Study of the influence of the surfactants on the size distribution and the mass ratio of wheat starch granules by Sedimentation/Steric Field – Flow Fractionation

The determination of the particle size distribution and mass ratio of two types (small and large) of starch granules is of great significance in the food industry, since the size of the granules influences the gelatinization, digestibility and thermomechanical behavior of starch. In order to achieve that, the ideal experimental conditions for sample analysis should be determined. The influence of the various surfactants (FL-70, a mixture of anionic and nonionic surfactants; Triton X-100, a nonionic surfactant; and SDS, an ionic surfactant) used during the analysis on these results was investigated, as the chemical structure of the suspending medium affects the interaction forces between the starch granules themselves, as well as the starch granules and the accumulation wall. Two different mathematical methodologies were applied, which were found to lead to approximately similar conclusions concerning the mass ratio of starch granules. The kind of detergent used was found to have a strong influence on the results of the experimental analysis. The total experimental procedure was performed by sedimentation field-flow fractionation (SdFFF). The results were compared with those obtained by scanning electron microscopy (SEM) or with those found in the literature.