Metabolic fingerprinting strategies for authentication challenge: EVOO adulterated by soft deodorized olive oil

Abstract

Extra virgin olive oil (EVOO) is a high value commodity that might be subject of various fraudulent practices. One of them, addition of lower grade, soft-deodorized olive oil to EVOO has recently become of concern, as such adulterant detection is not an easy task. In this study, aqueous methanolic extracts of a unique set of authentic EVOOs, soft-deodorized oils and their admixtures obtained within the OLEUM EU project (http://www.oleumproject.eu/) were investigated. Using ultra-high performance liquid chromatography coupled to hybrid quadrupole time-of-flight high-resolution tandem mass spectrometry (UHPLC-QTOF-HRMS/MS) for metabolomic fingerprinting, followed by  multi-dimensional chemometric evaluation, ´marker ions´ were recognized. Some molecules identified, whose etiology must be investigated, were: the methyl ester of hydroxy octadecenoic acid and a ester derivative of oleic acid. As far as these markers can be confirmed as diagnostic, detection of soft-deodorized olive oil addition can be enabled through a simpler and highly sensitive target analysis employing high performance liquid chromatography coupled to triple quadrupole tandem mass spectrometry (HPLC-QqQ-MS/MS).