Characterization of starch polysaccharides by flow field-flow fractionation-multi-angle laser light scattering-differential refractometer index.

The coupling between flow field-flow fractionation (FFF), multi-angle laser light scattering and differential refractometer index provides a promising technique for fractionation of starch polysaccharides in aqueous conditions. Native starches with different amylose/amylopectin levels (0-70%) as well as a pure amylose sample were characterized. By applying a sudden drop in the cross-flow-rate, clear separation was achieved between amylose (which elutes first) and amylopectin. Flow FFF produced correct relationships between the molecular mass or the gyration radius versus elution volume for the fractionated amylopectin population. The results are also considered in terms of the macromolecular composition of starches.