Olive oil is a vegetable oil mainly used for culinary purposes. It is obtained from the fruit of the olive tree (Olea europaea), called olive or olive. Almost a third of the olive pulp is oil. For this reason, since ancient times it has been easily extracted with a simple pressure exerted by a mill. In Spain, the facilities where the oil is obtained are called oil mills. It has also been used for other diverse uses such as cosmetics, medicine, religion and for oil lamps.
The olive or olive is not usually eaten raw due to the bitterness of its flavor (mainly due to the presence of phenolic compounds). This flavor is greatly reduced by applying various maceration processes. However, 90% of the world's olive production is used to produce oil. Historically and culturally it has been a product closely linked to the Mediterranean area. Today only 3% of world production is obtained outside the Mediterranean area. Spain produces almost half of the world's olive oil, followed by Italy and Greece. These three countries account for three quarters of world production.
The oil is extracted from ripe olives between six and eight months old, when they contain their maximum amount of oil, which usually occurs in late autumn. The olives are subjected to a first pressure in order to extract their juice. The quality of the oil depends largely on subsequent processing. For this reason, producers monitor these steps very carefully. The quality of olive oil is judged by its organoleptic properties and its free fatty acid content. There are regulations in the European Union on the classifications of oil into six categories, depending on the concentration of fatty acids.
It is worth distinguishing olive cultivation and its scientific study (called oliviculture) from the extraction of olive oil and its study (called elaiotecnia, from the Greek elaion, which means oil). More generally, elaiotecnia is the science that studies the extraction of vegetable oils of any origin, such as olive oil, sunflower oil, peanut oil, palm oil, etc. Today olive oil is sold packaged in bottles (glass or plastic), as well as in drums protected from light.
Vegetable oils have been used regularly throughout history. It has been used in gastronomy, although it has also been given other uses such as religious, cosmetics and as fuel in lighting for oil lamps in daily life and in temples.
The origin of olive oil production must be sought in ancient times in the Fertile Crescent (which runs from the Tigris and Euphrates rivers to the Nile). In 4000 BC. C. A cross was made between an African variety of olive tree and another oriental one to produce a species with large fruits to extract its oil. In excavations carried out in the area, oil mills have been found. It is suspected that the first plantations were made in the extensive area from Syria to Canaan (from 5000 BC to the beginning of 3000 BC). It is believed that this use of the olive perhaps arose with agriculture. However, uses of the olive tree are known in the Upper Paleolithic (12,000 BC).
In Egypt, around 2000 BC. C., olive oil began to be used for cosmetic purposes. The Egyptians already pointed to Isis as the goddess who taught men the cultivation of the olive tree. The Egyptians themselves began to market olive oil by importing it from Crete. Inside the funerary chambers, vessels and amphorae with olive oil are represented. This oil would be a common product in the Mediterranean, along with bread and wine.
Olives should be harvested from olive groves in late fall or early winter. The moment in which the olives have their maximum level of fatty acids in the olive pulp is chosen. Olive harvesting is an agricultural task with great importance in production costs and a marked influence on the quality of the oil obtained. The harvest season directly influences the composition of the oils and their sensory characteristics. These variations in the polyphenol content affect the sensory characteristics of the oils. As the fruit ripens, the aromas fade and the flavors soften. The color also undergoes changes depending on the olive harvest season, at first green oils predominate, of various shades depending on the variety, turning towards yellow-gold as the harvest season progresses as a consequence of the gradual decrease. of the chlorophyll-carotene ratio. In very cold areas it is recommended to collect the fruit before the first frosts appear, which cause loss of attributes in the oil obtained. If, on the other hand, the harvest is delayed with respect to the appropriate time, the natural fall of the fruit appears, enhanced by the winds and directly related to the variety. Once the fruit is in the ground it undergoes a series of alterations that deteriorate the quality of the oils obtained, essentially the acidity increases as the time it remains in the ground passes. It is essential to collect, transport and process "separately" the fruits that have fallen to the ground and those caught from the olive tree, or from the flight, since small quantities of fruits from the ground can significantly alter those collected from the olive tree, if they are mixed for processing. The collection systems are: milking, shaking, vibration and soil collection.
He ordered
It is frequently used in the harvesting of table olives and, to a lesser extent, to obtain olive oil of the highest quality. The olive hardly suffers any damage and the process is carried out by hand or with little mechanization. The fruit must not be overripe because, if so, it would have fallen to the ground and milking could not be carried out.
A rod or pole of variable length is required (up to 4 m). The branches of the olive tree are beaten (shake) and the olive falls onto canvas or to the ground. This causes the tree to lose branches and leaves, which means that it does not produce as many olives the following year (a phenomenon called vecería). However, it is a widespread method due to its great productivity.
The vibration
Nowadays it is done mechanically with self-propelled vibrators, which are vibrating clamps attached to the tractor, or with hand-held motorized vibrators. In the past, the braceros manually shook the branches to loosen the olives. There is vibrating machinery that consists of a self-propelled vibrator with something similar to an umbrella to collect the olive.
Soil collection. Whether the olive is felled due to ripening, shaking or vibration, a mechanism is necessary to collect it later. This is usually done with blankets or canvas, or through a collecting mechanism that incorporates something similar to an umbrella. To collect the olive from the ground, it is necessary to have flattened and fenced the soil around the olive tree to facilitate the task (this is known as "making soil"). The most rudimentary method to pick the olives from the ground is to do it manually one by one, which is very tedious. You can also sweep the olives, vacuum them with a specially designed vacuum cleaner, or blow on the olives to pile them up.
The use of herbicides at the base of olive trees tends to be abandoned because it leaves residues in the oils.