agar (ä´gär, ā´–, ăg´är), product obtained from several species of red algae, or seaweed, chiefly from the Ceylon, or Jaffna, moss (Gracilaria lichenoides) and species of Gelidium, harvested in eastern Asia and California. Chemically, agar is a polymer made up of subunits of the sugar galactose; it is a component of the algae's cell walls. Dissolved in boiling water and cooled, agar becomes gelatinous; its chief uses are as a culture medium (particularly for bacteria) and as a laxative, but it serves also as a thickening for soups and sauces, in jellies and ice cream, in cosmetics, for clarifying beverages, and for sizing fabrics. See also Rhodophyta.

agar Dried extracts from various seaweeds, including Gelidium and Gracilaria spp. It is a partially soluble non‐starch polysaccharide, composed of galactose units. It swells with water to form a gel, and is used in soups, jellies, ice‐cream, and meat products. It is also used as the basis of bacteriological culture media, as an adhesive, for sizing silk, and as a stabilizer for emulsions. Also called agar‐agar, Macassar gum, vegetable gelatine.

a·gar / ˈäˌgär; ˈāˌgär/ (also a·gar-a·gar / ˈägär ˈäˌgär; ˈāgär ˈāˌgär/ ) • n. a gelatinous substance obtained from various kinds of red seaweed and used in biological culture media and as a thickener in foods.

agar An extract of certain species of red seaweeds that is used as a gelling agent in microbiological culture media, foodstuffs, medicines, and cosmetic creams and jellies. Nutrient agar consists of a broth made from beef extract or blood that is gelled with agar and used for the cultivation of bacteria, fungi, and some algae.

agar Complex substance extracted from seaweed; its powder forms a ‘solid’ gel in solution. It is used as a thickening agent in foods; as an adhesive; as a medium for growing bacteria, mould, yeast and other microorganisms; as a medium for tissue culture; and as a gel for electrophoresis.

agar A complex polysaccharide obtained from certain types of seaweed. When heated with water and subsequently cooled to about 45°C, agar readily forms a gel (jelly); an agar gel supplemented with nutrients is used widely as a medium for the culture of bacteria and other micro-organisms.

agar A complex polysaccharide obtained from certain types of seaweed. When heated with water and subsequently cooled to about 45°C, agar readily forms a gel (jelly); an agar gel supplemented with nutrients is used widely as a medium for the culture of bacteria and other micro-organisms.

agar (ay-ger) n. an extract of certain seaweeds that forms a gel suitable for the solidification of liquid bacteriological culture media. Agar may also be used as a laxative.

Agar (ā´gər), the same as Hagar.