Wakame- an edible seaweed poised to be acknowledged as -Vegetable of the future

Shruti Sinha, ICAR-IINRG, Namkum-834010

2021-05-21 13:53:00

Credit: alibaba

Credit: alibaba

Over 10000 species of plant-like organisms inhabit and flourish the sea/ocean waters and are collectively called seaweeds. Biologically these seaweeds are a group of marine algae either uni- or multi-cellular (micro-and macro-algae) growing in shallow areas of water bodies often identified as reefs/coral reefs. The name weeds attached to them comes from them being accused of the nuisance they created to sailors and fishermen by entangling to their boats and ships.

Despite this, they are useful species and have been harvested and exploited extensively by industries for their hydrocolloid contents like agar-agar, carrageenan, alginate and several other bioactive compounds which have put to uses like food preservatives, thickeners, cosmetic products, etc. A handful of these seaweeds are long known to be edible and have been used as food by communities inhabiting coastal areas especially Korea, Japan, China. They are either raw, pickled, dried and/or powdered in several kinds of cuisines and this has gained them names as sea vegetables or sea veggies. Around 10 species of seaweeds are known to be eaten which are known as sea vegetables. They have been farmed by these Asian societies for centuries for their household purposes. Worldwide immigration in the past few decades lead to cultural diversity with simultaneous introduction as well as adaptation of culinary ideas. This has exposed these as food items to the West and the other parts of the world and has started to being embraced due to their distinctive umami flavor. Acceptance of these has also been recognized due to the health benefits they accrue owing to their composition of nutrients, minerals not naturally found in land plants in such amounts. These seaweeds are known to be a rich source of dietary fibers, proteins, polyunsaturated fatty acids especially long-chain Omega-3 fatty acids, vitamins and several minerals while keeping the calorific value low. Thus they are the sought-after food options in today’s world when the common man is switching to “functional foods” and nutraceuticals as part of their daily diet.


Sea vegetables are known to be composed of bioactive which are potent antioxidants, flourish and/or maintain the natural gut microbiome while a few of these are known to control diabetes and hypertension too. Southeast Asian countries have utilized them in soups, salads as part of their cuisine and are traditionally known to be a source of immense nutrients to pregnant and lactating mothers, adolescent girls for healthy menstruation and other health benefits. Thus, as functional foods, sea vegetables can be looked upon as a one-point power pack of nutrients which we usually get from several food items such as meat, fish, seafood, fruits, vegetables combined together. They can serve as an alternative source of such nutraceuticals without burdening the animal husbandry or aquaculture involving zero input of fertilizer or others while giving bountiful harvest. They are today advocated to be the vegan alternative to meat/ animal protein products. The visionary behind identifying sea vegetables’ potential and taking up their cultivation while generating employment opportunities for others is Bren Smith. He is the Executive Director of a new generation rage non-profit/for-profit organization GreenWave advocates that kelps are the new kale and they should be made present in each plate in coming years. It is time now to take up their production in a comprehensive way as it has already been visioned by CNBC that seaweed cultivation is going to show a boom in the next few years. An added advantage that encourages us to take up their production is that they decrease eutrophication of water bodies by utilizing those available C for their growth and are considered C- negative organisms protecting the ecosystem and environment which is good news for the planet as well. But there should always be caution associated with their use because of the heavy metal contamination as well as their Iodine content which can lead to aggravation or inhibition of thyroid organs.

Sea vegetables include members from three classes of algae namely, Chlorophyceae, Rhodophyceae and Phaeophyceae. There are some non-algae like cyanobacteria Spirulina well known to hit markets for their protein and chlorophyll content and are considered sea vegetables mistakenly. Some of the well-accepted sea vegetables are nori (Porphyra), dulce (Palmaria palmata), Irish moss (Chondrus crispus) which are red algae; Sea grapes or green caviar (Caulerpa lentillifera) and Sea lettuce (Ulva spp.) are green algae while kombu (Saccharina japonica), wakame (Undaria pinnatifida) are brown algae. All of these sea vegetables are nutritious in their content but the brown seaweeds contain an exceptional component- Iodine as well as such amounts of calcium which is otherwise lacking in red and green seaweeds. Kelp is a class of brown algae (Laminariales) that have long flattened-ribbon or leaf-shaped blades swaying in free water which originate from a common stem that itself grounds to the ocean floor by a root-like structure called a holdfast.

Brown algae naturally grow in cool sea waters thriving profusely at temperatures between 5-15°C of Japan, Korea and Russia. They are Iodine-rich nutrient source and are being recognized to be a palate-pleasing component in cuisine and culinary objects across the globe.  Known edible brown algae are Kombu (Saccharina japonica), Sugar kelp (Saccharina latissima), Wakame (Undaria pinnatifida), Sargassum sp. Etc. Kombu is well accepted by large populations as they are used in dishes like dashis used as dried or pickled forms or fresh. But it has way too high levels of Iodine and dietary fibers that are gas-causing. Wakame is yet another not so extensively utilized sea vegetable that has the potential to be taken up as the position of star vegetable in coming times. Wakame was introduced in other parts of the world as an invasive species but since recognizing its health and pharmacological benefits by the inhabitants it has been taken up as a farming venture by countries like New Zealand, Belgium, US, France, Tasmania, Great Britain, Spain, Italy, Argentina, Mexico, etc supplying to other parts of the world. Harvested product has already hit stores making common man accessible to these powerhouses.

Biology of Wakame: U. pinnatifida is an annual alga that grows quite fast at the rate of even 5cm/day and propagates by microspores naturally is brown in color due to the presence of fucoxanthin which is not present in other vegetables and has several nutritional as well as health and medicinal benefits. Its thallus/ body has a holdfast with numerous ramifications and forms several lanceolated blades which extend up to 3/4th length of the plant, and can reach an overall length to about 60 cm or even up to 2.5-3m. It has a midrib too with fine blades. Two parts of U. pinnatifida are edible: the leaf detached from the midrib called Wakame and the Sporophyll called Mekabu and is commercially sold as Wakame.  

 Wakame is eaten in its hydrated form which is done by hydrating the dried available product in water preferably blanching that changes its colour to green which is why it is also known as “sea mustard” because of its resemblance to cooked mustard leaves. The chlorophyll content is high in these and are good source of antioxidants. They are typically used in salads and soups because of its sweet, saltine and umami flavor and has already formed a part of vegan as well as macrobiotic diets.

Nutritional and nutraceutical properties of Wakame:  Wakame has been shown to have protein content especially essential amino acids similar to plant-based proteins as soy and eggs. Wakame is rich in vitamins such as Vitamin B1, B2, B3, B5, B9, C, E, K; minerals such as Zn, Ca, Fe, Mn, Mg, I,  fats such as Omega-3 fatty acids, as well as antioxidants along with high amount of dietary fibers. These have been identified to play role in regulating lipid profile as well as glucose levels therefore clinical studies have shown their role as antihypertensive agents as well as blood glucose regulators. Undaria has been shown to reduce the risk of breast cancer in women and has long been eaten by pregnant and lactating benefits by Koreans. Fucoids content of this kelp has shown cytotoxic effect on human colon cancer cells. Also reports are available that shows wakame regulates glucose and lipid metabolism and is now being exploited for research to control obesity and diabetes mellitus. Extracts and biochemicals from wakame when supplemented to diets in clinical trials have shown to have antihypertensive effects.

Future foods with wakame: Wakame has already made place in several future dishes explored using non-meat, non-dairy, vegan option for the easily available fast foods. Some of these are Seaweed burger, Wakame oil, as a constituted had-boiled egg developed by OsomeFood aa Singapore based manufacture which claims to have used up to 90% less land and water resources as would have been used by conventional production processes, vegetarian croquettes using wakame by Olijck Foods a Holland based food industry to present their exotic taste with vegan option, Space 10 project have developed Lean Green Algae Ball” using wakame for brand IKEA.

Thus wakame can be assumed to be futuristic vegetable because of its exotic taste bundled with nutrient dense characters consisting of protein, fibres, fucoxanthins, as well as micronutrients making it a super food. Wakame has an edge over kombu or other kelps in its right amount of Iodine content which is acceptable limit, higher total dietary fiber than kombu or nori, and exceptionally good amount of calcium. Wakame is an annual crop with short generation time producing profuse harvest with little seeding and other inputs. Dried wakame has fairly equal amount of nutrients than fresh ones and they are easy to store for longer periods of time. Additionally its production will save the water bodies from eutrophication, utilizing less land and labor providing ecological and environmental benefits. In consonance with the current trend in food and cuisine acceptance by consumers to embrace naturally grown foods from clean environments it can be envisioned that Wakame is poised to be called “vegetable of the future”.