agar

agar

a complex gelatinous carbohydrate obtained from seaweeds, esp those of the genus Gelidium, used as a culture medium for bacteria, a laxative, in food such as ice cream as a thickening agent (E406), etc.

Collins Discovery Encyclopedia, 1st edition © HarperCollins Publishers 2005

Agar

A major constituent of the cell walls of certain red algae, especially members of the families Gelidiaceae and Gracilariaceae. Extracted for its gelling properties, it is one of three algal polysaccharides of major economic importance, the others being alginate and carrageenan. Agar is composed of two similar fractions, agarose and agaropectin, in which the basic unit is galactose, linked alternately α-1,3-( d -galactose) and β-1,4-(α- l -galactose).

Agar is prepared by boiling the algae in water, after which the filtered solution is cooled, purified, and dried. It is an amorphous, translucent material that is packaged in granules, flakes, bricks, or sheets. One of its chief uses is as a gelling agent in media for culturing microorganisms. It is also used in making confections, as an emulsifier in cosmetics and food products, as a sizing agent, as an inert carrier of drugs in medicine, and as a laxative. See Culture

McGraw-Hill Concise Encyclopedia of Bioscience. © 2002 by The McGraw-Hill Companies, Inc.

agar

[′äg·ər]

(materials)

A gelatinous product extracted from certain red algae and used chiefly as a gelling agent in culture media.

McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.