AGAR AGAR is gel forming substance obtainable from species of seaweeds called AGAROPHYTES, composed of neutral gelling molecules, Agarose and to a lesser extent Acidic non gelling molecules agaropectin.

Agarose is a strongly gelling non-ironic polysaccharide long chain molecule formed by B-D galacto Pyranose residues connected through C-1 and C-3 woth 3.6- Anhydro-L- Galactose residues connected through C2-C4. Both residues are repeated alternatively. Depending on the orgin of the seaweeds some units of 3.6- Anhydro-L- Galactose are replaced by L- Galactose.Also some D- Galactose and L- Galactose units can be methylated.

Agaropectin is less clearly defined ,more complex polysaccharide having Sulphate group attached to it.

Agar is insoluble in cold water and soluble in hot water. A1% solution gels at 45°C to 35°C to form a gel melting at 80°C to 95°C.