Kelp (Laminaria digitata)

Kelp Laminaria digitata

Kelp Laminaria digitata – photo courtesy and copyright of Prof M Guiry

Scientific classification :

Kingdom : Chromalveolata

Division : Heterokontophyta

Class : Phaeophyceae

Order : Laminariales

Family : Laminariaceae

Genus : Laminaria

Species : Laminaria digitata   (Huds) Lamouroux 1813

 

Common Names :

Kombu, Konbu, Oarweed, Kombu, Tangleweed, Sea Girdle, Sea Tangle, Sea Ribbon.

 

Distribution :

Kelp – Laminaria digitata – is a very common brown seaweed / algae found at the Low Water Shore area in the Irish, North European and Eastern North American Coastline. It can be found growing in depths of up to 10m.

Description :

Kelp – Laminaria digitata – can vary in colour from dark brown to olive green, but is more commonly a golden brown colour.

It can grow up to 2.5m long and 60 cm across the frond. It holds onto the rocks / substrate by a holdfast, that is thin and intertwining.

The frond is large and flat, smooth and rubbery with finger like sections.

It is often confused with Laminaria hyperborea – but this species grows deeper and is more rigid that Laminaria digitata.

Uses of Kelp :

Kelp – Laminaria digitata – was traditionally used as a fertilizer and also in the 18th Century was burnt to create potash for the Glass Industry.

In the 19th Century it was discovered that Kelp (Laminaria digitata) was rich in Iodine (I) and was widely used as a supplement for under-active thyroids (myxoedema) and the treatment of goitre.

It is still used as an organic fertiliser today and also within the Alginate Industry for the extraction of alginic acid.

Alginic acid is a polysaccharide within the plant cells and when combined with water forms a viscous gum. In an extracted form alginates are capable of holding 200 to 300 times their own weight in water.

Alginates are used widely throughout the pharmaceutical, medical and food industries – with uses ranging from slimming aids, indigestion remedies, the manufacture of paper, textiles, waterproofing and fireproofing fabrics, burns dressings, thickening, emulsifying and stabilising foods – such as drinks, ice cream, toothpaste and jellies.

In March 2010, researches at Newcastle University found that dietary alginates can reduce human fat uptake by more than 75% and its is widely used in the weight loss industry as an appetite suppressant.

In Japan and China – kelp – is used to make Dashi – a soup stock that simple to make – heat the kelp to near boiling point in water and strain the resultant liquid. This is suitable for vegetarians and vegans as Dashi can contain Bonito flakes.

See Our Recipe page for more details