Effects of inorganic cations on the rheology of aqueous welan, xanthan, gellan solutions and their mixtures

• Effects of inorganic cations on the rheology of polysaccharides have been studied.
• The addition of inorganic cations enhances the viscosity of xanthan and gellan solutions.
• The viscosity retention rate increases by mixturing the polysaccharides.
• The salt induced gelation expands the range of the application for polysaccharides.
• Combining polysaccharides is an effective strategy to control their rheology.

The effects of different inorganic cations (Na+, K+, Ca2+ and Al3+) on the rheological properties of single and mixture polysaccharide solutions have been systematically investigated. The apparent viscosity and viscoelasticity of welan solutions decrease with the addition of inorganic cations. Meanwhile, the addition of Al3+ and K+, respectively, enhances the apparent viscosity and viscoelasticity of xanthan and gellan solutions by promoting the gelation. The viscosity retention rate of welan/xanthan mixtures is higher than that of the single components in Na+, K+ and Ca2+ solutions, and the viscosity retention rate of welan/gellan mixtures is higher than that of the single components in Ca2+ solutions. The salt induced gelation expands the application for polysaccharides, and it is also believed that the method of combining welan and xanthan (or gellan) is an effective strategy to control the rheology and morphology of solutions in the presence of inorganic salts.