Virgin olive oil differentiation in relation to extraction methodologies

Sensory green attribute intensities, the total amount of complex phenolic c ompounds and the composition of volatile compounds from lipoxygenase pathwa ys were measured in oils obtained from both industrial centrifugation plant s and different kinds of laboratory mill. These data were evaluated by hier archical cluster analysis, principal component analysis and linear discrimi nant analysis with the aim of distinguishing oil samples in relation to the extraction methodology. The statistical tests showed that the mentioned va riables were able to differentiate oils according to the method adopted for their extraction from olive pastes. Oils from laboratory mills were clearl y 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. Oi ls from dual-phase decanters in industrial plants were more similar to samp les extracted in conventional tri-phase industrial plants, even if they wer e all well differentiated according to the oil extraction methodology. (C) 2000 Society of Chemical Industry.