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What You Didn't Know About Olive Pomace Oil: Uses, Benefits and Controversies

Olive pomace oil is made using chemical solvents and heat. Still, the lowly olive oil grade offers some health benefits and useful culinary applications.
By Daniel Dawson
Updated Dec. 30, 2023 19:55 UTC

Olive oil ter­mi­nol­ogy is con­fus­ing.

Supermarkets are full of olive oil bot­tles embla­zoned with all sorts of mean­ing­ful (extra vir­gin, vir­gin, early har­vest, organic) – and mean­ing­less (light, pure, ultra-pre­mium) pre­fixes.

However, one cat­e­gory of olive oil increas­ingly stands out in a mar­ket where prices hover near record highs in much of the world: olive pomace oil.

See Also:Olive Oil Basics

Olive pomace oil, occa­sion­ally referred to incor­rectly as pomace olive oil, sits at the bot­tom of the hier­ar­chy of olive oil grades. It is pro­duced from the byprod­ucts of the vir­gin and extra vir­gin olive oil pro­duc­tion process using chem­i­cal sol­vents and heat.

This process yields crude olive pomace oil, which is unfit for human con­sump­tion and must be treated into refined olive pomace oil and usu­ally blended with vir­gin or extra vir­gin olive oil to become olive pomace oil. (Even the offi­cial nomen­cla­tures are con­fus­ing.)

The Codex Alimentarius, a col­lec­tion of inter­na­tion­ally rec­og­nized food stan­dards, says refined olive pomace oil must be made using meth­ods that do not alter the ini­tial glyc­eridic struc­ture and have a free acid­ity, expressed as oleic acid, of less than 0.3 grams per 100 grams.

Meanwhile, olive pomace oil must have free acid­ity, expressed as oleic acid, less than or equal to one gram per 100 grams, or 1.0%.

The grade is far infe­rior – in terms of fla­vor and health ben­e­fits – to vir­gin and extra vir­gin olive oil. However, a grow­ing body of research demon­strates that it is bet­ter than some other edi­ble oils.

The grade is demo­nized due to its use by some unscrupu­lous actors who exploit cheaply made olive pomace oil to adul­ter­ate extra vir­gin olive oil and sell it at a steep profit.

While its use in fraud is a prob­lem, the olive pomace oil grade fills a valu­able niche in the olive oil world due to its health ben­e­fits (com­pared to other edi­ble oils) and culi­nary appli­ca­tions.

How olive pomace oil is pro­duced

Olive pomace oil is obtained from the wet fatty pomace paste, the main byprod­uct of the olive oil pro­duc­tion process.

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Olive oil pomace being collected as a production waste in a modern oil mill

During the milling process to make vir­gin or extra vir­gin olive oil, the olives are crushed into a thick paste, which is kneaded in a malaxer to aggre­gate the drops of oil before being cen­trifuged to sep­a­rate the oil from the rest of the olive mate­r­ial, known as olive pomace paste.

The olive pomace paste, which includes water, skin, olive pits and some olive oil, makes up 80 to 90 per­cent of the mass of the milled olives.

See Also:How Olives Are Processed Into Oil

Many pro­duc­ers col­lect the olive pomace paste after pro­duc­tion to sep­a­rate the remain­ing oil, rep­re­sent­ing five to eight per­cent of the total olive oil yield.

If the olive pomace paste is not sent to be extracted and refined, pro­duc­ers must pay to have it removed and dis­posed of since it can be toxic to soil and water in indus­trial quan­ti­ties. In small quan­ti­ties, it can be spread in the olive groves and degrade nat­u­rally.

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The paste is taken to an extrac­tion plant, where it is dried and sep­a­rated into dry fatty pomace, bio­mass and steam.

The fatty pomace, which is dried into pow­der and pressed in pel­lets, is show­ered in a chem­i­cal sol­vent, usu­ally hexane, which dis­solves the fats but not the rest of the solid pomace. The mix­ture of fats and sol­vent is then heated from 60 ºC to 90 ºC until the sol­vent evap­o­rates.

This is the same method used to pro­duce most other edi­ble oils, includ­ing canola, sun­flower and soy­bean.

The result is crude olive pomace oil, which is unsafe for human con­sump­tion and must be processed into refined olive pomace oil.

The refin­ing process includes sev­eral steps, start­ing with set­tling.

In this step, the recently lib­er­ated crude olive pomace oil is left in tanks for a min­i­mum of four weeks to allow any remain­ing water, sed­i­ment, impu­ri­ties or waxes to set­tle at the bot­tom of the tank and be drained out.

After set­tling, the remain­ing crude olive pomace oil still retains unde­sir­able sub­stances, includ­ing free fatty acids and phos­phatides and must be neu­tral­ized to remove them.

Neutralization, also called purifi­ca­tion, involves cen­trifug­ing the set­tled crude olive pomace oil while adding steam and phos­phoric acid to remove phos­phatides and other impu­ri­ties.

After neu­tral­iza­tion, the crude olive pomace oil is cold-fil­tered using water and caus­tic soda to elim­i­nate alco­hol that clouds the oil at low tem­per­a­tures. This phase, known as win­ter­i­za­tion, pro­duces clear and shiny oil.

Next, the crude olive pomace oil is dehy­drated to remove the water added in the pre­vi­ous two steps, and then the oil is car­bon-fil­tered to remove its pig­ments. The process can also remove harm­ful com­pounds that may have formed in the oil dur­ing neu­tral­iza­tion, such as poly­cyclic aro­matic hydro­car­bons and ben­zopy­renes.

After it is dis­col­ored, the crude olive pomace oil is deodor­ized to remove free fatty acids and sub­stances that give the oil an odor or fla­vor by inject­ing steam in a high-pres­sure vac­uum. After, the oil is fil­tered once again.

Refined olive pomace oil, now fit for human con­sump­tion, is taken to a bot­tling plant and usu­ally blended with vir­gin or extra vir­gin olive oil to add fla­vor and aroma.

The poten­tial dan­ger of the olive pomace oil pro­duc­tion process

Heat plays a fun­da­men­tal role in pro­duc­ing olive pomace oil. However, the tem­per­a­ture must be kept below 90 ºC to pre­vent the pro­duc­tion of dan­ger­ous chem­i­cals that can harm human health.

If the tem­per­a­ture is not reg­u­lated, the refin­ing process can cre­ate poly­cyclic aro­matic hydro­car­bons (PAHs), includ­ing ben­zopy­rene, which research has shown to be highly car­cino­genic and muta­genic.

The risk of ben­zopy­rene con­t­a­m­i­na­tion occurs when the heat­ing method used to evap­o­rate the sol­vent exceeds 300 ºC.

In these instances, the fat is liq­ue­fied and drips out of the olive pomace. However, the extremely high heat results in the par­tial com­bus­tion of the oil, caus­ing the rapid accu­mu­la­tion of ben­zopy­renes in the final prod­uct.

Benzopyrenes, which are highly reac­tive, can dis­solve eas­ily into cel­lu­lar mem­branes and enter a cell’s inte­rior.

This result­ing action has been shown to cause either intra­cel­lu­lar oxi­da­tion – the aging and death of cells – or intox­i­ca­tion, which results in the muta­ge­n­e­sis of the genetic mate­r­ial in the cell’s nucleus.

In some instances, this spreads as an uncon­trolled mul­ti­pli­ca­tion of dam­aged cells, which can result in a can­cer­ous tumor.

As a result, spe­cific stan­dards have been set in var­i­ous regions of the world lim­it­ing the allow­able amount of ben­zopy­renes in olive pomace oil.

Within the European Union and mem­ber states of the International Olive Council, the limit is two parts per bil­lion or two micro­grams per kilo­gram, as decided in Resolution RES‑1/93-IV/05 Madrid in November of 2005.

Health ben­e­fits of olive pomace oil

If olive pomace oil is pro­duced cor­rectly, its con­sump­tion pro­vides health ben­e­fits com­pared to other com­mon edi­ble oils.

While the refin­ing process removes the vast major­ity of the phe­no­lic com­pounds – which are respon­si­ble for most of the health ben­e­fits asso­ci­ated with extra vir­gin olive oil – a grow­ing body of research demon­strates that there are still ben­e­fits to olive pomace oil con­sump­tion.

Like vir­gin and extra vir­gin olive oil, 75 per­cent of olive pomace oil is com­prised of monoun­sat­u­rated fatty acids.

See Also:Common Olive Pomace Compound Demonstrates Anticancer Potential

All types of fats help the body absorb vit­a­mins and min­er­als, build cell mem­branes and are essen­tial for the mech­a­nisms that cause blood clot­ting, mus­cle move­ment and inflam­ma­tion.

However, stud­ies have demon­strated that monoun­sat­u­rated fats lower LDL cho­les­terol, also known as bad cho­les­terol,” lead­ing to a lower risk of heart dis­ease and stroke.

Up to 85 per­cent of monoun­sat­u­rated fatty acids in olive pomace oil are oleic acid, an omega‑9 fatty acid.

An exten­sive body of research has found oleic acid con­sump­tion to be asso­ci­ated with the pre­ven­tion of dif­fer­ent types of dis­or­ders, such as car­dio­vas­cu­lar or autoim­mune dis­eases, meta­bolic dis­tur­bances, skin injury and can­cer.

A four-year study pub­lished in 2022 by the Institute of Food Science and Technology and Nutrition in Spain found that olive pomace oil con­sump­tion improved car­diometa­bolic risk bio­mark­ers in healthy and high-cho­les­terol patients.

See Also:Reducing the Size of Pomace Oil Particles Increases Its Healthy Properties, Study Shows

Specifically, the con­sump­tion of olive pomace oil reduced para­me­ters related to cho­les­terol, waist cir­cum­fer­ence and lipid oxi­da­tion.

The researchers also found that olive pomace oil con­sump­tion pos­i­tively affected insulin resis­tance and sen­si­tiv­ity, sug­gest­ing its con­sump­tion could lead to a lower risk of type 2 dia­betes.

Additionally, olive pomace oil does retain some polyphe­nols. While its con­sump­tion does not pro­vide any­where near the same ben­e­fits asso­ci­ated with extra vir­gin olive oil, it is a healthy alter­na­tive to other edi­ble oils.

Culinary uses of olive pomace oil

The com­bi­na­tion of a neu­tral fla­vor, high smoke point (240 ºC), asso­ci­ated health ben­e­fits and lower price com­pared to vir­gin or extra vir­gin olive oil make olive pomace oil ideal for a range of culi­nary appli­ca­tions.

Recent research from Spain’s Instituto de la Grasa, or Fat Institute, found olive pomace oil to be a supe­rior ingre­di­ent in bak­ery prod­ucts.

Researchers replaced the sun­flower oil in tra­di­tional cup­cake and torta recipes with olive pomace oil. They found the sub­sti­tu­tion did not dimin­ish the taste of the baked goods while increas­ing their shelf life and improv­ing their health pro­files.

See Also:Use Extra Virgin Olive Oil for Healthy and Delicious Baking

A sep­a­rate study from the Institute of Food Science and Technology and Nutrition found mar­garine made from olive pomace oil to be an ade­quate sub­sti­tute for but­ter in puffy pas­try, such as vol-au-vents, crois­sants, crodots and palmiers.

Pastries made from olive pomace oil-based mar­garine had 25 to 37 per­cent less sat­u­rated fat con­tent than but­ter. At the same time, pan­elists found no dif­fer­ences in sen­sory attrib­utes between the two types of pas­tries and a min­i­mal dif­fer­ence in tex­ture.

Along with bak­ing, olive pomace oil is also an excel­lent choice for deep fry­ing. Olive pomace oil is health­ier than other com­mon deep fry­ing oils, with research indi­cat­ing it passes along some health ben­e­fits to fried food and is a more afford­able (though less healthy) option than vir­gin or extra vir­gin olive oil.

See Also:Cooking With Extra Virgin Olive Oil

A 2021 study pub­lished by researchers from the Instituto de la Grasa found that fry­ing food in olive pomace oil improved its fatty acid pro­file and enriched it with antiox­i­dant com­pounds com­pared to other types of edi­ble oil.

Analysis of the oil after fry­ing also found the level of polar com­pounds, asso­ci­ated with neg­a­tive health con­se­quences, was 25 per­cent below those set by Spanish law.

Further research from the Food and Nutrition Science and Technology Institute found olive pomace oil out­per­forms sun­flower and high oleic sun­flower oil for deep fry­ing pota­toes.

Due to its high per­cent­age of oleic acid and bioac­tive com­pounds, includ­ing squa­lene and beta-sitos­terol, researchers said olive pomace oil was more sta­ble for deep fry­ing over extended peri­ods both in domes­tic and com­mer­cial set­tings, with tasters rat­ing the fla­vor, tex­ture and appear­ance as supe­rior to that of sun­flower and high oleic sun­flower oil.

Final thoughts

Olive pomace oil is a widely mis­un­der­stood cat­e­gory of olive oil.

Unlike vir­gin and extra vir­gin olive oil, it is obtained using heat and chem­i­cal meth­ods. As a result, it lacks the organolep­tic qual­i­ties and health ben­e­fits of the high­est olive oil cat­e­gories.

Still, there is a place for olive pomace oil. It is cheaper than vir­gin or extra vir­gin olive oil and health­ier than other edi­ble oils and but­ter.

When pro­duced cor­rectly, olive pomace oil is bet­ter for bak­ing and fry­ing than many alter­na­tives.


Know the Basics

Things to know about olive oil, from the Olive Oil Times Education Lab.

  • Extra vir­gin olive oil (EVOO) is sim­ply juice extracted from olives with­out any indus­trial pro­cess­ing or addi­tives. It must be bit­ter, fruity and pun­gent — and free of defects.

  • There are hun­dreds of olive vari­eties used to make oils with unique sen­sory pro­files, just as many vari­eties of grapes are used in wines. An EVOO can be made with just one vari­ety (mono­va­ri­etal) or sev­eral (blend).

  • Extra vir­gin olive oil con­tains healthy phe­no­lic com­pounds. Substituting a mere two table­spoons of EVOO per day instead of less healthy fats has been shown to improve health.

  • Producing high-qual­ity extra vir­gin olive oil is an excep­tion­ally dif­fi­cult and costly task. Harvesting olives ear­lier retains more nutri­ents and extends shelf life, but the yield is far less than that of fully ripe olives that have lost much of their healthy com­pounds.



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