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Nature Protocols 7, 1590–1607 (2012) doi:10.1038/nprot.2012.081

The very basic method of characterizing polysaccharides is to hydrolyse and check for the simple sugars which can be done by HPLC, GC or even TLC on camparison with its standards. 

A simple method to prove the presence of polysaccharides in an extract is their acid hydrolysis /H2SO4/ on a boiling water bath. After neutralization with BaCO3, or with anion exchange resin in -OH cycle  mix the sample with 1vol/1vol mixture of Fehling 1 and Fehling 2 solutions. Heat the final solution on a boiling water bath for short time.  If originally blue color of Fehling solutions mixture turns brown, and precipitate of Cu2O appears at the bottom of testing  tube, the sample contained reducing compounds /also reducing sugars/.

The above mentioned reaction /oxidation of reducing moieties/ runns also with other reducing agents if present in the extract/, so it is not a specific reaction for saccharides. From this reason it could be useful to verify the presence of monosaccharides in the hydrolyzed extract by chromatographic methods, as mentioned in the previous ansver of S.E.