Dynamic headspace/GC-MS to control the aroma fingerprint of extra-virgin olive oil from the same and different olive varieties

A reliable, sensitive and effective automated method based on dynamic headspace-thermal desorption (DHS-TD) combined to gas chromatography-mass spectrometry (GC-MS) was developed to identify and quantify simultaneously 51 characteristic volatile compounds from extra-virgin olive oils (EVOOs). The most important parameters affecting the DHS extraction were evaluated by two chemometric approaches: a screening 23 factorial design and a Box-Behnken response surface design. The method was validated to ensure the quality of the results. The precision was satisfactory with relative standard deviations (RSD %) less than 10% and 13% for repeatability and reproducibility, respectively. The method showed good linearity and limits of detection were in the range 4.2-110.2 ng/g. The accuracy of the method was also evaluated by means of recovery tests undertaken on EVOO samples fortified at two concentration levels. The recoveries obtained ranged from 50.9 to 113.9%. Finally, the proposed method was applied to control for the first time the flavour profile of EVOOs from an emerging production area in north-western Spain (Galicia), with the aim of detecting quantitative differences in two cases: (a) small differences among oils from different trademarks based on the same olive variety or coupage, and (b) larger differences among oils based on different olive varieties or coupages. To achieve the identification of the major potential impact odorants, the odour activity value (OAV) was also calculated.

► Factorial design & Box-Behnken response surface design to optimize extraction. ► Successfully applied to the first analysis of commercially EVOO from Galicia. ► Main volatiles were from lipoxygenase pathway, especially from linolenic acid. ► Varieties and blends could be the main factor of volatile profile variability. ► OAVs help to describe their potential importance of volatiles in the aroma.