Impact of fine structure of galactomannans on their interactions with xanthan: Two co-existing mechanisms to explain the synergy

• Fine structure of galactomannans determined by enzymatic cleavage.
• Impact of guar gum fine structure on xanthan/guar interaction.
• 2 Different co-exiting interaction mechanisms are proposed.

The objective of the study is to investigate the role of fine structure of galactomannan (guar and locust beam gum) on the molecular interactions occurring in the presence of xanthan in aqueous solution. First, 2 Locust bean and 2 guar gums were characterized from a structural point of view thus pointing out some differences. Both Intrinsic viscosity and retention of hydrophobic probe were determined for pure polysaccharide solutions and mixtures. Results clearly indicate the crucial role of galactomannan fine structure on the synergy with xanthan in the case of guar gums. More precisely, the impact of the galactose units distribution along the main chain is linked to the synergetic mechanism. For high M/G only junction zone associations govern the synergy. Oppositely, for low M/G, segregative and junction zone associations co-exist and depend on the fine structure of the galactomannan.

Figure optionsDownload as PowerPoint slide