`USDA Surveys the Chemical Profiles of American Olive Oils - Olive Oil Times

USDA Surveys the Chemical Profiles of American Olive Oils

Feb. 23, 2012
Curtis Cord

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A new study by the UC Davis Olive Center under the direc­tion of the California Olive Oil Council (COOC) illus­trates the chem­i­cal diver­sity of oils made from the most com­mon olive vari­eties grown in the United States.

Funded under the USDA’s Technical Assistance for Specialty Crops (TASC) grant, the research is the sec­ond phase of an ear­lier study and part of an ongo­ing ini­tia­tive to estab­lish the chem­i­cal pro­files of domes­tic olive oils, in order to eval­u­ate and fine-tune U.S. stan­dards and pre­vent trade restric­tions for American olive oil exporters.

The tech­ni­cal stan­dards for olive oil estab­lished by the International Olive Council (IOC) are based on the chem­i­cal pro­files of European and North African olive oils. The unique chem­i­cal char­ac­ter­is­tics of New World olive oils can exceed cer­tain lim­its in the inter­na­tional stan­dards, caus­ing a down­grade and clos­ing off poten­tial mar­kets to American pro­duc­ers.

Ninety per­cent of the global olive oil con­sump­tion is beyond American shores.


In this study, which was designed by UC Davis Olive Center Research Director Selina Wang, 60 domes­tic mono­va­ri­etal extra vir­gin olive oils from the 2010 har­vest were col­lected directly from pro­duc­ers from February through April, 2011 and put through a bat­tery of tests at labs in the U.S and Australia.

Specifically, test­ing was car­ried out by the UC Davis Olive Center, the Blakely Laboratory, the Australian Oils Research Laboratory (AORL) and the COOC taste panel.

Ten of the sam­ples (around 17 per­cent) were found to have sen­sory defects and would there­fore not be con­sid­ered to be extra vir­gin on that basis alone.

All 60 sam­ples passed the test for free fatty acids (FFA) with lev­els below the 0.8 per­cent limit in both the USDA and IOC stan­dards.

Several oils tested were found to have campes­terol lev­els too high for the extra vir­gin grade accord­ing to the IOC stan­dards, which sets the limit at 4.0 per­cent, but only one of the 60 sam­ples exceeded (and just barely) the campes­terol limit of 4.5 per­cent set in the 2010 USDA Standards for Olive Oil and Olive Pomace Oil.

And while 10 sam­ples failed taste tests, 4 failed the chem­i­cal qual­ity tests (acid­ity, per­ox­ide and UV) and 16 failed purity tests (FAP, sterols, wax and ECN 42), not one of the sam­ples failed the PPP and DAG lim­its adopted by the Australian Olive Association, rais­ing ques­tions, the researchers said, about what the lim­its should be if they are going to be con­sid­ered part of the U.S. pic­ture. The PPP and DAG results sug­gested that all of the olive oils tested were rea­son­ably fresh.

Although the size of the sur­vey was lim­ited and focused on mono­va­ri­etals, the results amounted to less than a per­fect report card for the sam­ples that were ana­lyzed, with more than 25 per­cent falling short of extra vir­gin qual­ity.

One sam­ple failed a wax” test sug­gest­ing it had likely been extracted from left­over pomace. That sam­ple also failed a num­ber of other tests includ­ing the sen­sory pan­els. Dr. Wang declined to dis­close the brand, not­ing that pro­duc­ers sup­plied sur­vey sam­ples with the under­stand­ing that the brand name would be kept con­fi­den­tial.

Looking for­ward, the report calls for a stream­lin­ing” of the meth­ods used to mea­sure olive oil qual­ity, such as the PPP and DAG tests, and a bet­ter under­stand­ing of how those tests, and stor­age time, impact the ini­tial qual­ity indi­ca­tors like acid­ity.

With word­ing rem­i­nis­cent of the recent Australian Olive Association con­fer­ence and repeated lately in Napa, Dixon and Sacramento, the report closes with the pre­dic­tion that, with a lit­tle more work, the life” of an olive oil can be estab­lished and new tools will enable olive oil buy­ers to make more informed deci­sions.

See Also:Composite Chemical Picture of US Olive Oil (UC Davis Olive Center
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