Composition of Olive Oil
- Omega 3 and Omega 6 acids
- Pigments and aromatic components
- Free fatty acids
Generally oils contain mostly fatty acids that can be saturated, unsaturated, monounsaturated and polyunsaturated. Unlike other vegetable oils, olive oil has in its composition more oleic acid (monounsaturated fatty acid). Oleic acid makes olive oil very resistant to oxidation, a very important fact since oxidation affects flavour and nutritional values of the oil.
Read more about Oxidation of Fatty Acids
Oleic acid can be up to 83% of the composition of olive oil. It reduces LDL cholesterol (the bad cholesterol) which can create atherosclerotic plaque and increases the HDL cholesterol (the good one). There is no other naturally produced oil to have so big amount of monounsaturated fats as olive oil.
Read more about Fats and Olive Oil
The protective effects of olive oil against the chronic and degenerative diseases are attributed to the phenolic components rather than to the unsaturated fatty acids content of the olive oil. Polyphenols have the following health benefits: antioxidant activity, anti-inflammatory activity, anti-microbial activity, anti-atherogenic activity, anti-tumor, anti-platelet aggregation, anti-hypertensive activity, increased vitamin A and B carotene activity, anti-allergenic activity and reduction in the levels of plasma cholesterol and oxidized LDL. At least 30 phenolic compounds can be found in olive oil. The amount of polyphenols in olive oil composition, depend on maturation stage, variety, season, packaging, storage, climate and the degree of technology used. There are the following classes of phenols in olive oil composition: phenolic acids, phenolic alcohols, hydroxyl-isocromans and flavonoids (all four in small amount) and secoiridoids and lignans (the most prevalent). Secoiridoids are derivates of Oleuropein. The most abundant secoiridoids are Hydrohytyrosol and an isomer of the oleuropein aglycon. The other important group of phenols, lignans, have been isolated and classified together with other phenolic compounds as phenolic derivates. Generally there are 5 mg of polyphenols in 10 gr of extra virgin olive oil. Refined olive oil mostly lost phenols in the refining process.
Squalene is a natural organic compound and an important metabolic factor. It is part of the synthesis of cholesterol, steroid hormones, and vitamin D in the human body. Squalene is used in cosmetics, and more recently as an immunologic adjuvant in vaccines. It is also believed to have anti-cancer properties. Squalene content in olive oil composition is especially high, up to 0.7% (7 mg/g), compared to other oils and human dietary fats. Squalene is found in high amounts in sebum (around 12% of its composition) and acts as a potent scavenger of singlet oxygen, inhibiting the lipo-peroxidation induced by ultraviolet (UV) radiations, thus having anti-neoplastic influence on the colon, breast, and prostate, it seems to have immune-stimulating properties and it can inhibit the development of various tumors. Also it has major protective effect against skin cancer.
Olive oil has in its composition the Alfa, beta, gamma, delta tocopherols . Tocopherols are compounds with vitamin E activity, which is a natural antioxidant. Olive oil also contains Vitamin A, D, B complex and K. These compounds are known to contribute to the antioxidant capacity of olive oil, as well as enhance oil stability during frying by protecting it from thermo-oxidative degradation. They increase oxidation stability of oils during storage due to preventing from the light. Moreover, α-tocopherol defends the body against free radical attacks, and prevents skin disorders, cancer and arteriosclerosis. Some researchers have demonstrated a synergistic relationship between the antioxidant actions of some phenolics and tocopherols.
Omega-3 and Omega-6 acids
Olive oil contains both Omega-3 and Omega-6 fatty acids, which are essential acids that cannot be made by the human body. Olive oil is generally 10% linoleic acid (omega-6 oil) and less than 1% linolenic acid (an omega-3 oil). Omega-3 fatty acids are important in preventing cardiovascular disease.
Pigments and aromatic components
The olive oil colour is given by the pigments like chlorophyll, pheophytin, and carotenoids. The presence of these components depends on several factors such as the fruit maturation, the cultivar, the soil and climate and the extraction procedures. The aroma and the taste components are the result of enzymatic reactions. Approximately 280 compounds have been identified in the volatile fraction of virgin olive oils. Fruitiness, bitterness and pungency as well as undesired attributes are correlated to different volatile compounds of olive oil. The colour pigments and the flavour compounds increase the stomach secretion and help a better absorption of the natural antioxidants.
Free fatty acids
The free fatty acids are formed as a result of breakdown of the triacylglycerols. The classification of olive oil is made according to its acidity (extra virgin can have maximum 0.8%). The factors that lead to a high free fatty acidity are: disease of the fruit, fly infestation, bruised or damaged olives, delayed extraction after harvesting, storage and transportation of the olives etc. The lower is the acidity, the higher grade the olive oil will be.