2.6.3 Linseed
Synonym Flax seed.
Biological Source It consists of the dried fully ripe seeds of Linum usitatissimum Linn. Belonging to family Liliaceae.
Geographical Sources It is cultivated extensively as a source of fibres in Algeria, Egypt, Greece, Italy and Spain; as a source of oil in Afghanistan, India and Turkey; and in Russia (now CIS – countries) for both oil and fibre. It is also found in several temperate and tropical zones.
Preparation The cyanogenetic glycoside linamarin is prepared from the defatted oil meal, seedskins or embryos of flax by standard methods available for glycosides.
Description
Colour : Reddish brown
Odour : Characteristic odour
Shape : Oval and strongly flattened
Size : Length = 4-6 mm; Width = 2-3 mm.
Chemical Constituents The ripe seeds of linseed contain small quantitites of a cyanogenetic glycosides known as linamarin (or phaseolunatin) as given below:
Interestingly, linamarin evolved HCN with linseed meal only but not with emulsin. However, pure linamarin is a bitter needle like crystalline substance. It is freely soluble in water, cold alcohol, hot acetone, slightly in hot ethyl acetate, ether, benzene, chloroform and practically insoluble in petroleum ether.
Besides, linseed seeds comprise of fixed oil (33-43%) mucilage present in testa (6%), proteins (25%) and an enzyme called linase.
Linamarin upon enzytmatic hydrolysis yields HCN which actualy renders the seeds highly poisonous.
Chemical Test The mucilage of linseed seed gives a distinct red colour on being treated with Ruthenium Red Solution.
Uses
1. Therapeutically, the linseed oil is mostly recommended for the external applications only; liiments and lotions.
2. It is employed in the treatment of scabies and other skin disease in combination with pure flowers of sulphur.
3. As the linseed oil has an inherent very high ‘iodine value’ it is used mostly in the preparation of non staining ‘Iodine Ointment’ and several other products such as: ‘Cresol with Soap’.
4. Commercially, it is one of the most important ‘drying oil’; and, therefore, substantially huge amounts are exclusively used for varnishes and paints.
5. Linseed oil finds its extensive application in the manufacturer of soap, grease, polymer, plasticizer,
polish and linoleum.
