`Most EVOOs Score Well in New Test for Phenolic Compounds - Olive Oil Times

Most EVOOs Score Well in New Test for Phenolic Compounds

May. 28, 2014
Athan Gadanidis

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Back in October, 2013 Prokopios Magiatis and Eleni Melliou from the University of Athens could be seen in stores around Northern California stock­ing up on dozens of bot­tles of EVOO as part of a pri­vately-funded research project to mea­sure phe­no­lic com­pounds using NMR (Nuclear Magnetic Resonance) and to deter­mine how many of the store-bought EVOOs would qual­ify for the EU label­ing reg­u­la­tion 432/2012.

The test results were pre­sented at the FOODMR2014 con­fer­ence in Cesena, Italy last week which focused on appli­ca­tions of mag­netic res­o­nance, espe­cially NMR in the study of foods. More than 200 par­tic­i­pants pre­sented new appli­ca­tions.

During the con­fer­ence, Magiatis pre­sented a new ver­sion of the recently-reported NMR method that can quickly mea­sure phe­no­lic com­pounds that sup­port the EU 432/2012 health claim that 5mg per day of hydrox­y­ty­rosol and deriv­a­tives (oleu­ropein com­plex and tyrosol) offer pro­tec­tion against LDL oxi­da­tion: Olive oil polyphe­nols con­tribute to the pro­tec­tion of blood lipids from oxida­tive stress.”

Oleocanthal and olea­cein are the two most abun­dant forms of con­ju­gated hydrox­y­ty­rosol and tyrosol in most olive oils, together with oleu­ropein agly­con and ligstro­side agly­con.

The sam­ples the team col­lected in California were tested by the UC Davis Olive Center for oleo­can­thal, olea­cein, oleu­ropein agly­con and ligstro­side agly­con. The study was per­formed by Prokopios Magiatis, Eleni Melliou and Brian Killday.


Our tar­get was to develop a reli­able method to mea­sure all the com­pounds men­tioned in the reg­u­la­tion in one exper­i­ment and pro­vide the nec­es­sary data for the health claims,” Dr. Magiatis said.

The good news is that 56 out of 110 of the EVOOs bought at super­mar­kets and local stores had an excel­lent phe­no­lic pro­file, accord­ing to the results and almost half of those would qual­ify for the EU label­ing health claim.

The EU is in the process of decid­ing whether the mea­sure­ment of oleo­can­thal can be included in the nec­es­sary total to make the new claim. Dr. Maria-Isabel Covas who con­ducted the EUROLIVE human tri­als that formed the basis of EU 432/2012 has cat­e­gor­i­cally stated that oleo­can­thal should be mea­sured and included, and other sci­en­tists inter­viewed have agreed.

If oleo­can­thal were included, half of the EVOOs tested in California would qual­ify to make the claim. If it is finally decided that oleo­can­thal should not be mea­sured, then fewer than 1 in 5 would qual­ify.

Magiatis went on to explain: It is not only the brand that plays a role but also the vari­ety, and the type of olive mill is a crit­i­cal point. The total polyphe­nols con­tent is not so char­ac­ter­is­tic if we don’t know which exactly is the dom­i­nat­ing one.

NMR Pulse Diagram image pro­vided by Brian Killday

For exam­ple, the Mission vari­ety from California pre­sented in all ana­lyzed sam­ples sig­nif­i­cantly higher (5 times more) con­cen­tra­tion of oleu­ropein agly­con than all Mediterranean vari­eties. Characteristically the Berkeley Olive Grove Mission showed the high­est con­cen­tra­tion among all stud­ied sam­ples at 397 mg/kg. In fact, all California oils con­tain­ing Mission oil, even within a blend, were found to be very rich. This spe­cific phe­no­lic com­pound has been related to activ­ity against Alzheimer’s dis­ease.”

Another impor­tant fac­tor is the type of mill used. Apollo Olive Oil, also from Northern California, con­tained the most phe­no­lic com­pounds in total. This could be attrib­uted to the vac­uum-sealed olive mill they are using.”

Invented by the late Marco Mugelli, the inter­na­tion­ally rec­og­nized agri­cul­tural sci­en­tist, engi­neer and olive oil expert, the vac­uum mill can achieve higher polyphe­nol lev­els by extend­ing the malax­a­tion period with­out increas­ing oxi­da­tion.

The EVOOs tested with the high­est amounts of each phe­no­lic com­pound were:

oleu­ropein agly­con — 397.2 — Berkeley Olive Grove 1913 — California
olea­cein — 400.6 — Apollo Sierra Organic — California
ligstro­side agly­con — 174.5 — Lucini — Italy
oleo­can­thal — 403.2 — Colavita — Italy

An organolep­tic analy­sis is also being con­ducted on all of the EVOOs. Magiatis said he will present the NMR data in con­junc­tion with an organolep­tic analy­sis in the near future. Perhaps this could lead to a new class of EVOOs com­bin­ing the best of both worlds, giv­ing addi­tional mean­ing to the phrase, taste test.”

Magiatis went on to say: One of the most impor­tant aspects of our research in mea­sur­ing phe­no­lic con­tent of EVOO using NMR is that we dis­cov­ered that the HPLC method does not mea­sure the indi­vid­ual phe­no­lic com­pounds very accu­rately. This prob­lem is caused by the sol­vents used to extract and ana­lyze the phe­nols from the olive oil. How can we imple­ment a reg­u­la­tion that demands the pre­cise mea­sure­ment of indi­vid­ual phe­no­lic com­pounds using a method that is proven inac­cu­rate?”

The test results should not be seen as a guar­an­tee the spe­cific brands will con­tain the same amounts when bought in a dif­fer­ent time or place. Some phe­no­lic com­pounds tend to main­tain them­selves over time bet­ter than oth­ers. Many fac­tors affect the phe­no­lic lev­els, includ­ing the type of mill, time of har­vest and bot­tling, the type of bot­tle used, the amount of time spent on the shelf, and con­di­tions in the ware­house or in trans­port. The brand names that failed the test will not be pub­lished but many of them were very close to qual­i­fy­ing. A strict cut-off point for phe­no­lic con­tent was used, based on the EU reg­u­la­tion 432/2012 of 250 mg per kilo­gram.

It should also be noted the NMR method has been ver­i­fied as a valid research tool and peer-reviewed. The NMR method of mea­sure­ment was invented in Greece but has not been sub­mit­ted for accep­tance by the IOC (International Olive Council). An inquiry was made to the min­istry respon­si­ble as to why it has not been sub­mit­ted for offi­cial recog­ni­tion to the IOC or the EU. As of the date of pub­li­ca­tion, there has been no response. One well-placed source in the min­istry who wished to remain anony­mous did admit the issue is polit­i­cal”.

The 56 store-bought EVOO brands that showed high phe­no­lic totals and their test results can be found here.


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