Physicochemical properties of starch dispersed in 1-allyl-3-methylimidazolium chloride

In recent years, considerable concerns have arisen over new efficient and environmentally friendly way for utilizing ionic liquids to dissolve starch. In this study, corn, wheat, potato, rice, and mung bean starches were dispersed in 1-allyl-3-methylimidazolium chloride (AMIMCl). The maximum solubilities of corn, wheat, rice, mung bean, and potato starches measured by turbidimetry were 11.75, 11.25, 11.00, 10.50, and 9.00 g/100 g of AMIMCl, respectively. And steady shear behavior of starch–AMIMCl mixtures, morphology, thermal properties, and molecular weight of native starch, and starch dissolved in AMIMCl were analyzed. All the starch/AMIMCl solutions were typical pseudoplastic fluids. Thermal properties showed that all starches dispersed in AMIMCl had no endotherm except potato starch. Scanning electron microscopy (SEM) and gel permeation chromatography (GPC) revealed that shapes and structures of native starch granules were destroyed, and starch molecules endured different degrees of degradation during dissolution process.

Turbidity and polarized micrographs of potato starch dissolved in AMIMCl at 90 °C.Figure optionsDownload as PowerPoint slideHighlights
► Five starches were dispersed in 1-allyl-3-methylimidazolium chloride (AMIMCl).
► The maximum solubilities of five starches measured by turbidimetry.
► All the starch/AMIMCl solutions were typical pseudoplastic fluids.
► All starches dispersed in AMIMCl had no endotherm except potato starch.
► Starch molecules endured different degrees of degradation during dissolution process.