Agar is a natural polysaccharide colloid extracted from red algae seaweed. It is structurally composed of (1-3) -β-D-galactose and (1-4) -3,6-endo-α-L-galactose Composed of chain polymer. Agar and carrageenan. Alginate is the most widely used three seaweed gum in the world. It has been widely used in many fields such as food industry, pharmaceutical industry, daily chemicals,
bioengineering, etc.
Agar is insoluble in cold water and can absorb 20 times its own volume of water. It is easy to dissolve in boiling water. The diluent remains liquid at 42 () but condenses into a compact gel at 37 (). Agar is a component of cell wall and contains complex carbohydrates, calcium and sulfate.