Mannan

Type 1: (→3)-α-D-mannose(1→).

Type 2: (→6)-α-D-mannose(1→). Most commonly 6-linked main chains with 2-linked side chains, terminated by (1→3) link.

Type 3: (→3)-β-D-mannose(1→) and (→4)-β-D-mannan(1→), alternating.

Type 4: (→4)-β-D-mannose(1→). Linear, limited branching and sulfated in Codidum pusillum (red algea). In higher plants the (→4)-β-D-mannans(1→) form linear backbones of galactomannans [2]. The mannan exists in two distinct crystalline forms [10]. The β-(1,4) mannan exist in an acetylated form (acemannan from Aloe barbardensis Miller), the acetylation ratio is C(2)/C(3):C(6)=1:1 [4]