Extraction of olive oil is the process of extraction of oil present in olives, known as olive oil. Olive oil is produced in mesocarp cells, and is stored in a certain type of vacuole called a lipo vacuole, that is, every cell contains small olive oil droplets. Extraction of olive oil is the process of separating oil from other fruit contents (liquid vegetative extracts and solids). It is possible to achieve this separation only by physical means, ie, oil and water are not mixed, so they are relatively easy to separate. This contrasts with other oils extracted with chemical solvents, generally hexane. The first operation when extracting olive oil is washing olives, to reduce the presence of contaminants, especially soils that can create a certain flavor effect called "ground flavor".
Video Olive oil extraction
Suppress olive
People have been using olive presses since the first Greeks started pressing olives more than 5,000 years ago. Pressing the Roman olive survives to this day, with the famous collection in Volubilis in Morocco. The olive press works by applying pressure on the olive paste to separate the liquid oil and vegetation water from solids. Oil and vegetation water are then separated by standard decantation.
This basic method is still widely used today, and it is still a valid way to produce high quality olive oil if adequate precautions have been taken.
First, the olives are ground into an olive paste using a large millstone in an oil mill. The olive pasta is generally under the rock for 30-40 minutes. It has three purposes:
- Make sure that the olives are well grounded
- Give enough time for olive drops to merge to form the largest oil granules
- Let the fruit enzyme produce some aroma of oil and flavor
Olive oil plants rarely use modern methods of destruction with the traditional press.
After grinding, olive paste is spread on a fiber disc, which is stacked on top of each other, then placed into the press. Traditionally discs are made of hemp or coconut fibers, but in modern times they are made of synthetic fibers that are easier to clean and care for.
This disk is then inserted into a hydraulic piston, forming a pile. Pressure is applied to the disc, thereby solidifying the solid phase of the olive paste and soaking up the liquid phase (oil and vegetation water). The applied hydraulic pressure can reach 400Ã, atm. To facilitate the separation of the liquid phase, water flows to the side of the disc to increase percolation speed. The liquid is then separated either by a standard decantation process or by a faster vertical centrifuge.
The traditional method is a valid form to produce high quality olive oil, if after each disc extraction is cleaned properly from the remains of the paste; otherwise the remaining paste will begin to ferment, resulting in a flavor inconsistency (called a flaw) that will pollute the next produced olive oil. Similar problems can affect grinding stones which, to ensure perfect quality, also need to be cleaned after each use.
Advantages and disadvantages
Proper cleaning produces higher quality oil. Grindstones, while ancient in design, are a great way to grind olives, as this method breaks down the drupe slurry while only slightly touching the nuts and skin. This reduces the release of oxidizing oil enzymes present in these organs. In addition, in this method of extraction, the introduction of water is minimal when compared with modern ones, thereby reducing polyphenolic leaching. Paste that has been dried, called pomace, has a low water content, making it easier to manage.
Benefits
- Better grinding of olives, reducing release of oil oxidation enzymes
- Reduce added water, minimize polyphenol leaching
- Pomace with low water content is easier to manage
Disadvantages
- Difficult to clean
- Process without continuous with waiting time so as to expose olive paste to oxygen and light
- Needs more manual labor
- Longer production time starts from harvest to press
Maps Olive oil extraction
Decanter centrifugation
The modern method of olive oil extraction uses industrial decanters to separate all phases by centrifugation. In this method the olives are crushed into a fine paste. This can be done with a hammer crusher, disc crusher, depitting machine or knife crusher. The paste is then malaxed for 30 to 60 minutes to allow small olive droplets to clot. The aroma is made in these two steps through the action of the fruit enzyme.
After that the pasta is pumped into the industrial decanter where the phase will be separated. Water is added to facilitate the extraction process with the paste.
The decanter is a large horizontal centrifuge that rotates about 3,000 rpm, a high centrifugal force made allowing the phases to be separated according to their different densities (solids & gt; vegetable water & oil). In the cone drum rotating decanter there is a coil that rotates more slowly, pushing solid material out of the system.
The oil is separated and the vegetation water then repeats through a vertical centrifuge, working around 6,000 rpm which will separate a small amount of vegetable water still contained in oil and vice versa.
Three, two, and two half decanter phases
With the three-phase oil decanter, a portion of the oil polyphenol is washed because of the higher amount of additional water (compared to the traditional method), resulting in larger amounts of vegetable water that needs to be processed.
The two-phase oil deck was created in an attempt to solve this problem. To sacrifice some of its extraction ability, it uses less water thereby reducing phenol leaching. The olive pasta is separated into two phases: oil and wet pomace. This type of decanter, instead of having three outputs (oil, water, and solid), has only two outputs. Water is released by the decanter coil along with pomace, producing a wet pomace that is much more difficult to process in the industry. Many pomace oil extraction facilities refuse to work with these materials because the cost of pomace drying energy for hexane oil extraction often makes the sub-economical extraction process. In practice, then, the two decanter phases solve the problem of phenol leaching but improve the residual management problem. This residue management problem has been reduced by collecting this wet pomace and transported to a special facility called an extractor that heats pomace between 45Ã,ºc and 50Ã,ºc and can extract up to 2 liters further per 100 kilo pomace using two adapted decanter phases..
The two-and-half-phase oil decanter is a compromise between the two previous decanter types. It separates the olive paste into three standard phases, but has a smaller need for additional water as well as smaller water vegetation output. Therefore, the water content of the obtained pomace comes very close to the standard three-phase decanter, and the vegetation water output is relatively small, minimizing the residual management problem.
Depending on the olives and their processing, the Decanter or Tricanter can extract between 85 and 90% of the olive oil in the first extraction. The yield of olive oil production can be further enhanced by the 2nd extraction. Olive oil yields increase by 96% by combining first and second extractions.
Advantages and disadvantages
Benefits
- Quick machine: only one decanter is needed
- Continuous and automatic
- Limited workforce required
- The highest percentage of oil extraction
- Watering vegetable water is less of a problem
- Olive oil from a two-phase centrifugation system contains more phenol, tocopherol, trans-2-hexenal, and total aroma compounds and is more resistant to oxidation than oil from the three phases and from hydraulic presses
Disadvantages
- Expensive
- More technical personnel needed
- high energy consumption
- Pomace may be damp
- Bigger amount of vegetable water to dump
- Reduce antioxidants due to added water
- Can be worn from stone, sand
Sinolea Method
The Sinolea method for extracting oil from olives was introduced in 1972; in this process, a row of metal discs or plates is immersed in the paste; This oil typically dries and attaches to the metal and is removed by scraping in a continuous process. It is based on the different surface tensions of the vegetation and oil water, this different physical behavior allows the olive oil to adhere to the steel plaque while the other two phases remain behind.
Sinolea works by continuing to introduce several hundreds of steel plaque into the paste so as to extract the olive oil. This process is not entirely efficient leaving a large amount of oil still in the paste, so that the remaining paste must be processed by standard modern methods (industrial decanter).
Advantages and disadvantages
Benefits
- The content of polyphenols is higher than oil
- Low temperature method
- Automatic
- Low labor
- Oil/water separation step is not required
- Low energy requirements
Disadvantages
- Often should be combined with one of the above methods to maximize oil extraction that requires more space and labor
- Large surface area can cause rapid oxidation of olive products
- Future machine sales are currently banned in the EU due to difficulties in clearing large surface areas
The first cold pressed - cold extraction
Many oils are marketed as cold extraction or first cold extraction. "Cold" refers to the fact that no heat is added during extraction. "Pressed" refers to the concept that olives are smashed in grinding to extract oil.
In the EU, this appointment is governed by Article 5 of Regulation of the Commission (EC) No 1019/2002 of 13 June 2002 on marketing standards for olive oil. This article states that to use this designation the olive oil bottling should prove that the malaxation and extraction temperatures are below 27 ° C (80 ° F).
For olive oil bottled outside the EU countries, this rule does not apply, and thus the consumer has no assurance that this statement is true.
The temperature of malaxation and extraction is very important because of its effect on the quality of olive oil. When high temperatures are applied, the more readily lost aroma is lost and the oxidation rate of the oil increases, resulting in lower quality oil. In addition, the chemical content of polyphenols, antioxidants, and vitamins present in the oil is reduced by higher temperatures. The temperature is adjusted basically by controlling the water temperature added during these two steps. High temperatures are used to improve the yield of olive oil obtained from the paste.
Alternate configuration
Some manufacturers, to maximize product quality, choose to combine traditional milling methods, stone milling, with modern decanter. This technique results in more selective olive milling, reduces olive paste during malaxation, and avoids complicated cleaning of olive press fiber disks. Since the use of a stone mill requires a loading-unloading phase, this method of extraction is discontinuous, that is, there are times when all machines are discontinued, therefore generally not used on a large commercial scale, applied only on a small scale. olive plants produce high quality olive oil.
Consumer point of view
High quality olive oil can be obtained by all methods if proper action is taken. The quality of olive oil is dependent on the quality of the olives themselves and when they have to wait from harvest to extraction, in addition to the extraction method itself.
The two main agents that cause olive oil degradation are oxygen and light. Once the olives are harvested, it should be pressed within 24 hours. Oxidation begins immediately after harvest. In the period between harvest and milling, the fruit enzyme is very active and further decreases the endogenous oil, and therefore the oil obtained after a longer wait has lower quality, presenting higher acidity (percentage free fatty acids).
In addition, if additional oxygen is allowed to interact with the olive paste during the extraction process, the acidity level will increase further. The closed extraction method is the best way to prevent the continuous influx of oxygen, as well as the light on the oil.
Once the extraction is complete, in many cases the unfiltered olive oil looks a bit murky, mainly because of the minute amount of water and the solids of the pulp and the suspended olive seed. This type of oil is therefore sometimes called cloudy or veiled olive oil .
It is common practice that unfiltered olive oil is temporarily "tortured", which is stored in a cold stainless steel silo with an oxygen-shaped conical base to allow for two-phase deposition and separation and facilitate later screening; it will also contribute to the integrity and stability of oil.
Future prospects
The future of the olive extraction point to reduce the negative aspects of this method, reduces the degradation of the oil produced by the extraction process itself.
- Reduces oxidation by performing part of the malaxation process and extraction under a controlled nitrogen atmosphere
- Extracting the olive nuts before grinding, this will reduce the release of oxidative enzymes present in these organs, and produce a pomace that is free from wood residue, making it possible to use in animal feeding
- Reduce water addition to minimize polyphenol leaching
- Fixed the sinolea method, by increasing the efficiency of oil adsorption to the plate, thereby reducing the need to use standard extraction methods
See also
- Amurca, a by-product of olive oil extraction, historically used for many purposes
Note
References
- Polyphenols in olive oil. T. Gutfinger, Journal of the American Chemical Petroleum Society, Volume 58, Number 11, 966-968, doi: 10.1007/BF02659771
External links
- Commission Regulation (EC) No 1019/2002 of 13 June 2002 on marketing standards for olive oil
- http://www.oilmillmachinerysuppliers.com/Get complete technical information on Oil Treatment, Oil Extraction, Seed Processing, Oil Refining, Oil Filtering, Seed Extraction and more @ http://www.oilmillmachinerysuppliers.com/
Source of the article : Wikipedia
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