Observations on the crystallization of oligogalacturonates

Oligogalacturonates were produced by the limited enzymic hydrolysis of polygalacturonic acid and purified by ion-exchange chromatography. The fractions obtained were of limited polydispersity, determined by analytical ion-exchange chromatography. Oligomers with an average degree of polymerization of 10–15 were readily crystallized from aqueous salt solutions at neutral pH as single crystals. Crystal morphology of the salts examined, Na+, K+ and Ca2+ were characteristic of the salt. The wide-angle X-ray diffraction patterns obtained for the sodium salt were consistent with published fibre diffraction data of this salt form.