For Properties OF Extra Virgin Olive Oil (EVO) is meant an oil obtained from the first pressing of the drupes, or of the fruits (olives), of the European Olea Leccino plant (better known as olive). The extraction processes of extra virgin olive oil are MECHANICAL and the use of chemical means or processes is totally excluded; Properties of Extra Virgin Olive Oil at various stages of processing must NOT affect the quality of the oil which, when finished, must be intact and well preserved.
What reflects in a realistic way the suitability of the oil processing processes (olive harvest, conservation of the same, extraction and processing times) is the ACIDITY parameter; on balance, the pH of extra virgin olive oil represents, together with some organoleptic and gustatory properties, the fundamental parameter in the qualitative evaluation of the product.
NB. The pH of extra virgin olive oil is expressed in oleic acid-free fatty acids (C 18: 1); from a food law point of view, an EVO oil must not exceed 0.8% of free C 18: 1.
Nutritional properties and cooking
Extra virgin olive oil is made up of 99% lipids. The saponifiable portion of these fats is organized mainly in simple triglycerides (or triacylglycerols) (esters of glycerol with three fatty acids) and/or mixed
The quality of the fatty acids of extra virgin olive oil determines their chemical-physical properties and, in practice, their relevance within the various culinary preparations. In parallel, the unsaponifiable portion of the extra virgin olive oil provides many essential macro-molecules (fat-soluble vitamins – tocopherols and B-carotene), or in any case very useful for the human organism (phytosterols and polyphenols); well, some of these molecules contribute, together with the typical fatty acids, to determine the chemical-physical properties of the finished product (antioxidants).
The fatty acids most present in the triglycerides of extra virgin olive oil are: oleic acid (monounsaturated – predominant over others), palmitic acid (saturated), linoleic acid (polyunsaturated – a family of ω ‰ 6) and α-linolenic acid (polyunsaturated – the family of ω ‰ 3). The prevalence of oleic acid gives the extra virgin olive oil unparalleled properties; this chemically monounsaturated fatty acid determines:
- A sufficient smoke point for FRYING; this parameter is physically determined by the saturation level of fatty acids (saturated have a higher smoke point than unsaturated and monounsaturated have a higher smoke point than polyunsaturated) and by the quantity of free fatty acids (> free fatty acids <point of smoke). It is true that lard, refined and/or seed and/or hydrogenated oils boast greater resistance to high temperatures, but the quality of fatty acids and their impact on metabolism are not even remotely comparable to those of oil extra virgin olive oil. To learn more read the article: ideal oils for frying.
- Oxidative stability useful for STORAGE; they are particularly stable to oxidation and therefore contribute to determining the conservative properties indispensable in immersion packaging; on the contrary, the other fats used in cooking (with the necessary differences) do not have equally good oxidation resistance characteristics. To learn more read the article: preservation in oil.
At the same time, unsaponifiable micro-molecules such as glucosides (polyphenols) and antioxidant vitamins (tocopherols / Vit. E + Β-carotene or carotenoids in general) contribute to the increase of the conservative properties of extra virgin olive oil. However, it is also necessary to remember that: in the event heat treatments were used (cooking/frying or simply post-pot heating for storage in oil), the number of antioxidant molecules and the integrity of the polyunsaturated fatty acids could undergo a notable molecular decline.
Find out more about how to check oil temperature without a cooking thermometer blogpost.
% typical fatty acid composition of an extra virgin olive oil
Oleic acid 73.13%
Saturated fatty acids 16.5%
Palmitoleic acid 1%
Linoleic acid 8.12%
A-linolenic acid 0.7%
Nutritional properties and dietary contextualization of extra virgin olive oil
As already mentioned, extra virgin olive oil represents a discreet substrate for frying and excellent food for preservation in oil. The nutritional properties, compared to any seasoning gas, are much better; starting from the assumption that it is a widely appreciated food thanks to its typical taste and palatability, extra virgin olive oil deserves to be used “raw” with free frequency but in doses proportionate to the subject’s real caloric needs.
Finally, remember that extra virgin olive oil provides vitamins, antioxidants, phytosterols and monounsaturated fatty acids, therefore, in place of the saturated lipid portion of animal origin (fats contained in cheese, meat and fatty derivatives, in eggs etc.) it can determine a significant nutritional advantage.
Focusing on the content in monounsaturated fatty acids, it is not uncommon to hear that extra virgin olive oil is compared to other vegetable oils and discredited for the lower content of essential fatty acids ω3 (more abundant in linseed, soy, walnut oil etc.); in reality, this comparison has no reason to be supported. First of all, I would challenge anyone to fry or store food in oils rich in polyunsaturated fatty acids; the result would be a real disaster as the presence of double bonds gives the fatty acids a remarkable instability to heat and oxidation. Secondly, it is necessary to remember that:
- Even monounsaturated fatty acids, like many polyunsaturates, are characterized by a POSITIVE metabolic impact; they are distinguished by the beneficial effect on the blood lipid picture and, therefore, contribute to the prevention of cardiovascular diseases.
- The polyunsaturated fatty acids of the ω3 family present in vegetable oils are NOT totally bioavailable; the ω ‰ 3 contained in soybean, flax, walnut oil etc. they mainly contain α-linolenic acid (abbreviations ALA, AaL, LNA or 18: 3-ω3) which, unlike eicosapentaenoic acid (EPA, 20: 5 ω ‰ 3) and of docosahexaenoic acid (DHA, 22: 6 ω ‰ 3), requires a molecular conversion to perform the related metabolic functions.
Obviously, the same goes for extra virgin olive oil … however, if the presence of ω3 fatty acids represents the only discriminating factor in the choice between extra virgin olive oil and other seasoning oils, in my opinion, there are no differences sufficient to prefer a less pleasant oil than EVO, which is also endowed with great culinary “ductility”.
We conclude by recalling that the extra virgin olive oil, although characterized by the excellent supply in NON-energy functional macro-molecules, the excellent lipid profile, the conservative usefulness, the possibility of use in frying and the excellent taste characteristics, however, it represents a seasoning fat that provides 899 kcal per 100g of product.
In the context of a balanced diet (and especially in the case of any dysmetabolic pathology) the lipid content of EVO (and that of bluefish) should replace as much as possible the saturated fatty portion deriving from meat, eggs and milk derivatives … but this does not mean that it can be consumed in freedom! Ten grams of extra virgin olive oil (sufficient for seasoning, for example, a plate of salad or boiled zucchini) alone provides three times the calories provided by the side dish itself; it follows that exaggerating the seasoning of the various dishes with extra virgin olive oil has a more than the decisive impact on the overall energy supply and on the distribution of macronutrients (which should provide for a lipid contribution of between 25 and 30% of the total kcal).
Other applications of extra virgin olive oil
Extra virgin olive oil also has very different properties and applications from the culinary ones; it, as we have already mentioned, has both a saponifiable portion and a NON-saponifiable portion of the liquid constitution and yellow colour (also called Olea European Oil Unsaponifiables). The latter is made up of 80% SQUALENE and 20% hydrocarbons, triterpene and aliphatic alcohols, sterols, tocopherols and carotenoids.
Some studies have shown a positive effect on the skin sebum thanks to its emollient and sebum-reconstituting characteristics; moreover, it seems that the NON-saponifiable portion also boasts an important positive action on skin tropism thanks to the stimulation of reparative processes on the dermis and epidermis.
Other properties of extra virgin olive oil include the mildly laxative and the pain-relieving effect conferred by the presence of oleocanthal.