Dynamic light scattering and electrophoretic mobility studies of starch-fatty acid complexes in solution

Electrophoretic mobility and dynamic light scattering measurements were carried out to investigate the physical characteristics of amylose inclusion complexes with a series of long chain fatty acids, in alkaline solution (0.1 N or 0.01 N KOH). Amylose molecules exhibited lower values of electrophoretic mobility compared to those of the amylose-fatty acid complexes. The presence of amylopectin affected the electrophoretic mobility of starch-fatty acid complexes. Particle size distribution measurements of amylose-fatty acid complexes in aqueous suspension (pH 4.6) were performed employing the laser light scattering technique. The size of the diameter of the complexes in alkaline solution was found to be much smaller than that of the size of the complexes in aqueous suspension. The results are discussed in the light of solvent contribution to the conformational changes of the complexes occurred in the environments employed.