Flax
From Wikipedia, the free encyclopedia
Flax (also known as common flax or linseed)
(binomial name: Linum usitatissimum) is a member of the genus Linum
in the family Linaceae. It is a food and fibre crop that is grown in cooler
regions of the world. Flax fibres are taken from the stem of the plant and are
two to three times as strong as those of cotton. As well, flax fibers are
naturally smooth and straight. Europe and North America depended on flax for
cloth until the nineteenth century, when cotton overtook flax as the most
common plant used for making linen paper. Flax is grown on the Canadian
Prairies for linseed oil, which is used as a drying oil in paints and varnish
and in products such as linoleum and printing inks. It is native to the region
extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent. Flax was extensively cultivated in ancient China and ancient Egypt.[1]
A discovery reported in 2009 of spun, dyed, and knotted wild flax fibers in a
prehistoric cave in the Republic of Georgia shows that the plant was already in use by humans at the
surprisingly early date of 30,000 BC.[2][3]
New Zealand flax is not related to flax but was named after it, as both
plants are used to produce fibers[citation needed].
Description
Flax is an erect annual plant
growing to 1.2 m (3 ft 11 in) tall, with slender stems. The
leaves
are glaucous
green, slender lanceolate, 20–40 mm long and 3 mm broad. The flowers
are pure pale blue, 15–25 mm diameter, with five petals; they can also be
bright red. The fruit is a round, dry capsule
5–9 mm diameter, containing several glossy brown seeds shaped like an apple pip, 4–7 foot long.
In addition to referring to the
plant itself, the word "flax" may refer to the unspun fibers of the
flax plant.
History
Flax fibers are amongst the oldest fiber crops
in the world. The use of flax for the production of linen goes back at least to ancient
Egyptian times. Dyed flax fibers found in a cave in Dzudzuana (prehistoric Georgia) have been dated to 30,000 years ago.[4]
Pictures on tombs and temple walls at Thebes
depict flowering flax plants. The use of flax fiber in the manufacturing of cloth in northern Europe dates back to Neolithic
times. In North America, flax was introduced by the Puritans.[citation needed]
Uses
Flax is grown for its use as an
edible oil, as a nutritional supplement, and as an ingredient in many wood
finishing products. Flax is also grown as an ornamental plant in gardens. Flax fibers are used to make linen. The Latin species name
usitatissimum means most useful, pointing to the several
traditional uses of the plant and their importance for human life[citation needed].
Flax
seeds
Flax seeds come in two basic
varieties: (1) brown; and (2) yellow or golden. Most types have similar
nutritional characteristics and equal numbers of short-chain omega-3 fatty acids. The exception is a type of yellow flax called solin (trade
name Linola),
which has a completely different oil profile and is very low in omega-3 FAs.
Although brown flax can be consumed as readily as yellow, and has been for
thousands of years, it is better known as an ingredient in paints, fiber and
cattle feed. Flax seeds produce a vegetable oil
known as flaxseed or linseed oil, which is one of the oldest commercial oils, and
solvent-processed flax seed oil has been used for centuries as a drying oil
in painting and varnishing.[citation needed]
One hundred grams of ground flax
seed supplies about 450 calories, 41 grams of fat, 28 grams of fiber,
and 20 grams of protein.[5]
Flax seed sprouts
are edible, with a slightly spicy flavor. Excessive consumption of flax seeds
with inadequate water can cause bowel obstruction.[6]
Flaxseed, called ('Tisi' or 'Alsi') in northern India, has been roasted,
powdered and eaten with boiled rice, a little water, and a little salt since
ancient times in the villages.[citation needed]
Whole flax seeds are chemically
stable, but ground flaxseed can go rancid
at room temperature in as little as one week.[7]
Refrigeration and storage in sealed containers will keep ground flax from
becoming rancid for a longer period; under conditions similar to those found in
commercial bakeries, trained sensory panelists could not detect differences
between bread made with freshly ground flax and bread made with milled flax
stored for four months at room temperature.[8]
Milled flax is remarkably stable to oxidation when stored for nine months at
room temperature if packed immediately without exposure to air and light[9]
and for 20 months at ambient temperatures under warehouse conditions.[8]
Three natural phenolic glucosides, secoisolariciresinol diglucoside,
p-coumaric
acid glucoside and ferulic acid glucoside,
can be found in commercial breads containing flaxseed.[10]
Nutrients
and clinical research
Flax seeds contain high levels of dietary fiber
as well as lignans,
an abundance of micronutrients and omega-3 fatty acids (table). Studies have shown that
flax seeds may lower cholesterol levels, although with differing results in
terms of gender. One study found results were better for women [11]
whereas a later study found benefits only for men.[12]
Initial studies suggest that flax seeds taken in the diet may benefit
individuals with certain types of breast[13][14]
and prostate cancers.[15]
A study done at Duke University suggests that flaxseed may stunt the growth of
prostate tumors,[15]
although a meta-analysis found the evidence on this point to be inconclusive.[16]
Flax may also lessen the severity of diabetes by stabilizing blood-sugar
levels.[17]
There is some support for the use of flax seed as a laxative
due to its dietary fiber content[6]
though excessive consumption without liquid can result in intestinal blockage.[18]
Consuming large amounts of flax seed may impair the effectiveness of certain
oral medications, due to its fiber content,[18]
and may have adverse effects due to its content of neurotoxic
cyanogen glycosides and immunosuppressive cyclic nonapeptides.[19]
One of the main components of flax
is lignan,
which has plant estrogen as well as antioxidants
(flax contains up to 800 times more lignans than other plant foods contain).[20]
Flax
fibers
Flax fiber is extracted from the bast
or skin of the stem of the flax plant. Flax fiber is soft, lustrous and
flexible; bundles of fiber have the appearance of blonde hair, hence the
description "flaxen". It is stronger than cotton
fiber but less elastic. The best grades are used for linen fabrics such as damasks,
lace
and sheeting. Coarser grades are used for the manufacturing of twine and rope. Flax fiber is also a raw material
for the high-quality paper industry for the use of printed banknotes
and rolling paper for cigarettes and tea bags. Flax mills
for spinning flaxen yarn were invented by John Kendrew and Thomas Porthouse
of Darlington
in 1787.[21]
New methods of processing flax and the rising price of cotton have led to
renewed interest in the use of flax as an industrial fiber. Naturally Advanced's Crailar technology is one proprietary method that is
increasing the industrial adoption of this plant.[22]
Cultivation
The significant linseed producing
countries are Canada (~34%) and China (~25.5%), though there is also
production in India
(~9%), USA
(~8%), Ethiopia
(~3.5%) and throughout Europe. Almost all of the United States
crop is from the states of North Dakota,
South Dakota,
Minnesota,
and Montana.[23]
The soils most suitable for flax, besides the
alluvial
kind, are deep loams,
and containing a large proportion of organic matter.
It is often found just above the waterline in cranberry
bogs. Heavy clays
are unsuitable, as are soils of a gravelly
or dry sandy
nature. Farming flax requires few fertilizers
or pesticides.
Within 8 weeks of sowing, the plant will reach 10–15 cm in height, and
will grow several centimeters per day under its optimal growth conditions,
reaching 70–80 cm within fifteen days.
Production
2011 production in the United States
was 70,890 metric tons,[24]
2007 was 149,970 metric tons,[25]
2006 production was 279,900 metric tons [26]
Production of linseed in Russia in 2011: 230,000 metric tons according to FAO
unofficial estimage [27]
|
Country
|
Footnote
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||
|
633,500
|
|||
|
47,490
|
|||
|
45,000
|
*
|
||
|
41,000
|
F
|
||
|
34,000
|
|||
|
World
|
1,875,018
|
A
|
|
|
No symbol = official figure, P =
official figure, F = FAO estimate, * = Unofficial/Semi-official/mirror data,
C = Calculated figure A = Aggregate (may include official, semi-official or
estimates)
|
|||
Maturation
Flax is harvested for fiber
production after approximately 100 days, or a month after the plant flowers and
two weeks after the seed capsules form. The base of the plant will begin to
turn yellow. If the plant is still green the seed will not be useful, and the
fiber will be underdeveloped. The fiber degrades once the plant is brown.
Harvesting
methods
There are two ways to harvest flax,
one involving mechanized equipment (combines), and a second method, more manual
and targeted towards maximizing the fiber length.
Mechanical
The mature plant is cut with mowing
equipment, similar to hay harvesting, and raked into windrows. When dried
sufficiently, a combine then harvests the seeds similar to wheat or oat
harvesting. The amount of weeds in the straw affects its marketability, and
this coupled with market prices determined whether the farmer chose to harvest
the flax straw. If the flax was not harvested, it was typically burned, since
the straw stalk is quite tough and decomposes slowly (i.e., not in a
single season), and still being somewhat in a windrow from the harvesting
process, the straw would often clog up tillage and planting equipment. It was
common, in the flax growing regions of western Minnesota, to see the harvested
flax straw (square) bale stacks start appearing every July, the size of some
stacks being estimated at 10-15 yards wide by 50 or more yards long, and as
tall as a two-story house.[citation needed]
Manual
The mature plant is pulled up with
the roots (not cut), so as to maximize the fiber length. After this, the flax
is allowed to dry, the seeds are removed, and is then retted.
Dependent upon climatic conditions, characteristics of the sown flax and
fields, the flax remains on the ground between two weeks and two months for
retting. As a result of alternating rain and the sun, an enzymatic action
degrades the pectins which bind fibers to the straw. The farmers turn over the
straw during retting to evenly rett the stalks. When the straw is retted and
sufficiently dry, it is rolled up. It will then be stored by farmers before
scutching to extract fibers.
Flax grown for seed is allowed to
mature until the seed capsules are yellow and just starting to split; it is
then harvested by combine harvester and dried to extract the seed.
Threshing
flax
Threshing is the process of removing
the seeds from the rest of the plant. As noted above in the Mechanical
section, the threshing could be done in the field by a machine, or in another
process, a description of which follows:
The process is divided into two
parts: the first part is intended for the farmer, or flax-grower, to bring the
flax into a fit state for general or common purposes. This is performed by
three machines: one for threshing out the seed, one for breaking and separating
the straw (stem) from the fiber, and one for further separating the broken
straw and matter from the fiber. In some cases the farmers thrash out the seed
in their own mill and therefore, in such cases, the first machine will be
unnecessary.
The second part of the process is
intended for the manufacturer to bring the flax into a state for the very
finest purposes, such as lace, cambric, damask, and very fine linen. This second part is performed by
the refining machine only.
The threshing process would be
conducted as follows:
- Take the flax in small bundles, as it comes from the
field or stack, and holding it in the left hand, put the seed end between
the threshing machine and the bed or block against which the machine is to
strike; then take the handle of the machine in the right hand, and move
the machine backward and forward, to strike on the flax, until the seed is
all threshed out.
- Take the flax in small handfuls in the left hand,
spread it flat between the third and little finger, with the seed end
downwards, and the root-end above, as near the hand as possible.
- Put the handful between the beater of the breaking
machine, and beat it gently till the three or four inches, which have been
under the operation of the machine, appear to be soft.
- Remove the flax a little higher in the hand, so as to
let the soft part of the flax rest upon the little finger, and continue to
beat it till all is soft, and the wood is separated from the fiber,
keeping the left hand close to the block and the flax as flat upon the
block as possible.[citation needed]
- The other end of the flax is then to be turned, and the
end which has been beaten is to be wrapped round the little finger, the
root end flat, and beaten in the machine till the wood is separated,
exactly in the same way as the other end was beaten.
Preparation
for spinning
Before the flax fibers can be spun
into linen, they must be separated from the rest of the stalk. The first step
in this process is called retting. Retting is the process of rotting away the inner stalk,
leaving the outer fibers intact. At this point there is still straw, or coarse
fibers, remaining. To remove these the flax is "broken," the straw is
broken up into small, short bits, while the actual fiber is left unharmed, then
"scutched," where the straw is scraped away from the fiber, and then
pulled through "hackles," which act like combs and comb the straw out
of the fiber.
Retting
flax
There are several methods of retting
flax. It can be retted in a pond, stream, field or a tank. When the retting is
complete the bundles of flax feel soft and slimy, and quite a few fibers are
standing out from the stalks. When wrapped around a finger the inner woody part
springs away from the fibers.
Pond retting is the fastest. It
consists of placing the flax in a pool of water which will not evaporate. It
generally takes place in a shallow pool which will warm up dramatically in the
sun; the process may take from only a couple days to a couple weeks. Pond
retted flax is traditionally considered lower quality, possibly because the
product can become dirty, and easily over-retts, damaging the fiber. This form
of retting also produces quite an odor.
Stream retting is similar to pool
retting, but the flax is submerged in bundles in a stream or river. This
generally takes longer than pond retting, normally by two or three weeks, but
the end product is less likely to be dirty, does not smell as bad and, because
the water is cooler, it is less likely to be over-retted.
Both Pond and Stream retting were
traditionally used less because they pollute the waters used for the process.
Field retting is laying the flax out
in a large field, and allowing dew to collect on it. This process normally
takes a month or more, but is generally considered to provide the highest
quality flax fibers,[citation needed] and produces the least pollution.
Retting can also be done in a
plastic trash can or any type of water tight container of wood, concrete,
earthenware
or plastic.
Metal containers will not work, as an acid is produced when retting, and it
would corrode
the metal. If the water temperature is kept at 80°F, the retting process under
these conditions takes 4 or 5 days. If the water is any colder then it takes
longer. Scum will collect at the top and an odor is given off the same as in
pond retting. Currently 'enzymatic' retting of flax is being researched as a
retting technique to engineer fibers with specific properties (Foulk Akin Dodd
(2008). "Pectinolytic enzymes and retting," BioResources 3(1),
155-169) (Foulk Akin Dodd (2001) "Processing techniques for improving
enzyme-retting of flax," Industrial Crops and Products 13 (2001) 239–248).
Dressing
the flax
Dressing the flax is the term given
to removing the straw from the fibers. Dressing consists of three steps:
breaking, scutching, and heckling. The breaking breaks up the straw, then some
of the straw is scraped from the fibers in the scutching process, then the
fiber is pulled through heckles to remove the last bits of straw.
The dressing is done as follows:
Breaking: The
process of breaking breaks up the straw into short segments. To do it, take the
bundles of flax and untie them. Next, in small handfuls, put it between the
beater of the breaking machine (a set of wooden blades that mesh together when
the upper jaw is lowered, which look like a paper cutter but instead of having
a big knife it has a blunt arm), and beat it till the three or four inches that
have been beaten appear to be soft. Move the flax a little higher and continue
to beat it till all is soft, and the wood is separated from the fiber. When
half of the flax is broken, hold the beaten end and beat the rest in the same
way as the other end was beaten, till the wood is separated.
Scutching:
In order to remove some of the straw from the fiber, it helps to swing a
wooden scutching knife down the fibers while they hang vertically, thus
scraping the edge of the knife along the fibers and pull away pieces of the
stalk. Some of the fiber will also be scutched away, this cannot be helped and
is a normal part of the process.
Heckling:
In this process the fiber is pulled through various different sized heckling combs
or heckles. A heckle is a bed of "nails" - sharp, long-tapered,
tempered, polished steel pins driven into wooden blocks at regular spacing. A
good progression is from 4 pins per square inch, to 12, to 25 to 48 to 80. The
first three will remove the straw, and the last two will split and polish the
fibers. Some of the finer stuff that comes off in the last hackles is called
"tow" and can be carded
like wool and spun. It will produce a coarser yarn than the fibers pulled
through the heckles because it will still have some straw in it.
Genetically
modified flax contamination
In September 2009 it was reported
that Canadian flax exports had been contaminated by a de-registered genetically modified (GM) variety, known as Triffid. Triffid had food and
feed safety approval in both Canada and the U.S. However, Canadian growers and
the Flax Council of Canada had raised concerns about the marketability of this
variety in Europe. The variety was subsequently de-registered in 2001 and never
grown commercially in Canada or the U.S. All stores of the seed were
purportedly crushed or destroyed. Despite these precautions flax exports were
found to contain traces of this transgenic flax variety which resulted in
problems for Canada's flax growers and the industry at large, who export 70% of
their product to Europe. The EU currently has a zero tolerance
policy regarding unapproved GMOs.[29]
As
a symbolic image
Flax is the emblem of Northern Ireland and used by the Northern
Ireland Assembly. In a coronet, it appeared on the
reverse of the British one pound coin to represent Northern Ireland on coins minted in 1986 and
1991. Flax also represents Northern Ireland on the badge of the Supreme Court of the United Kingdom and on various logos associated with it.
In early tellings of the Sleeping Beauty
tale, such as Sun, Moon, and Talia by Giambattista Basile, the princess pricks her finger not
on a spindle but on a sliver of flax, which is later sucked out by her children
conceived as she sleeps.
The entire wiki link with images can be found at: https://en.wikipedia.org/wiki/Flax
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