Influence of Ripe Table Olive Processing on Oil Characteristics and Composition As Determined by Chemometrics

Abstract

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, K(270), and DeltaK increased during storage. Acidity also increased after sterilization, whereas K(270) decreased after darkening; K(232) 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.

Oil Content and Fatty Acid Profile of Spanish Cultivars During Olive Fruit Ripening

“…2c). These values are in agreement with those found in the literature for drupes from the same cultivars [18,23,25]. Figure 2c shows the percentage of monounsaturated fatty acids present in the oil extracted from drupes of different cultivars and ripeness states.…”

Chemometric characterisation of the fats released during the conditioning processes of table olives

“…A marked acidity increase was observed (up to %1.20%) in the oil from Manzanilla cv. during the storage phase of ripe black olive processing (López-López et al, 2009). A similar effect might be expected when subjecting this cultivar to fermentation as green olives.…”

“…The value obtained in the PGF fat was only slightly higher than that expected after only fermentation; then, the effect of pitting, including the brine recycling during the operation, had a limited effect. However, the acidity in ripe olives after darkening was about 0.8% (López-López et al, 2009) and the effect of recycling during conditioning could have been slightly higher in PRF. The acidity in PSGVF was significantly higher (Table 1) than in PGF, meaning that the introduction of other materials in the process had a marked effect on this parameter.…”

Saturated and Unsaturated Fatty Acids Composition of Olive Oils Obtained from Less Salty Black Table Olives Preserved with Vacuum, MAP and Gamma Irradiation Technologies

“…With regard to the indices of oxidative degradation, the PV significantly increased during natural-style treatment, although the final values were relatively low (11.7-13.1 meqO 2 /Kg oil, depending on cultivar). The observed values were lower than those reported for California-style processed olives [33], and were within the limit of 20 meqO 2 /Kg oil required for extra virgin olive oils (EC Commission).…”

“…Lopez et al, peroxide value (similar in Manzanilla and Hojiblanca raw material) significantly increased during the storage phase; later, it showed a non-significant, slight decrease [33]. The formation of hydro peroxides during storage is due to autoxidation or to the action of lipoxygenase, which requires free fatty acids (preference: linolenic>linoleic>oleic) that are easily available in these olives due to the fatty acid increase during storage.…”