Table 3.

Common determination methods of glycosidic bonds of polysaccharides.

Method	Information	Characteristic	References
Partial acid hydrolysis	Ranking of stability of various sugar: the pyran sugar residue>the furan sugar residue, the hexose sugar>the pentose sugar, the sugar residues in main chain>the branched sugar residues	Poor selectivity, requires precise reaction conditions, not suitable for the complex mixed polysaccharides or heterogeneous structure products	(88–90)
Periodic acid oxidation	The position of glycosidic bonds; the degree of polymerization of linear polysaccharides; the number of branches of branched polysaccharides.	Carried out in the dark in an aqueous solution with pH 3–5, less polysaccharide samples are required	(4)
Smith degradation	Degradation product erythrose: 1 → 4 combined glycosidic bonds; glycerol:1 → 6, 1 → 2 glycosidic bonds or a reducing terminal glucose residue; monosaccharides such as glucose, galactose, mannose: 1 → 3 glycosidic bonds.	Combined with periodic acid oxidation	(91)
Methylation reaction	GC/MS spectral library; the standard PMAA spectrum; the ionization law of PMAA.	α/β stereochemical information cannot be obtained	(92, 93)
Enzymatic digestion	α-glucosidase hydrolysis α-glycosidic bond; β-glucosidase hydrolysis β-glycosidic bond.	Specific, few by-products, little digestive enzymes for polysaccharide	(94, 95)