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Suit Yourself™ International Magazine #24: Seaweed

  

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Suit Yourself™ International Magazine #24: Seaweed

 

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SEAWEED

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Animated Seaweed // Les Algues Animation

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This week's subject is seaweed.  This is the 24th in our articles series and I hope this information is helpful!

All previous articles in the series can be found in our library and in the magazine archives.  Upon request, reprint permission and an addendum of substantiating resources are available for all magazine articles. When requesting reprint permission or addenda, please include the issue date and full issue title. All magazine articles are copyright © Debra Spencer, Suit Yourself ™ International. All rights reserved. ISSN 2474-820X. 

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SEAWEED

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"Seaweed" is a colloquial term; it lacks a formal definition. Seaweed usually refers to one of several different groups of multicellular algae, including red, green, brown, and some turf-forming bluegreen cyanobacteria also sometimes considered seaweed. Thus seaweed are a polyphyletic group; they're entirely different organisms classified into the same group but don't share a common multicellular ancestor. They came from different ancestors and some say they are amongst the oldest plants on earth.

Seaweed requires light for photosynthesis, and salt water, as seawater, or brackish briny water (water that has more salinity than fresh water, occurring when fresh water meets seawater). Some seaweed can float freely, and some seaweed have adapted to live in tidal rock pools, however most seaweed commonly require a firm attachment point, preferring the littoral zone, that part of the sea closest to shore, with rocky shores preferred over sand or shingle. 

Seaweed have adapted to withstand rapid changes in elevation, temperature, pressure, water salinity, and even occasional drying. Sunlight availability is crucial and is really the only limiting factor; in some locations, seaweed found in the littoral zone can literally extend several miles out to sea. The deepest living seaweed are some species of red algae.

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SEAWEED USES

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Album of Seaweed Pictures (1848).

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A Victorian era pastime, still enjoyed today, is seaweed collecting; seaweed was collected, dried, and pressed, and the resulting shapes studied and sketched as drawings. 

Much seaweed is edible. Most people around the world consume it in some form or other; it's ubiquitous in foods.  Some forms of red algae are used in producing food additives, such as Chondrus crispus (also called 'Irish moss' or carrageenan moss), Kappaphycus, and gigartinoid seaweed. Seaweed is used in toothpaste, cosmetics, and paint, and brine is used as a source for intravenous magnesium.

There are a number of Maine coast businesses hand harvesting and drying Atlantic seaweeds and sea vegetables. Downeast Maine Magazine has an article on the edible Maine coast seaweed varieties here:
THE ALGAE INDEX: A GUIDE TO EDIBLE SEAWEEDS ON THE MAINE COAST
http://downeast.com/the-algae-index/

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Tides transform this landscape.

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Seaweed is used to wrap rice (sushi and onigiri), and dried Porphyra, a red algae, is used in soups and as a seasoning.  In Wales, it's used to make laver; a popular dish there is laverbread, made from oats and the seaweed laver. Edible seaweed in northern Belize are mixed with milk, nutmeg, cinnamon, and vanilla, to make a popular drink called "dulce" or "sweet".  

Cochayuyo is a form of kelp used as a vegetable in Chile; in Chilean Cuisine, the Durvillaea antarctica stem and holdfast, known as "hulte", is used for different recipes like salads and stews (Quechua: cochayuyo from Cocha: Lake, and yuyo: weed). The Durvillaea antarctica reproduces sexually by producing egg and sperm that are released into the water. The eggs and sperm are produced on specific sites of the frond, and large individual seaweed can produce 100 million eggs in twelve hours. The reproduction season varies with location, but is generally during winter months. For more information, see https://en.wikipedia.org/wiki/Durvillaea_antarctica

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This Wikipedia table lists a very few example genera of seaweed.

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From seaweed are extracted various gelatinous colloids such as alginate, agar, and carrageenan. These hydrocolloids have gelling, water-retention, emulsifying, expanding (through fluid retention), and various other physical properties.  These are used in many ways, including but not limited to food additives.

For example, agar is used as a biology culture medium, and also in confections, meat and poultry products, desserts, beverages, and to mould and shape food. 

Carrageenan is used in salad dressings, sauces, dietetic foods, and as a preservative in meat and fish products, dairy items, and baked goods. 

Carrageenans, alginates, and agaroses (prepared from agar by purification), with other lesser-known macroalgal polysaccharides, have several important biological activities or applications in biomedicine. Alginates and carrageenan have been put to similar uses, in paper coatings, adhesives, dyes, gels, explosives, and in various industrial processes, including paper sizing, textile printing, hydro-mulching, and drilling.

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Album of Seaweed Pictures (1848) .

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Seaweed is often used as a filter. Algae's strong photosynthesis behavior can be purposely applied to remove undesired nutrients from water. Growing seaweed rapidly consumes such elements as ammonia, ammonium nitrate, nitrite, phosphate, iron, and  copper. Seaweed also consumes CO2 (carbon dioxide). Seaweed naturally filters reefs and lakes in this way, and then the seaweed in turn is consumed by fish and invertebrates. Human-made algae scrubbers are seaweed filters duplicating this process.

Seaweed is used as fertilizer, landscaping compost, and as beach filler to combat beach erosion.  Fresh seaweed can be collected and used as organic fertilizer. Rotting seaweed, however, is  a potent source of hydrogen sulfide gas, and overexposure to it can cause vomiting and diarrhea. 

In terms of soil structure, seaweed doesn't add much bulk, but its' jelly like alginate content helps bind soil crumbs together, and it contains all the essential amino acids and soil nutrients, 0.3% Nitrogen, 0.1% Phosphorus, 1.0% Potassium, along with  a range of trace elements.

If fresh seaweed isn't available near you, there is a commercially available dried 'meal' form, as well as a concentrated liquid extract although this is active in significantly smaller rates. For compost, seaweed (especially bladderwrack, kelp or laminaria) can be applied directly to the soil as a mulch (although it will tend to break down very quickly) or added to the compost heap, where it's an excellent activator.  The salt content is high, and while it's unlikely to seriously upset the soil salt balances, worms don't like it, and won't live in it. To reduce the salt content, you can hose it down before adding it to the soil or leave it outside and let the rain desalinate it, however rinsing seaweed is risky; valuable alginates are potentially lost to runoff.

According to Wikipedia (https://en.wikipedia.org/wiki/Seaweed_fuel), three seaweed species ( Alaria esculenta, Laminaria saccharina, and Palmaria palmata ) are being investigated as ethanol and butanol sources; they may be suitable species for alternatives to liquid fossil fuels. When burnt, seaweed fuel releases carbon dioxide like fossil fuel, but unlike fossil fuel, algae fuel and other biofuels only release the carbon dioxide recently removed from the atmosphere via their own photosynthesis, as the seaweed or plant grew. Seaweed doesn't require fresh water to grow and can be grown in the sea.

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NUTRITIONAL VALUE

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Album of Seaweed Pictures (1848).

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There are four seaweeds most commonly used as edibles:

Pyrphora, a red algae

Sargassum, a brown algae

Laminaria (kelp), a brown algae 

Ecklonia, a green algae 

Laminaria is sometimes called haidai, to distinguish it from Ecklonia or other sources.

Seaweed's strong photosynthesis behavior causes it to draw mineral elements from the sea that can account for up to 36% of its' dry mass. The mineral macronutrients include sodium, calcium, magnesium, potassium, chlorine, sulfur and phosphorus. The micronutrients include iodine, iron, zinc, copper, selenium, molybdenum, fluoride, manganese, boron, nickel and cobalt.

Seaweed contains a large proportion of iodine and is one of the richest plant sources for calcium. The calcium content of seaweeds is typically about 4-7% of dry matter. At 7% calcium, one gram of dried seaweed provides 70 mg of calcium, compared to a daily dietary requirement of about 1,000 mg, higher than a serving of most non-milk based foods.

The highest iodine content is found in brown algae, with dry kelp ranging from 1500-8000 ppm (parts per million) and dry rockweed (Fucus) from 500-1000 ppm. In most instances, red and green algae will have lower contents, about 100-300 ppm in dried seaweeds, but these are still high in comparison with land plants. Daily adult requirements, currently recommended at 150 µg/day, can be met with small quantities of seaweed. One gram of dried brown algae provides between 500-8,000 µg of iodine. A single gram of green and red algae (such as the purple nori used in Japanese cuisine) provides between 100-300 µg.

Protein content in seaweed is variable.  Protein content is low in brown algae at approximately 5-11% of dry matter, but comparable quantitatively to legumes, at  approximately 30-40% of dry matter in some species of red algae. Green algae, currently not much harvested, also have a significant protein content, approximately up to 20% of dry matter. Spirulina, a micro-algae, has a relatively high protein content, approximately 70% of dry matter.
 

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Album of Seaweed Pictures (1848).

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Seaweed contains several vitamins. Red and brown algae contain carotenes, used as dietary supplements for natural mixed carotenes; the content ranges from 20-170 ppm. Vitamin C in red and brown algae ranges from 500-3000 ppm. Other vitamins are also present, including B12, not found in most land plants.

Seaweed has very little fat, ranging from 1-5% of dry matter, although seaweed lipids have a higher proportion of essential fatty acids than land plants. Green algae, whose fatty acid make-up is the closest to higher plants, have a much higher oleic and alpha-linoleic acid content. Red algae have a high EPA content, a substance mostly found in animals, especially fish. Seaweed has a relatively high fiber content, with fiber making up 32% to 50% of dry matter. The soluble fiber fraction accounts for 51-56% of total fibers in green (ulvans) and red algae (agars, carrageenans and xylans) and for 67-87% in brown algae (laminaria, fucus, and others). 

 

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ASIAN FOOD

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Calories in seaweed salad.

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Probably the most widely known seaweed used for food is Porphyra, which literally means purple; that's this seaweed's natural color. The Chinese name for Porphyra is zicai, which means purple vegetable. Porphyra is classified among the red algae, which have red to purple pigments.  Upon processing Porphyra to yield the food, known as "nori" in Japan, the red pigments are lost and the final product has a dark greenish color. Nori is used to wrap sushi and for making snack foods. 

Another seaweed widely used in Japan is known as wakame, or Undaria pinnatifida. 

Kelp is another readily available edible seaweed; it has a low cost / high nutrition ratio. Kelp is "kunbu" in Chinese and "kombu" in Japanese. Kombu is usually sold dried in 5 inch to 6 inch long pieces; it's found in health food stores and Japanese groceries. You can buy kombu that cooks quickly, as marinated with vinegar,  as "instant" shaved kombu requiring little or no cooking, as boiled, as soy sauce flavored, lightly pickled, and in powdered form that can be sprinkled on food or in drinks. Dried kombu strips should be simmered in liquid for at least 20 minutes to soften them and flavor the liquid. If used only for flavoring the liquid stock, the kombu itself is removed from the liquid at the end of the cooking time, and discarded. 
 

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TRADITIONAL CHINESE MEDICINE: MEDICINAL USES

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Album of Seaweed Pictures (1848).

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Seaweeds have a salty taste; in Chinese Traditional Medicine (TCM), this indicates seaweed can disperse phlegm accumulation, particularly when phlegm forms soft masses, such as with goiter (the thyroid swelling indicative of severe iodine deficiency). 

The following seaweed descriptions are from the Oriental Materia Medica:

Kunbu (Laminaria and Ecklonia)
Essence and Flavor: Salty, Cold
Channel Entered: Liver, Stomach, Kidney
Actions: Softens hardness, disperses accumulation, resolves phlegm, cleanses heat
Applications: Scrofula, goiter, tumor, edema, accumulation, testicular pain and swelling

Haizao (Sargassum)
Essence and Flavor: Bitter, Salty, Cold
Channel Entered: Liver, Stomach, Kidney
Actions: Disperses accumulated phlegm, disperses goiter and tumor, delivers water, cleanses heat
Applications: Scrofula, goiter, tumor, edema, testicular pain and swelling

Zicai (Porphyra)
Essence and Flavor: Sweet, Salty, Cold
Channel Entered: Lung
Actions: Resolves phlegm, softens hardness, dispels heat, promotes diuresis
Applications: Goiter, beriberi [leg swelling], edema, urinary infection, sore throat

 

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Album of Seaweed Pictures (1848).

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Because the descriptions for kunbu and haizao are quite similar, Yang Yifan in the Oriental Materia Medica wrote about the differences between these commonly used seaweeds:

"Haizao and Kunbu are salty and cold; both enter the liver, lung, and kidney meridians. Both can clear heat, transform phlegm, soften hardness, and dissipate nodules. They can also promote urination and reduce edema. In clinical practice, they are often used together to treat nodules such as goiter and scrofula. There are some differences between the two herbs. Haizao is stronger in transforming phlegm and dissipating nodules, and it is more suitable for treating goiter and scrofula. Kunbu is stronger in softening hardness and reducing congealed blood; it is more suitable for treating liver-spleen enlargement, liver cirrhosis, and tumors."

One of the best known TCM seaweed formulas Haizao Yuhu Tang, also known as the "Sargassum Decoction for the Jade Flask". It is an ancient formula of 12 ingredients including Sargassum, Ecklonia, and Laminaria. It was used to treat a goiter condition so severe the throat resembled a large flask. Today, these seaweeds have been adopted into modern TCM formulas for treating other soft swellings, including ovarian cysts, breast lumps, lymph node swellings, lipomas, and fat accumulation from simple obesity.

For more information, see http://www.itmonline.org/arts/seaweed.htm and Traditional Chinese Medicine texts.

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The antique images source for the dried seaweed on doilies is
"An Album of Seaweed Pictures (1848)" 
http://publicdomainreview.org/collections/album-of-seaweed-pictures-184

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I sign our magazine articles "See Into The Invisible". Thanks for reading.

Best Wishes, 
Debra Spencer

All Content is © Debra Spencer, Suit Yourself™ International. Technical Library FAQ Index ISSN 2474-820X. All Rights Reserved. Please do not reproduce in part or in whole without express written consent. Thank you.
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All Content is ©2019 Debra Spencer, Appanage™at www.suityourself.international Suit Yourself ™ International, 120 Pendleton Point, Islesboro Island, Maine, 04848, USA 44n31 68w91 Technical Library FAQ Index ISSN 2474-820X. All Rights Reserved. Please do not reproduce in part or in whole without express written consent. Thank you.

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All Content is ©2019 Debra Spencer, Appanage™at www.suityourself.international Suit Yourself ™ International, 120 Pendleton Point, Islesboro Island, Maine, 04848, USA 44n31 68w91 Technical Library FAQ Index ISSN 2474-820X. All Rights Reserved. Please do not reproduce in part or in whole without express written consent. Thank you.
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