INVESTIGATION OF THE VARIATION OF THE MASS RATIOS FOR LARGE AND SMALL STARCH GRANULES WITH THE pH AND IONIC STRENGTH OF THE DISPERSING MEDIUM BY SEDIMENTATION/STERIC FIELD-FLOW FRACTIONATION

ABSTRACT

The relatively new technique of Sedimentation/Steric Field-Flow Fractionation (Sd/St FFF) is a simple, fast, and accurate method for the size separation and characterization of starch granules. In the present work, the Sd/St FFF technique was used for the calculation of the mass ratios of the A-large and B-small granules from barley and wheat starch samples. The mass ratios were obtained from the distribution curves of the starch samples at various pH and ionic strength of the suspending medium, in the presence or the absence of the surfactant FL-70. The influence of the suspension pH and ionic strength on the mass ratios of A- and B-granules is discussed in relation to the zeta potentials of the particles, which were measured by a microelectrophoresis apparatus.

Keywords:

• Sedimentation/steric FFF
• Starch characterization
• Starch mass ratios

ACKNOWLEDGMENTS

The authors would like to pay tribute to the services of the late Professor J. C. Giddings, who supplied the SdFFF system. This work was financially supported by the European Commission Contract No. ERB ICI15-CT98-0909.