Description and Cultivation
Linseed comes from the family Linaceae, Genus Linum, which includes the vast majority of the herbs and shrubs found in temperate and sub-tropical regions bordering the Mediterranean Sea. The lin/flax plant has not only been a source of fibre for linen since ancient times, but has a long history as a healing herb as well. First cultivated in Europe, the flaxseeds were crushed and used against inflamed skin and constipation.
Flaxseeds have benefits in food. Its oil is richer than any other vegetable oil in linolenic acid. Alpha-linolenic acid (ALA) contributes to the maintenance of normal blood cholesterol levels. The beneficial effect is obtained with a daily intake of 2 g of ALA. This is the case if the food contains at least 0,3 g alpha-linolenic acid per 100 g and per 100 kcal, or at least 40 mg of the sum of eicosapentaenoic acid and docosahexaenoic acid per 100 g and per 100 kcal. This was recognised by EFSA (see http://www.efsa.europa.eu/en/efsajournal/doc/1252.pdf and http://www.efsa.europa.eu/en/efsajournal/doc/2203.pdf) and is approved as a health claim in EU (Regulation (EU) 432/2012).
In addition, it is also recognised that essential fatty acids are needed for normal growth and development of children. The beneficial effect is obtained with a daily intake of 2 g of α-linolenic acid (ALA) and a daily intake of 10 g of linoleic acid (LA).This was recognised by EFSA (see http://www.efsa.europa.eu/en/efsajournal/doc/783.pdf) and is approved as a health claim in EU (Regulation (EU) 983/2009 as amended by Regulation (EU) 376/2010).
Other sources of -linolenic acid are rapeseed and soybean oils with approximately 10 %, whereas flaxseed oil contains up to 55 % of this fatty acid.
Canada, Russia, Kazakhstan, China and the United States are the main production areas.
Refined linseed oil primarily lends itself to uses in the industrial production of paints and coatings. In combination with resins and pigments, linseed oil has long been employed as an ingredient in conventional coatings and inks. Today, there is a demand for refined linseed oil of many different grades. These are obtained by a refining process involving the steps of degumming, deacidification, and bleaching.
Linseed oil is used to make synthetic resins, especially linseed alkydes for printing inks, stand oils, and varnishes. Linseed oil is also used as a binder for pigment pastes.
Linseed stand oil of varying viscosity and acidity is obtained by polymerization at high temperatures. It is used to produce coatings of many kinds, inks, corrosion-proof and aluminum paints, and brake linings.
Blown linseed oil, thickened with air at high temperatures, exhibits excellent wettability and is therefore used in the ink industry and as a major binder in foundries and paint production.
Whilst the oil has limitations in the animal feed market due to its amino acid make-up, the expeller meal is a valuable protein livestock feed (particularly for ruminants) and has a crude protein level of 38%. Whilst this does not compare directly with the higher protein feeds such as soybean meal, it is comparable with more direct competitors such as rapeseed meal.
The range of uses is so incredibly broad that even methods thousands of years old are now being revived. Linseed oil is also regaining importance as a renewable raw material.