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| A bottle of Italian olive oil |
Olive oil
From Wikipedia, the free encyclopedia
Not to be confused with the cartoon character Olive Oyl.
| Fat composition | |
|---|---|
| Saturated fats | |
| Total saturated | Palmitic acid: 13.0% Stearic acid: 1.5%<br / |
| Unsaturated fats | |
| Total unsaturated | yes |
| Monounsaturated | Oleic acid: 70.0% Palmitoleic acid: 0.3–3.5% |
| Polyunsaturated | Linoleic acid: 15.0 % α-Linolenic acid: 0.5% |
| Properties | |
| Food energy per 100 g (3.5 oz) | 3,700 kJ (880 kcal) |
| Melting point | −6.0 °C (21.2 °F) |
| Boiling point | 300 °C (572 °F) |
| Smoke point | 190 °C (374 °F) (virgin) 210 °C (410 °F) (refined) |
| Specific gravity at 20 °C (68 °F) | 911 kg/m3 |
| Viscosity at 20 °C (68 °F) | 84 cP |
| Refractive index | 1.4677–1.4705 (virgin and refined) 1.4680–1.4707 (pomace) |
| Iodine value | 75–94 (virgin and refined) 75–92 (pomace) |
| Acid value | maximum: 6.6 (refined and pomace) 0.6 (extra-virgin) |
| Saponification value | 184–196 (virgin and refined) 182–193 (pomace) |
| Peroxide value | 20 (virgin) 10 (refined and pomace) |
Olive oil is a fat obtained from the olive (the fruit of Olea europaea; family Oleaceae), a traditional tree crop of the Mediterranean Basin. The oil is produced by pressing whole olives.
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 countries and, in particular, in Portugal, Spain, Italy and Greece, which has the highest consumption per person.
History
Early cultivation
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 or in ancient Greece. 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 and Israel to modern Turkey in the 4th millennium, or somewhere in the Mesopotamian Fertile Crescent in the 3rd millennium. |
| Ancient Greek olive oil production workshop in Klazomenai, Ionia (modern Turkey) |
Archeological evidence shows that olives were turned into oil by 4500 BC by Canaanites in present-day Israel. Until 1500 BC, eastern coastal areas of the Mediterranean were most heavily cultivated. Evidence also suggests that olives were being grown in Crete as long ago as 2,500 BC. 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. 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, as it did across the Mediterranean.
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.
Production and trade
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| Ancient oil press (Bodrum Museum of Underwater Archaeology, Bodrum, Turkey) |
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.
Besides food, olive oil has been used for religious rituals, medicines, as a fuel in oil lamps, soap-making, and skin care application. 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.[citation needed] Olive tree growing reached Iberia and Etruscan cities well before the 8th century BC through trade with the Phoenicians and Carthage, then was 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.[citation needed] 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, an 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.
Many ancient presses still exist in the Eastern Mediterranean region, and some dating to the Roman period are still in use today.[citation needed]
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| Olive crusher (trapetum) in Pompeii (79 AD) |
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| The Manufacture of Oil, 16th century engraving by J. Amman |
Varieties
Main article: List of olive cultivars
There are many different olive varieties or olives,
each with a particular flavor texture and shelf-life that make them
more or less suitable for different applications such as direct human
consumption on bread or in salads, indirect consumption in domestic
cooking or catering, or industrial uses such as animal feed or
engineering applications.Production and consumption
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| Oil press in the Israeli settlement Katzrin. |
Australia now produces a substantial amount of olive oil. Many Australian producers only make premium oils, while 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, Europe and the United States.
In North America, Italian and Spanish olive oils are the best-known, and top-quality extra-virgin oils from Italy, Spain, Portugal 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.
Turkey, New Zealand, The Republic of South Africa, Argentina and Chile also produce extra virgin olive oil.
Olive orchards in Arizona, California, and Texas are producing olive oil that is appearing on U.S. grocery market shelves alongside the Mediterranean olive oils.
| Country | 2000 (tonnes) | % | 2005 ( tonnes) | % | 2009 ( tonnes) | % |
|---|---|---|---|---|---|---|
 Spain |
962,400 | 38.2% | 819,428 | 32.1% | 1,199,200 | 41.2% |
 Italy |
507,400 | 20.1% | 671,315 | 26.3% | 587,700 | 20.2% |
 Greece |
408,375 | 16.2% | 386,385 | 15.1% | 332,600 | 11.4% |
 Syria |
165,354 | 6.6% | 123,143 | 4.8% | 168,163 | 5.8% |
 Tunisia |
115,000 | 4.6% | 210,000 | 8.2% | 150,000 | 5.2% |
 Turkey |
185,000 | 7.3% | 115,000 | 4.5% | 143,600 | 4.9% |
 Morocco |
40,000 | 1.6% | 50,000 | 2.0% | 95,300 | 3.3% |
 Algeria |
30,488 | 1.2% | 34,694 | 1.4% | 56,000 | 1.9% |
 Portugal |
25,974 | 1.0% | 31,817 | 1.2% | 53,300 | 1.8% |
 Argentina |
10,500 | 0.4% | 20,000 | 0.8% | 22,700 | 0.8% |
 Lebanon |
5,300 | 0.2% | 6,800 | 0.3% | 19,700 | 0.7% |
 Jordan |
27,202 | 1.1% | 17,458 | 0.7% | 16,760 | 0.6% |
 Libya |
6,000 | 0.2% | 7,900 | 0.3% | 15,000 | 0.5% |
| TOTAL | 2,518,629 | 100.0% | 2,552,182 | 100.0% | 2,911,115 | 100% |
| FAO | ||||||
Regulation
Main article: Olive oil regulation and adulteration
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| International Olive Council building |
The United States is not a member of the IOC and is not subject to its authority, but on October 25, 2010, the U.S. Department of Agriculture adopted new voluntary olive oil grading standards that closely parallel those of the IOC, with some adjustments for the characteristics of olives grown in the U.S. Additionally, U.S. Customs regulations on "country of origin" state that if a non-origin nation is shown on the label, then the real origin must be shown on the same side of the label and in comparable size letters so as not to mislead the consumer. Yet most major U.S. brands continue to put "imported from Italy" on the front label in large letters and other origins on the back in very small print. "In fact, olive oil labeled 'Italian' often comes from Turkey, Tunisia, Morocco, Spain, and Greece." This makes it unclear what percentage of the olive oil is really of Italian origin.
Commercial grades
All production begins by transforming the olive fruit into olive paste by crushing or pressing. This paste is then malaxed (slowly churned or mixed) to allow the microscopic oil droplets to agglomerate. The oil is then separated from the watery matter and fruit pulp with the use of a press (traditional method) or centrifugation (modern method). After extraction the remnant solid substance, called pomace, still contains a small quantity of oil.The grades of oil extracted from the olive fruit can be classified as:
- Virgin means the oil was produced by the use of mechanical means only, with no chemical treatment. The term virgin oil with reference to production method includes both Virgin and Extra-Virgin olive oil products, depending on quality (see next section).
- Lampante oil is olive oil extracted by virgin (mechanical) methods but not suitable as food; lampante is Italian for "lamp", referring to the use of such oil for burning in lamps. Lampante oil can be used for industrial purposes, or refined (see below) to make it edible.
- Refined means that the oil has been chemically treated to neutralize strong tastes (characterized as defects) and neutralize the acid content (free fatty acids). Virgin olive oil (including the grades extra-virgin olive oil and virgin olive oil) therefore cannot contain any refined oil.
- Olive pomace oil means oil extracted from the pomace using solvents, mostly hexane, and by heat.
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| Italian label for "extra vergine" oil |
- Extra-virgin olive oil Comes from virgin oil production only, and is of higher quality: among other things, it contains no more than 0.8% free acidity (see below), and is judged to have a superior taste, having some fruitiness and no defined sensory defects. Extra-virgin olive oil accounts for less than 10% of oil in many producing countries; the percentage is far higher in the Mediterranean countries (Greece: 80%, Italy: 65%, Spain 30%).
- Virgin olive oil Comes from virgin oil production only, but is of slightly lower quality, with free acidity of up to 1.5%, and is judged to have a good taste.
- Refined olive oil is the olive oil obtained from virgin olive oils by refining methods that do not lead to alterations in the initial glyceridic structure. It has a free acidity, expressed as oleic acid, of not more than 0.3 grams per 100 grams (0.3%) and its other characteristics correspond to those fixed for this category in this standard. This is obtained by refining virgin olive oils with a high acidity level and/or organoleptic defects that are eliminated after refining. Note that no solvents have been used to extract the oil, but it has been refined with the use of charcoal and other chemical and physical filters. Oils labeled as Pure olive oil or Olive oil are primarily refined olive oil, with a small addition of virgin-production to give taste.
- Olive pomace oil is refined pomace olive oil often blended with some virgin oil. It is fit for consumption, but may not be described simply as olive oil. It has a more neutral flavor than pure or virgin olive oil, making it unfashionable among connoisseurs; however, it has the same fat composition as regular olive oil, giving it the same health benefits. It also has a high smoke point, and thus is widely used in restaurants as well as home cooking in some countries.
Retail grades in the United States from the USDA
As the United States is not a member, the IOC retail grades have no legal meaning in that country, but as of October 25, 2010, the USDA established new Standards for Grades of Olive Oil and Olive-Pomace Oil, which closely parallel the IOC standards:- U.S. Extra Virgin Olive Oil for oil with excellent flavor and odor and free fatty acid content of not more than 0.8 g per 100 g (0.8%);
- U.S. Virgin Olive Oil for oil with reasonably good flavor and odor and free fatty acid content of not more than 2 g per 100 g (2%);
- U.S. Virgin Olive Oil Not Fit For Human Consumption Without Further Processing is a virgin (mechanically-extracted) olive oil of poor flavor and odor, equivalent to the IOC's lampante oil;
- U.S. Olive Oil is an oil mix of both virgin and refined oils;
- U.S. Refined Olive Oil is an oil made from refined oils with some restrictions on the processing.
Quantitative analysis can determine the oil's "acidity", which refers not to its chemical acidity in the sense of pH but as the percent (measured by weight) of free oleic acid. This is a measure of the hydrolysis of the oil's triglycerides: as the oil degrades, more fatty acids are freed from the glycerides, increasing the level of free acidity and thereby increasing hydrolytic rancidity. Another measure of the oil's chemical degradation is the peroxide value, which measures the degree to which the oil is oxidized (damaged by free radicals, leading to oxidative rancidity.
To classify it by taste, olive oil is judged by a panel of trained tasters in a blind taste test. This is also called its organoleptic quality.
Label wording
- Different names for olive oil indicate the degree of processing the oil has undergone as well as the quality of the oil. Extra-virgin olive oil is the highest grade available, followed by virgin olive oil. The word "virgin" indicates that the olives have been pressed to extract the oil; no heat or chemicals have been used during the extraction process, and the oil is pure and unrefined. Virgin olive oils contain the highest levels of polyphenols, antioxidants that have been linked with better health.
- "Made from refined olive oils" means that the taste and composition are chemically controlled, usually to improve lower quality oils. In Australia, Pure, Light and Extra-Light are terms introduced by manufacturers for refined oils to avoid labeling them as such. Standards Australia's code of practice for olive oil now recognises these words as meaning refined oil. Contrary to a common consumer belief, they do not have less calories than Extra-virgin oil as implied by the names.
- Cold pressed or Cold extraction means "that the oil was not heated over a certain temperature (usually 80 °F (27 °C)) during processing, thus retaining more nutrients and undergoing less degradation".
- First cold pressed means "that the fruit of the olive was crushed exactly one time-i.e., the first press. The cold refers to the temperature range of the fruit at the time it is crushed".
In Calabria (Italy) the olives are collected in October. In regions
like Tuscany or Liguria, the olives collected in November and ground
often at night are too cold to be processed efficiently without heating.
The paste is regularly heated above the environmental temperatures,
which may be as low as 10–15 °C, to extract the oil efficiently with
only physical means. Olives pressed in warm regions like Southern Italy
or Northern Africa may be pressed at significantly higher temperatures
although not heated. While it is important that the pressing
temperatures be as low as possible (generally below 25 °C) there is no
international reliable definition of "cold pressed".
Furthermore, there is no "second" press of virgin oil, so the term "first press" means only that the oil was produced in a press vs. other possible methods. - PDO and PGI refers to olive oils with "exceptional properties and quality derived from their place of origin as well as from the way of their production".
- The label may indicate that the oil was bottled or packed in a stated country. This does not necessarily mean that the oil was produced there. The origin of the oil may sometimes be marked elsewhere on the label; it may be a mixture of oils from more than one country.
- The U.S. Food and Drug Administration permitted a claim on olive oil labels stating: "Limited and not conclusive scientific evidence suggests that eating about two tablespoons (23 g) of olive oil daily may reduce the risk of coronary heart disease."
Adulteration
The adulteration of oil can be no more serious than passing off inferior, but safe, product as superior olive oil, but there are no guarantees. It is guessed that almost 700 people died in 1981 as a consequence of consuming rapeseed oil adulterated with aniline intended for use as an industrial lubricant, but sold as olive oil in Spain (see toxic oil syndrome).There have been allegations, particularly in Italy and Spain, that regulation can be sometimes lax and corrupt. Major shippers are claimed to routinely adulterate olive oil and that only about 40% of olive oil sold as "extra virgin" in Italy actually meets the specification. In some cases, colza oil (Swedish turnip) with added color and flavor has been labeled and sold as olive oil. This extensive fraud prompted the Italian government to mandate a new labeling law in 2007 for companies selling olive oil, under which every bottle of Italian olive oil would have to declare the farm and press on which it was produced, as well as display a precise breakdown of the oils used, for blended oils. In February 2008, however, EU officials took issue with the new law, stating that under EU rules such labeling should be voluntary rather than compulsory. Under EU rules, olive oil may be sold as Italian even if it only contains a small amount of Italian oil.
Extra Virgin olive oil has strict requirements and is checked for "sensory defects" that include: rancid, fusty, musty, winey (vinegary) and muddy sediment. These defects can occur for different reasons. The most common are:
- Raw material (olives) infected or battered
- Inadequate harvest, with contact between the olives and soil
On March 15, 2011, the Florence, Italy prosecutor's office, working in conjunction with the forestry department, indicted two managers and an officer of Carapelli, one of the brands of the Spanish company Grupo SOS (which recently changed its name to Deoleo). The charges involved falsified documents and food fraud. Carapelli lawyer Neri Pinucci said the company was not worried about the charges and that "the case is based on an irregularity in the documents."
In February 2012, an alleged international olive oil scam occurred in which palm, avocado, sunflower and other cheaper oils were passed off as Italian olive oil. Police said the oils were blended in an industrial biodiesel plant and adulterated in a way to hide markers that would have revealed their true nature. The oils were not toxic, however, and posed no health risk, according to a statement by the Guardia Civil. Nineteen people were arrested following the year-long joint probe by the police and Spanish tax authorities, part of what they call Operation Lucerna.
Global consumption
Greece has by far the largest per capita consumption of olive oil worldwide, over 26 liters per person per year; Spain and Italy, around 14 l; Tunisia, Portugal, Syria, Jordan and Lebanon, around 8 l. Northern Europe and North America consume far less, around 0.7 l, but the consumption of olive oil outside its home territory has been rising steadily.Global market
The main producing and consuming countries are:| Country | Production in tons (2010) | Production % (2010) | Consumption (2005) | Annual per capita consumption (kg) |
|---|---|---|---|---|
| World | 3,269,248 | 100% | 100% | 0.43 |
| Spain | 1,487,000 | 45.5% | 20% | 13.62 |
| Italy | 548,500 | 16.8% | 30% | 12.35 |
| Greece | 352,800 | 10.8% | 9% | 23.7 |
| Syria | 177,400 | 5.4% | 3% | 7 |
| Morocco | 169,900 | 5.2% | 2% | 11.1 |
| Turkey | 161,600 | 4.9% | 2% | 1.2 |
| Tunisia | 160,100 | 4.9% | 2% | 5 |
| Portugal | 66,600 | 2.0% | 2% | 1.8 |
| Algeria | 33,600 | 1.0% | 2% | 7.1 |
| Others | 111,749 | 3.5% | 28% | 1.18 |
Extraction
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| A cold press olive oil machine in Israel. |
Main article: Olive oil extraction
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:- The olives are ground into paste using large millstones (traditional method) or steel drums (modern method).
- 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 thorough. 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.
- 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 above 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). A higher grade extra virgin olive oil is mostly dependent on favourable weather conditions; a drought during the flowering phase, for example, can result in a lower quality (virgin) oil. It is worth noting that olive trees produce well every couple of years so greater harvests occur in alternate years (the year in-between is when the tree yields less). However the quality is still dependent on the weather. - 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 oil used to be popular only among olive oil small scale producers but is now becoming "trendy", in line with consumer's demand for more ecological and less-processed "green" products.
The label term "cold-extraction" on extra virgin olive oils indicates that the olive grinding and stirring was done at a temperature of maximum 25 °C (77 °F), as treatment in higher temperatures risks decreasing the olive oils' quality (texture, taste and aroma).
Constituents
Olive oil is composed mainly of the mixed triglyceride esters of oleic acid and palmitic acid and of other fatty acids, along with traces of squalene (up to 0.7%) and sterols (about 0.2% phytosterol and tocosterols). The composition varies by cultivar, region, altitude, time of harvest, and extraction process.
| Fatty acid | Percentage | ref. |
|---|---|---|
| Oleic acid | 55 to 83% | |
| Linoleic acid | 3.5 to 21% | |
| Palmitic acid | 7.5 to 20% | |
| Stearic acid | 0.5 to 5% | |
| α-Linolenic acid | 0 to 1.5% |
Phenolic composition
Olive oil contains phenolics such as esters of tyrosol and hydroxytyrosol, including oleocanthal and oleuropein, having acidic properties that give extra-virgin unprocessed olive oil its bitter and pungent taste. Olive oil is a source of at least 30 phenolic compounds. Elenolic acid is a component of olive oil and olive leaf extract. It can be considered as a marker for maturation of olives. Oleuropein, together with other closely related compounds such as 10-hydroxyoleuropein, ligstroside and 10-hydroxyligstroside, are tyrosol esters of elenolic acid.Both hydroxytyrosol and its precursor oleuropein exist in the fruit at levels on the order of 100 times that of shelf extra virgin olive oil. Phenolics are considerably higher in fresh cloudy olive oil than extra virgin that has been separated and aged.
Other phenolic constituents include aldehydic secoiridoids, flavonoids and lignans (acetoxypinoresinol, pinoresinol). The latter two compounds are only present in extra virgin oil.
Health benefits
Hydroxytyrosol (2-(3,4-Di-hydroxyphenyl)-ethanol or DHPE) is a phenolic component of extra-virgin olive oil. An olive oil fraction containing DHPE was shown to inhibit platelet aggregation and eicosanoid (thromboxane B2) formation in vitro.Oleocanthal from olive oil is a non-selective inhibitor of cyclooxygenase (COX) similar to classical NSAIDs like ibuprofen. It has been suggested that long-term consumption of small quantities of this compound from olive oil may be responsible in part for the low incidence of heart disease associated with a Mediterranean diet.
Nutrition
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 3,701 kJ (885 kcal) |
|
0 g
|
|
|
100 g
|
|
| Saturated | 14 g |
| Monounsaturated | 73 g |
| Polyunsaturated | 11 g
<1.5 g
3.5–21 g
|
|
0 g
|
|
| Vitamins | |
| Vitamin E |
(93%)
14 mg |
| Vitamin K |
(59%)
62 μg |
|
100 g olive oil is 109 ml
|
|
|
|
| Percentages are roughly approximated using US recommendations for adults. Source: USDA Nutrient Database |
|
As they are the least processed forms of olive oil, extra virgin or virgin olive oil have more monounsaturated fatty acids than other olive oil. These types also contain more polyphenols, which may have benefits for the heart.
One tablespoon of olive oil (13.5 g) contains the following nutritional information according to the USDA:
- Calories : 119
- Fat: 13.50
- Carbohydrates: 0
- Fibers: 0
- Protein: 0
Popular uses and research
Skin
Olive oil has a long history of being used as a home remedy for skincare. Egyptians used it alongside beeswax as a cleanser, moisturizer, and antibacterial agent since pharaonic times. In ancient Greece, the substance was used during massage, to prevent sports injuries, relieve muscle fatigue, and eliminate lactic acid buildup. In 2000, Japan was the top importer of olive oil in Asia (13,000 tons annually) because consumers there believe both the ingestion and topical application of olive oil to be good for skin and health.There has been relatively little scientific work done on the effect of olive oil on acne and other skin conditions. However, one study noted that the abundance of squalene in oils in general shows promise for sufferers of seborrheic dermatitis, acne, psoriasis, and atopic dermatitis. Squalene is used as an antioxidant, moisturizer, and as a convenient vehicle to carry other substances in topical application. Another researcher reported that a mixture of honey, beeswax, and olive oil alleviates diaper dermatitis, psoriasis, and eczema by inhibiting the growth of Staphylococcus aureus and Candida albicans.
Olive oil is popular for use in massaging infants and toddlers, but scientific proof of its efficacy is mixed. One analysis of olive oil versus mineral oil found that, when used for infant massage, olive oil can be considered a safe alternative to sunflower, grapeseed and fractionated coconut oils. This stands true particularly when it is mixed with a lighter oil like sunflower, which "would have the further effect of reducing the already low levels of free fatty acids present in olive oil". The study also notes that there appears to be much confusion surrounding mineral oil, and that further studies should be done on refined mineral oil to back up claims about its superiority to olive oil. Another trial echoes this claim, stating that olive oil lowers the risk of dermatitis for infants in all gestational stages when compared with emollient cream. However, yet another study found that topical treatment with olive oil for newborns "significantly damages the skin barrier" when compared to sunflower oil, and that it may make existing atopic dermatitis worse. The researchers conclude that they do not recommend the use of olive oil for the treatment of dry skin and infant massage.
Clinical trials have found that olive oil does not act to prevent or reduce stretch marks.
The fatty substance was found to reduce inflammation via oleuropein, which is touted for its antioxidant, anti-atherosclerotic, and anti-inflammatory characteristics.
Potential health effects attributed to fat composition
Preliminary clinical studies provide evidence that consumption of olive oil may lower risk of heart disease risk factors such as lower blood cholesterol levels and reduced LDL cholesterol oxidation, and that it may also possibly influence inflammatory, thrombotic, hypertensive and vasodilatory mechanisms. Although epidemiological studies indicate that a higher proportion of monounsaturated fats in the diet may be linked with a reduction in the risk of coronary heart disease, a cause and effect relationship has not yet been established with sufficient scientific evidence.In the United States, producers of olive oil may place the following restricted health claim on product labels:
- Limited and not conclusive scientific evidence suggests that eating about 2 tbsp. (23 g) of olive oil daily may reduce the risk of coronary heart disease due to the monounsaturated fat in olive oil. To achieve this possible benefit, olive oil is to replace a similar amount of saturated fat and not increase the total number of calories you eat in a day.
Other possible effects of olive oil may be a property to balance omega-6 fats and omega-3 fats[citation needed] and to affect blood sugar levels and blood pressure, but these effects were dismissed in reviews by the Scientific Committee of the European Food Safety Authority.
Olive oil contains the monounsaturated fatty acid oleic acid, vitamin E and oleuropein, a chemical that may affect the oxidation of LDL particles.
Preliminary research indicates that olive oil could possibly be a chemopreventive agent for peptic ulcer or gastric cancer, but confirmation requires further in vivo study. Pilot studies showed that olive oil may reduce oxidative damage to DNA and RNA, revealing a possible anti-carcinogenic factor. Consumption of olive oil may prevent the onset of Alzheimer's disease, possibly through a mechanism related to oleocanthal inhibiting fibrillization of tau protein.
See also: Alzheimer's disease and diet
Uses
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This section needs additional citations for verification. (August 2012) |
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| Olives in olive oil |
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| Vinegar and olive oil |
Culinary use
Olive oil is the main cooking oil in countries surrounding the Mediterranean Sea.Extra virgin olive oil is mostly used as a salad dressing and as an ingredient in salad dressings. It is also used with foods to be eaten cold. If uncompromised by heat, the flavor is stronger. It also can be used for sautéing.
The higher the temperature to which the olive oil is heated, the higher the risk of compromising its taste. When extra virgin olive oil is heated above 210–216 °C (410–421 °F), depending on its free fatty acid content, the unrefined particles within the oil are burned. This leads to deteriorated taste. Also, the pronounced taste of extra virgin olive oil is not a taste most people like to associate with their deep fried foods. Refined olive oils are perfectly suited for deep frying foods and should be replaced after several uses.[citation needed]
Choosing a cold-pressed olive oil can be similar to selecting a wine. The flavor of these oils varies considerably and a particular oil may be more suited for a particular dish. Also, people who like lots of tannins in their red wines might prefer more bitter olive oils.
An important issue often not realized in countries that do not produce olive oil is that the freshness makes a big difference. A very fresh oil, as available in an oil producing region, tastes noticeably different from the older oils available elsewhere. In time, oils deteriorate and become stale. One-year old oil may be still pleasant to the taste, but it is surely less fragrant than fresh oil. After the first year, olive oil should be used for cooking, not for foods to be eaten cold, like salads.
The taste of the olive oil is influenced by the varietals used to produce the oil from and by the moment when the olives are harvested and ground (less ripe olives give more bitter and spicy flavors - riper olives give a sweeter sensation in the oil).
For certain culinary uses, olive oil may be substituted with safflower or sunflower oils, canola oil, peanut oil, sesame oil, or coconut oil.
Olive oil has various non-culinary uses as well. For example, it is also a natural and safe lubricant, and can be used to lubricate machinery that is used within the kitchen (grinders, blenders, cookware, etc.) It can also be used for illumination (oil lamps) or as the base for soaps and detergents. Some cosmetics also use olive oil as their base.
| Vegetable oils | |||||||
|---|---|---|---|---|---|---|---|
| Type | Saturated fatty acids |
Mono- unsaturated fatty acids |
Polyunsaturated fatty acids | Oleic acid (ω-9) |
Smoke point | ||
| Total poly | linolenic acid (ω-3) |
Linoleic acid (ω-6) |
|||||
| Not hydrogenated | |||||||
| Canola (rapeseed) | 7.365 | 63.276 | 28.142 | 9-11 | 19-21 | — | 400 °F (204 °C) |
| Coconut | 91.00 | 6.000 | 3.000 | — | 2 | 6 | 350 °F (177 °C) |
| Corn | 12.948 | 27.576 | 54.677 | 1 | 58 | 28 | 450 °F (232 °C) |
| Cottonseed | 25.900 | 17.800 | 51.900 | 1 | 54 | 19 | 420 °F (216 °C) |
| Flaxseed/Linseed (European) | 6–9 | 10–22 | 68–89 | 56–71 | 12–18 | 10–22 | 225 °F (107 °C) |
| Olive | 14.00 | 72.00 | 14.00 | <1.5 | 9–20 | — | 380 °F (193 °C) |
| Palm | 49.300 | 37.000 | 9.300 | — | 10 | 40 | 455 °F (235 °C) |
| Peanut | 16.900 | 46.200 | 32.000 | — | 32 | 48 | 437 °F (225 °C) |
| Safflower (>70% linoleic) |
8.00 | 15.00 | 75.00 | — | — | — | 410 °F (210 °C) |
| Safflower (high oleic) |
7.541 | 75.221 | 12.820 | — | — | — | 410 °F (210 °C) |
| Soybean | 15.650 | 22.783 | 57.740 | 7 | 50 | 24 | 460 °F (238 °C) |
| Sunflower (<60% linoleic) |
10.100 | 45.400 | 40.100 | 0.200 | 39.800 | 45.300 | 440 °F (227 °C) |
| Sunflower (>70% oleic) |
9.859 | 83.689 | 3.798 | — | — | — | 440 °F (227 °C) |
| Fully hydrogenated | |||||||
| Cottonseed (hydrog.) | 93.600 | 1.529 | .587 | .287 | |||
| Palm (hydrogenated) | 47.500 | 40.600 | 7.500 | ||||
| Soybean (hydrogen.) | 21.100 | 73.700 | .400 | .096 | |||
| Values as percent (%) by weight of total fat. | |||||||
Religious use
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| Olive tree in Portugal |
Olive oil also has religious symbolism for healing and strength and to consecration— setting a person or place apart for special work. This may be related to its ancient use as a medicinal agent and for cleansing athletes by slathering them in oil then scraping them.
Judaism
In Jewish observance, olive oil is the only fuel allowed to be used in the seven-branched Menorah in the Mishkan service during the Exodus of the tribes of Israel from Egypt, and later in the permanent Temple in Jerusalem. It was obtained by using only the first drop from a squeezed olive and was consecrated for use only in the Temple by the priests and stored in special containers. A menorah similar to the Menorah used in the Mishkan is now used during the holiday of Hanukkah that celebrates the miracle of the last of such containers being found during the re-dedication of the Temple (163 BC), when its contents lasted for far longer than they were expected to, allowing more time for more oil to be made. Although candles can be used to light the hanukkiah, oil containers are preferred, to imitate the original Menorah. Another use of oil in Jewish religion is for anointing the kings of the Kingdom of Israel, originating from King David. Tzidkiyahu was the last anointed King of Israel.Christianity
The Catholic and Orthodox Churches use olive oil for the Oil of Catechumens (used to bless and strengthen those preparing for Baptism) and Oil of the Sick (used to confer the Sacrament of Anointing of the Sick or Unction). Olive oil mixed with a perfuming agent such as balsam is consecrated by bishops as Sacred Chrism, which is used to confer the sacrament of Confirmation (as a symbol of the strengthening of the Holy Spirit), in the rites of Baptism and the ordination of priests and bishops, in the consecration of altars and churches, and, traditionally, in the anointing of monarchs at their coronation. The Church of Jesus Christ of Latter-day Saints (Mormons) and a number of other religions use olive oil when they need to consecrate an oil for anointings.Eastern Orthodox Christians still use oil lamps in their churches, home prayer corners and in the cemeteries. A vigil lamp consists of a votive glass containing a half-inch of water and filled the rest with olive oil. The glass has a metal holder that hangs from a bracket on the wall or sits on a table. A cork float with a lit wick floats on the oil. To douse the flame, the float is carefully pressed down into the oil. Makeshift oil lamps can easily be made by soaking a ball of cotton in olive oil and forming it into a peak. The peak is lit and then burns until all the oil is consumed, whereupon the rest of the cotton burns out. Olive oil is a usual offering to churches and cemeteries.
In the Orthodox Church, olive oil is a product not consumed during lent or penance while Orthodox monks use it sparingly in their diet. Exceptions are in feast days and Sundays.
Islam
In Islam, olive oil is mentioned in the Quranic verse:"Allah is the Light of the heavens and the earth. The parable of His Light is as (if there were) a niche and within it a lamp: the lamp is in a glass, the glass as it were a brilliant star, lit from a blessed tree, an olive, neither of the east (i.e. neither it gets sun-rays only in the morning) nor of the west (i.e. nor it gets sun-rays only in the afternoon, but it is exposed to the sun all day long), whose oil would almost glow forth (of itself), though no fire touched it. Light upon Light! Allah guides to His Light whom He wills. And Allah sets forth parables for mankind, and Allah is All-Knower of everything." ( سورة النور , An-Noor, Chapter #24, Verse #35)
Other
- Olive oil may be used in soap making, as lamp oil, a lubricant, or as a substitute for machine oil.
- Olive oil has also been used as both solvent and ligand in the synthesis of cadmium selenide quantum dots.
- In one study, monounsaturated fats such as from olive oil benefited mood, decreased anger, and increased physical activity.
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