Olive unsaponifiable component

Most oils contain low levels of saturated and unsaturated hydrocarbons. In olive oil, the unsaturated hydrocarbon squalene can constitute up to 40% of the unsaponifiable fraction (Boskou, 1996). Other hydrocarbons commonly present in olive oil are straight chain alkanes and alkenes with 13 to 35 carbon atoms, along with very low amounts of branched chain hydrocarbons. Variations are found between different olive varieties but the main hydrocarbons are those with 23, 25, 27 and 29 carbon atoms (Guinda et al., 1996). Olive oil can clearly be differentiated from other vegetable oils on the basis of hydrocarbon components, and levels of 2.6% crude rapeseed oil or crude sunflower oil can be detected by hydrocarbon analysis (Webster et al., 1999). Terpenes have been identified in the volatile fraction of crude sunflower oil (Bocci and Frega, 1996). 

The epicarp contains a number of components of relatively high polarity that are not removed by mechanical extraction and remain in the pomace. Removal of these components along with the oil by solvent extraction of the pomace accounts for the higher unsaponifiable content of olive-pomace oil. 

The unsaponifiable fraction of olive oil contains a variety of minor components including tocopherols (mainly a-tocopherol, in amounts from 12 to 25 mg/100 g), phenols, flavor compoimds, hydrocarbons, and sterols, Ohve biophenols (OBPs, which are inaccurately referred to as polyphenols in some cases) are used as flavorants, colorants, and antioxidants. The best known olive oil phenols are hydroxytyrosol, tyrosol, oleiuopein, apigenin, and luteolin, in both free and derivative forms,... 

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