Metabolomic approaches for olive oil quality discrimination by gas chromatography coupled to mass spectrometry

Abstract

In this work, a gas chromatography coupled to mass spectrometry (GC-EI-Q(MS)) has been used for markers identification for a metabolomics approach. It has been carried out in order to create a statistical model to perform a correct classification between different quality olive oils (extra, virgin and lampante). A dynamic headspace purge and trap (DHS-P&T) was used to the extraction of volatile organic compounds (VOCs) responsible for olive oil flavours and they were eluted from the SPE cartridges with a mixture of hexane:diethyl ether (50/50, v/v). The methodology is based on the application of P&T extraction followed by gas chromatography coupled to mass spectrometry in full-spectrum acquision mode. The data acquired by this equipment was pre-treated by a new program called PARAFAC. After that these acquired data was normalized and the differentiation between the different groups of olive oil has been carried out with a multivariate analysis using Ez-Info. This methodology was applied to process 47 olive oil samples (11 extra, 19 virgin, 17 lampante) in order to create and check the classification model. The different models were performed with 37 samples. Finally, the whole developed method was correctly validated by the other 10 samples which were kept for the validation. Four of the seven evaluated model achieved around a 60% of correct classification. And with one of the studied models was obtained a classification of 90%. So with that result, it can be said that with this methodology and with these markers the PANEL TEST could be substituted.