INFLUENCE OF XANTHAN ON THE RHEOLOGICAL PROPERTIES OF AQUEOUS STARCH-EMULSIFIER SYSTEMS

Interactions between potato starch and complex-forming emulsifiers in the presence of xanthan, and their consequences on the rheological pro perties were investigated. The aqueous starch-xanthan-emulsifier syste ms were prepared by mixing the separately dispersed components or by h eating the components together. The amount of leached amylose and the formation of starch-emulsifier complexes were determined by amperometr ic iodine titration. The viscoelasticity was measured with small-defor mation oscillatory tests The results show that while the incompatibili ty between starch and xanthan does not affect the formation of starch- emulsifier complexes, it does hinder the gelation process induced by s tarch complexation and reduce the firmness of the resulting gels. The combination of starch with small amounts of an incompatible biopolymer like xanthan and a complex-for ming emulsifier allows the generation of different gel structures.