Dried extracts from various seaweeds, including Gelidium and Gracilaria spp. It is a partially soluble non-starch polysaccharide, composed of galactose units, which swells with water to form a gel, and is used in soups, jellies, ice cream and meat products. Also used as the basis of bacteriological culture media, as an adhesive, for sizing silk and as a stabiliser for emulsions.
Also called agar-agar, macassar gum, vegetable gelatine. Blood agar is a microbiological culture medium containing 5–10% horse blood.