Olive oil, squalene

Smith, T.I., Yang, G.Y., Seril, D.N., Liao, I. and Kim, S. (1998) Inhibition of 4-(methylnitrosamino)-l-(3-pyridyl)-l-butanone induced lung tumorigenesis by dietary olive oil squalene. Carcinogen., 19, 703-706. 

The transition temperatures of a (squalene + olive oil + ethyl lactate) mixture are given in Table 20.4.7. The mixture contains an olive oil/squalene ratio of 70 30. Figure 20.4.10 depicts the data corresponding to the transition temperature of the (squalene + olive oil + ethyl lactate) mixture vs. ethyl lactate wt%. As can be observed in Figure 20.4.10, the UCST of the ternary system is higher (323.15K) than the corresponding temperatures for squalene + ethyl lactate (312.15K) and olive oil + ethyl lactate (317.15K) mixtures, respectively. 

Table 20.4.7. Transition temperatures of the ternary mixture squalene + olive oil (olive oil/squalene ratio = 70 30) and ethyl lactate at atmospheric pressure. ...

Squalene Vegetable oil, olive oil, rice bran oil Myrtenol Myrtus cuninus... 

Thiourea inclusion compounds have also found recent applications as diverse as the separation of liquid crystal isomers 84 ), isolation of petroleum constituents 85,86), and the recovery of squalene during olive oil refining87), to cite just a few examples. 

OE036 Newmark, H. L. Squalene, olive oil, OE048 and cancer risk a review and hypothesis. Cancer Epidemiol Biomark Prevent 1997 6(12) 1101-1103. 

Major flaxseed sterols are stigmasterol, camp sterol, and 5-5 avenasterol (Daun et al., 2003). Obtusifoliol, gramisterol, and citrostadienol constituted 45%, 22%, and 12%, respectively, of the total 4a-monomethylsterol in flaxseed (Kamm et al., 2001). Squalene content of flaxseed oil was reported as 4 mg/100 g oil, which was significantly lower than olive, corn, and rice bran oils. Squalene content is an intermediate compound of biosynthesis of plant sterols, which may have protective effects on lipid quality. Squalene could act as a peroxy radical scavengers in high polyunsaturated fatty acid oil (Dessi et al., 2002). 

The official method of analysis of steradienes in olive oil (Commission regulation (EC) No. 656/95) involves saponification of the oil with an internal standard of cholesta-3,5-diene, followed by extraction of the unsaponifiable fraction into hexane. The steradiene fraction is then separated from other hydrocarbons, such as alkanes and squalene isomers, by column chromatography on silica gel. Quantitative analysis is then performed by GC. 

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). 

Owen, R.W., Mier, W., Giacosa, A., Hull, W.E., Spiegelhalder, B. and Bartsch, H. (2000b) Phenolic compounds and squalene in olive oils. Food Chem. Toxicol., 38(8), 647-659. 

Grigoriadou, D. Androulaki, A. Psomiadou, E. Tsimidou, M.Z. 2007. Solid phase extraction in the analysis of squalene and tocopherols in olive oil. Food Chem. 105 ... 

Plant sterols inhibit the intestinal absorption of cholesterol and so have a useful hypocholesterolemic action. They also inhibit endogenous synthesis of cholesterol, by inhibiting and repressing the regulatory enzyme of cholesterol synthesis, hydroxymethylglutaryl (HMG)-CoA reductase. Other compounds synthesized from mevalonate also inhibit and repress HMG-CoA reductase and have a hypocholesterolemic action, including squalene (found in relatively large amounts in olive oil), ubiquinone (Section 14.6), and the tocotrienols (Section 4.1). 

Hydrocarbons are very minor components of oils and fats but are of dietary and legislative interest. They include alkanes, alkenes such as squalene and carotenes, and polycyclicaromatic hydrocarbons. Squalene (C30H50) is a highly unsaturated open-chain triterpene. It is used in the cosmetic industry after hydrogenation to squalane (C30H62). The most abundant source of squalene is the liver oil of the deep-sea dogfish (Squalus acanthus—hence the name squalene) and some other marine species. Vegetable sources of potential interest include olive oil and amar-anthus (Section 6). 

Hydrocarbons. Both even- and odd-chain w-paraffins, including branched-chain (iso and anteiso) compounds, which are minor components of the hydrocarbon fraction, are present in virgin olive oil. The polyunsaturated triterpenic hydrocarbon squalene, and biochemical precursor of sterols, is the main component of the hydro carbon fraction. The squalene content of olive oil ranges from 150 to 700 mg per 100 g (27-30). p-Carotene is also present in olive oil as are aromatic hydrocarbons, including benzenoid, napthalenic, and more complex aromatic hydrocarbons (30-37). 

Supercritical CO2 column fractionation has also been investigated for the production of squalene concentrates from olive oil deodorizer distillates (56, 87). Bon-dioli et al. (87) used saponification and esterification steps to convert the FFA and fatty acid esters to triacylglycerols in order to improve squalene separation prior to countercurrent continuous fractionation. The highest squalene purity and extraction yield was achieved at 15 MPa and 313 K, using a temperature gradient of 303-323 K along the column to improve the squalene purity and yield. Ruivo et al. 

One of the components in this olive oil residue that may be of interest for the industry is squalene. Squalene is used as industrial lubricant, and is widely used in several cosmetic applications as a carrier for lipid-soluble components since it is easily adsorbed by the skin (2). Squalene has also been claimed to enhance oxygenation of the blood, facilitate detoxification, strengthen immune system and protect against cancer (3). Traditionally squalene is mainly obtained from shark liver oil (4), which is an unethical use of sharks threatened by extermination and really is not acceptable. 

In order to achieve long term stability in society, industry should focus on renewable sources both as raw material and as process chemicals. Therefore, renewable raw material has been searched for to give a source of squalene, for example olive oil (5,6) and amaranth seed oil (7,8). Another component of interest in olive oil pomace is a-tocopherol, which is traditionally considered as the major antioxidant of olive oil. 

The aim of this work was to develop a simple, environmentally sound and fltst method for the extraction and determination of squalene in an olive biomass using the PFE technique, and investigate if this technique could be a viable processing technology for the extraction of squalene from olive oil pomace. The effects of different solvents and mixtures of solvent, extraction temperature and extraction time were also evaluated for their influence on yield of squalene. Squalene in the olive biomass extracts were quantified by liquid chromatography with UV absorbance and fluorescence detection. In addition, the proposed method was used to determine the content of a-tocopherol in the olive biomass. 

The olive biomass samples (olive oil pomace) were obtained from an olive oil processing ctory in Cdrdoba (Spain), which used a two phase centrifugation technique to extract the oil. The samples were kept frozen at -20°C. Two different samples (A and B) were used in all the experiments, which had been obtained using the same process, but at different time of the year. Sample A consisted of well grounded biomass, while sample B was crude and contained visual traces of kernels. The a-tocopherol and squalene standards were from Sigma Chemical (St. Lx>uis, USA). 

Table I. Extraction yield in g/g of squalene obtained with a central composite design from olive oil pomace, batch A.

Figure 2. Response surface plot of the extraction yield of squalene from olive oil pomace using 2 propanol as solvent, as a function of extraction time and...

The C30 hydrocarbon squalene is present at about 200-500 ppm in crude palm oil sesquiterpene (C15) and diterpene (C20) hydrocarbons are present at lower levels. Abdul Gapor and Hazrina (2000) reported squalene as high as 979 ppm in some crude oils and 791 ppm in refined oils. These levels are generally higher than that of other vegetable oils, with the exception of olive oil. Palm fatty acid distillate has 5000 ppm to 8000 ppm of squalene. Crude palm oil also has 10-80 ppm of ubiquinone 10 (Hazura et al. 1996). 

Two hydrocarbons are present in olive oil in considerable amounts, squalene and (3-carotene (see Section 9.3.3.3). 

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