Effects of ionic liquids with different alkyl chain lengths and heat treatment on the physicochemical properties of high amylose maize starch and its resultant inclusion complex

This study investigated the effects of ionic liquid (ILi) with different cationic alkyl chain lengths (ACLen) on the dissolution behaviour of high-amylose maize starch (HAMStarch) and V-type complex formation under heat treatment. Results showed that the destruction degree of HAMStarch in a water/ILi solution increased with increasing temperature. At 70 degrees C, the polarisation cross of HAMStarch completely disappeared and the shortrange molecular order was significantly decreased. The formation of a V-type complex with lauric acid (LAc) enhanced the short-range molecular order of HAMStarch. Rheological measurements showed that the viscosity of the water/ILi solution decreased with increasing system temperature and increased with increasing cationic ACLen. However, the relative crystallinity (RC) of HAMStarch gradually decreased with increasing treatment temperature and ILi cationic ACLen. At 50 degrees C and 70 degrees C, when the number of carbon atoms in the alkyl chain was increased from 2 to 4, the diffraction peaks of the involved samples became stronger and sharper and the total melting enthalpy (Delta H) values gradually increased. The maximum RC (29.17 %) and Delta H (5.86 J/g) values of the HAMStarch-LAc complex were obtained when HAMStarch was pretreated by 1-butyl-3-methylimidazolium chloride at 70 degrees C.