The answer would be Dehydration Synthesis
Dehydration Synthesis is the process where water is removed from the bonds of these polysaccharides, so they can be combined to make a coherent whole of new bonds.
Hydrolysis is the opposite of Dehydration Synthesis. This process adds water to the process, which in turn hydrolyzes the polysaccharide breaking it down to its monomers or dimers (disaccharide or monosaccharide).