An investigation into the structure, morphology and thermal properties of amylomaize starch-fatty acid complexes prepared at different temperatures.

Amylomaize (Hylon VII) starch-fatty acid (capric, myristic, palmitic, stearic, oleic) complexes prepared at 30, 50 or 70°C were studied using XRD, DSC, SEM, TGA and FTIR techniques. XRD diffractograms displayed the typical V-form of complexed amylose regardless the temperature of preparing the complexes. The degree of crystallinity of the complexes increased while the size of the crystals formed decreased as the preparation temperature of the complexes increased. DSC thermograms showed that the dissociation temperature of the complexes was increased proportionally to the chain length increase of the fatty acid. TGA indicated that oleic acid was adequately protected in the form of complexes. SEM micrographs showed the presence of crystals of the complexes either in the form of spherulites or in the form of lamellae. Enzymatic hydrolysis of the complexes led to quantitative recovery of the guest molecules. Hylon VII proved to be a suitable prospective complexing agent for the production of complexes of lipids.