Characterization and properties of starch-dicarboxylic acid inclusion complexes prepared by excess steam jet cooking

A series of dicarboxylic-amylose inclusion complexes (AIC) were prepared by excess steam jet-cooking high amylose corn starch with linear C10, C12, C14, and C16 dicarboxylic acids to examine the influence of two polar head groups on complex formation. The C12, C14, and C16 dicarboxylic acid AIC were prepared in 48-63 % yields and contained 8.9-11.8 % diacid while the C10 AIC gave 30 % and contained 2.6 % diacid. These AIC had V6 helical amylose structures by XRD and complexation was further confirmed by DSC, FTIR, and TGA. SEM of the C12-C16 AIC revealed micron-sized toroidal spherulites while the C10 AIC was predominantly amorphous. DSC showed two AIC related transitions. This work provides a better understanding of the formation and physicochemical properties of these diacid AIC. Preparation by excess steam jet cooking demonstrates practical and commercial utility to prepare AIC as off-the-shelf materials for food and nonfood applications.