Olive oil is an oil obtained from the olive (Olea europaea; family Oleaceae), a traditional tree crop of the Mediterranean Basin. It is commonly used in cooking, cosmetics, pharmaceuticals, and soaps and as a fuel for traditional oil lamps.
Olive oil is used throughout the world, but especially in the Mediterranean.
The olive tree is native to the Mediterranean basin; wild olives were collected by Neolithic peoples as early as the 8th millennium BC. The wild olive tree originated in Asia Minor in modern Turkey. It is not clear when and where olive trees were first domesticated: in Asia Minor in the 6th millennium; along the Levantine coast stretching from the Sinai Peninsula to modern Turkey in the 4th millennium; or somewhere in the Mesopotamian Fertile Crescent in the 3rd millennium.
A widespread view exists that the first cultivation took place on the island of Crete. The earliest surviving olive oil amphorae date to 3500 BC (Early Minoan times), though the production of olive is assumed to have started before 4000 BC. An alternative view retains that olives were turned into oil by 4500 BC by Canaanites in present-day Israel.
Homer called it “liquid gold.” In ancient Greece, athletes ritually rubbed it all over their bodies. Olive oil has been more than mere food to the peoples of the Mediterranean: it has been medicinal, magical, an endless source of fascination and wonder and the fountain of great wealth and power.
Besides food, olive oil has been used for religious rituals, medicines, as a fuel in oil lamps, soap-making, and skin care application.
Recent genetic studies suggest that species used by modern cultivators descend from multiple wild populations, but a detailed history of domestication is not yet understood. Many ancient presses still exist in the Eastern Mediterranean region, and some dating to the Roman period are still in use today.
Over 5,000 years ago oil was being extracted from olives in the Eastern Mediterranean. In the centuries that followed, olive presses became common, from the Atlantic shore of North Africa to Persia and from the Po Valley to the settlements along the Nile.
Olive trees and oil production in the Eastern Mediterranean can be traced to archives of the ancient city-state Ebla (2600–2240 BC), which were located on the outskirts of the Syrian city Aleppo. Here some dozen documents dated 2400 BC describe lands of the king and the queen. These belonged to a library of clay tablets perfectly preserved by having been baked in the fire that destroyed the palace. A later source is the frequent mentions of oil in Tanakh.
Dynastic Egyptians before 2000 BC imported olive oil from Crete, Syria and Canaan and oil was an important item of commerce and wealth. Remains of olive oil have been found in jugs over 4,000 years old in a tomb on the island of Naxos in the Aegean Sea. Sinuhe, the Egyptian exile who lived in northern Canaan about 1960 BC, wrote of abundant olive trees.
Until 1500 BC, the eastern coastal areas of the Mediterranean were most heavily cultivated. Olive trees were certainly cultivated by the Late Minoan period (1500 BC) in Crete, and perhaps as early as the Early Minoan. The cultivation of olive trees in Crete became particularly intense in the post-palatial period and played an important role in the island’s economy. The Minoans used olive oil in religious ceremonies. The oil became a principal product of the Minoan civilization, where it is thought to have represented wealth. The Minoans put the pulp into settling tanks and, when the oil had risen to the top, drained the water from the bottom. Olive tree growing reached Iberia and Etruscan cities well before the 8th century BC through trade with the Phoenicians and Carthage, then spread into Southern Gaul by the Celtic tribes during the 7th century BC.
The first recorded oil extraction is known from the Hebrew Bible and took place during the Exodus from Egypt, during the 13th century BC. During this time, the oil was derived through hand-squeezing the berries and stored in special containers under guard of the priests. A commercial mill for non-sacramental use of oil was in use in the tribal Confederation and later in 1000 BC, the fertile crescent, and area consisting of present day Palestine, Lebanon, and Israel. Over 100 olive presses have been found in Tel Miqne (Ekron), where the Biblical Philistines also produced oil. These presses are estimated to have had output of between 1,000 and 3,000 tons of olive oil per season.
Olive trees were planted in the entire Mediterranean basin during evolution of the Roman republic and empire. According to the historian Pliny, Italy had “excellent olive oil at reasonable prices” by the first century AD, “the best in the Mediterranean”, he maintained, a claim probably disputed by many ancient olive growers. Thus olive oil was very common in Hellene and Latin cuisine. According to legend, the city of Athens obtained its name because Athenians considered olive oil essential, preferring the offering of the goddess Athena (an olive tree) over the offering of Poseidon (a spring of salt water gushing out of a cliff).
The Spartans were the Hellenes who used oil to rub themselves while exercising in the gymnasia. The practice served to eroticise and highlight the beauty of the male body. From its beginnings early in the seventh century BC, the decorative use of olive oil quickly spread to all of Hellenic city states, together with naked appearance of athletes, and lasted close to a thousand years despite its great expense.
Today over 750 million olive trees are cultivated worldwide, 95% of which are in the Mediterranean region. Most of global production comes from Southern Europe, North Africa and the Near East.
World olive oil production in 2006-2007 was 2.767 million tonnes, of which Spain contributed 40% to 45%. Of the European production, 93% comes from Spain, Italy, Portugal and Greece.
Greece devotes 60% of its cultivated land to olive growing. It is the world’s top producer of black olives and has more varieties of olives than any other country. Greece holds third place in world olive production with more than 132 million trees, which produce approximately 350,000 tons of olive oil annually, of which 82% is extra-virgin. About half of the annual Greek olive oil production is exported, but only some 5% of this reflects the origin of the bottled product. Greece exports mainly to European Union (EU) countries, principally Italy, which receives about three-quarters of total exports. Olives are grown for oil in Greece, with Peloponnese being the source of 65% of Greek production, as well as in Crete, the Aegean Islands and Ionian Islands. The most prized Greek olive variety for oil production is the Koronéiki, originating from the area of Korone in Messenia. This variety grows well on mountain slopes and produces very small fruit; the high ratio of skin to flesh giving the oil its coveted aromatic qualities. The variety is also suited to the production of agourélaio, oil from olives that are slightly unripe. When crushed in presses that are not capable of grinding the stone, this oil is entirely free of acidity and possesses top-tier organoleptic characteristics. Because not crushing the stones reduces oil yield, production of agourélaio is limited to “boutique” presses run by entrepreneurs and small cooperatives.
Among the many different olive varieties or cultivars in Italy are Frantoio, Leccino Pendolino, and Moraiolo; in Spain the most important varieties are the Picual, Arbequina, Hojiblanca, and Manzanilla de Jaén; in Greece, Koroneiki; in France, Picholine; in California, Mission; in Portugal, Galega; in Croatia, Oblica and Leccino. The oil from the varieties varies in flavour and stability (shelf life).
Australia now produces much olive oil. Many Australian producers only make premium oils, whilst a number of corporate growers operate groves of a million trees or more and produce oils for the general market. Australian olive oil is exported to Asia and Europe.
In North America, Italian and Spanish olive oils are the best-known, and top-quality extra-virgin oils from Italy, Spain, and Greece are sold at high prices, often in “prestige” packaging. A large part of U.S. olive oil imports come from Italy, Spain, and Turkey. The U.S. imported 47,800,000 US gallons (181,000 m3) of olive oil in 1998, of which 34,600,000 US gallons (131,000 m3) came from Italy.
The Republic of South Africa also produces extra virgin olive oil, with production increasing to meet demand.
Olive oil is produced by grinding olives and extracting the
oil by mechanical or chemical means. Green olives usually produce more bitter oil, and overripe olives can produce oil that is rancid, so for good extra virgin olive oil care is taken to make sure the olives are perfectly ripened.
The process is generally as follows:
1) The olives are ground into paste using large millstones (traditional method) or steel drums (modern method).
2) If ground with mill stones, the olive paste generally stays under the stones for 30 to 40 minutes. A shorter grinding process may result in a more raw paste that produces less oil and has a less ripe taste, a longer process may increase oxidation of the paste and reduce the flavor. After grinding, the olive paste is spread on fiber disks, which are stacked on top of each other in a column, then placed into the press. Pressure is then applied onto the column to separate the vegetal liquid from the paste. This liquid still contains a significant amount of water. Traditionally the oil was shed from the water by gravity (oil is less dense than water).
This very slow separation process has been replaced by centrifugation, which is much faster and more accurate.
The centrifuges have one exit for the (heavier) watery part and one for the oil. Olive oil should not contain significant traces of vegetal water as this accelerates the process of organic degeneration by microorganisms. The separation in smaller oil mills is not always perfect, thus sometimes a small watery deposit containing organic particles can be found at the bottom of oil bottles.
3) In modern steel drum mills the grinding process takes about 20 minutes. After grinding, the paste is stirred slowly for another 20 to 30 minutes in a particular container (malaxation), where the microscopic oil drops unite into bigger drops, which facilitates the mechanical extraction. The paste is then pressed by centrifugation, the water is thereafter separated from the oil in a second centrifugation as described before.
The oil produced by only physical (mechanical) means as described is called virgin oil. Extra virgin olive oil is virgin olive oil that satisfies specific high chemical and organoleptic criteria (low free acidity, no or very little organoleptic defects).
4) Sometimes the produced oil will be filtered to eliminate remaining solid particles that may reduce the shelf life of the product. Labels may indicate the fact that the oil has not been filtered, suggesting a different taste. Unfiltered fresh olive oil that has a slightly cloudy appearance is called cloudy olive oil. This form of olive that was popular only amongst olive oil small scale producers is now becoming “trendy”, in line with consumer’s demand for more ecological and less-processed “green” products.
The remaining paste (pomace) still contains a small quantity (about 2-6%) of oil that cannot be extracted by further pressing, but only with chemical solvents. This is done in specialised chemical plants, not in the oil mills. The resulting oil is not “virgin” but “pomace oil”.
Benefits of Olive Oil
Olive oil is an excellent source of monounsaturated fatty acids, commonly referred to as MUFAs. Research has shown that monounsaturated fatty acids can lower low density lipoprotein (LDL), the so-called bad cholesterol. There is also evidence that it may increase high-density lipoprotein (HDL), the good cholesterol.
Another one of the benefits of olive oil is its high concentration of antioxidants. Antioxidants help slow down and prevent the oxidation of cells. By slowing down oxidation, it reduces the formation of free radicals, which damage cells.
An article published in the April 2002 issue of the European Journal of Clinical Nutrition found that olive oil was effective in as little as a week. When participants were given 25 ml, or approximately 2 tablespoons, per day of olive oil for one week, the researchers noted a reduction in LDL while levels of antioxidants increased.
Olive oil has digestive benefits as well. It initiates the release of pancreatic hormones and bile. This lowers the occurrence of gall stones. It also has protective benefits, helping to prevent both gastritis, a condition of stomach inflammation, and ulcers.
According to a study published in 2000 in Gut, there is a relationship between olive oil and colon cancer rates. Researchers supplemented rats with either olive oil or safflower oil. They found that the rats supplemented with olive oil had lower rates of colon cancer
There are other cancer-related benefits of olive oil. In Annals of Oncology in January 2005, researchers noted that olive oil contains a MUFA called oleic acid. This compound helps lower the effect of a specific gene, oncogene, that converts healthy cells to cancerous ones. The researchers indicated that oleic acid, when used in combination with drug therapy, made the cancer cells, especially those that are aggressive and typically resistant to treatment, self-destruct.
Diabetics can benefit from olive oil as well. One study found that when diabetics, or those at risk of diabetes, ate a low-fat, high carbohydrate diet supplemented with olive oil, blood sugar levels were controlled better. As it also helps reduce triglyceride levels, it reduces the risk of heart disease, which is common with diabetics.
Olive oil has anti-inflammatory benefits. The body converts the healthy fats in the oil to natural anti-inflammatory. This can help reduce arthritis and asthma. Olive oil has also been linked to lower rates of osteoporosis and dementia.
One of the most surprising benefits of olive oil is its effects on weight loss. In September 2003, researchers published a weight loss study in the British Journal of Nutrition. When dieters substituted olive oil for saturated fats in their diet, they lost weight and had a lower body mass index (BMI) than those that ate saturated fats. This was regardless of whether the dieters increased physical activity.
With health benefits and delicious flavor, you have nothing to lose with olive oil.