Toward a Better Understanding of Different Dissolution Behavior of Starches in Aqueous Ionic Liquids at Room Temperature

Abstract

The purpose of this study was to understand the dissolution behavior of maize and potato starches in 1-ethyl-3-methylimidazolium acetate ([Emim][OAc]):water mixtures at room temperature. With an increasing ratio of ionic liquid (IL):water, the long- and short-range ordered structures and granule morphology of both starches were disrupted progressively. The multiscale structure of maize starch was disrupted completely after treatment with the [Emim][OAc]:water mixture of 6:4, indicating good dissolution performance of this mixture for maize starch. This mixture seemed to provide a balance between the viscosity of the solvent and availability of ions to disrupt starch H-bonds. The different dissolution behaviors of maize and potato starches in [Emim][OAc]:water mixtures were attributed to structural differences of the granule surfaces. Our results showed that the dissolution behavior of starches was affected by both starch sources and properties of [Emim][OAc]:water mixtures, which may provide guidance for the development of green technology for processing of biopolymers with low energy consumption.

Applications of ionic liquids in starch chemistry: a review

“…64 Starches are generally divided into three main polymorphs (A-, B-, and C-type crystallites), which have distinct functional properties. [65][66][67] Native starch granules are characterized on structural scales ranging from nano-to micrometer, including granule, growth ring, blocklet, lamellae, and double-helix. 63,68 The multiscale structures of the starch granule plays a key role in determining functionality and suitability for different applications of starch ( Fig.…”

“…at ambient temperature, potato starch was not dissolved completely, which were attributed to structural differences of the granule surfaces. 67 While the maximum solubility of starch in ILs has been found when there is a certain content of water mixed with the IL, this is not the case for cellulose, another polysaccharide with the same glucose repeat structure but different glycosidic bonds. For cellulose, the dissolution efficiency of ILs will significantly decrease with increasing water content in the system, 88 which makes the dissolution mechanism of polysaccharides by aqueous ILs more mysterious.…”

Novel Green Synthesis of Octenyl Succinic Anhydride Esters of Granular Starch

“…The diagrammatic sketch of starch esterification with OSA in water is shown in Figure 9 Scheme C. In the IL/water mixture of 2:8 (w/w), the surface of maize starch granules was reported to have more depressions and channels compared with native starch, 38 thus facilitating the contact and reaction between OSA and starch granules and enhancing the RE and DS (Figure 9 Scheme A). In contrast, potato starch granules were reported to become roughened with some cracks or erosions on the surface in the IL/water mixture of 2:8 (w/w), 38 also promoting the modification of starch with OSA (Figure 9 Scheme B). With increasing ratio of IL/water, the RE of starch esterification with OSA and DS of OSA-starches decreased, which seemed to be contradictory with the notion that a greater extent of disruption of starch granules results in the higher RE of esterification and DS of OSA-starches.…”

Structure and Morphological Properties of Starch Macromolecule Using Biophysical Techniques

“…[ 26,27 ] Wang et al. [ 28 ] used SEM to observe the degradation of corn and potato starches in aqueous ionic liquids at room temperature. It was noted that treatment with ionic liquids did not affect the surface morphology of the starch granules.…”