doi:10.1094/CCHEM-84-3-0276 |  VIEW ARTICLE

Study of Wheat-Flour-Based Agropolymers: Influence of Plasticizers on Structure and Aging Behavior.

R. Saiah (1), P. A. Sreekumar (1,2), N. Leblanc (1,3), M. Castandet (3), and J.-M. Saiter (1,4). (1) Laboratoire Polymères, Biopolymères et Membranes, Unité CNRS 6522, équipe LECAP, Institut des Matériaux Rouen, Université de Rouen, Faculté des Sciences, Avenue de L’université BP 12, 76801 Saint Etienne du Rouvray, France. (2) National Institute of Technology Calicut, NITC P O, Calicut, Kerala-673601, India. (3) Laboratoire de Génie des Matériaux de (LGMA), Esitpa rue grande, BP 607, 27106 Val de Reuil Cedex, France. (4) Corresponding author. Phone: 33 (0)2 32955085. Fax: 33 (0)2 32955082. E-mail: <jean-marc.saiter@univ-rouen.fr> Cereal Chem. 84(3):276-281. Accepted January 12, 2007. Copyright 2007 AACC International, Inc.

Wheat-flour-based agropolymers are prepared using an extrusion method. The morphology of the native and extruded wheat flours are analyzed by scanning electron micrography (SEM). During plasticization using water (9%, w/w) and glycerol (12.8%, w/w), a change in morphology of native wheat flour occurs. The structure of these materials was investigated by X-ray diffraction (XRD) with special reference to the amount of plasticizers used, such as water and glycerol molecules. The introduction of these plasticizers decreases the crystallinity rate and also increases the average distance between chains in the remaining vitreous phase of the extruded wheat flour. Replacing water molecules with glycerol reduces the crystalline phase and diminishes the average size of crystalline structures. The plasticization effects were confirmed by mechanical investigations. Indeed, increasing the amount of glycerol from 12.8 to 20% decreases the stress at failure and the tensile modulus, while the strain at failure increases. Finally, aging studies show that the percentage of crystallinity increases with time.