Branching polysaccharide-water interactions

Four features of a polymer solute figure prominently in the polysaccharide-water interactions, viz., bonding, branching, ionization, and nonuniformity of the repeating structure (Glass, 1986). 

Solubility of polysaccharides depends on intermolecular hydrogen bonding and whether steric hindrance (often in the form of branches) keeps the chains at a distance from each other so that water can penetrate and hydrate the polymers. Single, neutral monosaccharide units with one type of linkage and few or no branches are usually insoluble in water and are difficult to solubilize. They form orderly conformation within the chain and chain-chain interaction. Branched polysaccharides are more water soluble. Branches reduce chain-chain interaction, which allows easier hydration. Dried branched polysaccharides rehydrate more quickly than do dried nonbranched polysaccharides. 

The linear, but highly branched, molecular structure of the galactomannans is the reason for some specific properties which are quite different from those of the unbranched cellulose-like and water-insoluble mannans and glucomannans. Galactomannans are hydrated in cold water and give stable solutions even in acidic formulas. The interactions of galactomannans with other polysaccharides are the base of a variety of industrial applications. 

---