Virgin olive oil differentiation in relation to extraction methodologies

Sensory green attribute intensities, the total amount of complex phenolic compounds and the composition of volatile compounds from lipoxygenase pathways were measured in oils obtained from both industrial centrifugation plants and different kinds of laboratory mill. These data were evaluated by hierarchical cluster analysis, principal component analysis and linear discriminant analysis with the aim of distinguishing oil samples in relation to the extraction methodology. The statistical tests showed that the mentioned variables were able to differentiate oils according to the method adopted for their extraction from olive pastes. Oils from laboratory mills were clearly different from samples extracted industrially. This implies that results derived from investigations carried out using oils obtained from laboratory mills cannot be immediately transferred to oils from industrial plants. Oils from dual-phase decanters in industrial plants were more similar to samples extracted in conventional tri-phase industrial plants, even if they were all well differentiated according to the oil extraction methodology. (C) 2000 Society of Chemical Industry.