A sundew with a leaf bent around a fly trapped by mucilage.

Mucilage is a thick gluey substance produced by most plants and some microorganisms. It is a polar glycoprotein and an exopolysaccharide.

It occurs in various parts of nearly all classes of plant, usually in relatively small percentages, and is frequently associated with other substances, such as tannins and alkaloids.

Mucilage in plants is thought to aid in water storage and seed germination, and to act as a membrane thickener and food reserve. Among the richest sources are cacti (and other succulents) and flax seeds.

Mucilage has a unique purpose in some carnivorous plants. The plant genera Drosera (Sundews), Pinguicula, and others have leaves studded with mucilage-secreting glands, and use a "flypaper trap" to capture insects.

Exopolysaccharides are the most stabilising factor for microaggregates and are widely distributed in soils. Therefore exopolysaccharide-producing "soil algae" play a vital role in the ecology of the world's soils. The substance covers the outside of, for example, unicellular or filamentous green algae and cyanobacteria. Amongst the green algae especially, the group Volvocales are known to produce exopolysaccharides in a certain part of their life cycle.

[edit] Human uses

Mucilage is edible, but tastes rather bland. It is used in medicine for its demulcent properties. Traditionally marshmallows were made from the extract of the mucilaginous root of the marshmallow plant and due to the demulcent nature of the extract, worked as a cough suppressant. Because it is sticky, it is mixed with water to create a type of glue for paper (e.g., postage stamps and envelope flaps). Some carnivorous plants with mucilage are used for the traditional production of a dairy product in Sweden, called filmjölk.

During the fermentation of natto soybean, extracellular enzymes produced by Bacillus natto react with soybean sugars to produce mucilage. The amount and viscosity of the mucilage are important natto characteristics and contribute to natto’s unique taste and smell.

[edit] Plant sources

The following plants are known to contain far greater concentrations of mucilage than is typically found in most plants:

• Aloe vera
• Basella alba (Malabar Spinach)
• Cactus
• Chondrus crispus (Irish moss)
• Dioscorea opposita (Nagaimo, Japanese Mountain Yam)
• Drosera (sundews)
• Fenugreek
• Flax seeds
• Kelp
• Liquorice root
• Marshmallow
• Mullein
• Okra
• Parthenium
• Pinguicula (butterwort)
• Salvia hispanica (chia) seed
• Ulmus rubra bark (slippery elm)

[edit] See also

• Marine mucilage

[edit] External links

Look up mucilage in Wiktionary, the free dictionary.

• Mucilage McGraw-Hill Encyclopedia of Science and Technology, 5th edition
• Mucilage Columbia Encyclopedia, Sixth Edition (2007)
•  "mucilage". Encyclopædia Britannica (11th ed.). 1911.