- Department of Molecular Sciences, Swedish University of Agricultural Sciences
Angellier-Coussy, Helene; Putaux, Jean-Luc; Molina-Boisseau, Sonia; Dufresne, Alain; Bertoft, Eric; Perez, Serge
The insoluble residues obtained by submitting amylopectin-rich native starch granules from waxy maize to a mild acid hydrolysis consist of polydisperse platelet nanocrystals that have retained the allomorphic type of the parent granules. The present investigation is a detailed characterization of their molecular composition. Two major groups of dextrins were found in the nanocrystals and were isolated. Each group was then structurally characterized using beta-amylase and debranching enzymes (isoamylase and pullulanase) in combination with anion-exchange chromatography. The chain lengths of the dextrins in both groups corresponded with the thickness of the crystalline lamellae in the starch granules. Only similar to 62 mol % of the group of smaller dextrins with an average degree of polymerization ((DP) over bar) 12.2 was linear, whereas the rest consisted of branched dextrins. The group of larger dextrins ((DP) over bar 31.7) apparently only consisted of branched dextrins, several of which were multiply branched molecules. It was shown that many of the branch linkages were resistant to the action of the debranching enzymes. The distribution of branched molecules in the two populations of dextrins suggested that the nanocrystals possessed a regular and principally homogeneous molecular structure. (C) 2009 Elsevier Ltd. All rights reserved.
Starch; Nanocrystals; Acid hydrolysis; Enzymatic hydrolysis; Structure
2009, Volume: 344, number: 12, pages: 1558-1566
Publisher: ELSEVIER SCI LTD