Nomenclature
CAS number: 9000-21-9
Furcellaria gum; Danish agar; Burtonite 44.
Description and references
A gum obtained from a seaweed of the Rhodophyceae, the red alga Furcellaria fastigiata, fam. Furcellariaceae, order Gigartinales. The weed is found primarily in Northern
European waters, especially in the Kattegat (between Sweden and Denmark).
The gum is the potassium salt of the sulfuric acid ester of a high
molecular weight polysaccharide. Consists mainly of d-galactose,
3,6-anhydro-d-galactose, and the half-ester sulfates of these
sugars; one sulfate group occurs for each three or four monomeric
units, which are arranged in an alternating sequence of (1→3) and
(1→4)-linked units. Review: Bjerre-Petersen et al. in Industrial Gums, R. L. Whistler,
Ed. (Academic Press, New York, 2nd ed., 1973) pp 123-136.
Properties
The processed gum is a white, odorless powder.
Sol in hot or warm water. Easily dispersed in cold water to a homogeneous
suspension without lumps; the furcellaran particles hydrate, swell
and become almost invisible but do not dissolve unless heated. Forms
agar-like gels at low concns. The strength of the gel can be increased
by adding salts, esp potassium salts. Highly viscous. Solns in neutral
medium are not adversely affected by prolonged exposure to high heat.
However, exposure to heat in acidic media results in rapid hydrolysis
and loss of gelling power.Use
Natural colloid, gelling agent, viscosity control
agent used primarily in food products but also in pharmaceuticals.
Also in products for diabetics, proprietaries for reducing excess
body wt, toothpastes. As carrier for food preservatives, bactericides.
In bacteriological culture media.