Influence of ripe table olive processing on oil characteristics and composition as determined by chemometrics

The changes in ripe olive fat produced by processing were studied according to cultivars using the general linear model, principal component analysis (PCA), predictive discriminant analysis (DA), and hierarchical clustering. Acidity, peroxide value, K270, and ΔK increased during storage. Acidity also increased after sterilization, whereas K270 decreased after darkening; K232 showed a progressive decrease during processing. Fatty acids (except C17:0, C18:0, and C24:0), triacylglycerols (except PLLn, OOLn+PoOL, PLL+PoPoO, SOO, and POS+SLS), polar compounds, diacylglycerol, and monoacylglycerols also suffered statistically significant changes during processing. A PCA discriminated between cultivars and, within the same cultivar, among the raw materials from the rest of the treatments. Using fatty acid and triacylglycerol compositions, predictive DA discriminated between cultivars (100% correct), but high discriminant capacity among processing steps (95% correct assignation and 87% in cross-validation) was achieved only with fatty acids. A hierarchical clustering analysis successfully grouped cultivars and processing steps according to overall olive oil composition and quality.This work was supported by the Spanish government (AGL-2006-03540/ALI, partially financed by European regional development funds, ERDF) and Junta de Andalucía (through financial support to group AGR-125).Peer reviewe