Olive oil

Olive oil is a type of vegetable oil made by pressing whole olives, the fruit of the Olea europaea tree, which grows in the Mediterranean Basin. People have been growing these trees for thousands of years.

Olive oil is very useful in cooking. It can be used for frying food, as a condiment, or as a salad dressing. It is also used in some cosmetics, pharmaceuticals, soaps, and even as fuels for old oil lamps. It is an important part of Mediterranean cuisine.

The taste and health benefits of olive oil can change depending on where the olives grow and how the oil is made. Extra virgin olive oil is considered the best quality.

History

Olive oil has been a big part of Mediterranean cuisine, including in ancient Greek and Roman cuisine for a very long time. Wild olives, which began in Asia Minor, were picked by people as far back as the 8th millennium BC. Besides eating, olive oil was used for special rituals, medicines, lighting oil lamps, making soap, and skincare.

We do not know exactly when and where olive trees were first grown. The modern olive tree may have started in ancient Persia and Mesopotamia and spread to the Levant and North Africa. Some think it began in Egypt.

The oldest signs of olive oil in Italy are from the 3rd millennium BC. Olive trees reached Greece, Carthage, and Libya around the 28th century BC, carried west by the Phoenicians. Olive farming grew in Crete and spread across the Mediterranean, reaching Spain and later the Roman Empire.

Olive trees were brought to the Americas in the 16th century, starting in places like Chile, Argentina, and California.

Archaeological finds in Galilee show olives were turned into oil as early as 6000 BC. Olive oil was traded and valued in ancient times, used in religious ceremonies and as wealth. It was a major export from Mycenaean Greece around 1450–1150 BC.

Olive oil production grew in Italy during the Roman time. Better ways to make olive oil, like screw presses, were used from Spain to the eastern Mediterranean. Some old presses from Roman times are still used today.

The olive tree has been a symbol of peace. In Greek mythology, it is linked to the city of Athens and the goddess Athena.

Varieties

Main article: List of olive cultivars

There are many kinds of olives. Each kind has its own taste, feel, and how long it stays good. Some olives are best eaten right away, like on bread or in salads. Others are better for cooking or even for animal food. As olives grow, they change color from green to violet and then to black. The taste of olive oil depends on when the olives are picked.

Uses

Olive oil is a common cooking oil in countries around the Mediterranean Sea. It is a main part of Mediterranean cuisine, with wheat for bread and pasta, and grapes for fruit and wine. Extra virgin olive oil is often used to add flavor to salads or other dishes. It can also be used for cooking when heated carefully.

Olive oil has special uses in many religions. In Christian churches, it is used in important ceremonies. In Judaism, olive oil was used for the menorah in the Temple, and it is a key part of the Hanukkah story.

Besides cooking, olive oil can be used to lubricate machines, light oil lamps, make soaps, and create some cosmetics. It also has uses in science and in special awards for writings about olive oil.

Extraction

Olive oil is made by crushing ripe olives and taking out the oil using machines. If olives are not ripe, the oil can taste bitter. If they are too ripe, the oil might not taste good.

First, olives are crushed into a paste. Then, this paste is pressed to get the oil out. The oil is separated from water using a fast spinning machine called a centrifuge. The oil made this way is called virgin oil. Extra virgin olive oil is a higher quality type that depends on good weather when the olives grow. Sometimes the oil is filtered to make it last longer, and unfiltered oil can look a little cloudy.

Global market

Production

In 2022, the world made about 2.7 million tonnes of olive oil. Spain made the most, with 24% of all the olive oil. Other big makers were Italy, Greece, Turkey, and Tunisia.

Villacarrillo, Jaén, in Andalucía, Spain, is a key place for making olive oil. About 75% of Spain’s olive oil comes from Andalucía, especially from Jaén province. The biggest olive oil mill in the world is in Villacarrillo, Jaén. It can process many olives each day.

In Italy, the main areas for olive oil are Calabria and Apulia. These places make many special olive oils. Extra-virgin olive oil is also made in Tuscany, in cities like Lucca, Florence, and Siena. Italy buys a lot of olive oil from Spain.

Global consumption

Greece uses the most olive oil per person in the world. Spain, Italy, and Syria also use a lot. Canada and the US use less.

Regulation

The International Olive Council is a group of countries that grow olives or make olive oil. It controls most of the world's olive oil production. The European Union has special rules for labeling olive oil.

The United States is not part of the International Olive Council, but in 2010, the U.S. Department of Agriculture made new rules for grading olive oil. These rules are similar to the International Olive Council's but adjusted for American olives. U.S. rules say that if a label says "imported from Italy," the real origin must also be shown clearly on the bottle.

Commercial grades

Making olive oil starts by crushing or pressing olives to make olive paste. This paste is mixed to bring the oil together, then separated from the rest using a press or a machine called a centrifuge. Some oil can also be made from the leftover material, called pomace.

The quality of olive oil is measured in two main ways. Acidity tells us how much free oleic acid is in the oil, which increases as the oil gets older and breaks down. Another measure is the peroxide value, which shows how much the oil has changed due to exposure to air and light.

Olive oil can be grouped into different grades based on how it was made and its quality:

• Virgin olive oil is made only by pressing the olives, without using chemicals. This includes extra virgin, virgin, ordinary virgin, and Lampante virgin oil.
• Lampante virgin oil is made by pressing olives but needs more processing before it can be used as food. It can be used for things like lighting lamps or made into edible oil.
• Refined olive oil is made from any virgin olive oil after cleaning it to remove color, smell, and taste. It is very pure and has almost no smell or taste.
• Crude olive pomace oil is made from the leftover material after pressing olives. It is cleaned and mixed with virgin oil to make olive pomace oil.

International Olive Council

In countries that follow the International Olive Council rules, and in Australia, as well as under U.S. Department of Agriculture rules in the United States:

Extra virgin olive oil is the highest quality. It has no more than 0.8% free acidity and tastes great with no bad flavors. It is made without using heat or chemicals.

Virgin olive oil is a lower grade, with up to 2.0% free acidity. It tastes good but might have some off flavors.

Refined olive oil is cleaned virgin oil. It has no more than 0.3% free acidity and tastes neutral.

Olive pomace oil is made from cleaned pomace oil and often mixed with virgin oil. It tastes milder but has the same health benefits.

United States

The United States has its own grading rules, similar to the International Olive Council’s:

• U.S. extra virgin olive oil has excellent taste and smell, with no more than 0.8% free acidity.
• U.S. virgin olive oil has good taste and smell, with no more than 2% free acidity.
• U.S. virgin olive oil Not Fit For Human Consumption Without Further Processing needs more processing before it can be eaten.
• U.S. olive oil is a mix of virgin and refined oils.
• U.S. refined olive oil is made from refined oils with some processing limits.

These grades are voluntary, but farmers can pay to get certification from the USDA.

In 2014, California made its own rules for olive oil made from California-grown olives. These rules are required for makers of more than 5,000 gallons of olive oil.

Country codes like I for Italy, GR for Greece, and E for Spain can be found on labels to show where the oil comes from.

Label wording

Different names for olive oil tell us how it was processed and its quality. Extra virgin olive oil is the best quality. Virgin olive oil means the olives were pressed without heat or chemicals.

Olive Oil may be a mix of refined and virgin oils. Words like Pure, Classic, Light, and Extra-Light mean the oil is 100% olive oil but can taste different.

Cold pressed or Cold extraction means the oil was not heated above a certain temperature during making. In Europe, oil made with a machine must be called Cold Extracted, while oil pressed by hand can be called Cold Pressed.

First cold pressed means the olives were crushed only once. It does not mean there is a “second” pressing.

Protected designation of origin (PDO) and protected geographical indication (PGI) are for oils with special qualities from their place of origin.

Labels may say where the oil was bottled, but this does not always mean it was made there. The real origin might be listed somewhere else on the label.

The U.S. Food and Drug Administration allows a claim that eating about two tablespoons of olive oil daily may help reduce the risk of heart disease.

Adulteration

Some places, like Italy and Spain, have had problems with olive oil being mixed with cheaper oils or falsely labeled as higher-quality oil. This can mislead customers. Authorities work to catch and stop these practices to protect consumers.

Constituents

Olive oil is made mostly of a mix of triglyceride esters from oleic acid, linoleic acid, palmitic acid, and other fatty acids. It also has small amounts of squalene (up to 0.7%) and sterols (about 0.2%, including phytosterol and tocosterols). What olive oil contains can change depending on the type of olive, where it’s grown, how high up it is, when it’s picked, and how it’s made.

Comparison to other vegetable oils

Phenolic composition

Olive oil has tiny amounts of polyphenols (about 0.5%), such as esters of tyrosol, hydroxytyrosol, oleocanthal, and oleuropein. These give olive oil a slightly bitter taste and a special smell. Olive oil includes many polyphenols, such as elenolic acid, which shows that olives are fully grown, and alpha-tocopherol, a type of vitamin E. Oleuropein and similar compounds like 10-hydroxyoleuropein, ligstroside, and 10-hydroxyligstroside are also tyrosol esters of elenolic acid. Other helpful parts in olive oil include flavonoids, lignans, and pinoresinol.

Polyphenols are good for health but can break down, especially with heat. It’s best to process the olives soon after picking them and keep them away from oxygen. Storing the oil in a dark glass container at a cool temperature or even in the fridge helps keep the polyphenols. When cooking with olive oil at high temperatures, the polyphenols decrease.

If olive oil tastes peppery or bitter, it usually means it has more polyphenols.

Nutrition

Olive oil is made of fat. It does not have carbohydrates, dietary fiber, protein, or water. In 100 grams of olive oil, there are 884 calories and lots of vitamin E and vitamin K.

One tablespoon of olive oil has 119 calories. It contains different types of fats, including monounsaturated fat, polyunsaturated fat, and a little saturated fat.

Potential health effects

See also: Mediterranean diet

In the United States, the FDA says olive oil makers can tell people that eating about 2 tablespoons of olive oil each day may help lower the risk of heart disease. This is because olive oil has healthy fats that can replace less healthy fats in your food.

Studies show that eating olive oil may help keep your heart healthy. Some research suggests it might lower the chance of heart problems and strokes. But more studies are needed to learn more about how olive oil affects health.