Nature of phase transitions of waxy maize starch in water-ionic liquid mixtures

The nature of phase transitions of waxy maize starch heated in mixtures of water and ionic liquid (IL) was elucidated using a variety of analytical methods. The transition from a single endotherm to an exotherm followed by an endotherm, and then to a single exotherm was observed with the increasing concentration of IL The results showed that at T-o of DSC phase transition no structural disruption had occurred. Except for the water/IL ratios of 1.5:1 and 1:1, there was considerable structural disruption of starch samples that were preheated to T-p or T-p2 of gelatinization transition. No residual structural order was observed at T-c of the gelatinization transition. An exothermic transition at water:IL ratios of 3:1 and 2:1 was attributed to the interaction of ionic liquid and amorphous regions in starch. The molecular disassembly of starch granules during gelatinization in different water:IL mixtures proceeded to completion at different rates. (C) 2018 Published by Elsevier B.V.