ABSTRACT
Fructan is a polymer that consists of fructose units and a terminal glucose residue. It occurs in a variety of organisms such as bacteria, fungi, and in approximately 15% of owering plants. Fructan can be divided into three groups based on its linkage type: (1) levan, with β(2-6)-linked fructosyl units-this mainly occurs in bacteria (Dedonder 1966), monocotyledonous plants (where it can also be called phlein) (Bonnett et al. 1997), and also in a member of the order Buxales according to a recent discovery (Van den Ende et al. 2011); (2) inulin, a β(2-1) linear polymer found in dicotyledonous plants (Koops and Jonker 1996); and (3) fructan neo-series, a mixed type of fructan found in Liliaceae (Pollock 1986) where β(2-1) chain elongation occurs at the C1 and C6 positions of the glucose residue. A schematic representation of the fructan biosynthesis reactions occurring in plants and the molecules involved is given in Figure 1.1.
