Rheological and gel properties of corn starch-xanthan mixed systems

In order to investigate the effects of hydrocolloid on the rheological and gel properties of starch paste, rheolgical and gel behaviors of corn starch and corn starch/xanthan gum mixed systems were studied. The mechanism of interaction between corn starch and xanthan gum was also analyzed. The results showed that corn starch and corn starch/xanthan gum mixed pastes were the typic yield-pseudoplasticity. A significant synergistic effect on consistency index was evident. The flow behavior index of mixed pastes was increased as the ratio of xanthan gum in the mixtures was raised. The mixture pastes exhibited more pseudoplasticity., but the effect was no pronounced as the proportion of xanthan gum was greater than 10%.The dynamic oscillatory test showed that the mixture pastes had a more superior viscoelastic property. The xanthan gum molecules exerted intermolecular interactions with the amylose molecules by hydrogen bond. The short-term retrogradation of amylose was prolonged and restricted by the present of xanthan gum. The mixed gels were more softer. Based on an overall consideration, a 9.0:1.0 (g/g) mixture of corn starch and xanthan gum proved to be the optimal additive. The research results will provide a theoretical basis for application and quality control of corn starch/xanthan gum mixed system in food industry.