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While extra virgin olive oil is often denoted as being “first cold-press,” what is termed “pomace oil” cannot even qualify as being “second press.” Once the typical, mechanized extraction of olive oil from the olive fruit is complete, some 5-8 percent of the oil still remains in the leftover olive pulp or “pomace.” Although the pomace oil that is extracted is still technically oil that comes from olives, this is done via the use of chemical solvents, and therefore should never be termed, directly or indirectly, as olive oil.
The International Olive Council, the intergovernmental organization responsible for outlining quality standards and monitoring olive oil authenticity, clearly defines olive oil as, “oil obtained solely from the fruit of the olive tree, to the exclusion of oils obtained using solvents or re-esterification processes.” The amount of oil contained in the leftover pomace, which consists of the solid remains of the olive including skins, pulp, seeds, and stems, is so minimal that it cannot be extracted by pressing, but only through the combined use of chemical solvents (like Hexane) and extremely high heat.
This very process, the same high heat technique used in producing canola, sunflower, and other vegetable oils, is why unregulated olive pomace oil sometimes contain harmful components known as polycyclic aromatic hydrocarbons (PAHs) like benzopyrene, which research has shown to be highly carcinogenic and mutagenic. Benzopyrenes result from the incomplete combustion of the fats present in the olives. When fats are exposed to levels of high heat, like in the pomace oil extraction processes where there is no complete combustion and no smoke is produced, benzopyrenes are likely to be produced as a result.
The process to extract olive pomace oil is as follows: a chemical solvent is first administered to the olive pomace which has the ability to dissolve the fats but not the rest of the solid pomace. This application extracts the oil and then afterward, in a refining process, the product is heated so the solvent evaporates completely and cleanly without leaving any sort of harmful residue — so long that this heating method does not exceed 90 degrees Celsius (194 degrees Farenheit). Using this system, the final product is not likely to contain polycyclic aromatic hydrocarbons (PAHs) like benzopyrene.
The risk of benzopyrene contamination occurs when the heating method used to evaporate the solvent exceeds 300 degrees Celsius (572 degrees Farenheit). In these instances, the fat is liquefied into fluid and then drips out of the olive pomace, but the problem is that the insanely high heat results in the partial combustion of the oil with the rest of the physical pomace. This can cause the rapid accumulation of benzopyrenes in the final product.
In instances of heat applications above 300 degrees Celsius, the resulting oil comes with a definite health risk for consumers which depends entirely on the aggressiveness of the heat treatment as well as the amount and frequency of the pomace oil consumed. Because the degree of contamination depends on the type of treatment used, it is necessary for health authorities to clarify what kind of treatment has been applied to produce particular pomace oils and to establish a permissible limit of the amount of benzopyrenes present.
Benzopyrenes, being themselves highly reactive fats, can dissolve easily into cellular membranes and thereby enter a cell’s interior. This resulting action has been shown to cause either intracellular oxidation–the aging and death of cells–or an intoxication which results in the mutagenesis of the genetic material in the cell’ s nucleus. In some instances, this of course spreads as an uncontrolled multiplication of damaged cells which can result in a cancerous tumor.
Concerned about the levels of PAHs like benzoyprene in pomace oil, the Spanish government introduced a temporary ban on pomace oil in July of 2001 and halted all exports of pomace oil until tests were conducted and limits of the allowable amounts of PAH’s present in the oil were made concrete.
Other countries followed suit: the New Zealand Health and Food Safety authority recalled olive pomace oil from several manufacturers and the German ministry acted similarly issuing this warning: “As a preventative health protection measure, the ministry for consumer affairs, nutrition and agriculture has appealed to the German states and industry to review the remains of the 170 tons of Spanish olive-pomace oil and products containing this oil.”
This article was last updated December 27, 2011 - 8:34 AM (GMT-4)