Lichenin

Lichenin (from gr. lichen = lichen) is a colourless and tasteless, water-soluble, unbranched polysaccharide made up of 60-299 glucose residues, which occurs as a storage carbohydrate mainly in various lichens and mosses (in high concentrations e.g. in Icelandic moss). The sugar monomers of lichenin are linked to each other by 30% beta-1,3- and 70% beta-1,4-glycoside.

In oats and barley, lichenin can account for 6-8% of dry matter, in wheat and rye at most about 2%. Lichenin is strongly swelling. When boiled in water, it produces a colloidal solution which forms a jelly when cooled. Lichenin is indigestible for humans (humans lack the enzyme lichenase) and is used as a mucus drug and expectorant.

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