Olive oil is the pure juice of the fruit of olive trees, does not need any chemical processing, does not contain any preservatives or enhancers, is produced purely by mechanical means and is ready for consumption immediately after its production procedure, contrary to other vegetable oils. It is the vegetable oil that is produced by the fruit’s flesh and not by the kernel, contrary to other vegetable oils. In this manner, all the nutritional, tasty, aromatic substances of the fruit of the olive tree are maintained.


Olive oil is a product of healthy nutrition due to its bigger proportional content in monounsaturated fat. The main source of fatty acid in olive oil is monounsaturated fat and in particular oleic acid, contrary to animal fats, which are entirely made from saturated fatty acid.

Composition of olive oil

Olive oil is mainly a mixture of ester and glycerin (triglycerides) with the higher
fatty acids, some of which are unsaturated, whereas others are saturated.
Apart from the triglycerides, olive oil also contains small quantities of other ingredients, such as:
free fatty acids, phosphatides (lecithin), sterols, phenols, tocopherol,
coloring and various resinous and jelly-like substances. (Kyritsakis,1988).

Triglycerides constitute approximately 98.5 - 99.5 % of the ingredients of olive oil and are the ones we call the saponifiable fraction, whereas the remaining 0.5 - 1.5 %, which constitutes the insaponifiable fraction of olive oil, is responsible for its main taste and olfactory properties.
The content of olive oil in fatty acids, as of the other vegetable oils, depends on the variety, the climate conditions of the area where the trees are cultivated, as well as on various other factors.
The biggest part of the fatty acids of olive oil comprises unsaturated acids. Among them the monounsaturated oleic acid ( 18:1 ), which is the dominant one. The second in order unsaturated fatty acid of olive oil is linoleic acid ( 18 :2 ). The other unsaturated acids, linoleic (18:3), arachidonic (20:4) and palmitoleic acids (16:1 ) are found in olive oil, but in very small quantities.

Out of the saturated acids, the palmitic acid ( 16:0 ) is found at a bigger percentage, followed by stearic acid (18:0 ). The main glycerides of olive oil are those in oleic acid, which exceed 70 - 80 % of the oil’s weight on their own. Due to the fact that such glycerides are in liquid form in room temperature, when the olive oil in whole is in normal room temperatures, it remains in liquid form. Kyritsakis,1988

Percentage fluctuation of the content of fatty acids in olive oil.

FATTY ACIDS               

Content (%)


56,0 - 83,0


7,50 -20,0





















International Olive Oil Council (1984)

The biological value of olive oil is great, due to:

- The good ratio of saturated and unsaturated fatty acids it contains.

- The good ratio of Vitamin E and the polyunsaturated fatty acids (mainly linoleic).

- The presence of linoleic acid at a percentage of approximately 10%, which is a necessary percentage for the requirements of the organism in basic fatty acids.

- The presence of natural antioxidant substances. It contains a big variety of vitamins and antioxidant substances, out of which the most biologically drastic form of vitamin E (a-tocopherol), carotenes, antioxidant phenols such as oleuropein.

- The fact that it contains squalene, a forerunner substance of sterols and an antioxidant, at a bigger percentage than in other fatty substances, which plays an important role in metabolism.

- The fact that it has an excellent ratio of linoleic to a-linolenic acid, which is similar to the one of fat in human milk.
The composition of the olive oil’s fat is similar to human milk.
Only the fat in human milk is digested at a bigger percentage than the one in olive oil. (Gyorgy 1969).

- Due to its small content in polyunsaturated fat and its wealth in antioxidants, olive oil is particularly durable against oxidations, which is a property other fatty substances do not have.

- Olive oil does not contain any Trans – unsaturated fatty acids, cholesterol and salts.



Bitter taste, advantage for health. Why does olive oil taste bitter?

The phenols and the oleuropein contained in the olive oil’s composition are responsible for the bitter taste of olive oil and the throat burning.

The main ingredients contained in the insaponifiable fraction of olive oil are: Carbohydrates, Sterols, Tocopherols, Carotenoid coloring substances, Triterpene alcohols, Phenols, Phospholipids, Coloring substances, Volatile ingredients, Oleuropein. Such ingredients are responsible for the main taste and olfactory properties of olive oil.

Phenols are a significant category of natural antioxidants that are found in olive oil and in fact at a significant quantity. The most important ones found in olive oil are tyrosol and hydroxytyrosol and phenolic acids, such as caffeic and protocatechuic. The existence of phenols significantly strengthens the durability of olive oil against oxidization. Such natural antioxidants are responsible for the bitter taste and the throat burning.

Furthermore, oleuropein is a phenolic compound in olive oil, which gives it its distinctive bitter taste. Its content varies depending on the species of the olive, the climate and the technique used for taking the olive oil from the olive. When the olive oil is stored, the content of Oleuropein is reduced, due to enzymatic hydrolysis and the olive oil’s taste loses its fruity and bitter taste. With regard to its antioxidant effects, Oleuropein works together with phenols. Furthermore, oleuropein is also responsible for the anti-hyperpiesis effects, the anti-inflammatory effects, the antibiotic and the peptic effects.