Partial fractionation of wheat starch amylose and amylopectin using zonal ultracentrifugation

A novel technique for partial separation of amylose and amylopectin using zonal ultracentrifugation is introduced, supported by analytical ultracentrifuge measurements. Starch was first solubilised in 90% DMSO and 5% sucrose and then layered onto a gradient forming solution of 10–30% sucrose in 90% DMSO, with a cushion made up of 36% caesium chloride and 25% sucrose in water. Solutions were then run in a preparative ultracentrifuge at a rotor speed of 14000 rpm for approximately 25 min. The results for wheat starch showed that this method produced highly purified amylopectin in both soluble and highly aggregated forms, and at least partial purification of the amylose fractions.