Influence of the method of purification on some solution properties of welan gum

The origin and some consequences of the presence of aggregates and impurities (deriving from the fermentation procedure) on the solution properties of welan gum have been studied. For this purpose, a method of purification was developed for a fermentation welan broth. It was verified that this method is ineffective for the dissociation of aggregates in the commercial product. This demonstrates the irreversible nature of the intermolecular interactions of welan samples isolated by precipitation in the presence of impurities. The purified products were characterized (Mw, [eta], kH) and the results were compared to those obtained from commercial samples of welan. The influence of the method of purification on the rheological properties was analysed.