Algin comprises about 10% of the dry weight of the kelps and is mostly the salt of alginic acid.
The derivatives are sodium, ammonium, and potassium alginates of which the sodium salt is most common.
The process for algin manufacturing involved a prewash of the seaweed, followed by extraction with a dilute alkaline solution that soluble the alginic acid present in the seaweed. The resulting thick and viscous mass is clarified and the algin is obtained as free alginic acid on treatment with mineral aid.
They used to provide thickening, gelling, and binding.
A derivative designed for improved acid and calcium stability is propylene glycol alginate.
The algins are soluble in cold water and form non-thermoreversible gels in reaction with calcium ions and under acid conditions.
Algin is used in ice-cream, icings, pudding, dessert gels, in the production of dairy products, candies, processed cheese, and fabricated fruit.
They act as stabilizers in cream substitutes and chocolate suspensions. They prevent the formation of ice-crystals during the process of freezing and produce uniform viscosity, good whipping–ability, smooth melting and full development of aromatic components.
Algin was first discovered by Stanford in thee early 1880s. Stanford, when he first prepared this substance, did not succeed obtaining it in the pure state, and because of the impurities he described it as a nitrogen-containing compound.
It was late properly prepared by Krefting in 1896, who thought he had a new substance which he called ‘tangsaure’, or seaweed acid.
Algin
