Flowability, cohesive, and granulation properties of wheat powders

The objective of the present work is to investigate the diversity in flowability, cohesive, and granulation properties for a large variety of wheat powders, obtained from different wheat grain species (durum wheat or common wheat) by different milling conditions. The flowability, cohesive, and granulation properties were evaluated at low (15-16% db) and high (33% db) moisture contents, during mixing and under different stress conditions (confined or unconfined compression). The properties are discussed in regard with the initial physical and biochemical characteristics of particles. Results demonstrate a large diversity in flowability and cohesive properties for the selected wheat powders at initial moisture content. At low moisture content, the particle size distribution of wheat particles is found to significantly contribute to flowability and cohesive properties. The flowability and cohesion properties at high moisture content was found to be partly dependent on physico-chemical and biochemical mechanisms, because of the plasticizing effect of water molecules on the wheat components. The glass transition concept was used to discuss changes in mechanical properties of wheat powders due to changes in moisture content. (C) 2007 Elsevier Ltd. All rights reserved.