Quality Evaluation of Olive Oil by Statistical Analysis of Multicomponent Stable Isotope Dilution Assay Data of Aroma Active Compounds

An instrumental method for the evaluation of olive oil
quality
was developed. Twenty-one relevant aroma active compounds were quantified
in 95 olive oil samples of different quality by headspace solid phase
microextraction (HS-SPME) and dynamic headspace coupled to GC-MS.
On the basis of these stable isotope dilution assay results, statistical
evaluation by partial least-squares discriminant analysis (PLS-DA)
was performed. Important variables were the odor activity values of
ethyl isobutanoate, ethyl 2-methylbutanoate, 3-methylbutanol, butyric
acid, E,E-2,4-decadienal, hexanoic
acid, guaiacol, 2-phenylethanol, and the sum of the odor activity
values of Z-3-hexenal, E-2-hexenal, Z-3-hexenyl acetate, and Z-3-hexenol. Classification
performed with these variables predicted 88% of the olive oils’
quality correctly. Additionally, the aroma compounds, which are characteristic
for some off-flavors, were dissolved in refined plant oil. Sensory
evaluation of these models demonstrated that the off-flavors rancid,
fusty, and vinegary could be successfully simulated by a limited number
of odorants.