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

The effects of different inorganic cations (Na(+), K(+), Ca(2+) and Al(3+)) 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 Al(3+) 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 Ca(2+) solutions, and the viscosity retention rate of welan/gellan mixtures is higher than that of the single components in Ca(2+) 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.