depends on the amounts of potassium ions
present. i-Carrageenan (obtained mostly
fromEucheuma spinosum) forms thermally
reversible elastic gelatin-like gels with calci-
um ions.
Solutions and gels of carrageenan are
degraded rapidly by low pH and high tem-
peratures. Degraded carrageenans (molecular
weight approximately 15,000) do not have the
viscosity or gelling properties of food-grade
carrageenans (molecular weight>100,000).
PHARMACOLOGY AND BIOLOGICAL
ACTIVITIES
Carrageenan has been reported to exhibit
many pharmacological activities in animals,
including lowering of blood cholesterol level,
reducing gastric secretions and food absorp-
tion, and increasing water content of the gut
when large doses are ingested. However,
carrageenan is not absorbed following oral
administration and does not undergo metabo-
lization to lower molecular weight substances.
When administered parenterally, it has
shown anticoagulant, hypotensive, and immu-
nosuppressive activities. Furthermore, when
injected into a rodent’s paw, carrageenan
produces a reproducible inflammatory condi-
tion, which is extensively used as a model
for screening potential anti-inflammatory
drugs.2,8,9
Carrageenan, both in the degraded (poli-
geenan; molecular weight20,000) and un-
degraded forms, has been reported to alleviate
peptic and duodenal ulcers in humans (MARTIN-
DALE). Carrageenan has inhibitory effects on
pepsin activity in vitro. Its degraded form
(no viscosity) and forms with low and high
viscosities, all exhibit antiproteolytic activi-
tiesin vitroagainst papain.^10
TOXICOLOGY
At high doses the degraded form of carrageen-
an (poligeenan) shows various toxic effects,
especially when administered by injection.
Food-grade carrageenan (molecular weight
>100,000) has undergone extensive toxico-
logical testing, which demonstrated that they
are not absorbed through the gutand and are
nontoxic,^2 noncarcinogenic, nongenotoxic,
and not tumor promoting. Studies that have
shown any toxicity from carrageenan involved
injecting the substance into animals or used
doses far in excess of amounts that pertain to
human exposure.^7USESMedicinal, Pharmaceutical, and Cosmetic.
Used extensively as binder, emulsifier, or
stabilizer in toothpastes; also in hand lotions,
creams, tablets, and others.
The degraded form has been used in pre-
parations for treating peptic ulcers, primarily
in Europe (France).Food. Carrageenan (or its salts) is extensive-
ly used in food products for its gelling, stabi-
lizing, and thickening properties. Carrangee-
nans have been used by the meat processing
industry to improve the texture of produced
meat products with reduced fat.^11 Other pro-
ducts that incorporate carrageenans include
milk products such as chocolate milk, ice
cream, sherberts, cottage cheese, cream
cheese, evaporated milk, milk desserts, pud-
dings, yogurts, infant formulas, and others.
Carrageenan is also used in gravies, thicken-
ing sauces, bread doughs, jams, and jellies,
among others. Its major functions are as thick-
ening, gelling, emulsifying, stabilizing, and
suspending agents, preventing the settling of
solids, and in the case of ice cream, to prevent
ice crystal formation, among others. For use in
gel products such as jams and jellies, its use
level is usually 0.5–1.1%;locust bean gumis
often used with carrageenan to improve its gel
strength and elasticity.Dietary Supplements/Health Foods. Carra-
geenan is used in various weight-loss146 Carrageenan