1) Why is it better to fry in Virgin Olive Oil than in other vegetable fats?
Antonia Chiou and Nick Kalogeropoulus demonstrate in their study 'Olive oil as frying oil' that Virgin Olive Oil performs better than other vegetable oils when frying because it shows better heat resistance. This is mainly due to its fatty acid profile and the presence of a variety of natural antioxidants, which serve as protection against heat stress, making olive oil the preferred choice for frying. Olive oil contains between 55% and 83% monounsaturated oleic acid, which is 50 times less prone to oxidation than linoleic acid (Chiou and others, 2017), the polyunsaturated fatty acid that predominates in most vegetable oils. Under normal cooking conditions, with temperatures between 180 and 190 degrees, as is common when frying, the behaviour of olive oil is superior to that of other vegetable oils. Moreover, virgin olive oil continues to perform even better than vegetable oils high in oleic acid, such as high oleic sunflower oil, due to the antioxidants present in virgin olive oil.
Frying with olive oil also improves the quality of fats consumed. The addition of olive oil to food when frying results in a favourable fatty acid profile high in monounsaturated fats and low in saturated fats. In addition, virgin and extra virgin olive oil when used for frying transfers to food its micronutrients: polyphenols, tocopherols, squalene, terpenic diols and natural sterols.
2) Which variety of Extra Virgin Olive Oil to use for frying?
Antonia Chiu and Nick Kalogeropoulus tell us that EVOOs produced from green olives that have not yet reached their peak of ripeness perform best when used for frying. This has been proven at Cortijo de Suerte Alta. Early harvest oils are much higher in polyphenols and micronutrients. These micronutrients confer greater stability to EVOOs. This is why early harvest oils are better for frying. In addition, there are also certain varieties that are higher in polyphenols and micronutrients, such as Picual versus Arbequina. This makes Picual a better oil for frying than Arbequino, as it is more stable.
3) The smoke point of extra virgin olive oil
Seed and refined oils have a higher smoke point than olive oil. The smoke point is the temperature at which the oil starts to smoke. Some people think that seed and refined oils are better for frying because they have a higher smoke point, because they understand this data as an indicator that at higher temperatures these oils do not spoil. What this actually means is that the food needs to be heated to a higher temperature in order to fry with these oils. The fact that the smoke point is lower, as in the case of virgin olive oil, does not mean that the oil fries less but that it fries at a lower temperature. A refined sunflower oil with a smoke point of 230º you have to set the oil at 230º for it to fry. With extra virgin olive oil, which has a smoke point of 160º, you have to heat the oil less. By heating the oil less, it degrades less. You also heat the food less and it also degrades less. It is important to underline that it is extra virgin olive oil that has a smoke point of 160º and not refined sunflower oil or olive oil which both have a smoke point of 230º.
The problem with a high smoke point is also that you have to heat the food more and this has the consequence that if you fry a meat with a seed oil the fat in the meat dissolves. When you use that oil for frying a second time the oil is no longer just seed oil but a mixture of seed fat and saturated animal fat. When you use olive oil, because it fries at a lower temperature, the animal fat does not dissolve, and when you use the oil a second time, you are frying with vegetable fat only. If you fry fish with sunflower oil, the fish fat remains in the oil.
In addition, there is an economic advantage to using olive oil for frying. Firstly, the fryer does not need to be heated as much, which saves energy. Secondly, less olive oil is needed for frying. When frying with EVOO in the fryer it is important to set the temperature to 180º.
4) An important part of fat intake in Mediterranean countries comes from the consumption of fried foods.
Gregorio Varela in his article 'The frying of food in olive oil' states that in Spain and in general in the countries of the Mediterranean area, approximately 50% of the total fat intake comes from culinary fat. But the most interesting thing is that only a small fraction of this culinary fat is consumed raw, in the seasoning of food, and that most of it is used in frying in oil baths. Hence the vital importance of the oil we use for frying, as selecting the oil with which we fry enables us to manipulate our lipid intake.
5) The benefits of frying food
Gregorio Varela, Professor of Nutrition at the Complutense University of Madrid, explains in his article 'The frying of food in olive oil' that when the frying process (also called deep frying) is done correctly, it is less aggressive than other culinary techniques for the nutritional value of the food and also improves lipid intake. This is due to the fact that the food does not exceed 100°C for 2/3 of the time during which the food is fried, regardless of the temperature of the oil used. This is because before the oil penetrates the food, the water in the food must evaporate. This is very important because it means that the aggression of the oil on the food is low. Deep Frying (DP) has a number of benefits according to Varela:
1) The action time of the hot oil on the food is extremely short.
2) The oil bath frying process is less aggressive for the nutritional value of the fried food than other culinary processes.
3) The amount of fat that is ingested and therefore its caloric value is also less than in other processes.
6) EVOO does not soak the fried food in fat.
When frying, EVOO 'seals' the food before and at a very low temperature, so it does not penetrate inside and avoids soaking the food with fat. Seed oil does not create a crust and therefore penetrates more into the croquette. EVOO creates a crust which means that less oil enters the croquette. We will therefore have less oily croquettes if we fry with EVOO.
BIBLIOGRAPHY
Varela, G. (1994) “La fritura de los alimentos en aceite de oliva”. Consejo Oleícola Internacional. Madrid.
