OLIVE OIL IS PRODUCED
& COOKING ARTICLE
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Passion for Olive Oil
order to extract the precious oil from the mesocarp,
or flesh cells, of the olive fruit, the extraction process
naturally focuses on the separation of the oil and supplementary
liquids from the solid material.
the harvested olives with potable water and removing
the leaves are the preliminary steps in this ancient
process. The foreign material, if left, would adversely
affect the flavor of the resulting product and damage
the modern equipment that is currently used.
the olives with either stone mills or metal crushers
produces a paste with easily extracted oil droplets
within the resulting crushed substance. The older of
the two methods is the use of stone crushers consisting
of a stone base and upright millstones enclosed in a
metal basin. There are usually scrapers to clean the
millstones and paddles and blades to circulate and expel
the paste. This process ensures that the paste is not
overheated (which would adversely affect the flavor
of the oil), the oil is not contaminated with the metal
and the emulsified paste produced is easy to extract.
Due to the consistency and texture of the paste that
this process produces, stone crushed olive oil is usually
combined with pressing, although sometimes centrifugation
is used. The difficulties associated with this process
are the slowness of the bulky machinery, the cost and
the fact that the equipment cannot be continuously operated.
crushers rotate at high speed throwing the olives against
a metal grating. The oil is usually extracted from the
paste by continuous centrifugation. The advantages include
speed, continuous operation, low cost and high output.
The primary disadvantages include the likelihood for
metal contamination and high temperatures which damage
the flavor of the oil. In addition, this process produces
a paste which contains smaller droplets of oil, more
emulsified, and therefore harder to extract.
or beating the paste prepares the paste for separation
of the oil from the pomace. This part of the process
is important if the paste was made from metal crushers.
This process will maximize the amount of oil to be extracted
from the paste by breaking up the oil/water emulsion
and forming larger oil droplets. (If the speed, time
and temperature devoted to the process are miscalculated,
a stronger emulsion with oil more difficult to extract
of the "liquid gold" is accomplished by pressing,
percolation or centrifugation. Pressing is the oldest
and most common method of oil extraction by applying
pressure to stacked mats, smeared with paste, that alternate
with metal disks. The oil is then expressed through
a central spike. The advantages of this method include
the use of simple, reliable machinery and little initial
investment; the low energy requirement; a resulting
pomace that is low in moisture/liquid content and precious
little oil is lost to the water component. The disadvantages
include a high labor intensity and the production is,
therefore, not continuous.
incorporates the use of a metal plate dipped into the
mixed paste which in theory becomes wetted with oil,
and not with oil mixed with water, when withdrawn. The
oil then drips off the plate. The disadvantage of this
process is that it is inefficient because the wet pomace
remaining still contains a great deal of olive oil.
That is why the percolation process, if used at all,
is usually combined with another process such as pressing
or centrifugation, discussed below; however, the high
initial cost and energy requirements, the resulting
wet pomace and a high amount of remaining olive oil
still attached to water make this procedure less than
uses high-speed centrifuges that extract the oil from
the beaten paste through a fine screen. The advantages
include speed of process, efficient and compact equipment/machinery
and low labor requirement. The disadvantages include
a high investment cost for equipment and trained personnel,
high energy requirements, a pomace with a high moisture
content and lost oil still attached to the water.
three methods produce oil must and pomace. The oil must
consists of edible olive oil and vegetable water. Centrifugal
decanting is used to separate the oil from the water
with the help of the naturally different densities of
these liquids. Concentric spinning tanks pull off the
oil, and the vegetable water drains into lower tanks.
"waste" consists of solid and liquid waste.
The solid waste uses include: (1) Fuel, (2) Fertilizer/Mulch,
(3) Herbicide, (4) Animal Feed, (5) Road Construction
Material, (6) Olive Bricks and (7) Worm Breeding Material.
most exciting use is fuel due to the extremely high
cost of energy sources around the world. In Jordan,
the primary use of pressing waste is fuel to heat households
and power kilns. If completely dried, the solid waste
is pressed into logs for burning yielding extremely
intense burning and an aromatic scent. Commercially
sold charcoal consists in part of dried solid olive
waste. This fuel source is environmentally non-polluting
and biodegradable. The Turkish Daily News recently reported
that Selcuk Gida has applied to the Energy Ministry
for permission to produce energy from the olive oil
cake. This kind of energy production would be a first
in Turkey. The energy power station will cost $20 million
and be established in Aydin's Germencik district. Sixty
percent of the energy will be sold to Turkey Electric
Distributing Company (TEDAS). The company Selcuk Gida
is known to consumers of dried fruit which is sold under
the Eagle Brand.
a component of fertilizer and mulch, the olive waste
should be mixed with soil and bark and should not be
concentrated over the olive tree roots because the roots
may burn. Usually, the olive waste is distributed around
an orchard or farm and it serves as a natural herbicide,
discouraging grass and weed growth. Some American farmers
have reported the emergence of red clover where previously
none existed. Red clover is a dynamic accumulator of
nitrogen and phosphorous, and the presence of red clover
(trifolium protense) is also an indicator of potassium.
olive residue material is also a component of feed for
animals such as cattle and poultry; however, goats and
sheep eat it "straight" separating the edible
portion from the woody parts. Americans use tons of
the olive waste mixed with bitumen as a component of
road construction material. Olive bricks, although lighter
than traditional bricks, are also created from this
solid residue as well as breeding material for worm
chemical analysis of the solid waste consists of: nitrogen
(1.18%), phosphorous (0.14%), potassium (2.03%), sulphur
( 0.11%), calcium (0.18%), magnesium (0.09%), sodium
(0.02%), manganese (110 ppm), zinc (8 ppm), copper (4.2
ppm), cobalt (0.26 ppm), boron (26.4 ppm), molybdenum
(0.16 ppm), cadmium (0.39 ppm), lead (10.01 ppm), mercury
(<0.001 ppm), organic carbon (54%), moisture content
(23.8%) and PH of 4.7.
liquid waste water, according to ancient Roman texts,
was used as a herbicide and insecticide. Modern research,
however, has not yet uncovered viable uses to which
this waste can be put. On the contrary, science has
warned against depositing this substance into lakes,
rivers or the sea due to the polyphenol. The acidity
renders an excess of this waste water phytotoxic which
can result in pollution.
The Olive Tree World
article came from Constantine Alexander better known
as Papa Constantine. Papa Constantine is a Certified
Olive Oil Consultant based in Connecticut, USA. His
website is no longer available.
Constantine Alexander, 2001
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