DESCRIPTION

Agar is commercially available as white to pale yellow bundles consisting of thin, membranous agglutinated strips, or in cut, flaked, granulated, or powdered forms. Agar is a generic name given to a group of related molecules with a repeating unit of agarobiose formed basically by d-and l-galactose units interlinked with α-1,3 and β-1,4 linkages. Approximately every tenth d-galactopyranose unit contains a sulfate ester group. It is extracted from the cellular walls of agarophyte seaweed, considering as such the red seaweed from phylum Rodophyta, which belong to the Gelidiceae, Gracilariaceae, and Ahnpheltiaceae families. It is insoluble in cold water, but it is soluble in boiling water.