AMYLOPECTIN - PROPERTIES AND FINE-STRUCTURE

Five amylopectins from different sources were studied to compare their physicochemical properties and structure. Physicochemical properties such as iodine binding capacity (IBC), maximum absorption (lambda(max) ) and intrinsic viscosity ([eta]) were assayed. Normal corn amylopecti n and potato amylopectin gave high values of IBC whereas waxy corn, co rn commercial and amaranth exhibited low values of this parameter; all values for lambda(max) were in the range 525-595 nm and those for [et a] varied from 23 to 104 ml/g. Results suggested structural difference s in the amylopectins. These macromolecules were eluted by high-perfor mance size exclusion chromatography (HPSEC) with refractive index (RI) showing different elution times, which indicate structural difference s among such components. The five amylopectins were debranched with is oamylase and pullulanase, and the fractions, studied both by HPSEC wit h RI and by high-performance anion-exchange chromatography (HPAEC) wit h pulsed amperometric detection (PAD), showed structural differences a mong amylopectins and differences in debranched patterns of isoamylase and pullulanase. Copyright (C) 1996 Elsevier Science Ltd