`Chemists Recognize Australian Lab's Mailer - Olive Oil Times

Chemists Recognize Australian Lab's Mailer

May. 15, 2014
Alexandra Kicenik Devarenne

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Dr. Rod Mailer received AOCS Fellow recog­ni­tion from board pres­i­dent Timothy Kemper

The annual meet­ing and expo of the American Oil Chemists’ Society (AOCS) took place this year in San Antonio, Texas, on 4 – 7 May. Olive oil was the sub­ject of a num­ber of oral pre­sen­ta­tions and posters as well as an expert com­mit­tee meet­ing.

The olive oil-related activ­i­ties got off to a good start at the annual busi­ness meet­ing and lun­cheon on Monday when Rod Mailer of Australian Oil Research was made a Fellow of AOCS. The sta­tus of AOCS Fellow is granted to vet­eran mem­bers for excep­tional achieve­ment in sci­ence or unusu­ally impor­tant ser­vice to the Society or the pro­fes­sion.

Although Dr. Mailer had been involved for many years in canola breed­ing and qual­ity improve­ment, in recent years he has worked exten­sively with olive oil. The Australian Oil Research Laboratory (AORL) at the New South Wales Department of Agriculture in Wagga Wagga became a lead­ing olive oil research and test­ing cen­ter under Mailer’s lead­er­ship. An AOCS mem­ber since 1983, Mailer belongs to the AOCS Expert Panel on Olive Oil and was one of the found­ing mem­bers of the Australasian Section (AAOCS). He is an Elected Fellow of the Royal Swedish Academy of Agriculture and Forestry and recip­i­ent of many other awards and recog­ni­tions.

Posters were avail­able for view­ing in the after­noons, and detect­ing adul­ter­ation was the dom­i­nant topic in olive oil posters, includ­ing a calori­met­ric approach to mea­sure the response of olive oil to tem­per­a­ture changes in order to detect adul­ter­ation. A ses­sion enti­tled Analysis of Vegetable Oil Authentication and Adulteration,” chaired by Pierluigi Delmonte of US FDA and Lars Reimann of Eurofins, USA, con­tained sev­eral pre­sen­ta­tions on olive oil analy­sis.

Wenceslao Moreda of Instituto de la Grasa in Seville, Spain made a pre­sen­ta­tion Detection of the Addition of Vegetable Oils to Olive Oil by Comparison of Theoretical and Experimental TAG (tri­a­cyl­glyc­erol).” The International Olive Council (IOC) stan­dard con­tains 22 para­me­ters for authen­tic­ity, designed to detect adul­ter­ation with seed oils or refined olive oil. The value of the fatty acid pro­file as an authen­tic­ity mea­sure – that is the amount of var­i­ous fatty acids such as oleic acid con­tained in olive oil ver­sus seed oils – has been com­pro­mised recently as high oleic every­thing” has entered the mar­ket.

This pre­sen­ta­tion looked at the suc­cess of the IOC Global Method” to detect adul­ter­ants. The method com­pares exper­i­men­tal TAG com­po­si­tion with the­o­ret­i­cal val­ues obtained from the analy­sis of fatty acid methyl esters. The global method detected Turkish hazel­nut oil in the range of 2 to 20%, but had dif­fi­culty when the adul­ter­ant was des­terolyzed high oleic sun­flower oil.

Pierluigi Delmonte of FDA gave a sum­mary of test­ing results in Evaluation of the Authenticity of Olive Oil in the US Market Through the Analysis of the Triglyceride Composition.” For this study they pur­chased 93 sam­ples in the US mar­ket in late 2013 – 90 sam­ples labeled as extra vir­gin” and 3 labeled as olive oil” or other” blends. The sam­ples were ana­lyzed for fatty acid pro­file and TAG. They also cre­ated spiked” oils to test their method.

They found that fatty acid pro­file by itself was not use­ful for detect­ing adul­ter­ation. Using the equiv­a­lent car­bon num­ber ECN 42 method did not detect the spik­ing with palm olein, peanut or hazel­nut oil. The Global Method was suc­cess­ful in detect­ing all the adul­ter­ant oils except palm olein oil.

A pre­sen­ta­tion by Zhu of University of California Davis on Characterization of Volatile Compounds in Virgin Olive Oil Produced in the United States” showed work done on oils pro­duced with the lab­o­ra­tory Abencor sys­tem at UC Davis. Olives for the study were gath­ered from Oregon, Georgia and sev­eral loca­tions in California and ana­lyzed for their volatiles con­tent.

Frederica Camin of Fondazione Emund Mach in Trento, Italy described research Using Stable Isotope Ratio Analysis of Carbon, Oxygen and Hydrogen to Determine the Origin of Extra-Virgin Olive Oil.” The ratio of the C, H and O iso­topes in a plant – and in an olive oil – can be ana­lyzed by gas chro­matog­ra­phy and mass spec­troscopy and linked to geo­graph­i­cal ori­gin through the water and CO2 taken up by the plant. The iso­tope ratios are affected by cli­mate, and lat­i­tude, show­ing clear dif­fer­ences between north­ern and south­ern regions, for exam­ple. The method has been used since the late 1980’s to detect mis­la­beled ori­gins for honey, cheese and other prod­ucts.

The sys­tem is of par­tic­u­lar value in authen­ti­cat­ing prod­ucts bear­ing a des­ig­nated ori­gin cer­ti­fi­ca­tion, such as a PDO. The iso­tope ratios are not affected by the pro­cess­ing of the olive oil, or by stor­age con­di­tions, oxi­da­tion, aging or refin­ing, but prod­ucts from very sim­i­lar cli­matic and geo­graphic ori­gins can be dif­fi­cult to dis­tin­guish. But bet­ter accu­racy in dis­tin­guish­ing between oil from Southern Italy and Tunisia, for exam­ple, was achieved by using NMR metabo­lite pro­fil­ing. Dr. Camin pointed out that an annual updat­ing of the data­base is impor­tant for accu­racy and amass­ing more data is also an objec­tive of the project. The method has been sub­mit­ted to IOC for approval and the researchers are wait­ing for an answer.

Kangming Ma of Eurofins lab­o­ra­tory reported on work done on rapid analy­sis of olive oil using near infra-red and mid infra-red. IR is fast and eas­ily per­formed analy­sis, so it is of great inter­est for com­mer­cial analy­sis. Working with 97 sam­ples from the EU – all pre-ana­lyzed by their lab with wet chem­istry – and 20 sam­ples of US and Australian ori­gin, they ran the stan­dard tests and com­pared results with the wet chem­istry. Correlations on some tests such as fatty acid pro­file, DAGs and K232 were good, but oth­ers such as K268 did not cor­re­late as well. Continuing work is needed to build a data­base and val­i­date the accu­racy of the process.

The AOCS Expert Panel on Olive Oil had its 6th meet­ing to dis­cuss the panel’s pro­gram and progress. A gen­eral dis­cus­sion of future pro­grams started with an update by chair­man Richard Cantrill on the Horizon 2020 pro­gram of the European Union. A 5 mil­lion Euro grant under the Sustainable Food Security cat­e­gory has been allo­cated for work on olive oil authen­ti­ca­tion and the pro­pos­als were due in March. Those ini­tial pro­pos­als are being culled, with a small num­ber pass­ing to the final stage.

An update on olive oil stan­dards from Paul Miller of the Australian Olive Association men­tioned that the Australian Standard AS 5264 – 2011 is being used by var­i­ous enti­ties as a ref­er­ence point for new stan­dards, as well as by peo­ple within the trade who are inter­ested in mon­i­tor­ing qual­ity. Bruce Golino of the California Olive Oil Council said the USDA olive oil stan­dard is cur­rently being used by the USDA Quality Monitoring Program (QMP) but that the pro­gram has only one par­tic­i­pant to date. The USDA has moved its chem­istry lab from Georgia to North Carolina and its sen­sory panel to Fresno.

For the US Olive Oil Survey report, Dan Flynn of UC Davis Olive Center said they had ana­lyzed another 23 sam­ples this year for a total of 38 over two years. Campesterol exceeded 4.5 (the USDA limit) in 24 per­cent of the sam­ples, and palmitic acid looks like it can be an issue in Georgia, Texas and the Imperial Valley. Linoleic acid is also out­side the stan­dard in some areas. This is con­sis­tent with the expe­ri­ence of pro­duc­ers out­side the tra­di­tional olive grow­ing regions of the Mediterranean: the nat­ural vari­abil­ity of olive oils from var­i­ous cli­mates can result in chem­i­cal analy­ses that fall out of the cur­rent stan­dards which is why a robust data­base of olive oil com­po­si­tion cov­er­ing diverse grow­ing con­di­tions is impor­tant.

A pro­posed new method from Agilent for mea­sur­ing pheo­phytin and pyropheo­phytin was described and dis­cussed. Although the cycle time for the test is the same as the stan­dard method, the clean-up time is much less. Four labs agreed to test the method over the next year to see how it works.

Claudia Guillaume of Modern Olives talked about her work test­ing the use of an ultra­vi­o­let test – K225 – as a bit­ter­ness index.” There is a decent cor­re­la­tion between the K225 and a find­ing of bit­ter taste by a sen­sory panel. The value of an objec­tive mea­sure of bit­ter­ness would be to serve as a tool for cal­i­brat­ing pan­els by pro­vid­ing a ref­er­ence. It was pro­posed that the method be writ­ten up with a tem­po­rary AOCS ref­er­ence num­ber so labs can start to test it.

Richard Cantrill gave the update on lab­o­ra­tory and sen­sory panel pro­fi­ciency test­ing pro­grams in the US. Although there are a num­ber of labs doing pro­fi­ciency test­ing for a por­tion of the tests used in olive oil analy­sis, only one lab in the US is doing the full suite of tests (and they are a pri­vate lab that does not do work for out­side clients).

There are 23 pan­els from around the world cur­rently enrolled in the sen­sory panel pro­fi­ciency test­ing pro­gram. There have been six cycles of sam­ples to date, and the results are ready for adju­di­ca­tion. The first round of deci­sions on panel pro­fi­ciency are expected soon.

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