If you can, better fry with extra virgin olive oil

Antioxidants preserve the properties of the product against thermal stress to which it is subjected when we perform frying.

Previous studies have revealed that some oils, such as sunflower, form more toxic compounds than olive oil when heated to frying temperature. Now researchers from the Innovation group in chemical analysis at the University of Jaén, in collaboration with the Laboratory of Bromatology and Hydrology of the Faculty of Pharmacy of the University of Porto, have demonstrated that the extra virgin olive oil presents a greater resistance to the process of Frying than others available in the market.

After a comparison with other vegetable fats, experts point out that the large number of antioxidants present in extra virgin olive oil contributes greatly to less degrading and slower than the others, besides being the most Stable and produces fewer toxic compounds.

Experts have come to these results after comparing the process of thermal oxidation of some of the most recommended oils in frying. Specifically, they have analyzed the extra virgin olive, the most used in the Mediterranean countries; That of peanut, used for use in Portuguese school canteens; And canola, a type of rapeseed oil, very common in some countries of Central and Eastern Europe.

To carry out the experiment, the oils were kept hot for long hours and frying, with each, at different times. After each frying, they were analyzed considering the substances that were forming and that could be harmful to health. Thus, they have identified more than 30 toxic compounds derived from the thermal stress to which they are subjected when we perform frying.

Less toxic compounds when fried

In the study, published in the Journal of the American Oil Chemists Society, have shown that the benefits of extra virgin olive oil compared to others commonly used for frying are also due to a lower percentage of polyunsaturated fatty acids, Such as omega 3 and a higher percentage of monounsaturated fatty acids, such as oleic (omega 9), one of its main components.

Although all oils studied have a low content of polyunsaturated fatty acids, it was observed that extra virgin olive oil produces fewer toxic compounds when fried and takes longer to appear compared to peanut and canola due, in Largely, to the high content of antioxidant compounds. These help the olive to undergo degradation slower and to a lesser degree than the others.

Therefore, these investigations have confirmed that extra virgin olive oil is the most suitable for its stability after several hours at high temperatures. "For the consumer it is advisable to use the oil for up to eight hours of use, since a high prevalence of toxic products of thermal oxidation has not yet been observed. In addition, the extra virgin olive still has a good nutritional value and consequently, there is a greater use by our organism, "says the researcher at the University of Jaén Lucía Molina, one of the authors of the article.

The best among the healthiest

The project has included the study of the nature and concentration of compounds that are altered or appear during the frying process, especially those that have some implication detrimental to human health, such as volatile aldehydes.

In addition, the study provides detailed information on the volatile compounds that originate during frying as a result of the thermal degradation of the oils, which provides a better understanding of the chemical reactions that develop in the process. Thus, these substances can be established as indicators of quality to control and ensure their nutritional value and useful life.

The tests consisted of frying potatoes in the three oils for six minutes, every 30 minutes and for 30 hours. Each time a frying was carried out, a sample of the oil was taken and the volatile compounds were extracted and analyzed.

The extraction of the volatile compounds has been carried out through a process characterized by being simple, fast and low cost besides not using organic solvents and not being contaminating. Once extracted, they are analyzed by gas-mass chromatography, a technique indicated for the separation of volatile and semi-volatile organic compounds, and which allows analyzing and quantifying compounds in complex mixtures with a high degree of effectiveness.