Deep eutectic solvents based on urea, polyols and sugars for starch treatment

Deep eutectic solvents (DES) based on urea (U), polyols (glycerol -G, sorbitol - S) and monosugars (glucose -Glu, fructose - Fru) were obtained, thermally characterized and used for potato starch treatment: dissolution and plasticization. The polysaccharide was dissolved in U/glycerol mixtures forming transparent, non-retrograded gels. The dissolution process was confirmed by microscopic observations and DSC analysis. Plasticizing efficiency of DES in thermoplasticized starch (TPS) via compression molding was investigated using mechanical tests, DMTA, XRD, TGA and FTIR analysis. Although all studied DES were able to plasticize starch effectively, the most flexible films were with urea/glycerol mixture: the highest elongation at break exceed 200%. XRD analysis confirmed high amorphization of starch with the urea-based DES after thermocompression. Moreover, introduction of urea as DES inhibited its recrystallization in the polysaccharide matrix. (c) 2021 Elsevier B.V. All rights reserved.

Automated summary

This study explored deep eutectic solvents based on urea, polyols, and monosugars for potato starch treatment, finding that urea/glycerol mixture was the most effective in plasticizing starch, resulting in highly flexible films with elongation at break exceeding 200%. The introduction of urea as a DES inhibited recrystallization of starch in the polysaccharide matrix.