Production Of Olive Oil
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PRODUCTION OF OLIVE OIL
INTRODUCTION
Olive oil is a pale yellow to greenish oil extracted from the fruit of the European olive tree (Olea europaea L.), which originated in the Mediterranean area. The olive is originally native to the eastern Mediterranean region but the cultivated form is now grown throughout that area and in other parts of the world with Mediterranean-type climates. It hardens at refrigerator temperatures – around 10 degrees F.
Today a market certainly exists for olive oil, since the U.S. imports about 35 million gallons each year. Interest in the health aspects of olive oil is expanding and increasing demand each year. Demand has increased over 20% each year for the last 5 years. California produces about 300,000 gallons of oil each year about half of that is sold each year as the gourmet treat classified as extra-virgin and sold from $10 to $40 per half-liter.
Among global producers, Spain leads with more than 40% of world production, followed by Italy and Greece. Much of the Spanish crop is exported to Italy, where it is both consumed and repackaged for sale abroad as Italian olive oil.
Different Grades Of Olive Oil
Extra-virgin olive oil comes from the first pressing of the olives, contains no more than 0.8% acidity, and is judged to have a superior taste. There can be no refined oil in extra-virgin olive oil.
Virgin olive oil with an acidity less than 2%, and judged to have a good taste. There can be no refined oil in virgin olive oil.
Olive oil is a blend of virgin oil and refined virgin oil, containing at most 1% acidity. It commonly lacks a strong flavor.
Olive-pomace oil is a blend of refined olive-pomace oil and possibly some virgin oil. It is fit for consumption, but it may not be called olive oil. Olive-pomace oil is rarely found in a grocery store; it is often used for certain kinds of cooking in restaurants.
Lampante oil is olive oil not used for consumption; lampante comes from olive oils ancient use as fuel in oil-burning lamps. Lampante oil is mostly used in the industrial market.
OLIVE OIL CHEMICAL COMPOSITION
Olive oil is a triacylgylceride (three fatty acids attached to a glycerol backbone). Technically it is a type of glycerolipid. Triacylglycerols (Triglycerides or Fats) are the major energy reserve for plants and animals.
A fatty acid has the general formula: CH3(CH2)nCOOH where n is typically an even number between 12 and 22
PRODUCTION PROCESS DESCRIPTION
There are many methods of producing Olive oil. Traditionally, olive oil was produced by beating the trees with sticks to knock the olives off and crushing them in stone or wooden mortars or beam presses. Nowadays, olives are ground to tiny bits, obtaining a paste that is mixed with water and processed by a centrifuge, which extracts the oil from the paste, leaving behind pomace.
The process of producing a high quality olive oil is described below.
Washing
The first step in making high quality olive oil is to wash the olives and to eliminate any leaves or debris. The olives are unloaded in a hopper and brought to the stainless steel washer via a conveyor belt, where the washing process takes place automatically. The special washing system of the Pieralisi hydropneumatic olive washer guarantees total removal of earth attached to the olives as well as leaves and any other foreign bodies.
Crushing
Next the olives are crushed into a paste. The purpose of crushing is to tear the flesh cells to facilitate the release of the oil from the vacuoles. In this mill, crushing is done with a double-hammer double-grid hammer mill. The hammer mill crusher offers a continuous and clean method. The crushing is done quickly, resulting in less heat build-up and exposure to oxygen than with stone mills. The double-hammer double-grid setup allows us to decrease the bitterness sometimes found when using traditional hammer mills. The mill rotates much more slowly than traditional hammer mills and the size of the grids can be adjusted to optimize the crushing process based on the characteristics of the olives.
Malaxation
After the olive fruit has been crushed, the resulting paste is mixed for 20 to 45 minutes, depending on the characteristics of the olives. The purpose of this operation is to increase the percentage of free oil. It also aids the coalescence of small drops into larger ones, thereby facilitating the separation of the oil and water phases. Our mill presents several advantages. The malaxers are covered; resulting in minimal exposure to oxygen during what is the longest phase of oil production. A movable arm transfers the olive paste directly from the crusher to the malaxers, which are fitted with a small door that opens and closes in synchronism with the arm. A non-drip device prevents oil loss during the movement of the loading arm. A special washing system facilitates the cleaning of each single malaxer and of the swiveling screw after each batch of olives has been processed.
Extraction and separation
The main constituents of the olive paste are: olive oil, small pieces of kernel (pit), water and cellular debris of the crushed olives. The oil is extracted from the rest of the paste through a horizontal centrifuge spinning at 3600 rpm. This results in a high yield at lower costs than with traditional hydraulic presses and allows a high level of cleanliness and sanitation. No water is added, resulting in better preservation of the original oil flavors and anti-oxidants. The centrifugation process can be adjusted according to the olive quality and characteristics. As in the other stages of the operation, exposure to oxygen is minimal. The final separation is accomplished through a vertical centrifuge spinning at 7000 rpm to eliminate the last remaining water.
OLIVE MILL WASTE WATER TREATMENT
The Olive Mill Waste water, OMW (called “Alpechin” in Spanish) is part of the wastes generated from olive oil presses. Because no water is typically added, waste production is minimal. Washing mats may consume water and produce waste water but this is not usually a disposal problem.
The olive water is a big problem in many parts of the world. It is a brown watery liquid which has been separated from the oil by centrifugation