Looking much like wrinkled cellophane, Porphyra species are extremely low in calories and contain a high
degree of iodine.
ling 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, joghurts,
powdered milk (including baby formula), etc, all possess red seaweed
carrageenan extracts. Believe it or
not, carrageenan is even used in
toothpaste, cosmetics, shampoos,
paints and pet food. A number of
carrageenophyte seaweeds are being investigated in South Africa.
These include Hypnea spicifera
(green tips), and various species of
Gigartina (tongue weed), Sarcothalia (twisted gigartina), and Aeodes
(slippery orbits).
Agar on the other hand, has its
most important use as a medium
on which to culture fungi and bacteria in microbiological and medical
pathological research. In food for
human consumption, however,
agar can be found in baking and
confectionary products and is also
widely used to clarify wine, juice
and vinegars due its excellent protein binding properties. In larger
industries, agar is used to make
adhesives and capsules for tablets.
South African agarophytes include
species of seaweed from the genera
Gracilaria (which was harvested
extensively in Saldanha Bay) and
especially Gelidium.
The brown seaweed Splachnidium rugosum (dead
man’s fingers) is common along the South African
west and southern west coasts.
Red Seaweeds (calcified)
Encrusting coralline (made of lime
deposits) red seaweeds are important in the ecology of nearshore marine ecosystems where
they serve as food and shelter for
many marine animals. Due to their
hard, calcified nature, they have a
number of economic uses. In modern medical science coralline algae
are used in the preparation of dental bone implants. Coralline rubble
known as maerl is used in calcium
mineral supplements, as soil pH
conditioners, in the filtration of
acidic drinking water, and even as
food additives for livestock. Coralline algae are commonly used as
“live rock” in the marine aquarium
Kelp are both ecologically and economically important species of brown algae.