Any mixture of complex, colloidal, macromolecular plant galacturonans containing a large proportion of D-galactopyranosyluronic acid residues in alpha-(1->4) linkage, the carboxy groups of which may be esterified to varying degrees by methyl groups or be partially or completely converted into salts. The structure shown is that of the parent polygalacturonan. (Chemical Entities of Biological Interest Ontology, CHEBI_17309)
