Extra virgin olive oil

Content

Introduction

L "extra virgin olive oil, often abbreviated to Extra virgin olive oil, represents one of the symbols of the Mediterranean diet and one of the major contributors to the benefits for which it has long been known. The "EVO oil is obtained from the fruits of the"Olea europaea L., family of the Oleaceae, commonly called olive and the merit of its beneficial properties is to be attributed to its peculiar composition.

Composition

Olive oil is made up of 99% fats. Specifically, we can distinguish:

  • monounsaturated fatty acids (63-83%), especially Oleic Acid
  • saturated fatty acids, of which 7-17% of Palmitic Acid and 1,5-4% Stearic Acid
  • polyunsaturated acids, of which about 13% of Linoleic Acid and about 1% of Linolenic Acid.

In addition to the high content of fatty acids, EVO oil contains a series of compounds capable of positively influencing health by carrying out important functions within the organism (bioactive compounds). most of these compounds are responsible for the taste, the bitter aromas and the spicy sensation of the oil (organoleptic properties).The amount of these compounds depends on several factors, such as the species (cultivar) of olives used, the ripening phase of the fruits, some environmental factors such as altitude, cultivation practices and quantity of irrigation, the extraction conditions such as heating, addition of water, extraction systems used to separate the oil from the residue that remains after the pressing of the olives (olive paste) and the storage conditions. For these reasons, the oils can be extremely different from each other.

The minor constituents of olive oil are represented by about 220 different substances, equal to 1-2% of the total. They are what make EVO oil different from other liquid fats. Some confer the aromatic note of the oil (perfumes-flavors), others are effective natural antioxidants capable of providing the product with resistance to aging and rancidity.

They include:

  • hydrocarbons
  • tocopherols
  • polyphenols
  • alcohols
  • sterols
  • pigments

Classification

Few foods have scrupulous regulations like those that regulate the classification, production and marketing of olive oil, of which Italy, after Spain, is the largest producer. The legislation referred to is Regulation (EEC) no. 2568/91 which establishes the classification of oil intended for food consumption on the basis of various parameters.

The main ones are:

  • acidity, that is the quantity of free oleic acid present. Oleic acid is freed from triglycerides as a result of degradation processes. A high quantity of oleic acid and, therefore, high acidity, indicates excessive ripening of the fruit or problems in the production, storage, etc. processes.
  • number of peroxides, substances that are formed from fatty acids for oxidative processes favored by oxygen, heat and air.These are reactions that can occur both during processing and during storage of the product if carried out in an inappropriate manner

The denominations used for the marketing of olive oil are:

  • virgin olive oil, obtained from the fruit of the olive tree by exclusively mechanical or other physical processes that do not cause alterations of the oil. The olives must not undergo any treatment other than washing, decanting, centrifugation and filtration. Virgin olive oil is in turn classified into:
    • extra virgin olive oil (EVO oil), with acidity lower than 0.8% and number of peroxides lower than 20 milliequivalents / kilo (Meq / Kg)
    • virgin olive oil with acidity lower than 2% and number of peroxides lower than 20 Meq / Kg
    • lampante virgin olive oil, with acidity higher than 3.3% and number of peroxides higher than 20 Meq / Kg
  • refined olive oil, obtained from virgin oils with refining techniques that do not modify the chemical structure of the fats contained in the oil. Acidity less than 0.5% and number of peroxides less than 5 Meq / Kg
  • olive oil, obtained by blending virgin oil with refined oil. Acidity higher than 0.5% and number of peroxides lower than 15 Meq / Kg
  • crude olive pomace oil, obtained by treating pomace (a by-product of the olive oil extraction process composed of the skins, pulp residues and stone fragments) with solvent. Intended for refining and technical uses. Acidity greater than 0.5%
  • refined olive pomace oil, obtained by refining crude olive pomace oil. Acidity lower than 0.5% and peroxide number lower than 5 Meq / Kg
  • olive pomace oil, obtained by blending refined olive pomace oil with virgin oil. Acidity less than 1.5% and peroxide number less than 15 Meq / Kg

In the "food label (regulated like all food products by Reg. (EU) no. 1169/11 of 25/10/11), the" indication of origin is mandatory for "extra virgin olive oil and for" virgin olive oil. Indications of origin can be:

  • reference to the Member State of the European Union (EU), to the Union or to the Third Country, in the case of oils originating in a Member State or a third country (eg. "Italian product")
  • one of the following:
    • blend of olive oils originating from the EU
    • blend of non-EU olive oils
    • blend of olive oils originating in the European Union and not originating in the Union, in the case of blends of oils originating in one or more Member States or third countries
  • indication of the states of harvesting and processing of the olives, for example:
    • extra virgin olive oil obtained in Italy from olives harvested in Italy
    • extra virgin olive oil obtained in the EU from olives harvested in the EU
    • extra virgin olive oil obtained in Italy from olives harvested in Spain
  • indication of origin in accordance with specific Regulations, in the case of oil with Protected Designation of Origin (PDO) or Protected Geographical Indication (PGI)

A very important index of the quality of the oil, which however is rarely indicated on the label, is the value of total polyphenols, substances that contribute both to the organoleptic, bitter and spicy characteristics, and to the beneficial effects on health, with their powerful antioxidant action. The phenolic compounds of olive oil differ from those contained in olives, and their qualitative-quantitative aspect is strongly conditioned by the variety of olives that make up the oil, by their stage of ripeness at the time of harvesting and by the extraction process of the olive oil. "oil.However, virgin and extra virgin olive oils are the only vegetable fats that naturally contain appreciable quantities (50-500 milligrams per kilo, mg / kg) of phenolic substances. The strong antioxidant power gives the polyphenols a consolidated role on the stability of olive oil. The literature is rich in information that highlights the positive correlation between the quantity of total polyphenols in virgin oils and resistance to oxidation over time.

Since the beneficial effects of EVO oil are linked to its composition, it is important that it is good at the start and that it is not altered over time.

Even within the extra virgin category, we can find extremely different oils and it is important to always choose a quality oil, which respects precise chemical and sensory characteristics, such as:

  • low acidity (less than 0.8%)
  • clear smell / taste attributable to the fruit from which it comes, the olive (hint fruity)
  • bitter and spicy sensations, indices of a good content of polyphenols

Oil and health

In the scientific literature there are numerous studies that have demonstrated the beneficial properties of EVO oil. These properties are linked above all to the presence of polyphenols (the best known are the tyrosol, L"hydroxytyrosol, L"oleuropein and the "oleocanthal) which have a strong antioxidant activity.

In particular, they are able to:

  • reduce the level of free radicals, protecting the cells of our body from oxidative damage
  • inhibit the activation of inflammatory and proliferative processes (of tumor growth and transformation of cells) and of toxicity to cells (cytotoxicity)

These substances, in addition to characterizing the oil from a sensory point of view, have beneficial effects towards all those diseases that persist over time (chronic) which have oxidation and inflammation at the basis of their appearance. For example, diseases related to metabolic alterations such as type 2 diabetes and cardiovascular disease.

Several studies conducted in humans have shown that the consumption of extra virgin olive oil is associated with a reduction in mortality, particularly that due to cardiovascular events.

The polyphenols present in the EVO oil are able to favor an improvement of lipid metabolism with a reduction in the amount in the blood of:

  • triglycerides
  • total cholesterol
  • LDL cholesterol

and contrast the formation of atherosclerotic plaque, ie the accumulation of fats and fibrotic material that alters the walls of the arteries making them less elastic and hindering the normal flow of blood.

The antioxidant action of polyphenols and other compounds of EVO oil (such as vitamin E) has beneficial implications also on blood pressure, thanks to a direct effect on blood vessels, whose elasticity is improved.

Furthermore, although the mechanisms by which tumors are formed are very complex, the consumption of EVO oil seems to have a protective action against some types of cancer, in particular:

  • colon
  • otherwise
  • skin

The protective effect would be due both to the antioxidant action of the various phenolic compounds, to their ability to reduce the formation of new blood vessels, essential for tumor growth, and to hinder the development of cancer cells.

On this basis, in November 2018, the American Food and Drug Administration (FDA), as previously the European Food Safety Authority (EFSA) had done, admitted the insertion of health advertising phrases (claims) on the EVO labels that meet the following requirements: the concentration of total polyphenols must be greater than or equal to 300 milligrams / kilogram (mg / kg) up to the minimum shelf life (generally 18 months), i.e. that period of time within which the EVOs maintain their specific properties as long as they are kept in optimal conditions.

How to store EVO oil

The main enemies of the quality of EVO oil are temperature, oxygen and light. For this reason, the best home preservation method is in dark glass or stainless steel containers (5 liters maximum). Once the container is opened, the oil should be divided into similar but smaller containers (500/750 milliliters) to avoid the continuous and repeated exposure to oxygen in the air due to its use. The containers should be kept in cool and dry places (without humidity), for example in a wall unit away from the stove or in a pantry. The ideal storage temperature is around 14-18 ° C.

How to use EVO oil

In order for the positive effects on health to develop, the composition of the EVO oil must not be altered, so it is preferable to consume it raw.

Cooking at high temperatures, in fact, causes an "alteration and deterioration of many substances contained in the EVO oil that do not resist heat, such as vitamin E.

However, its particular lipid composition (ie the fats it contains) makes EVO oil more “stable” to heat (ie less sensitive to alteration processes such as oxidation) than other oils. Oils rich in polyunsaturated fats, such as corn oil or soybean oil, degrade faster than those rich in monounsaturated fats such as olive, hazelnut or peanut oils, mainly composed of oleic acid.Therefore, while in general it is recommended to prefer foods that have a higher quantity of polyunsaturated fats because they tend to be better for health, for cooking foods it is better to use oils rich in monounsaturated.

The longer the heating time, the more the degradation of the oil increases. The higher the temperature, the faster the degradation. Once a certain temperature is exceeded, called smoke point, the oil begins to produce smoke and harmful substances such as acrolein. It goes without saying that the cooking method that most puts the stability of an oil to the test is frying, whose ideal temperature is about 180 ° C (at lower temperatures the food becomes soaked in oil while at higher temperatures it risks to burn quickly).

Of course, it is a good idea not to exceed the consumption of fried foods. However, EVO oil differs positively from seed oils and even more from other fats of animal origin that can be used for frying (butter, lard) precisely because it contains antioxidant molecules and is more resistant to heat.

Recommended quantities

The recommended quantities of EVO oil consumption depend a lot on the meal plan followed by each person. In general, they are between 20 grams (g) (2 soup spoons) and 40-50 g per day (4 soup spoons).

Bibliography

Council for Agricultural Research and Analysis of the Agricultural Economy (CREA). Food composition tables. Vegetable oils

Gomez-Rico A, Inarejos-Garcia AM, Salvador MD, Fregapane G. Effect of malaxation conditions on phenol and volatile profiles in olive paste and the corresponding virgin olive oils (Olea europaea L. Cv. Cornicabra) [Summary]. Journal of agricultural and food chemistry. 2009; 57: 3587-3595. doi: 10.1021 / jf803505w

Krichene D, Salvador MD, Fregapane G.Stability of Virgin Olive Oil Phenolic Compounds during Long-Term Storage (18 Months) at Temperatures of 5-50 degrees C [Summary]. Journal of agricultural and food chemistry. 2015; 63: 6779-6786. doi: 10.1021 / acs.jafc.5b02187

EEC Regulation n. 2568/91 of the Commission of 11 July 1991 concerning the characteristics of olive oils and olive pomace oils as well as the methods relating to them

Guasch-Ferré M, Hu FB, Martínez-González M.A. et al. Olive oil intake and risk of cardiovascular disease and mortality in the PREDIMED Study. BMC Medicine. 2014; 12. doi: 10.1186 / 1741-7015-12-78

Bulotta S, Celano1 M, Lepore SM, Montalcini T, Pujia A, Russo D et al. Beneficial effects of the olive oil phenolic components oleuropein and hydroxytyrosol: focus on protection against cardiovascular and metabolic diseases. Journal of Translational Medicine. 2014; 12: 219

U.S. Food and Drug Administration (FDA). FDA Statement. Statement from FDA Commissioner Scott Gottlieb, M.D., on a new qualified health claim for consuming oils with high levels of oleic acid to reduce coronary heart disease risk. 2018.

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