Effect of water and methanol on the dissolution and gelatinization of corn starch in [MMIM][(MeO)HPO2]

Abstract

The effect of water and methanol on the dissolution and gelatinization of corn starch in [MMIM][(MeO)HPO₂] was investigated by optical microscopy and differential scanning calorimetry. The presence of an appropriate amount of water can accelerate the dissolution while methanol has the opposite effect. A [MMIM][(MeO)HPO₂]/water mass ratio of 7/3 is the best ratio for corn starch to disperse a [MMIM][(MeO)HPO₂]–water mixture in, since it can dissolve starch at lower temperature. When methanol was added to the mixture of [MMIM][(MeO)HPO₂]/water at a ratio of 8/2 (w/w), the methanol accelerated the dissolution process of the corn starch, since it can penetrate the starch granules and swell the outer layer of granules with water. It is demonstrated that [MMIM][(MeO)HPO₂]/water/methanol at a ratio of 8/2/3 (w/w/w) is a good mixed solvent like [MMIM][(MeO)HPO₂]/water 7/3 (w/w) for corn starch.