The lower intertidal and shallow subtidal
zones are rich in diversity of seaweeds.
In the oceans, along with microscopic algae
known as phytoplankton, seaweeds form
the base of the food chain.
Considered excellent detoxifying agents.
Produce alginate, a substance of considerable economic value and used as a gelling
and emulsifying agent. For example, alginate prevents the formation of ice crystals
in ice cream. In the medical industry, alginate is used to encapsulate tablets in powder form and to form fracture castings and
moulds. Other products containing alginate include brownie mix, frozen foods,
desserts, relishes, salad dressings, sauces,
gravies and even beer foam.
Kelp also contains an astonishing amount
of vitamins and minerals, particularly iodine, which has a normalizing effect on
the thyroid gland that controls the body’s
growth and development.
In many countries, kelp is harvested as a
feed and nutritional supplement for commercially farmed animals.
Due to its high micronutrient contents,
kelp is widely used as fertilisers and as
plant growth stimulants.
Fleshy Red seaweeds
While the seaweed industry in the West is
based mainly on seaweed extracts, in the
east seaweeds are cultivated in huge quantities for human consumption. Red seaweeds from 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.
Red seaweed extracts
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 gelling
agents. The main phycocolloids derived
from red seaweeds are carrageenan and
agar.
Carrageenan is highly sort after in western
societies where it is especially important in
the dairy industry. Milkshakes, cheese, yoghurt, powdered milk (including baby formula) all possess red seaweed carrageenan
extracts. Carrageenan is also used in
toothpaste, cosmetics, shampoos, paints
and pet food.
Agar on the other hand, has its most important use as a medium on which to culture fungi and bacteria in microbial and
medical pathological research. In food for