Extra Virgin Olive Oil: Healthy Choice For Frying Fish

The researchers from UPV/EHU-University of the Basque Country have concluded that best oil for frying fish is the extra virgin olive oil. This resulted from their study on the changes that take place in fish lipids and in the oil during frying processes.

The study was printed in the journal Food Research International. It was led by Bárbara Nieva-Echevarría, Maria Dolores Guillen, Encarnación Goicoechea and María José Manzanos, according to Science Daily.

In the study, the researchers fried fillets of European sea bass and gilthead sea bream in a frying pan and in a microwave oven. They used the extra virgin olive oil and refined sunflower oil for frying. The team used the Proton Nuclear Magnetic Resonance Imaging (H-1NMR) in examining the changes that took place in the lipid composition of the fish and of the frying oil.

The researchers showed that the frying techniques, the nature of the oil used and the fish species could have great influence in food safety and human health. The cooking oil particularly has an impact on the lipid profile in the fish and could possibly generate toxic compounds in the oil during frying.

The results showed that during the shallow-frying of the fish, the fish lipids migrated to the frying oil as well as the components of the oil were transferred to the fillet of the fish. This made the composition of the oil modified. It enriched the acyl groups or the fatty acids in the fish fat than in the original oil and depleted the acyl groups in the original oil than in the fish fat. So after frying, the extra virgin olive oil became rich in omega-3, linoleic, omega-1 acyl groups and saturated fats. On the other hand, the oleic, which is the main acyl group in olive oil lessened.

Meanwhile, the sunflower oil became richer in all the acyl group types after frying except the linoleic, which is the majority acyl group in sunflower oil. Both oils were enriched by small amounts of cholesterol from the fish after frying.

The composition of the fat in the fish fillets also changed during the frying process. It became enriched by the acyl groups that were present in a higher concentration in the frying oil than in the fillet and in plant sterols. The thermal oxidation did not occur too in the extra virgin oil used for frying. If there was an oxidation that might occur as in the case of sunflower oil, some of the oxidation compounds are considered toxic. The team, therefore, concluded that the healthiest option for frying is the extra virgin olive oil and fry in the microwave.

Olive oil is a fat that is taken from the olive, which is a fruit that belongs to Olea europaea. It is produced by pressing the whole olives. It is mostly used in cooking, pharmaceuticals, cosmetics, soaps and as fuel for traditional lamps.