Carrageenans

Carrageenans are the sulfated polysaccharides that are obtained from red algae. They are most commonly applied as gelling agents. They are made up of alternating disaccharide units of 1, 3 linked beta galactose linked to either 1,4 alpha galactopyranose or 3,6 anhydrogalactose. They are classified as either λ, κ, ι, ε, μ, depending on the degree of sulfation. The extraction process makes use of alkali, acids and salts and requires energy for heating and additional processes to recover and purify carrageenan from seaweed biomass. These are considered in evaluating the environmental impact of carrageenan production. Presently, carrageenan is more commonly used for its rheological properties as a gelling agent in food and other consumer goods. Some studies have also presented potential application as a bioactive compound and in renewable energy system components.