Study of the minor fraction of virgin olive oil by a multi-class GC-MS approach: Comprehensive quantitative characterization and varietal discrimination potential

Abstract

For the first time, a multi-class GC-MS method was applied to perform the quantitative-profiling of the minor fraction of VOOs (considering >40 compounds) in a single run. This comprehensive methodology has demonstrated a remarkable profiling ability on five groups of compounds (phenolic and triterpenic compounds, tocopherols, sterols and free fatty acids) with wide range of polarities/volatilities and chemical entities. After the complete analytical validation of the method, 32 VOO samples from eight different cultivars (some of them very scarcely studied before) were analyzed and the quantitative results were subjected to both non-supervised and supervised multivariate statistics for testing the capability of the determined VOO minor compounds to discriminate the varietal origin of the samples. Typical compositional profiles were defined for each cultivar and promising potential varietal markers were pointed out. The models built to discriminate Cayon and Maurino samples from the rest exhibited the best quality parameters. The relative levels of tocopherols together with characteristic concentration of luteolin, β-sitosterol and tyrosol were, for instance, the most specific features of Cayon VOOs.

Keywords: Chemometrics; Gas chromatography; Mass spectrometry; Minor fraction; Multi-class methodology; Olive cultivar; Varietal marker; Virgin olive oil.