Matrix exopolysaccharides discussed in this review. Shown is a graphical representation of exopolysaccharides with parentheses indicating repeating elements. Subscripts indicate possible number of residues in each element. Glc, glucose; Gal, galactopyranose; Man, mannose; Galf, galactofuranose; GalNAc, N-acetyl galactosamine; GalN, galactosamine. *, no specific arrangement of residues or polymer length has been defined. #, galactofuranose side chains of galactomannan can be linked to any of the indicated mannan residues. †, the degree of deacetylation of these polymers is not known.