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When it has been obtained in a sufficient degree of purity, structural characteristics of a polysaccharide can be determined by the analysis of (i) monosaccharide units, (ii) linkage types, (iii) anomeric configurations, (iv) noncarbohydrate substituent groups, and (v) molecular weight [3]. However, structural aspects of polysaccharides can be also described on the organizational levels, similar to protein primary, secondary, tertiary, and quaternary structural organizations. Polysaccharide primary structure can be described as a covalent sequence of monosaccharide units [21]. The secondary structure is the geometrically regular arrangement in space that the primary sequence can adopt. The establishment of the tertiary structure occurs via the packing of secondary structure arrangements together. Tertiary structure is stabilized mostly through intermolecular hydrogen bonds, but physical state and temperature can also affect the adoption of an ordered secondary or tertiary structure. Finally, a quaternary structure is the arrangement of single units of tertiary structure within a complex built by non-covalent interaction [21, 22]. Generally, the type of glycosidic linkage affects the molecular conformation more than monosaccharide type. Polysaccharide’s primary structure determines the nature and extent of intramolecular and intermolecular associations within a polysaccharide chain and configures secondary, tertiary, and quaternary structures. To achieve thermodynamically favored conformations, the extent of glycosidic bond rotation is restricted. Therefore, these favored conformations define the proximity of adjacent glycosyl units one to another and determine the three-dimensional configuration of a polysaccharide. For example, amylose, cellulose, and dextran are all linear chains of monosaccharide units, but they are different in the nature of their glycosidic linkages [21].

A systematic methodology and advanced analytical tools are required for separation, purification, modification and application of polysaccharides. Established techniques in the polysaccharide field aim to characterize the structural parameters such as chain conformation, chain length distribution, degree of substitution, degree of branching, crystallinity, and interactions with solvent [23]. The procedure to elucidate the structure of polysaccharides includes the isolation, purification, and molecular weight determination of polysaccharides, and the investigation of monosaccharide units and type of glycosidic linkages via FT-IR spectroscopy, periodate oxidation, partial acid hydrolysis, glycosyl linkage (methylation) analysis, Smith degradation, and GC–MS-based techniques. One-dimensional and two-dimensional NMR spectroscopy are used to describe the sequence of monosaccharides, the anomeric configuration of each sugar residue, and the degree of branching [24]. However, novel and more practical analyses methods, like bio-recognition based methods, immunochemical assays, enzymatic cleavage, are needed to be developed.