Effect of Preparation Conditions and Starch/Xanthan Concentration on Gelation Process of Potato Starch Systems

Abstract

The rheological properties of starch gels prepared by mixing starch and xanthan at different concentrations and temperatures, were investigated. Potato starch suspensions at concentrations: 10–15%, and xanthan gums at concentrations 0.1% and 0.3% were separately prepared at 75°C and 90°C and successively mixed. The gel‐cure behavior of these mixtures was studied by performing large deformation experiments and oscillatory shear tests during a period of 24 h. Both yield stress and apparent Young's modulus were mainly influenced by the time of gel aging and the starch concentration. Temperature of preparation and xanthan concentration, had less pronounced effects on the overall rheology. Similar observations were made by oscillatory experiments. Increase in xanthan concentration resulted in changes for all G′ and G″values (greater values). Xanthan addition accelerated gel setting but it not its further structure building. This was especially evident at 0.1% xanthan concentration, where similar G′ values to control samples were observed at the end of storage.