`USDA Researchers Develop New Tests for Olive Oil Adulteration


USDA Researchers Develop New Tests for Olive Oil Adulteration

May. 10, 2013
Nancy Flagg

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USDA food tech­nol­o­gist Carl Olsen and agri­cul­tural engi­neer Rebecca Mil­czarek

Sci­en­tists from the Agri­cul­tural Research Ser­vice (ARS) have turned their atten­tion to olive research and in the process devel­oped two new ana­lyt­i­cal meth­ods to test olive oil authen­tic­ity and iden­ti­fied poten­tial uses for olive byprod­ucts.

New Ana­lyt­i­cal Tests

As reported in the May/June 2013 issue of Agri­cul­tural Research mag­a­zine, ARS researchers in Albany, Cal­i­for­nia devel­oped a pro­ce­dure that uses PCR (poly­merase chain reac­tion) tech­nol­ogy to detect undis­closed oils mixed with olive oil. The tech­nol­ogy, cre­ated by chemist Tal­winder Kahlon and co-inves­ti­ga­tors, dis­tin­guishes the DNA of sev­eral genes found in olive oil from the genes in other veg­etable oils. The test can be done in sev­eral hours with equip­ment at DNA labs.
Selina Wang, research direc­tor at the UC Davis Olive Cen­ter com­mented that the method looks promis­ing. Bioin­for­mat­ics tech­nol­ogy has improved much in recent years and the area of DNA sequenc­ing is explod­ing,” said Wang.

Another ana­lyt­i­cal test, devel­oped by ARS researcher Jiann-Tsyh Lin, used a new tool to exam­ine triglyc­erides (three fatty acids) in deter­min­ing if olive oil sam­ples con­tained oils from other plants. Although ana­lyz­ing fatty acids is not new, the use of ESI-MS (elec­tro­spray ion­iza­tion mass spec­trom­e­try) tech­nol­ogy is new and should make the process sim­pler, as noted in the Agri­cul­tural Research arti­cle.


Milling Byprod­ucts

After extract­ing a gal­lon of olive oil in the milling process, 38 pounds of skin, pulp and pits are left over, accord­ing to ARS engi­neer Rebecca Mil­czarek. Mill oper­a­tors often pay to ship the byprod­uct, called pomace,” to other sites for dry­ing and sell­ing as an ingre­di­ent in cat­tle feed.

Mil­czarek researched bet­ter meth­ods for han­dling the pomace. She devel­oped a com­bi­na­tion microwave and con­vec­tion method that millers could use on site to par­tially dry the pomace before ship­ping it off. The dried mate­r­ial would weigh less and thus would cost less to ship.

Mil­czarek sug­gested that the dried pomace be sent to a cen­tral loca­tion for fur­ther devel­op­ment as a pos­si­ble ingre­di­ent in cos­met­ics or phar­ma­ceu­ti­cals.

Bet­ter Food Safety

Burg­ers could be safer to eat in the future because of olives. Chemist Mendel Fried­man exper­i­mented with adding olive pow­der to ground beef before cook­ing burg­ers on the grid­dle. Olive pow­der was found effec­tive in sup­press­ing E. coli bac­te­ria and the pos­si­bly car­cino­genic het­e­ro­cyclic amines that arise in the cook­ing process.

Pre­vi­ous stud­ies showed that olive extracts could kill pathogens, but Friedman’s study demon­strated that olive pow­der could reduce the bac­te­ria and two amines at the same time. Fried­man noted that fur­ther stud­ies are needed to see if the pow­der affects food taste.

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