Colours of seaweed.
Seaweed Color
Seaweeds are large algae (macro algae) that grow in a saltwater or marine environment. Seaweeds are plants, although they lack true stems, roots, and leaves. Seaweed need light to grow. When light enters the water it will loses the power to penetrate rapidly.
The colour difference:green, brown and red (different pigment composition) as result of the change in light. Long wavelengths (red and infrared) are absorbed in the top metres of water, the very short wavelengths (ultraviolet) of the light can penetrate much deeper and below 10 m it is mainly blue-green. The deeper the seaweed life the darker there colour will become. With the difference in colour different chemical compositions appear.
Colour,(photosynthetic pigments), food storage and Cell Wall components.
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Division |
Photosynthetic pigments |
Food reserve |
Cell Wall components |
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Chlorophyta (green algae) |
chlorophylls a and b, carotenoids |
starch |
Polysaccharides or cellulose |
| Phaeophyta (brown algae) |
chlorophylls a and c, carotenoids including fucoxanthin |
Laminarin and oils |
Laminarin and oils |
|
Rhodophyta (red algae) |
chlorophyll a and d, carotenoids, phycobilins |
Floridean starch |
Cellulose, pectin compounds, impregnated with calcium carbonate in some species |
The red ones. The reds (Rhodophyta) inhabit the lower zones.
Dulse/dillisk , another B-vitamin-laden seaweed, purple laver proved to elevate vitamin [B.sub.12] levels in deficient rats, as noted by researchers in Sakai, Japan, who published their findings in 2001 in the British Journal of Nutrition. They estimated purple laver contains five types of biologically active vitamin Bp compounds, as well as a whopping 54.5-58.6 micrograms (mcg) of vitamin [B.sub.12] per 100 grams of dry weight.
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Next the browns; The browns (Phaeophyta) are usually found in the mid-inter tidal and sub tidal zones.
According to a 1999 study published in the Journal of Agricultural and Food Chemistry by researchers at Kochi Women’s University in Japan, nori is “the most excellent source of vitamin [B.sub.12] among edible seaweeds, especially for strict vegetarians.”
Are well known for their healthful attributes, for example, brown seaweed containing 10 percent f fiber was shown by researchers at Japan’s KyotoUniversity to lower blood pressure and to reduce the risk of stroke in animals predisposed to cardiovascular problems. One study, featured in a 1986 supplemental issue office Journal of Hypertension, indicated alginic acid, a compound found in seaweed fiber, probably had something to do with the heart-healthy effects.
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The colour of seaweed and properties
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Macro-nutrients.
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Proteins: up to 45 % |
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Lipids: up to 5 %, generally about 2%, high in PUFA |
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Carbohydrates: Soluble fiber [agar, carrageenan & alginate] up to 45 % |
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Insoluble fiber: [cellulose, xylans & others] 3 to 8 % |
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Oligosaccharides, sugars & sugar alcohols: up to 22% |
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Minerals: up to 35 % – Ca, P, Mg, Fe, Na, K, & Cl. |
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MICRO COMPONENTS |
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Essential oligoelements: Zn, Cu, Mn, I, Se, Mo & Cr |
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Free Amino Acids: All essential AA generally present |
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Vitamins: A, B complex (B1, B2, B3, B5, B6, B12, & Folic Acid), C, & E |
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Carotenoids: several present |
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