`Researchers Use Ultrasound to Detect Adulterated Olive Oil - Olive Oil Times

Researchers Use Ultrasound to Detect Adulterated Olive Oil

By Ofeoritse Daibo
Mar. 10, 2024 22:56 UTC

As his­tor­i­cally high olive oil prices have made author­i­ties, retail­ers and con­sumers more wary of theft and fraud, researchers from the University of Extremadura have found a way to detect adul­ter­ated olive oil using ultra­sounds.

“[This] pio­neer­ing study shows that ultra­sound (sound waves out­side the human hear­ing range) can detect dif­fer­ent types of oils based on their unique sound wave fre­quency,” said Antonio Jiménez, a pro­fes­sor of applied physics at the University of Extremadura.

We have achieved excel­lent results so far and have dis­cov­ered that the inten­sity with which waves travel and their dis­tance change based on the type of oil. Each oil has a dif­fer­ent acoustic sound.- Antonio Jiménez, physics pro­fes­sor, University of Extremadura

Although his team began their research on ultra­sound waves more than two decades ago, they only started work on olive oil analy­sis in 2017. 

We pre­vi­ously researched wines, honey, cured meats, and even objects like stones and archae­o­log­i­cal struc­tures,” Jiménez said.

See Also:Researchers Develop Easier, Cheaper Method for Measuring Free Acidity

Once the team began inves­ti­gat­ing olive oil and other edi­ble oils, they tried to dis­tin­guish the acoustic pro­files of olive oil, sun­flower oil and soy­bean oil. Subsequently, we com­bined dif­fer­ent oils to study the mix with olive and sun­flower oil,” Jiménez added.

Sunflower oil is one of the most com­monly used edi­ble oils in adul­ter­at­ing extra vir­gin olive oil because of its low price and sim­i­lar fatty acid pro­file, espe­cially when high-oleic sun­flower oil is used.

Extra vir­gin olive oil can be adul­ter­ated with as lit­tle as five per­cent of other edi­ble oils, mak­ing it very dif­fer­ent to detect a change in fla­vor. As a result, Jiménez believes this new method will prove invalu­able.

Ultrasound trans­duc­ers are immersed in the oil to ana­lyze it,” he said. These trans­duc­ers are like micro­phones,” which can detect ultra­sounds in the two mil­lion hertz range com­pared to the 25-hertz range the human ear can detect. 

Jiménez explained that researchers can then deter­mine whether olive oil is authen­tic based on how the oil sounds,” adding that the oils have dif­fer­ent prop­er­ties, such as acid­ity or fatty acids, to which ultra­sounds are extremely sen­si­tive, so any change in their phys­i­cal struc­ture will be detected.”

We sent sound waves through the oil and lis­tened to what returned using a spe­cial device that can read sound waves,” Jiménez said. The results were out­stand­ing.” 

We were able to dis­tin­guish extra vir­gin olive oil with as lit­tle as one per­cent of refined olive oil or sun­flower oil,” he added. Normally, as much as a ten per­cent adul­ter­ation is unde­tectable to a con­sumer, yet our device can detect as lit­tle as one per­cent change in the oil.”

Compared to tra­di­tional meth­ods used to detect olive oil adul­ter­ation, Jiménez said ultra­sounds are not intru­sive, mean­ing the sam­ple does not need to be altered phys­i­cally or chem­i­cally to make the deter­mi­na­tion.

It’s very sim­i­lar to a preg­nant woman who goes to the doc­tor for an ultra­sound to find out if she’s going to have a boy, a girl or twins,” he said. Of course, the fetus does not expe­ri­ence any harm. Well, the same goes for the oil.” 

Jiménez also touted the ultra­sound method as more prac­ti­cal than other meth­ods used to test for olive oil adul­ter­ation, which often requires expen­sive lab­o­ra­tory equip­ment. 

Our tech­nique is also eco­nom­i­cally afford­able and portable,” he said. The device can be moved to where the oil sam­ples are.”

We have achieved excel­lent results so far and have dis­cov­ered that the inten­sity with which waves travel and their dis­tance change based on the type of oil,” Jiménez added. Each oil has a dif­fer­ent acoustic sound.”

The slight change in chem­i­cal pro­files among extra vir­gin olive oils means the tech­nol­ogy could also deter­mine olive oil prove­nance

Authorities could iden­tify whether an extra vir­gin olive oil with a Protected Designation of Origin or Protected Geographical Indication label is authen­tic by com­par­ing the results to known sam­ples.

Now, we want to take it a step fur­ther and try to ana­lyze the fatty acid com­po­nents in a given sam­ple, such as the amount of omega‑3 or omega‑6 and triglyc­erides in gen­eral,” Jiménez said.

Once up and run­ning, we expect these tests to be employed at mills and stores,” he added. The process can be car­ried out at a large scale with­out exten­sive aca­d­e­mic train­ing to oper­ate the device.”


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