Cationisation of Glycerol Plasticised Wheat Starch under Microhydric Molten Conditions

Cationisation of glycerol plasticised wheat starch was performed in a molten mixture under the action of thermo‐mechanical energy using two reagents: 3‐chloro‐2‐hydroxypropyltrimethylammonium chloride and 2‐epoxypropyltrimethylammonium chloride. The reaction was catalysed with sodium hydroxide under microhydric conditions. The results showed that under these conditions the reaction proceeds rapidly and reaches completion within a few minutes. The reaction efficiencies were higher for lower degrees of substitution (DS). The epoxide showed a higher reactivity than the chloro derivative. Both destructurisation of starch granules and increased sodium hydroxide concentration enhanced the reaction, but an increase in plasticiser concentration had a negative effect. Measurements of intrinsic viscosity showed a decrease of the average molecular weight of the product, which was attributed to the thermo‐mechanical melting process. An increase in water affinity with DS was seen in the water sorption properties of the chemically modified starch.