Cereal Chem. 73 (1):12-17 |
Molecular Characterization of Some Amylopectins.
L. A. Bello-Pérez (1), O. Paredes-López (1,2), P. Roger (3), and P. Colonna (3). (1) Depto. de Biotecnología y Bioquímica, Centro de Investigación y de Estudios Avanzados del IPN, Apartado Postal 629, 36500 Irapuato, Gto. México. (2) Corresponding author. E-mail: <email@example.com> (3) Laboratoire de Biochimie et Technologie des Glucides, Institute National de la Recherche Agronomique, BP 527, 44026 Nantes Cedex, 03, France. Accepted September 7, 1995. Copyright 1996 by the American Association of Cereal Chemists, Inc.
Amylopectins from different sources were studied to gain information on their molecular structure. High-performance size-exclusion chromatography was used to assess the profiles of isoamylase-debranched, pullulanase-debranched, beta-amylase-hydrolyzed, and alpha-amylase-hydrolyzed amylopectins. With the two debranching enzymes, two principal fractions were generated. However, amylopectin depolymerized with pullulanase left a higher amount of nondegraded polymer, indicating that the two enzymes follow a different mode of action on amylopectin structure. Profiles obtained after hydrolysis with beta- or alpha-amylase in general showed that shorter chains were generated at higher enzyme concentrations. Static and dynamic light scattering were used to determine solution behavior, molecular weight, gyration radius, and hydrodynamic radius of amylopectins. These parameters suggested substantial structural differences within tested amylopectins.