[化] 琼脂

[医] 琼脂, 洋粉

[ noun ]
a colloidal extract of algae; used especially in culture media and as a gelling agent in foods
<noun.substance>

Agar-agar \A`gar-a"gar\, n. [Ceylonese local name.]
1. A fucus or seaweed much used in the East for soups and
jellies; Ceylon moss ({Gracilaria lichenoides}).

2. A gelatinlike substance, or a solution of it, prepared
from certain seaweeds containing gelose (such as Ceylon
moss, {Gracilaria lichenoides} or other seaweeds of the
genera {Gelidium}, {Ceramium}, {Pterocladia}, and
{Eucheuma}), and used for solidifying growth media in the
artificial cultivation of bacteria, or as a gelling agent
in foods; -- usually called simply {agar}, by
abbreviation.

Note: In composition it is predominantly a polysaccharide,
and is not degraded by most bacteria. It thus almost
completely replaced the earlier protein-based gelatins
used for fixing bacterial colonies on culture plates,
as the gelatins were often dissolved by the proteolytic
enzymes common in bacteria.

Syn: gelose, agar.
[Webster 1913 Suppl.]