As the main ingredient to make agar-agar, seaweed gracilaria has an important
role in the seaweed production of agar-agar. Gracilaria is a group of warm water
seaweed and they can be found with wide range of species even more than one
hundred. The first source of agar is Gelidium from Japan till the beginning of
the 20th century when the demand exceeded the supply of this alga
and thus gracilaria is being used afterward. Agar-agar is extracted from these
seaweeds and they can be found in coastal areas such as the shores, coral
rubble, and abandoned nets, ropes as well as other objects left on the shore.
More detailed information regarding this amazing seaweed species below.
Seaweed
gracilaria for agar-agar ingredient
Seaweed gracilaria
human use is mainly to produce agar-agar. The seaweed
is harvested from either wildly method or seaweed farm while on the farm, they
are grown on the ropes for commercial uses. Around 30,000 tons of gracilarian
seaweed are produced each year and distributed around the world and about one
third of this wonderful sea plant are come from South Africa while China is one
of the first countries that cultivate gracilaria.
Agar-agar was known in both Japan and China
for centuries, they are called as kanten by the Japanese while Chinese prefer
called it as dongfen. Agar-agar used as flavored gel and sweetened. And it is
said that the Chinese brought it to the South East Asian by the migrants and
from that moment, dongfen called as agar-agar, a Malay name that even Chinese
migrants used it. When the Europeans brought it to the Europe (via the Dutch),
it was called as agar. Besides seaweed gracilaria,
there are other seaweed species used to make agar-agar such as Gelidiella, Ahnfeltiopsis,
Pterocladia, Gelidium, and Pterocladiella.
Gracilarian
farming production method
There are four gracilarian cultivation and
production methods which mostly used by seaweed farmers such as:
1.
Rope farming, gracilaria
seaweed results in different amount or level of production depending on the
species being cultivated and the climate conditions. The ropes used to
cultivate and growing gracilaria seaweed can be nylon, monofilament, as well as
other suitable lines. Before the ropes are used, they need to be checked
especially the durability of the lines in seawater before the farmers purchase
large amount of ropes.
2.
Pond farming
Cultivate seaweed in ponds
have been conducted for centuries even till now. The seed stocks supplied from
the wild and the ponds should be made in locations that are not exposed to the
strong wind and near seawater or freshwater as the source to grow seaweeds. The
water will be replaced after two to three days while the depth of the water
maintained at 30-40 cm. Moreover, to make the seaweeds growing healthier and
stronger, minerals like phosphates and nitrate can be added. Pond farming can
produce around 34 tons per ha each year.
3.
Tank farming
To control the growth of
gracilaria seaweed, tank farming can be used for the whole process. And this
method promising more satisfying result due to the clean water control and if
compared with other farming methods, it provides more productivity per unit
area. And to maintain high level of productivity, gracilaria
should be harvested periodically and the harvesting methods are varied
depending on the size of the tanks being used. Some of the manufacturers using
hand net to harvest the seaweed or the tank can be drained first into a net,
although this method is less efficient due to a lot of time spend to refill the
tanks with water.
4.
Bottom stocking
Bottom stocking cultivation
process is conducted by move rocks bearing the thalli in order to increase the
density on the farming area. And if the species of the seaweeds are already
growing on a site, this method could be more successful. The disadvantages for
having this cultivating method is that the cost of labor to plant and harvest
are usually high and thus this can be economic for areas with low labor costs.
Seaweed
gracilaria for agar-agar consists of three quality
grades: standard agar, sugar reactive agar, and food grade agar. In decades,
market demands for gracilaria have increased globally meaning that this kind of
species really play an important role in marine industry product.
