By Dietitian – Nutritionist Eliana Evangelou
Extra Virgin Olive oil: Mistakes in its use that undermine its nutritional value
Extra Virgin Olive oil is one of the first fats used by the peoples of the Mediterranean in their diet as well as in medicine and cosmetology. The contribution of olive oil to the prevention of various diseases is now recognized worldwide thanks to its beneficial and organoleptic characteristics. Olive oil contains fatty acids, ie monounsaturated and fatty, fat-soluble provitamins and vitamins such as provitamin A, vitamins E, D and K, antioxidants such as phenols and tocopherols, but also the bioactive substances oleocanthal and oleasin.
Extra Virgin Olive oil is an oil that can be consumed raw. Many times, however, in order to prepare a food, the oil needs to be heat treated, which can be frying, baking, microwave heating and / or boiling. However, when heat treatment is mediated, the preservation of its nutritional value is often called into question.
Extra Virgin Olive oil has the ability to maintain a fairly high nutritional value after cooking, compared to other edible oils such as corn oil, sunflower oil and soybean oil. In fact, a study published in the American Journal of Agricultural and Food Chemistry confirmed this claim and concluded that olive oil is the best choice for cooking and frying compared to other oils. The resistance of olive oil to high temperatures is mainly due to its high content of monounsaturated fats, but also to its oleic acid content. At the same time, the antioxidant capacity of phenolic compounds in combination with vitamin E seems to play an important role.
Regarding frying, it is recommended that the temperature be 160 ° C to 180 ° C and the time should not exceed 4-5 minutes. Especially for the “extra virgin olive oil” the frying time should not exceed 15-20 minutes and their temperature 180 ° C. It is important to emphasize that high temperatures and long frying periods can lead to the production of toxic substances. It is also important to know that with the repeated use of olive oil, its composition changes, as a result of which saturated and trans fats are increased and at the same time monounsaturated fats are reduced. In addition, tocopherols, which are antioxidants, appear to be reduced. Phenolic compounds and tocopherols are almost depleted after a short period of heating.
With regard to microwave heating, the temperatures reached are excessive, resulting in a significant undermining of the nutritional value of extra virgin olive oil. Of course it is important to mention the fact that the presence of food releases moisture and reduces the above effect. Under boiling water and olive oil conditions the main factors that affect the nutritional value of the oil become the heating time and the presence of food. It is recommended that olive oil be added as close as possible to the final cooking process.
In conclusion, olive oil and more specifically “extra virgin olive oil” has a high resistance to oxidation. This resistance is due both to the nature of its fatty acids, ie to the high ratio of monounsaturated to polyunsaturated fatty acids, and to the presence of antioxidants. Most of these compounds are removed during the heat treatment of olive oil and in order to maintain its nutritional value high processing temperatures should be avoided.
Eliana Evangelou was born, lives and works in the city of Athens. Her interest in nutrition began in her teenage years leading her to the following studies. He obtained a degree in Nutrition and Dietetics from the University of Thessaly, with a grade of “Excellent”. She did her internship at the University General Hospital of Attica, following a variety of clinical cases. Afterwards, her postgraduate studies at Harokopio University focused on Applied Dietetics – Nutrition, in the field of Clinical Nutrition. She has attended trainings, among which are: “Sports nutrition”, “The FODMAPs diet” and “Nutrition and lifestyle during pregnancy”.
At the same time, her research interest and activity is intense both in the field of oncology and in the field of diabetes. She undertakes incidents and provides her services as a self-employed person in the area of Agia Paraskevi in Athens, but also as a responsible Dietitian-Nutritionist at Katsianos Athens Medical Center. Attends and participates in scientific conferences and seminars in order to be informed about developments in the food industry. Its goal is through nutrition education to achieve a balanced diet, but also a lifestyle as a whole. Her motto is “to eat is a necessity, to eat intelligently is an art”.