oil. Therefore, the
chromatographic quantitative determination of these substances was found to be
problematic.
Afterwards, the four substances were quantified in olive oil with NMR and the
method was validated. Also, we studied the correlation between the content of
oleocanthal and oleacein and the organoleptic characteristics of some EVOO
samples.
The method of direct quantitative measurement of secoiridoids was applied to
291 samples of Greek olive oil, followed by statistical analysis of the results
based on three new indexes for olive oil assessment (Index D1, D2, D3).
Finally, the stability of olive oil and the changes observed in the
quantitative composition in terms of the olive harvest season and olive oil
production temperature were studied.
Keywords:
Extra virgin olive oil, Oleocanthal, Oleacein, Oleuropein and ligstroside aglycon, Quantitative NMR
