Abstract: The aim of this work was to explore the influence of adding different proportions of xanthan gum as a hydrophilic colloid to lotus root starch on its pasting, rheological and textural properties and microstructure. The results showed that final viscosity and peak time of starch paste were increased while peak viscosity, setback value and breakdown value were reduced by adding xanthan gum. The mixed system had better thermal stability and aging resistance. Shear stress was declined to different degrees with increasing addition of xanthan; furthermore, the consistency coefficient K was increased whereas the fluid index n was decreased. The starch paste was still a pseudoplastic fluid after addition of xanthan gum, but the mixed system had higher thickening capacity. G’ and G” were improved and tanδ was reduced by addition of xanthan gum; viscoelasticity and stability were increased as well. A 8.0:2.0 (m/m) mixture of xanthan gum and lotus root starch had the best thickening capacity, viscoelasticity and stability. The hardness, cohesion, gumminess and chewiness of mixed systems were decreased, and the elasticity was increased compared with neat starch. The texture of xanthan gum-starch mixed gels was softer. A more uniform and stable structure was observed after adding xanthan gum under scanning electron microscope (SEM).

Key words: xanthan gum, lotus root starch, pasting properties, rheological properties, texture properties, microstructure