Improved method for purifying extracts containing phytoglycogen or certain derivatives thereof which comprises the step of subjecting the extracts to ultrafiltration. Methods for providing a lower viscosity phytoglycogen material by subjecting an extract containing phytoglycogen (or purified phytoglycogen) to beta-amylase treatment. Methods for preparing beta-dextrins or derivatives thereof from phytoglycogens or derivatives thereof.
