Imidazole-based deep eutectic solvents for starch dissolution and plasticization

Abstract

Potato starch and high-amylose starch were treated with imidazole-based deep eutectic solvents (DESs) as dissolution and plasticization media. Beside imidazole (IM) for two-component DESs preparation choline chloride (CC), glycerol (G) or carboxylic acids (citric or malic) were used. An influence of water content in starch (as well as an extra water in the starch/DES system) on polymer dissolution and plasticization processes was investigated. Dissolution and gelatinization of starch in DESs were followed via DSC and laser scanning microscopy. A rheometric characteristics revealed an influence of starch/DES system storage time on the plasticization process. The tendency to recrystallization of compression-molded-starch films was evaluated using XRD technique. High dissolution and plasticization effectiveness of CC/IM and G/IM and a low tendency to film retrogradation of thermoplasticized starch were noted.

Keywords: 1-Ethyl-3-methylimidazolium chloride [EMIM]Cl (PubChem CID: 2734160); Choline chloride (PubChem CID: 6209); Citric acid (PubChem CID: 311); Deep eutectic solvents; Dimethyl sulfoxide (PubChem CID: 679); Dissolution; Glycerol (PubChem CID 753); Imidazole (PubChem CID: 795); Malic acid (PubChem CID 525); Plasticization; Starch; Urea (PubChem CID 1176).