| Flax | |
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| The flax plant | |
| Scientific classification | |
| Kingdom: | Plantae |
| Division: | Magnoliophyta |
| Class: | Magnoliopsida |
| Order: | Malpighiales |
| Family: | Linaceae |
| Genus: | Linum |
| Species: | L. usitatissimum |
| Binomial name | |
| Linum usitatissimum Linnaeus. |
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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 native to the region extending from the eastern Mediterranean to India and was probably first domesticated in the Fertile Crescent. This is called as Agasi/Akshi in Kannada, Jawas/Javas (जवस) or Alashi (अळशी) in Marathi.[1] Flax was extensively cultivated in ancient Ethiopia and ancient Egypt.[2] In a prehistoric cave in the Republic of Georgia dyed flax fibers have been found that date to 34,000 BC.[3][4] New Zealand flax is not related to flax, but was named after it as both plants are used to produce fibers.
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 mm long.
In addition to referring to the plant itself, the word "flax" may refer to the unspun fibers of the flax plant.
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Flax is grown both for its seeds and for its fibers. Various parts of the plant have been used to make fabric, dye, paper, medicines, fishing nets, hair gels, and soap. It is also grown as an ornamental plant in gardens.[citation needed]
| Nutritional value per 100 g (3.5 oz) | |
|---|---|
| Energy | 2,234 kJ (534 kcal) |
| Carbohydrates | 28.88 g |
| Sugars | 1.55 g |
| Dietary fiber | 27.3 g |
| Fat | 42.16 g |
| Protein | 18.29 g |
| Thiamine (Vit. B1) | 1.644 mg (126%) |
| Riboflavin (Vit. B2) | 0.161 mg (11%) |
| Niacin (Vit. B3) | 3.08 mg (21%) |
| Pantothenic acid (B5) | 0.985 mg (20%) |
| Vitamin B6 | 0.473 mg (36%) |
| Folate (Vit. B9) | 0 μg (0%) |
| Vitamin C | 0.6 mg (1%) |
| Calcium | 255 mg (26%) |
| Iron | 5.73 mg (46%) |
| Magnesium | 392 mg (106%) |
| Phosphorus | 642 mg (92%) |
| Potassium | 813 mg (17%) |
| Zinc | 4.34 mg (43%) |
| Percentages are relative to US recommendations for adults. Source: USDA Nutrient database |
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Flax seeds come in two basic varieties: (1) brown; and (2) yellow or golden. Most types have similar nutritional characteristics and equal amounts of short-chain omega-3 fatty acids. The exception is a type of yellow flax called Linola or solin, which has a completely different oil profile and is very low in omega-3. 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 kilo-calories, 41 grams of fat, 28 grams of fiber, and 20 grams of protein.[5]
One tablespoon of ground flax seeds and three tablespoons of water may serve as a replacement for one egg in baking by binding the other ingredients together. Ground flax seeds can also be mixed in with oatmeal, yogurt or any other food item where a nutty flavor is appropriate. Flax seed sprouts are edible, with a slightly spicy flavor. Excessive consumption of flax seeds with inadequate water can cause bowel obstruction.[6] Flaxseed is called 'Tisi' in northern India, particularly in the Bihar region.[citation needed] Roasted 'Tisi' is powdered and eaten with boiled rice, a little water, and a little salt since ancient times in the villages.[citation needed] It is aromatic and considered soothing for the stomach, useful as a laxative, and good for health.[citation needed]
Flax seeds are chemically stable while whole, and milled flax seed can be stored at least 4 months at room temperature with minimal or no changes in taste, smell, or chemical markers of rancidity.[7] Ground flaxseed can go rancid at room temperature in as little as one week.[8] Refrigeration and storage in sealed containers will keep ground flax from becoming rancid for a longer period.[citation needed]
Flax seeds contain high levels of lignans and Omega-3 fatty acids. Lignans may benefit the heart, possess anti-cancer properties and studies performed on mice found reduced growth in specific types of tumors. Flax seed may also lower cholesterol levels, especially in women.[9] Initial studies suggest that flaxseed taken in the diet may benefit individuals with certain types of breast[10][11] and prostate cancers.[12] A study done at Duke suggests that flaxseed may stunt the growth of prostate tumors [13]. A recent meta-analysis found the evidence on this point to be mixed and inconclusive (Am J Clin Nutr (March 25, 2009). doi:10.3945/ajcn.2009.26736Ev1). Flax may also lessen the severity of diabetes by stabilizing blood-sugar levels.[14] 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.[15] Consuming large amounts of flax seed can impair the effectiveness of certain oral medications, due to its fiber content.[15] May have adverse effect due to its content of neurotoxic cyanogen glycosides and immuno-suppressive cyclic nonapeptides.[16]
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.[17] 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. Currently most flax produced in the USA and Canada are seed flax types for the production of linseed oil or flax seeds for human nutrition.[citation needed]
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. Flax mills for spinning flaxen yarn were invented by John Kendrew and Thomas Porthouse of Darlington in 1787.[18]
The significant linseed producing countries are Canada (~34%), China (~25.5%) and India (~9%), though there is also production in USA (~8%), Ethiopia (~3.5%) and throughout Europe. In the United States, three states, North Dakota, South Dakota, and Minnesota, raise nearly 100% of this plant.[citation needed]
| Top ten linseed producers — 2007 | ||||
|---|---|---|---|---|
| Country | Production (Tonnes) | Footnote | ||
 Canada |
633,500 | |||
 People's Republic of China |
480,000 | * | ||
 India |
167,000 | |||
 United States |
149,963 | |||
 Ethiopia |
67,000 | * | ||
 Bangladesh |
50,000 | F | ||
 Russia |
47,490 | |||
 Ukraine |
45,000 | * | ||
 France |
41,000 | F | ||
 Argentina |
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); |
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The soils most suitable for flax, besides the alluvial kind, are deep friable loams, and containing a large proportion of organic matter. 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.
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.
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.
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 burnt, 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 wides by 50 or more yards long, and as tall as a two-story house.[citation needed]
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 in 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 is the process of removing the seeds from the rest of the plant. As noted above in the Method 1 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:
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.
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 odour 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 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:
In September 2009 it was reported that Canadian flax exports had been contaminated by an unapproved, illegal, genetically modified (GM) variety, known as Triffid. The Flax Council of Canada had raised concerns about the marketability of this variety in Europe and the Canadian Food Inspection Agency had declared it illegal to grow. Despite these precautions the flax crop has now been contaminated with this GM variety, threatening Canada's flax growers, who export 70% of their product to Europe where there is a zero tolerance policy regarding GMOs.[19]
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.
Common flax is the national flower of Belarus.
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.
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LINSEED, the seed of the common flax or lint, Linum usitatissimum. These seeds, the linseed of commerce, are of a lustrous brown colour externally, and a compressed and elongated oval form, with a slight beak or projection at one extremity. The brown testa contains, in the outer of the four coats into which it is microscopically distinguishable, an abundant secretion of mucilaginous matter; and it has within it a thin layer of albumen, enclosing a pair of large oily cotyledons. The seeds when placed in water for some time become coated with glutinous matter from the exudation of the mucilage in the external layer of the epidermis; and by boiling in sixteen parts of water they exude sufficient mucilage to form with the water a thick pasty decoction. The cotyledons contain the valuable linseed oil referred to below. Linseed grown in tropical countries is much larger and more plump than that obtained in temperate climes, but the seed from the colder countries yields a finer quality of oil.
Linseed formed an article of food among the Greeks and Romans, and it is said that the Abyssinians at the present day eat it roasted. The oil is to some extent used as food in Russia and in parts of Poland and Hungary. The still prevalent use of linseed in poultices for open wounds is entirely to be reprobated. It has now been abandoned by practitioners. The principal objections to this use of linseed is that it specially favours the growth of micro-organisms. There are numerous clean and efficient substitutes which have all its supposed advantages and none of its disadvantages. There are now no medicinal uses of this substance. Linseed cake, the marc left after the expression of the oil, is a most valuable feeding substance for cattle.
Linseed is subject to extensive and detrimental adulterations, resulting not only from careless harvesting and cleaning, whereby seeds of the flax dodder, and other weeds and grasses are mixed with it, but also from the direct admixture of cheaper and inferior oil-seeds, such as wild rape, mustard, sesame, poppy, &c., the latter adulterations being known in trade under the generic name of " buffum." In 1864, owing to the serious aspect of the prevalent adulteration, a union of traders was formed under the name of the " Linseed Association." This body samples all linseed oil arriving in England and reports on its value.
Linseed oil, the most valuable drying oil, is obtained by expression from the seeds, with or without the aid of heat. Preliminary to the operation of pressing, the seeds are crushed and ground to a fine meal. Cold pressing of the seeds yields a golden-yellow oil, which is often used as an edible oil. Larger quantities are obtained by heating the crushed seeds to 160° F. (71 ° C.), and then expressing the oil. So obtained, it is somewhat turbid and yellowish-brown in colour. On storing, moisture and mucilaginous matter gradually settle out. After storing several years it is known commercially as " tanked oil," and has a high value in varnish-making. The delay attendant on this method of purification is avoided by treating the crude oil with 1 to 2% of a somewhat strong sulphuric acid, which chars and carries down the bulk of the impurities. For the preparation of " artist's oil," the finest form of linseed oil, the refined oil is placed in shallow trays covered with glass, and exposed to the action of the sun's rays. Numerous other methods of purification, some based on the oxidizing action of ozone, have been suggested. The yield of oil from different classes of seed varies, but from 23 to 28% of the weight of the seed operated on should be obtained. A good average quality of seed weighing about 392 It) per quarter has been found in practice to give out 109 lb of oil.
Commercial linseed oil has a peculiar, rather disagreeable sharp taste and smell; its specific gravity is given as varying from 0.928 to 0.953, and it solidifies at about - 27°. By saponification it yields a number of fatty acids - palmitic, myristic, oleic, linolic, linolenic and isolinolenic. Exposed to the air in thin films, linseed oil absorbs oxygen and forms " linoxyn," a resinous semi-elastic, caoutchouclike mass, of uncertain composition. The oil, when boiled with small proportions of litharge and minium, undergoes the process of resinification in the air with greatly increased rapidity.
Its most important use is in the preparation of oil paints and varnishes. By painters both raw and boiled oil are used, the latter forming the principal medium in oil painting, and also serving separately as the basis of all oil varnishes. Boiled oil is prepared in a variety of ways - that most common being by heating the raw oil in an iron or copper boiler, which, to allow for frothing, must only be about three-fourths filled. The boiler is heated by a furnace, and the oil is brought gradually to the point of ebullition, at which it is maintained for two hours, during which time moisture is driven off, and the scum and froth which accumulate on the surface are ladled out. Then by slow degrees a proportion of " dryers " is added - usually equal weights of litharge and minium being used to the extent of 3% of the charge of oil; and with these a small proportion of umber is generally thrown in. After the addition of the dryers the boiling is continued two or three hours; the fire is then suddenly withdrawn„and the oil is left covered up in the boiler for ten hours or more. Before sending out, it is usually stored in settling tanks for a few weeks, during which time the uncombined dryers settle at the bottom as ” foots." Besides the dryers already mentioned, lead acetate, manganese borate, manganese dioxide, zinc sulphate and other bodies are used.
Linseed oil is also the principal ingredient in printing and lithographic inks. The oil for ink-making is prepared by heating it in an iron pot up to the point where it either takes fire spontaneously or can be ignited with any flaming substance. After the oil has been allowed to burn for some time according to the consistence of the varnish desired, the pot is covered over, and the product when cooled forms a viscid tenacious substance which in its most concentrated form may be drawn into threads. By boiling this varnish with dilute nitric acid vapours of acrolein are given off, and the substance gradually becomes a solid non-adhesive mass the same as the ultimate oxidation product of both raw and boiled oil.
Linseed oil is subject to various falsifications, chiefly through the addition of cotton-seed, niger-seed and hemp-seed oils; and rosin oil and mineral oils also are not infrequently added. Except by smell, by change of specific gravity, and by deterioration of drying properties, these adulterations are difficult to detect.
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