Scientists have found out whether olive oil loses its properties when fried

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Scientists have found that extra virgin olive oil, which is the basis of the Mediterranean diet, retains its beneficial properties even after frying. The results of the study were published in the journal Antioxidants.

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Extra virgin olive oil is believed to have a protective effect on the body due to its antioxidant content, which is higher than in any other oil. It is no coincidence that this product occupies a central place in the Mediterranean diet, which is popular today.

However, in Mediterranean cuisine, olive oil is often used for cooking, in particular for frying. It is known that heat treatment of food negatively affects many of the beneficial properties of products, including the fact that it destroys antioxidants.

Extra virgin olive oil is the main source of fat in the Mediterranean diet, and its health benefits are mostly due to compounds called polyphenols. Scientists from the University of Barcelona in Spain and the University of São Paulo in Brazil decided to find out whether polyphenols are preserved in olive oil after frying. At the same time, all experiments were carried out in the conditions of an ordinary home kitchen.

“The impact of cooking processes on olive oil polyphenols has always been studied in laboratory or industrial settings, far from the reality of our homes,” said study leader Rosa Maria Lamuela-Raventós, director of the Institute for Research in Nutrition and Food Safety at the University of Barcelona, ​​in a press release.

The authors studied the effects of short and long frying on the degradation of polyphenols and found that at 120 degrees Celsius, polyphenol content decreased by 40 percent, and at 170 degrees Celsius, by 75 percent, compared to antioxidant levels in the raw oil.

Cooking time affected individual phenols, such as hydroxytyrosol, but not the total phenol content. Even after long frying, the antioxidant levels of the oil were within the parameters declared by the European Union as “healthy”.

“Despite the reduction in polyphenol concentration during heating, olive oil has a level of polyphenols that meets European health standards. This means that it has properties that protect against oxidation of a portion of LDL cholesterol (“bad” cholesterol. – Ed. note),” says Julián Lozano-Castellón, first author of the article.

In the next stage of research, the authors plan to find out how the properties of olive oil change when preparing dishes with other ingredients of the Mediterranean diet, in particular with legumes and meat. “In addition, we need to conduct human studies to compare the potential benefits of extra virgin olive oil compared to other oils.”

The researchers also want to understand how olive oil is used in “non-Mediterranean” populations, whose culinary traditions differ significantly from those of southern Europe. The researchers say their findings are important for making sound dietary recommendations.