The olive tree has a long history that is linked to the evolution of the human. In Spain, the earliest fossil record of the olive tree ancestor dates from the Neolithic period (5,000 BC).
The current type of olive tree Olea Europaea exists since thousands of years and its origin is somewhere in the Middle East. Egyptians, Phoenicians, Greeks and Romans contributed to the dissemination of the olive tree in the Mediterranean area. The Arabs applied their vast knowledge to improve the performance of Spanish olive groves and from their language derives words such as almazara (oil mill), acebuche (wild olive trees), and also the name of oil, aceite, (in Arabic, az-zait).
Today Spain is the largest country producer with 50% of worldwide production, and the Mediterranean area concentrates 96%.
The olive grove gets limited by cold weather as barely resist temperatures below -12ºC, but is able to resist exceptional droughts and strong winds. The olive tree requires mild winters, rainy springs and autumns, dry summers, and sunlight. In the Mediterranean basin, olive trees are small, with deeps roots to capture the water reserves from underground, in order to compensate lack of irrigation. The fruit only matures after the warm months and harvest starts in autumn and could finish in winter season.
The long-lasting olive tree can live 300-600 years and worldwide there are more than 800 million trees. An olive tree reaches full production from 5 years and up to 150 years, giving 4-5 liters yearly per tree.
The quality of the oil, like in wine, is influenced by many factors: weather conditions, soil, type of tree, age of the tree, variety, harvesting method, etc. There are more than 250 varieties of olives trees in Spain although the most common are Picual, Hojiblanca, Arbequina and Cornicabra, all of this grown by our farmers.
The olive oil production process has remained almost unchanged over the years. New technologies have improved the time or yield but the steps from the field until the mill are still the same.
This process is: harvesting, cleaning, crushing, malaxing, separation and storage.
It is key to harvest the olives in their optimal moment of ripeness to ensure an oil of high quality and the best organoleptic attributes, this is detected when the majority of olives are changing color (ripening), with hardly any green olives left and some are completely mature. It is crucial to transport immediately the olives to the mill, so the fruit does not deteriorate. The usual practice is to not exceed 24 hours from harvesting to processing. At this stage the traceability control system is beginning. Each delivery of a farmer in the cooperative is identified when arrives to the mill; and gets segregated according to the quality of the olives and/or variety.
Olives are cleaned by air blowing to remove leaves and any other impurity; if necessary they can also be washed. In this moment olives are weighed and a sample is taken.
At the mill olives are crushed with its bone in order to break the vegetable cells and extract the oil from inside. The result of the mill is a paste composed by: oil, pulp of olive, crushed bones and water. In order to obtain a liter of oil at first extraction are needed, approximately, five kilos of olives.
The paste enters in a malaxer where it is shaken under controlled conditions in order to help the formation of the oil phase. The malaxing time and temperature are controlled; it should not exceed 90 minutes and 30ºC, to not lose properties of the oil.
This process is a physical separation. The paste is centrifuged and due to the different densities the solid, liquid get separated.
At most modern warehouses virgin oils are stored under temperature conditions controlled in order to avoid oxidation.
Since November of 2003, the EU has established a common regulation for labeling olive oil. The categories are determined by a chemical analysis and an organoleptic analysis:
Extra virgin olive oil: Superior category olive oil obtained directly from olives and solely by mechanical means. It is the natural olive juice, with no taste defects, and maximum acidity of 0.8%.
Virgin olive oil: Olive oil obtained directly from olives and solely by mechanical means. It is a natural olive juice that cannot obtain the category of extra due to minor defects. It can have up to 2% acidity and/or an organoleptic defect below 3.5.
Olive oil: The oils with organoleptic defects or without fruitiness are called lampantes and they cannot be consumed directly. Lampante needs to be refined. In order to be commercialized the refined olive oil gets mixed with a portion of virgin olive oil and that product is labeled under “Olive oil. Oil composed of refined olive oils and virgin olive oils”.
There is an official method to evaluate the oil following a pre-set list of organoleptic characteristics: positive and negative attributes.
The oil is classified as follows considering median of defects and the median for the fruity attribute:
Extra virgin olive oil contains the same calories per gram as other fats (9 kcal/g), but it its proportion of fatty acids and the presence of some antioxidants confers this oil exceptional nutritional properties.
Vitamin E (alpha-tocopherol), carotenoids and phenolic compounds (simple phenols such as hydroxytyrosol and complex phenols such as oleuropein) are all antioxidants whose activity has been demonstrated in vitro and recently in vivo, revealing further advantages in the prevention of certain diseases and also of ageing.
The phenolic content of olive oils varies according to the climatic conditions in the producing area, when the olives are harvested and how ripe they are when picked. Oil production and storage methods also have an influence. Phenols have countless biological properties. Regarding its proportion of fatty acids, it contains 55-80% of oleic acid and 3-20% of linoleic acid, which is an essential fatty acid.
Extra virgin olive oil can be fried at high temperatures, producing low levels of benzo pyrenes and can be reused for frying up to 5 times. Frying food in extra virgin olive oil, a common technique in Mediterranean countries, is now considered healthy. When the frying process is carried out correctly, ensuring correct temperature and frying time, a peripheral crust is formed and does not allow the penetration of hot fat inside the food. Because of this crust, there is lower loss of vitamins and minerals than with stewing or roasting, and fat consumption is also lower and therefore the caloric value of the food almost does not increase. The nutritive quality of fried food does not decrease compared to fresh products, the amount of vitamin C is unchanged, and the fat composition in meat is better after frying.