Starch treatment with deep eutectic solvents, ionic liquids and glycerol. A comparative study

In this work changes in potato starch during processing (dissolution and plasticization via thermocompression) in the presence of three types of media: deep eutectic solvents (DES) with different anions in choline salts and components molar ratios, ionic liquids (IL) and glycerol (G) were investigated. Urea-based DES and IL exhibited dissolving capacity towards starch (confirmed with microscopic observations and DSC). Plasticizing ability was studied using rheological characteristics of starch/media premixtures as well as mechanical tests, DMA, XRD and FTIR analysis of thermoplastic starch (TPS). Additionally, influence of concentration of two types of DES: dissolving and non-dissolving on final properties was investigated. Results revealed that viscosity of premixtures with DES and IL was lower that with G. Dissolving DES and IL led to highly amorphous materials with lower tensile strength and much higher elongation at break than TPS with non-dissolving DES and G. Imidazolium IL significantly decreased thermal stability of TPS.