The effect of electrostatic interactions on pasting properties of potato starch/xanthan gum combinations

Abstract

The effects of electrostatic interactions on pasting properties of potato starch (PS)/xanthan gum (XG) combinations were investigated. The RVA peak viscosity of combinations was decreased firstly and then increased with the adding of XG. The analysis and regression model performance of RVA measurement showed that there was the relationship between pasting properties of combinations and XG concentrations. Electrostatic repulsions between native potato starch or anionic modified potato starches (AP) and XG could be present by decreasing peak viscosity, but the pasting temperatures showed increasing trend. However, electrostatic attractions between cationic modified potato starch (CP) and XG showed the opposite effect. Negative zeta potential determination for combinations (− 54.6 mv) was higher than PS (− 35.2 mv) illustrated that combinations had more electronegativity and stability, in addition a phase-separated microstructure was exhibited in the combinations determined by Zeta potential results. SEM micrographs presented that XG film attached to the surface of PS granules, which inhibited the starch granules destruction and leaching of amylase. The electrostatic repulsion leaded to more stability of the three dimensional network structures of combinations. The strong electrostatic interactions between PS and XG were found to play an important role on the pasting properties of the combinations.