| Abstract: | Sedimentation Field Flow Fractionation in combination with multi angle laser light scattering was applied to fully destructured potato and waxy corn starches to investigate the molecular weight and radius distributions of the starch components. In a range of radii betwen 50 and 500nm, information could be obtained about the influence of the medium conditions on the distributions. The averages of molecular weight and particle radius were found to decrease when holding the solution at a given temperature for an extended period of time (from 20min up to 60min) and when the temperature was increased (from 160°C up to 175°C). The molecular weight and radii of gyration of the dissolved starch species typically panged from 106 to 109 daltons and 50nm-500nm respectively. Changes in the distributions due to different conditions during the dissolution process where also recognized by changes in the shape of the distribution curve. Thus the applied technique gave satisfactory results in a high molecular weight region where SEC fails. |
