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Seaweeds: A Staple Food for 21st Century
By:
Babita Kumari & Vinay Sharma
India has a diverse coastline of 8085 Km2 covering 27 states and 4 union
territories, which offers many advantages for utilization of marine
biological resources. Marine algae commonly known as Seaweeds are found
attached to the bottom in relatively shallow coastal water. They are found
in rocky seashore areas, lagoons and reed areas of Indian Sub-continent.
They are considered as the food supplement for 21st century as source for
proteins, lipids, polysaccharides, minerals, vitamins and enzymes. In
nature, there are about 900 species of green seaweeds including 4000 red
species and 1500 brown species. Some 221 species of seaweed are utilized
commercially. Of these, about145 species are used for food and 110 species
for phycocolloid production (agar, algin, carrageenan etc.). Seaweeds are
rich source of valuable compounds including food additives and biomedicines.
Seaweeds have a high nutritional value; therefore an increase in their
consumption would elevate the food to offer population. In India, seaweeds
exploited from natural seaweed beds are used as raw materials for the
production of agar, alginates and seaweed liquid fertilizer. Besides, they
are one of the major groups of biological organisms contributing to the
productivity of coastal regions. They are consumed in Asia as sea vegetables
but in western countries they have been used as a source of gelling or
thickening agents. The use of seaweeds in Asian food is well known. In
Western societies, it is mainly associated with localized coastal use or
historical anecdotes, but seaweeds are now attracting increasing attention
as a valuable food source. Seaweeds generally contain high amount of
minerals (10-20 times that of land plants) and many other vitamins needed
for metabolic processes. The content of vitamin C in red and brown algae
ranges from 500-3000 ppm. Some seaweeds(e.g. nori) have protein
concentrations as high as 50 percent. Vitamin A, B, C and E can also be
found in certain seaweeds. Hijiki and wakame contain ten times the calcium
of milk. Besides, seaweeds also play an important role in the biomonitoring
and biosorption of heavy metals (Kumari et al. 2012). The minerals like
calcium, iron, potassium, magnesium, sodium, iodine etc. are also present in
seaweeds.
Seaweeds provide few calories because of their high water and low fat
content, making them ideal for low-calorie diets. They have a great value in
providing low cost nutrition and therapeutic protection. Seaweeds are rich
source of valuable compounds including food additives and biomedicines. They
have a high nutritional value; therefore, an increase in their consumption
would alleviate the food scarcity to some extent. In contrast, the Journal
of Medicinal Food 2009 report points out that a few studies have been
performed to analyze the effects of seaweed consumption on overweight and
obese people. The main benefits of seaweed consumption appear to be
associated with cardiovascular and intestinal health. Its effects on bone
health and body weight regulation need further investigation. Additionally,
the presence of fiber molecule algin allows seaweed to attract various
metals (e.g. merry and lead) in the gastrointestinal track and draw them out
of the body. Besides, seaweeds constitute a source of dietary fibers that
differ chemically and physic-chemically from those of land plants. Undaria
pinnatifida contains antiviral compounds, which inhibit the Herpes simplex
virus. Extract of Undaria pinnatifida has been used to treat breast cancer
and HIV AIDS. In India, several research organizations like CSMCRI, CMFRI,
and University of Madras are involved in finding out the utility of seaweeds
along the coastal belts of south India.
According to FAO, between 1981 and 2000, world production of aquatic plants
increased from 3.2 million tons to nearly 10.1 million tons (wet weight),
increasing the world trade to US $ 6 in 2000, compared to US $ 250 million
trade in 1990. The contribution of cultured seaweeds was 15 % of the total
global aquaculture volume (45,715,559 tons) or nearly 5 % of total volume of
world fisheries production (141,798,778 tons) for 2000. The seaweeds that
are most exploited for culture are the brown algae with 4,906,280 tons (71 %
of total production) followed by the red algae (1,927,917 tons) and a small
amount of green algae (33,700 tons). East and South-East Asian countries
contribute almost 99 % cultured production, with half of the production (3
million tons) supplied by China. Most output is used domestically for food,
but there is a growing international trade. Several training programmes have
been organized for the Fisher Women to culture the different varieties of
seaweed in India.
Department of Biosciences and Biotechnology,
Banasthali University, Rajasthan, India,
<[email protected]> |
