Often we watch contestants in food programs cooking with these long leafy vegetables, sometimes wrapping other food with it and judges munching on their made snack. Little do we know how much nutritious and versatile this green slimy leafy vegetable is. Seaweeds are indeed extensively used and consumed in coastal cuisines around the world, originating from and prevalent in Asian countries. Seaweed has been a staple in Philippines, China, Japan and Korea since ancient era adding Australia in the 1800s. Porphyra (Nori), Laminaria (Kombu) and Undaria (Wakame) are few of the most used seaweeds in the Asian cuisines used for sushi, curries or simple salads. As of 2018, apart from China, Japan, 8 other countries have produced total of 2,165,675 metric tons of seaweed accounting for 96% globally. Although the use and consumption of seaweeds are dominated by countries like Japan, China and Republic of Korea, little population in Bangladesh is aware of its diverse potential and nutritional value. This article is objected to boost seaweed consumption, utilization offering a wide topic of research.
Seaweed is a marine alga which resembles non-arboreal terrestrial plants, so can be generally classified as a plant. Phytoplankton lives in the ground waters serve as producers for most aquatic food webs. Others such as kelps grow in abundant forests and towers from their roots at the bottom of the sea. Most seaweed species are Rhodophyta, red (6000 species), Phaeophyta, brown (2000 species) or Chlorophyta, green (1200 species). Mostly seaweeds inhabit the littoral zone (near-shore waters) and within that zone, on rocky shores, and seawater/ or brack water having sufficient light to support photosynthesis.
So why would it be beneficial to us?
Bangladesh is a riverine country located in South Asia with a coastal zone of 480 km coastline with 25,000 km2 of coastal area. This coastal area provides sandy and muddy beaches, invers and tidal forests provide suitable habitats for several seaweeds cultivation, therefore providing assortments of land exploitations for cultivation. Bangladesh is rich with 133 species of seaweed, 116 species of seaweed found in coastal areas alone and fourteen of them are commercially important. The Bangladesh Fish Research Institute (BFRI) has recognized 10 species of seaweedhaving an economic value. The species are as follows: Caulerpa sertularioides, C. racemosa, Entermorpha sp., Hydroclathrus clathretus, Sargassum sp., Gelidiella tenuissima, Helimenia discoidea, Hypnea valentiae, H. pannosa, Gelidium pusillum. A huge population of people in coastal districts depends on the sea for their daily livelihood and seaweed cultivation would provide an alternative livelihood along with fishing and other fishing usage with additional activities. This would grant many families to receive a fluent income any season, despite of any fishing ban, in a minimum amount of time. Seaweed grows quickly and takes no space on land, giving an opportunity to farmers to cultivate despite ownership of plots. Seaweed culture can be introduced in areas suitable for their cultivation by acquainting coastal farmers with inexpensive and accessible technology guided by various organizations. Utilization and consumption of seaweed would increase its demand, requiring cultivation more often round the year.
Seaweed’s diverse potential:
Consumption of seaweeds is next to negligible in our country, with only little restaurants having Japanese cuisine where it is mostly served in sushi. By accounting its highly nutritional value, seaweeds could be added to various other dishes in order to increase its consumption. Seaweed has plenty of essential nutrients, especially trace elements, such as Calcium, Folate, Potassium, Iron, Manganese, Copper and several other bioactive substances. Proteins made of various essential and non-essential amino acids are in abundant in seaweeds, with little but adequate amounts of lipid, mostly unsaturated fats. Seaweed has abundant vitamins, including β-carotene, which is the precursor of vitamin A, the vitamins of the B group, including B1, B2, B12, and vitamin C, D, E and K. The very high levels of enzyme activity in seaweed help the assimilation of all these vital elements. Seaweeds are enriched in Iodine thereby replenishing Iodine deficiency in patients and improve thyroid function and other related diseases. Other health benefits of seaweed include:
- Improves gut health.
- Treatment of goiter and Iodine deficiency.
- Improves heart health.
- Stabilizes blood sugar levels.
- Boost immunity.
- Reduce cancer risk.
- Have antibacterial, antifungal and antitumor properties.
- Great source of food for pregnant and lactating women, as well as malnourished children.
- Improve mental and thyroid problems.
Alginate, agar and carrageenan are gelatinous seaweed products that are today used as food additives. The food industry uses these products for their gelation, water-retention, ability to emulsify and other characteristics. Agar is used in foods such as confectionery, desserts, etc. whereas carrageenan is used as additives in dressings and sauces, dietetic diets, and as preservatives. Their nutritional value makes them eligible for consumption by people of every age, diabetics, and patients of other diseases.
In addition to as a food source, seaweeds are of great use in the medical sector. Alginates have been used extensively in wound dressing, drug delivery and tissue engineering. In microbiology, agar is used as a culture medium. Carrageenan, alginates and agaroses, with other macroalgal polysaccharides, have biomedicine applications. Delisea pulchra ccould be used an anti-microbial agent. Sulfated saccharides from red and green algae inhibit some DNA and RNA-enveloped viruses. Seaweed extracts are often used in few diet pills, entitling the user satiety.
Seaweed species puts up a habitable environment for fisheries and other marine species, increasing food sources for human consumption. Few other species, such as planktonic algae, play a vital role in capturing carbon, producing up to 90% of Earth’s oxygen. Capturing carbon results in reduction of carbon dioxide levels from environment allowing an eco-friendly carbon sequestration. According to a study, addition of Asparagopsis taxiformis—a red algal species—to cattle feed may reduce methane creation from beef cattle approximately by 99%. Additionally, growing seaweeds consume nutrients such as ammonia, ammonium nitrate, nitrite, phosphate, iron, copper, as well as CO2, serving as a natural filter of water. Therefore, growing seaweed provides an innate system of wastewater treatment so that water could be cleaned, thus increasing population of marine species. Seaweed species like Cladophora, Ulva (sea lettuce) and Chaetomorpha are preferred for filtration.
Apart from this major uses, seaweeds can be used in various other ways, including:
- Source of bioethanol.
- As fertilizer and soil conditioners.
- Compost for landscaping.
- Animal and fish feed.
- Produce edible packaging.
- Alginates used in products such as paper coatings, adhesives, dyes, gels, explosives.
- Processes such as sizing of paper, textile printing, hydro-mulching and drilling.
- Inside toothpastes, cosmetics and paints.
- For the production of bio yarn.
- Natural latex creaming and thickening for rubber.
- As additives in the composition of fertilizer and pesticides.
- Ingredient for bio-chemicals, pharmaceuticals and cosmetics industries.
Seaweed status in Bangladesh:
As of now few government organizations, such as Directorate of Fisheries and the Bangladesh Fish Research Institute (BFRI), are conducting seaweed related study along with government universities which are pouring research based on seaweed, however, mostly first base and taxonomic work. Currently, government officiated seaweed works and study are only carried out in few districts of the southeastern coast of Bangladesh and Sundarbans as well. However, the government is yet to take up any plan for development of mass seaweed cultivation and processing. Any seaweed farming system in the country is yet to be introduced. Due to lowered levels of seaweed utilization in the country, the present production from natural habits is very low. Although abundant seaweed sources are present in the coastal lines, there are no known seaweed-based industries of Bangladesh leading to no formal marketing system evolution. Considering the economics of production of seaweed, seaweeds are only harvested by gathering from natural stock, having little value from the economic point of utilization. Only localities where seaweeds are gathered utilize them either via consumption or in animal feed.
Due to immense lack of information on seaweed cultivation, shortfall of technology and educated and experienced researchers on this sector, limited socio-economic importance and deficient skilled manpower, the seaweed industry is yet to hit the accelerator pedal in the country. Compared to Bangladesh, our neighboring south-east Asian countries are drowning with experts on this field with highest consumption and utilization as of now. Despite having huge lands of practice and cultivation, Bangladesh could not establish a firm foot on seaweed utilization up till now though the country have a reason not to.
Major reasons for introducing and boosting seaweed utilization:
- Source of food to all classes of people in the country, consuming it for nutrition, in disease states, especially to coastline people with little or no income.
- Source of income and livelihoods of the poor farmers with low inputs, thus reducing poverty.
- Export various seaweed products, thereby increasing the overall economy of the country by a minimum percentage.
- Increase chances of employment by building industries surrounding seaweed derived products.
- Develop a major alternative livelihood for coastal people that would enable them to advance their lives resulting in urban development refined with education, knowledge and settled lives.
- Seaweed utilization through product and process development would ensure the food and nutritional security among the population as well as expanding the value of fisheries export.
How to achieve this state:
Combined efforts are required by both government and general people in order to boost seaweed utilization for the benefit and welfare of the people. Utilization of seaweed could be implemented in the following ways:
- Introduction and establishment of seaweed consumption and cultivation in local coast lines and then to rest of the country.
- Attempts to develop products suitable for the Bangladeshi palate and to popularize the same amongst the public.
- Introduce seaweed to local cuisine and making it available on restaurants as new dishes to create the hype.
- Training programs and demonstration services provided or sought from skilled south-east Asian experts.
- Development of seaweed cultivation practices along with fostering and planning it.
- Improvements can be made to harvesting methods and introducing artificial habitats to grow wild types.
- Introducing technology for the cultivation of different commercial seed reserves and their improvements through research.
- Producing commercial seaweed –based products of high quality for export business.
- Extensive surveys to identify suitable sites for mass scale seaweed cultivation within country.
- Introducing and acting on an established political system, legal system on seaweed cultivation improving the economic influence for rapid development.
- Taking economic factors such as cost of production and other factors into account.
- Improvement of technology, scientific knowledge and accounting for environmental factors for development of feasible seaweed cultivation.
- Increasing seaweed demand by various social influences possible.
- Introduction of seaweed polyculture is association with other marine source to increase harvest and profits.
- Mass education and marketing of seaweed to create a high demand of it.
As a valuable marine source, seaweeds can be used flexibly to counteract on aspects ranging from simple issue like depending as food source to exportation caliber. With proper balance of environmental and biological factors, large scale production of seaweed could be aimed in the country via promoting seaweed utilization and consumption using socio-economic influence. Therefore, collaborative research and efforts should be attempted to establish a status for seaweed and its diverse products by accounting both economic and social benefits.
Department of Biochemistry & Biotechnology
University of Science and Technology Chittagong, USTC
- Ahmed.N.,Taparhudee.W,. Seaweed Cultivation in Bangladesh: Problems and Potentials. KASETSART UNIVERSITY FISHERIES RESEARCH BULLETIN NO. 28(2005).
- Country status report on ‘STATUS OF PRODUCTION AND UTILIZATION OF SEAWEEDS IN BANGLADESH’ by Giasuddin Khan Project Director Marine Fishery Survey Management and Development Project, Chittagong.
- News report on ‘Seaweed farming: alternative livelihood for coastal people’ by Mehedi Al Amin. Published at 11:58 pm April 17th, 2019.
- Seaweed. Wikipedia.