agar (redirected from Agar agar)

Agar, in the Bible

Agar (ā`gər), the same as Hagar.

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agar, substance obtained from seaweed

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.

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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.

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agar [′äg·ər]

(materials)

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

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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