55
backbone and α-1,4 linking glucose as the side chain (Fig. 4.12). Dextran can be
produced commercially when L. mesenteroides, a bacterial species, is cultured on
sucrose (Table 4.4). Several other microorganisms also produce dextrans, but
according to Chen and Huang (2018), dextran which is extracted from different
microbial strain possesses varying structures. Dextran can be used for the separation
and purification of biomacromolecules. Due to its biocompatibility, it also can be
applied as the plasma expander for biomedical application (Friedman 2016).
4.5.2 Xanthan
Xanthan gum is a high molecular weight branched polysaccharide that consists of
glucose, mannose and glucuronic acid (Fig. 4.13). It is produced naturally by the
bacterium Xanthomonas campestris and manufactured commercially by aerobic
fermentation of glucose or sucrose solutions with pure cultures of Xanthomonas
campestris (Gupta and Diwan 2017). The primary structure of xanthan gum is a
linear (1 → 4) linked β-D-glucose backbone (similar to that of cellulose) with a
trisaccharide side chain on every other glucose at C-3 (Shang et al. 2018).
4.6 Relationship Between the Structure and Activities
of Bioactive Carbohydrates
Carbohydrates (especially polysaccharides) have diverse chemical structure, composition, molecular weight, potential, and linking sequence, all of which result in
different functionality and biological activity (Xie et al. 2016b). Xie et al. (2014,
2016b) indicated that polysaccharides have a different molecular weight (Mw) and
monosaccharide composition. They also exhibit differences in their configuration
and position of glycosidic linkages. Their structure range from those that are linear
Fig. 4.12 Dextran
4 Bioactive Carbohydrates, Biological Activities, and Sources
backbone and α-1,4 linking glucose as the side chain (Fig. 4.12). Dextran can be
produced commercially when L. mesenteroides, a bacterial species, is cultured on
sucrose (Table 4.4). Several other microorganisms also produce dextrans, but
according to Chen and Huang (2018), dextran which is extracted from different
microbial strain possesses varying structures. Dextran can be used for the separation
and purification of biomacromolecules. Due to its biocompatibility, it also can be
applied as the plasma expander for biomedical application (Friedman 2016).
4.5.2 Xanthan
Xanthan gum is a high molecular weight branched polysaccharide that consists of
glucose, mannose and glucuronic acid (Fig. 4.13). It is produced naturally by the
bacterium Xanthomonas campestris and manufactured commercially by aerobic
fermentation of glucose or sucrose solutions with pure cultures of Xanthomonas
campestris (Gupta and Diwan 2017). The primary structure of xanthan gum is a
linear (1 → 4) linked β-D-glucose backbone (similar to that of cellulose) with a
trisaccharide side chain on every other glucose at C-3 (Shang et al. 2018).
4.6 Relationship Between the Structure and Activities
of Bioactive Carbohydrates
Carbohydrates (especially polysaccharides) have diverse chemical structure, composition, molecular weight, potential, and linking sequence, all of which result in
different functionality and biological activity (Xie et al. 2016b). Xie et al. (2014,
2016b) indicated that polysaccharides have a different molecular weight (Mw) and
monosaccharide composition. They also exhibit differences in their configuration
and position of glycosidic linkages. Their structure range from those that are linear
Fig. 4.12 Dextran
4 Bioactive Carbohydrates, Biological Activities, and Sources