Structural features of fatty acid-amylose complexes

X-ray diffraction and Differential Scanning Calorimetry measurements were performed on highly crystalline complexes prepared from amyloses and fatty acids with different chain lengths. The complexes yielded very sharp Vh-type diffraction diagrams except those prepared with the shortest amylose chains. The melting temperature of the complexes increased with increasing amylose chain length. In parallel, the inclusion of the fatty acid inside a 65 amylose helix, similar to that determined for the Vh structure, was studied using molecular modelling. The aliphatic part of the fatty acid can be included in trans conformation. Six discrete positions per helix pitch were calculated. The polar group of the fatty acid cannot be included, due to both steric and electrostatic repulsions.