Olive and Olive Oil

Olive is well-known fruit used by mankind for 4000 years. In many resources, it is stated that the origin of olive goes back to Mesopotamia and it was spread to Mediterranean countries from that region. Mesopotamian images dating back to 2000 BC depict kings offering olives to their guests. Olive has been the symbol of peace, friendship and abundance throughout history and it was first spread to Aegean and Mediterranean regions with the expeditions of Alexander the Great. Later on, thanks to Phrygians and Phoenicians, Romans who invaded Aegean and Mediterranean coasts met the olive. Thus, the olives carried by amphoras in Roman ships were spread to the world. In those days, olive trees were considered to be sacred.

In Noah’s ark, the dove heralding the continuity of life held an olive branch in its mouth. Cecrops who built the city of Athens mentioned olive tree as “the one who can be reborn from itself and the one who cannot be destroyed” and showed how to extract the oil of its fruits. The goddess of peace, Pallas Athena created an olive tree with one move of her spear in Acropolis and taught people how to plant it. There are five sacred fruits that are mentioned in the holy books of popular religions; fig, date, grape, pomegranate and olive. It is the symbol of abundance, justice, health, peace, glory, pride, wisdom, intelligence, immortality, cleansing and rebirth. Holy books, millennial stories and fairy tales also mention the olive.

The first medicinal use of olive leaves takes place in Ancient Egypt. At the same time, it was a symbol of divine power. It was also used in embalming of pharaohs. In 1800s, people started to make syrup from olive leaves and used this as an antipyretic. Later on, green olive leaves were used in malaria treatment.

Modern medicine began to use olive leaves in 1995. First results were positive and further research revealed that it is a unique plant that can offer hope for many diseases.
It is beneficial for

• Regulating blood sugar,
• Regulating cholesterol,
• The treatment of sinusitis,
• Increasing blood circulation through the heart,
• Preventing heart attacks,
• The treatment of diarrhea,
• Preventing aging,
• The treatment of malaria,
• The treatment of Hepatitis B,
• The treatment of hemorrhoids,
• The treatment of flu and pneumonia,
• The treatment of upper respiratory infections.

Olive oil is obtained mechanically by extracting the ripe olives from the olive tree (Olea europeae L.) without any chemical process. This type of oil is in liquid state at the room temperature with a yellowish green colour. It is an important plant-sourced oil and has a unique taste and smell. The oils that are extracted by using solvents, processed by reesterification (oils with an altered triglyceride composition) and other mixed oils are not a type of a plant-sourced oil.

Oleic Acid
Olive oil mostly consists of single unsaturated oleic acid. Oleic acid causes the low density lipoproteins (LDL) to decrease and high density lipoproteins (HDL). This makes olive oil an essential factor in the diets.

Squalene (Hydrocarbon)
This component that has a metabolic importance is highly abundant in the olive oil.

Tochopherols
Olive oil contains alpha, beta and teta tochopherols where the main component is the alpha tochopherol making up 88%. The quantity of tochoperol is not solely dependent on the olive but it also depends on the transportation, storage and processing conditions.

Sterols
Phytosterols, a type of plant sterols covers a major fraction of sterols that is obtained by the saponification of sterol lipids. The most abundant phytosterols found in the olive oil are sitosterol and stigmasterol.

Pigments
The colour of the olive oil is associated with the presence of chlorophyll and phephytin. The other component that contributes to the colour is called carotenoids.The soil and weather quality of the colour associated substances are highly important for the ripening of olives.

Phenolic Components
Olive contains basic and complex phenolic components. Most of these components diffuse into oil and increase oxygen endurance, while also affecting its taste. Hydroxytirosol tirosol and some phenolic acids can be found in olive oil. The amount and composition of these phenolic substances found in olive oil depend on the time of harvest, the process conditions and the height of the area that olive trees grow.

Aroma Components
The fundamental sensory attributes of olive oil areformed by the aroma and taste. This sensory attribute is provided by a group of aroma components. The formation of these components which are found in olive fruit, occurs as a result of a series of enzymatic reactions.

Olive oil can be stored in a closed and dark place protected from light and air. It starts to freeze below 11 ℃. Glass packaging should be preferred. If plastic packaging is used, it might have contact with air. Olive oil’s shelf life is 2 years but after 1 year olive oil would lose its taste. It can also be refrigerated.

After the olive harvest, leaves and shells are sorted out, olives are washed and prepared to be pressed. In old days, stone or granite wheels were used to press olives. Today, stainless steel cylinders press the olives and turns them into paste. This paste is later kneaded. At the same time, water is added to the olive paste. This process helps to bring oil molecules together.

The paste is kneaded around 20-40 minutes. If the process is longer, there would be less oil and the paste would release different tastes into the oil. In addition, any contact with air would release free radicals and affect the quality.

In modern systems, the kneading is done in tanks filled with anti-oxidation gases. This method increases the amount and taste, and protects the quality of oil. The mix can be heated up to 27-28 ℃ to increase the amount but this would cause some oxidation. This press method in this temperature is called “cold-pressed”.

After kneading, the paste can be pressed more or put into a centrifuge machine. As the machine turns at a great speed, water and oil are collected in the central chamber. Later, oil is separated from water.

Following the oil separation process, the pulp would still have some oil in it. Some producers use steam, hexane or other solvents to extract this oil. We must state that this low quality oil is residue oil.

Furthermore, the oil can be refined and go through decolorization and/or deodorization processes. Refining the oil decreases acidity levels and bitterness. Decolorization process cleans the chlorophyl and carotenoids (pigments that give their color to plants) and possible leftovers of agricultural chemicals so the result would be a light-colored oil which has lower nutrition values. At last, eliminating the smell takes down the sharp smell of olive oil.

In order to protect the oil before bottling and transportation, it is kept in stainless steel tanks around 18 ℃.

Olive oil consists of a combination glycerin and oleic acid compounds. However, in this mix oleic acid does not completely blend with glycerin and some of it would be released. Less released oleic acid means better and more delicious oil. If the acidity level is high, the oil would be bitter. Acidity level determines the percentage of oleic acid in every 100 grams of olive oil. So 0,8 percent acidity means that in every 100 grams of olive oil there is 0,8 grams of released oleic acid.

We do not need high-end laboratories to measure the acidity levels of olive oil. A glass straw, a measuring flask and a glass balloon with ether alcohol and acid solution (which can easily be acquired from a pharmacy) would be sufficient to measure the acidity level.

Put 10 grams of olive oil in a measuring flask and 30 grams of ether alcohol in a glass balloon, then pour the olive oil into the ether alcohol. Then drip a few drops of alcohol solution with a glass straw. The balloon will become reddish and then yellow again. Keep dripping the solution until you have a constant red color. Check the straw’s indicator. This will show the level of rhythm. Divide this number to 10 and you will find the acidity level.

Some regions that produce olive oil use the term “rhythm” to describe the acidity level of olive oil. 1/10 of acidity is 1 rhythm. For example, olive oil with 0,8 acidity level is 8 rhythm.

The taste of a delicious aromatic olive oil is relative for everyone. Some people prefer strong aroma, some people prefer high acidity and some nice smell.

Factors that influence the production of olive oil significantly determine the taste, aroma and color. These olive oils are referred with different names.


Factors that influence the taste of olive oil are;

• The type of olivee
• The region and soil quality
• Environment and climate
• Maturity of olives
• Harvest time
• Harvest method
• The time between the harvest and pressing
• The method of pressing
• Packaging and storing techniques