Chemical composition of Olive Oil

 It's known that characteristics of an olive oil depends on many factors: cultivars, pedo-climatic environment, cropping system, time and collection system olives, technology and methods of processing and preservation product.
The olive oils are different both in organoleptic (Flavor, smell, taste), and for the chemical (composition, acidity, etc.). Many of these factors that influence the quality of an oil not be modified (for example, climatic conditions), since typical of a given place, while others can be easily adapted, as cultivation techniques and methods of extraction. Therefore, to produce a excellent oil need to identify and highlight the characteristics organoleptic and chemical best, worthy of attention by the consumer.

Olive oil is a fat that is presented to the physical state liquid at room temperature (20 ° C), and is made from a chemical point of view for the 98-99% of a mixture of triglyceride fraction called "saponifiable" and the remaining 1.2% a set of compounds that represent "unsaponifiable".

Fatty acids represented more are: 

• Monounsaturated Oleic Acid: It's a solid which melts at 16 ° C. At environment is presented as a liquid of variable appearance colorless to yellowish and distinctive smell. Under form of  triglyceride is an important component of animal fats and is the most abundant constituent of the majority of oil plant. Oleic acid is the acid of about 75% of olive oil. The percentage of free oleic acid present in olive oil determines its acidity and consequently its denomination. So that the olive oil be considered virgin, is allowed a percentage of free oleic acid not exceeding 0.8% by weight total. As part of  is present in important biological structures, such as cell membrane   lipoproteins.
  
•  Essential polyunsaturated Linoleic acid : It looks like a liquid colorless, with  melting point  -5 ° C. Linoleic acid is present in all oils plants and is abundant in many of these, including in particular seed oil Cannabis , oil safflower and oil  sunflower , but also, to a lesser extent, oil corn , oil soy , in the plant of green coffee and others. It is also present in some of fats animal origin. Linoleic acid is one of the fatty acids Essential and belongs to the group of </ span> Omega 6. It  is studied her role (in some cases established, in others only speculated) in the prevention or in the treatment of various diseases, including infarction ,  cancer, diabetes, fibrosis cystic. It also seems that this fatty acid is involved lowering of   cholesterol, acting on intestinal absorption.
• Saturated Palmitic: is one of the fatty acids saturated more common in animals and plants. It is a white solid which melts at 63.1 ° C. The name comes from the fact that it is the oil of palm, but it is also contained in the and meat. Palmitic acid is the first fatty acid produced during the acid synthesis fat and it can be produced more long chain fatty acids. Some derivatives palmitic acid were used during the War World for produce napalm.
• A stearic acid: a carboxylic acid ambient temperature (25 ° C </ span>) looks like a solid, white scales more or less large, rancid odor. Insoluble in water, slightly soluble in alcohol soluble acetone and ether. Together with the ' palmitic acid as the stearin used for the production of candles.

Acids unsaturated fat, which is rich in the right measure as required by modern dietetics contain between the minor constituents, but no less important:

• Beta-carotene (Provitamin A): The carotene is a provitamin terpene contained in carrots and many vegetables that gives red or orange. Since its metabolism produces two molecules of vitamin A.
• Tocopherols (vitamin E) : In oil olive tocopherols are present with forms α, β, γ and δ. 90% of the component is in the form α tocopherol, which is also the most biologically active and known as vitamin E. The tocopherols are natural antioxidants that inhibit the process of rancidity of product, and to carry out this protective function is necessary that the ratio between quantity of Vitamin E (mg) and that of polyunsaturated fatty acids (g) is not less than 0.79 mg / g;
• Phenolic compounds etc.:  a number of substances antioxidants (both important for the conservation of the oil, which for the nutritional aspect and anti-aging (antagonists of free radicals). The phenolic compounds in olive oil differ from those contained in the olives, and their quali-quantitative is strongly influenced by variety, stage of maturity at collection and extraction process. In fact, being water soluble, during the process of extracting a substantial proportion of polyphenols is removed with the vegetable water; also is known that the enzymatic actions that take place during the extraction determine the split into simpler molecules compared to those found in olives. The olive oil virgin and extra-virgin however, are the only vegetable fats which contain naturally quantity appreciable (50-500 mg / kg) of phenolic substances; the reference to oils virgin is not random because any kind of chemical treatment of correction be done on this product can only destroy fully phenolic natural heritage.
  The antioxidant power of polyphenols, highlighted by some scholars, has established the important role that these compounds play on the stability olive oil, the literature is full of information that calls into significant positive correlation between the amount of total polyphenols in oil virgins and resistance to oxidation over time (induction period). In addition, scholars have highlighted the synergistic action between polyphenols andα-tocopherol (vitamin E) on the stability of virgin olive oil;
• Phytosterols: important also for their regulatory action absorption of cholesterol. 

Other minor constituents of olive oil

• Colored Pigments: they give them the color characteristics of olive oil, they are represented by chlorophylls and carotenoids. The type of chlorophylls a and b give the oils extracted just the intense green color, can oscillate between 0 to 10 ppm, and also vary in relation to the cultivars and stage of fruit ripening. These substances are worthy of attention since in the presence of light acting on the oil as a pro-oxidant, while the dark, in synergy with phenols protect it from oxidation;
• Alcoli: in the oil are aliphatic alcohols and alcohols triperpenici, they are esterified in waxes and have a great importance analytical, for the identification of the oils obtained by extraction with solvent or by mechanical pressure;
• Other secondary elements: This aldehydes, terpeidi, esters, ketones, etc.. affecting the oil and thus compounds aromatic note involved in its assessment hedonistic. 

The oil virgin olive oil, for its peculiar qualities and its low acidity (0.00 ~ 0.50%), is the best kind of seasoning to be used raw.

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      The high content of monounsaturated fatty acids represents the element distinctive olive oil compared to other fats of vegetable origin.   Olive oil and olive-pomace oil, being mixtures of refined oils and virgin oils, have some typical components of virgin olive oil in lower percentages.