A method is disclosed for hydrolyzing an alpha-1,3 or alpha-1,6 glucosyl-glucose linkage in a saccharide (disaccharide or oligosaccharide). This method comprises contacting the saccharide with an alpha-glucosidase enzyme such as transglucosidase under suitable conditions, during which contacting step the enzyme hydrolyzes at least one alpha-1,3 or alpha-1,6 glucosyl-glucose linkage of the saccharide. This method is useful for reducing the amount of oligosaccharides in a filtrate isolated from a glucan synthesis reaction, for example.