Insights into interaction mechanism between xanthan gum and galactomannan based on density functional theory and rheological properties

To explore the interaction sites and energies of ordered and disordered xanthan gum with locust bean gum (LBG), we prepared xanthan with different conformations and used it to form synergistic complexes with LBG. The interaction strength between xanthan and LBG was analyzed by analog computation using the density functional theory (DFT) method. Furthermore, the viscoelastic changes of the xanthan-LBG complex in different solutions were analyzed to verify the DFT results. The results showed that the ordered xanthan interacted with LBG through the side chains, with an interaction energy (EInt) of -479.450 kcal/mol. On the other hand, the disordered xanthan and LBG formed gels through backbone-to-backbone interactions, with an EInt of -262.290 kcal/mol. Overall, the study provides insights into xanthan-galactomannan gel formation and a theoretical basis for the broader application of xanthan.