How good a spe­cific extra vir­gin olive oil is for your health could be eas­ier to assess with a new Greek sys­tem to mea­sure and rate the con­tent of key olive com­pounds oleo­can­thal and olea­cein.

Oleocanthal has anti-inflam­ma­tory effect sim­i­lar to Ibuprofen and Oleacein is a pow­er­ful antiox­i­dant, but until now they have been dif­fi­cult to ana­lyze chem­i­cally, accord­ing to Dr. Prokopios Magiatis, assis­tant pro­fes­sor of phar­ma­cog­nosy and nat­ural prod­ucts chem­istry at the University of Athens.

At the recent Terra Creta Olive Oil Conference on Crete, Magiatis said he and his team from the uni­ver­sity had devel­oped a method using 1H-NMR, a form of nuclear mag­netic res­o­nance, to directly mea­sure oleo­can­thal and olea­cein lev­els.

“The new method makes it pos­si­ble to iden­tify dif­fer­ences between extra vir­gin olive oils and to clas­sify them accord­ing to their poten­tial health effects” he said.

Inspiration from ancient medics

Ancient Greek doc­tor Dioscorides piqued the researchers’ inter­est. “He, and oth­ers after him, insisted that the best health effects come from fresh olive oil from unripe olives, or from spe­cific vari­eties.”

Dr. Eleni Melliou

This set them inves­ti­gat­ing ways to pin­point what mol­e­cules were respon­si­ble for health effects and to com­pare olive oils based on their con­tents of them.

Five years later, they have devel­oped an NMR test that just takes 50 sec­onds.

“You can ana­lyze hun­dreds of sam­ples in a very short time but of course you need a very expen­sive instru­ment and we’re happy to have one in our lab in Athens” Magiatis said.

New indexes pro­posed

The team homed in on the key olive polyphe­nols oleo­can­thal and olea­cein and rates EVOOs accord­ing to both the sum of their lev­els of these mol­e­cules, index D1, and to their oleo­can­thal to olea­cein ratio, index D2.

“D is for Davis because this study was done in col­lab­o­ra­tion with the UC Davis Olive Center” Magiatis said. He and Dr. Eleni Melliou, a co-author of the study, were vis­it­ing sci­en­tists at UC Davis in 2011. Dan Flynn, the Olive Center’s direc­tor, gave them advice and oil sam­ples.

The new sys­tem was applied to more than 250 sam­ples from mono­va­ri­etal olive oils from Greece and California over two years and, accord­ing to Magiatis, revealed big dif­fer­ences between oils.

“Among the nine­teen vari­eties stud­ied, the high­est con­cen­tra­tion was found in Koroneiki olive oil and it’s very good for Greece because more than 70 per­cent of its olive trees are this vari­ety.” Non-Greek vari­eties grown in California, like Barouni, Leccino, and Mission, also had high con­cen­tra­tions. Wider stud­ies are needed of other vari­eties around the world, he said.

High heat in mill, less healthy oils

Processing tem­per­a­ture is another fac­tor affect­ing oleo­can­thal and olea­cein lev­els.

“When we test the same olive fruit in the same olive mill but using dif­fer­ent tem­per­a­tures you can see a huge dif­fer­ence in the con­cen­tra­tion of these com­pounds, with high tem­per­a­tures hav­ing neg­a­tive effects” he said.

The trial also revealed a pos­i­tive link between early har­vest­ing and high lev­els of both com­pounds. Some olive vari­eties, how­ever, deliver low lev­els regard­less of geo­graphic ori­gin, har­vest time or if best prac­tices are fol­lowed.

Oils with high lev­els of oleo­can­thal and olea­cein retained most of this con­tent even 18 months after har­vest.

Olive oil heart-health claim

When last year the European Food Safety Authority approved the claim that con­sump­tion of olive oil polyphe­nols pro­tects LDL par­ti­cles from oxida­tive dam­age, it said this hinged on the daily con­sump­tion of “5mg of hydrox­y­ty­rosol and its deriv­a­tives (e.g. oleu­ropein com­plex and tyrosol) in olive oil”.

Magiatis said the new method made it pos­si­ble to mea­sure all the com­pounds men­tioned by EFSA in one exper­i­ment. “And we can pro­vide the nec­es­sary data for the health claims.” The lat­ter could help pro­duc­ers of olive oils with high quan­ti­ties of hydrox­y­ty­rosol gain bet­ter prices.

Why oleo­can­thal and olea­cein?

Oleocanthal and olea­cein were of most inter­est to the team as they are the two most abun­dant forms of con­ju­gated hydrox­y­ty­rosol and tyrosol in the olive oils they stud­ied.

“Oleacein is a deriv­a­tive of oleu­ropein and the most pow­er­ful antiox­i­dant con­stituent of olive oil” Magiatis said.

Oleocanthal is said to have poten­tial to inhibit tumor growth, to offer pro­tec­tion against Alzheimer’s dis­ease and to be a COX‑1 and COX‑2 inhibitor.

It is respon­si­ble for the pun­gency that comes from unripe olives in fresh olive oil and that irri­tates the throat.

“Chronic expo­sure to low doses of anti-inflam­ma­tory agents like oleo­can­thal offers pro­tec­tion against car­dio­vas­cu­lar dis­eases and aging” he said.

Applications: extra vir­gin olive oil as a new drug?

As for poten­tial appli­ca­tions of his research, Magiatis said one use could be to tar­get spe­cific olive oils at peo­ple with heart dis­ease.

However, con­sumers will need edu­ca­tion to accept and value the taste of oils with very high lev­els of poten­tial health effects because they are usu­ally more pun­gent and bit­ter.

“It will be dif­fi­cult for pro­duc­ers to achieve a bal­ance between taste and high con­cen­tra­tion of spe­cific polyphe­nols” Magiatis said.

At the same time, the new index can help cor­re­late the organolep­tic prop­er­ties of an olive oil, pre­dict­ing what pun­gency and bit­ter­ness should be expected.

“What we have pro­vided is a pow­er­ful new tool for the eval­u­a­tion of olive oil qual­ity” Magiatis said.

“Not all extra vir­gin olive oils are the same. Some present great poten­tial as health pro­tect­ing or ther­a­peu­tic agents and we have pro­vided the sci­en­tific com­mu­nity with a new index offer­ing an esti­mate of these health related prop­er­ties.”

foot­note: Magiatis and his research col­leagues recently pub­lished a paper relat­ing to their research in the Journal of Agricultural Food Chemistry.

Titled “Direct Measurement of Oleocanthal and Oleacein Levels in Olive Oil by Quantitative 1H-NMR. Establishment of a New Index for the Characterization of Extra Virgin Olive Oils”, it is avail­able here: pubs.acs.org…

The researchers are: Evangelia Karkoula , Angeliki Skantzari , Eleni Melliou , and Prokopios Magiatis.


Sources:

Link to Journal of Agricultural Food Chemistry paper “Direct Measurement of Oleocanthal and Oleacein Levels in Olive Oil by Quantitative 1H-NMR. Establishment of a New Index for the Characterization of Extra Virgin Olive Oils”
Olive oil health claim approved by EFSA


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