The olive tree, Olca europea L., able to grow for several hundred years, it thrives in temperate and tropical climates. Although its origin is unknown, probably it was originally cultivated in ancient Iran and Turkestan, and then spread to the west of Anatolia, Syria and Israel. During the archaeological excavations of the remains of the olive tree have been found in Israel relating to the 42 980 BC. e. Apparently, in the Middle and Late Bronze Age, the olives are grown in the region bordering the Mediterranean - from Palestine and Syria to Greece.
The International Olive Oil Council (International Olive Oil Council) has published the following definitions of olive oil:
Olive oil first cold pressing or variety "virgin» (vir¬gin) - oil obtained from the fruit of the olive tree by mechanical or other physical means under conditions, particularly thermal, causing no change in oil. Virgin olive oil pressing, suitable for human consumption, and is called "natural", then follow-differentiated manner:
"Extra virgin" -olivkovoe oil varieties (extra virgin) - oil that has organoleptichesuyu assessment 6,5 or more, the content is not more than 1,0% free fatty acids;
"Fine virgin" -olivkovoe oil grade (fine viigin) - oil which has organoleptichesuyu evaluation 5,5 or more content does not exceed 1,5% free fatty acids;
"Semifayn virgin" -olivkovoe oil varieties (semifine virgin) - oil, co-Thoroe has organoleptichesuyu assessment 3,5 or more, the content is not more than 3,3% free fatty acids;
• olive oil from the first pressing of lower sensory evaluation 3,5 or with the content of free fatty acids above 3,3% considered unfit for food purposes. It is used for the production of refined olive oil or for non-food applications;
• Refined olive oil is the oil obtained from the first pressing of olive oil refining methods which do not cause changes in the initial structure of triglycerides;
• olive oil may consist of a mixture of refined olive oils and virgin oils in different proportions.
Olive oil is usually greenish-yellow color and characteristic olive taste and smell. oil color is mainly due to the presence of chlorophyll and pheophytin, which also provides protection against oxidation in the dark. Karogipoidy also contribute to the formation of color and protect the photo-oxidation of the oil. The special aroma and taste of olive oil create many volatile compounds present in extremely low concentrations. Typically, the profile of volatile compounds affect the variety of olives, fruit maturity, methods kultiviroianiya and pressing olives parameters.
Good brands of olive oil are used without the usual processing of edible oils after extraction. The high content of free fatty acids in olive oil can be explained by damage to the fruit during harvest or by the high humidity of olive fruits, which favors enzymatic activity. Indicator of low-quality olive oil is either a high content of free fatty acids, or the presence of dipinerides. Olive oil varieties "virgin" has a very high cost compared to other vegetable oils, which provides a strong economic incentive for its falsification. Studies of fatty acid composition do not make it possible to clearly identify a fake; Triglyceride profiles will provide more accurate signs of falsification. Olive oil consists of triglycerides, which contain mainly unsaturated oleic acid. Only 10-18% of the fatty acids of olive oil are saturated. The content of oleic acid varies depending on the place of growth and climate. Like most other vegetable oils, olive oil generates more unsaturated fatty acids in cold climates and early ripening of fruits. The high content of oleic acid and low linoleic increase the resistance of olive oil to oxidation, which is higher than most liquid oils. Olive oil of the first pressing has a low content of tocopherol: 63 135 mg / kg a-tocopherol, depending on the degree of maturity of the fruit, but with respect to the level of polyunsaturated fatty acids such an amount is ideal. An additional increase in oxidative stability is provided by chlorophylls, which decompose into pheophytins. Of other vegetable oils, polyphenols are usually removed during processing. Light causes a significant deterioration in the quality of olive oil in the presence of air. The oil appears oxidized aftertaste, it becomes colorless due to the destruction of chlorophyll and carotene. For olive oil in hermetically sealed glass bottles stored in the dark, a shelf life of more than 2 years was set.