Effect of aqueous and alcoholic shear treatments on the properties of rigid plastics from wheat gluten

Two procedures conducive to blending wheat gluten with other polymers in view of enhancing the mechanical properties of rigid gluten materials, were investigated. Method 1 involved extrusion of an aqueous gluten dough at 30-110 degrees C. In method 2, gluten was processed in 70% ethanol at temperatures <= 130 degrees C in a pressurised reactor. After solvent removal, the dried powders were compression moulded into products exhibiting fewer defects than,gluten moulded directly without any pre-treatment, suggesting that application,of either method improved polymer flow. in temperature regimes where little or no crosslinking occurred during the shear treatments, the mechanical properties of compression moulded samples were also better than those of directly moulded gluten. Further improvements were observed when glutenin aggregates depolymerised via breaking of disulfide bonds. This occurred in method 2 at temperatures exceeding 90 degrees C Materials processed via method 2 at 110 degrees C displayed a high level of strain hardening in. compression tests, which suggests an increase in molecular entanglements. (C) 2015 Elsevier B.V. All rights reserved.