Mannans

Mannans are polysaccharides that are linear polymers of the sugar mannose.
Plant mannans have β(1-4) linkages. They are a form of storage polysaccharide. Ivory nut is a source of mannans.
Mannan may also refer to a cell wall polysaccharide found in yeasts. This type of mannan has a α(1-6) linked backbone and α(1-2) and α(1-3) linked branches. It is serologically similar to structures found on mammalian glycoproteins.
Detection of mannan leads to lysis in the mannan-binding lectin pathway. This mannan is the source of MOS used as prebiotics in animal husbandry and nutritional supplements.
Etymology.
From 'manna', produced by several species of tree and shrub e.g. "Fraxinus ornus" from whose secretions mannitol was originally isolated.