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Vol. 18 No. 4 - Oct 2012

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, <bbtmshr@yahoo.co.in>


This article has been reproduced from the archives of EnviroNews - Newsletter of ISEB India.


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