Treatment of wx corn starch dispersions in a microwave reactor and their hydrodynamic properties determined using asymmetrical flow field-flow fractionation

摘要

Hydrodynamic properties of aqueous wx corn starch (native, un-pregelatinised) dispersions treated in a dedicated single-mode microwave reactor at temperatures ranging from 180 to 210°C were determined using asymmetrical flow field-flow fractionationcoupled with an Rl detector. The dedicated microwave reactor enabled the fine control and monitoring of heating parameters (especially temperature) during the treatment. The translational diffusion coefficient and hydrodynamic radii (R_h) values determined for wx corn starch treated at 180 and 200°C indicate that the majority of the material (~98%) consisted of highly mobile, small and compact molecules/particles, with R_h values ranging from 10 to 90 nm, while the remaining -2% of the material consisted of considerably larger molecules/particles R_h values ranging from -100 to -200 nm). Degradation of wx corn starch was observed at 210°C.