The sea lettuce Ulva is rich in beta-carotene, a natural
antioxidant and cancer-fighting agent.
kelp, for example, are considered
excellent detoxifying agents. This is
because the alginate in their tissues
will bind with any toxins in the intestines, essentially rendering them
indigestible and carrying them out
of the system. Not many people
will, however, readily eat whole
kelp.
In South Africa, the seaweed industry is based largely on sea bamboo
(Ecklonia maxima) and split-fan kelp
(Laminaria pallida). Kelp is harvested extensively along our west and
southwest coasts as feed for commercially farmed abalone and is
even used as a nutritional supplement for farm animals in local agriculture. Kelp is widely used as a
fertilizer and is harvested on a large
scale for the production of a very
successful plant growth stimulant
having been shown to be a great
source of micronutrients and beneficial plant growth promoters.
Furthermore, alginate is a substance of considerable economic
importance as it is used as a gelling
and emulsifying agent in a number
of industries. Surprisingly though,
at present it is only the kelp that are
harvested commercially in South
Africa for alginate extraction. Perhaps it is because no other group of
brown seaweed occurs in large
enough biomass to be commercially
viable. Internationally, however, a
huge market exists for the harvest-
Encrusting coralline red seaweeds are important in the
ecology of near-shore marine ecosystems and also
present a number of economic uses.
ing of kelp and other brown seaweed for alginate production. In
the food industry alginate makes
water-based products thicker,
creamier, and more stable over extreme differences in temperature,
pH and time. For example, alginate
prevents the formation of ice crystals in ice cream. Other products
containing alginate include brownie
mix, frozen foods, desserts, relishes,
salad dressing, sauces, gravies and
even beer foam. Similarly, in the
cosmetics, pharmaceutical, paint,
textile and welding industries, alginate aids in the suspension and stabilization of agents over ranges of
temperature and pH. In the paper
industry alginate is important as it
enables sizing and polishing of the
finished paper product. Did you
know that alginate from kelp is
even used to make fibers for high
quality audio speakers?
Kelp is especially important to the
medical industry. Alginate is used
to encapsulate many things such as
tablets in powder form, fracture
castings and moulds, and even organs for transplant. Kelp also contains an astonishing amount of vitamins and minerals. The most important of these supplements
though is probably iodine. Iodine
has a normalizing effect on the thyroid gland (this gland controls the
body’s growth and development).
In Namibia, scientists have been
looking into the use of kelp as a
treatment of goiter and prevention
of (or reduction in the occurrence
of) cretinism in southern Africa.
Similarly, because iodine feeds the
thyroid, kelp is even used in weight
loss formulas. Just like carotenoids,
Japanese studies have also shown a
direct relationship between alginate
contained in kelp and the prevention of breast cancer in women.
Red Seaweeds (fleshy)
While the seaweed industry in the
Western world is based mainly on
seaweed extracts, in the East seaweeds are cultivated in huge volumes for human consumption.
Much of this industry though is
based on red seaweeds. The genus
Porphyra (purple laver) in particular,
contributes at least 80% of all seaweed harvested all over the world.
In Asia, Porphyra (known as nori) is
eaten as a whole seaweed either
dried or in soups, and globally as
tasty wrappings for sushi. The iodine and high vitamin and protein
content of nori makes it attractive,
as does the relative simplicity of its
mariculture (sea farming), which
began more than 300 years ago in
Japan.
Beside food for direct consumption,
red seaweeds are also important for
their phycocolloid extracts. Phycocolloids are seaweed derivatives
that cause particles to remain suspended in solution and are therefore excellent as stabilizing and gel-