The glycosidic torsion angles corresponds to low energy domains of the corresponding disaccharides. This model is only possible under the assumption of the occurrence of the 4C 1 and 1C 4 chair conformations in residue A and B, respectively. Well oriented fibers of Ca 2+, ι-carrageenan yield an X-ray diffraction pattern that indicate from the pitch (2c = 26.56 Å) and the presence of meridional reflections on the third and six layer lines, that the polymer conformation is a three-fold, right-handed, parallel, half-staggered double helix Lambda carrageenan is primarily used to thicken liquids and modify the texture of foods. This prevents gelation and promotes viscous solutions.

The ester sulfate distribution of lambda carrageenan is randomly distributed on the molecule. Lambda carrageenan is highly sulfated and therefore less likely to form a gel structure. The gels are more elastic, dry and provide excellent freeze/thaw stability. The 2-sulfate group on the outside of the iota carrageenan molecule does not allow the helices to aggregate to the same extent as kappa carrageenan, but forms additional bonds through calcium interactions. The divalent calcium ions help form bonds between the carrageenan molecules to form helices.

Iota carrageenan also binds water, but forms a dry, elastic gel, especially in the presence of calcium salts. As the level of potassium is increased, the resulting gel structure becomes tightly aggregated and may cause syneresis (moisture on the gel surface). Potassium salts are essential in order to form this firm gel structure. Kappa carrageenan binds water to form strong, rigid gels. Several members referred to as ι-, κ-, λ- carrageenans difer chemically in their degree of sulfation as well as in the position of the sulfate on the carbohydrate ring.įig.1 Chemical repeat unit of Carrageenans (a) Iota (b) kappa (c) lambdaĪs the molecular structures are not the same, significant functional properties are offered by this family of polysaccharides. Carrageenans belong to a family of gel forming sulfated polysaccharides found in the marine red algae Rhodophyceae.

Iota carrageenan calcium ions