agar+and+carrageenan

Carrageenans are large, highly flexible molecules which curl forming helical structures. This gives them the ability to form a variety of different gels at room temperature. They are widely used in the food and other industries as thickening and stabilizing agents. A particular advantage is that they are pseudoplastic—they thin under shear stress and recover their viscosity once the stress is removed. This means that they are easy to pump but stiffen again afterwards. carrageenans.

Same with carregeenan,it also forming helical structure.Agar consists of a mixture of agarose and agaropectin. Agarose is a linear polymer,made up of the repeating monomeric unit of agarobiose. Agarobiose is a disaccharide made up of D-galactose and 3,6-anhydro-L-galactopyranose. Its major differences from carrageenans are the presence of L-3,6-anhydro-α-galactopyranose rather than D-3,6-anhydro-α-galactopyranose units and the lack of sulfate groups. Agaropectin is a heterogeneous mixture of smaller molecules that occur in lesser amounts. Their structures are similar but slightly branched and sulfated, and they may have methyl and pyruvic acid ketal substituents. They gel poorly and may be simply removed from the excellent gelling agarose molecules by using their charge. The quality of agar is improved by toe treatment that converts of any L-galactose-6-sulfate to 3,6-anhydro-L-galactose.