Agar is the most ancient polycolloid, a colloid extracted from red seaweed, currently used as gelling, thickening and stabilizing food additive.

It has been discovered in Japan during the seventeenth century, two-hundreds years before the other two colloids extracted from seaweeds, Alginates and Carrageenan, were discovered in the West.

Only in late nineteenth century agar arrived in Europe and the first application of Agar in Europe was as gelling agent for solid microbiological cultures media, and has determined the development of microbiology science.

Agar is derived from the polysaccharide agarose, which forms the supporting structure in the cell walls of certain species of algae, and which is released on boiling. These algae are known as agarophytes and belong to the Rhodophyta (red algae) phylum.

Agar is actually the resulting mixture of two components: the linear polysaccharide agarose, and a heterogeneous mixture of smaller molecules called agaropectin.

It is maybe the strongest gelling agent among natural additives, also it  has a melting point of 85 °C, but it is solidifying from 32 to 40 °C. This peculiar property of heat resistance of the gel, lends a suitable balance between easy melting and good gel stability at relatively high temperatures.

Agar is a natural vegetable gelatin counterpart.

It can be used to make meat in gel, confectionery jellies, puddings, and custards.