Effect of Moisture Content and Particle Size on Physicochemical Properties of Wheat Meal

Abstract

<abstract> <bold>Abstract.</bold> The objective of the experiment was conducted to investigate the effect of moisture content (five wet basis moisture content, respectively 7%, 10%, 13%, 16%, 19%) and particle size(three kinds of particle size, geometric mean particle diameters are respectively 193, 342, 445 μm) on the friction and pasting characteristics of wheat meal. Friction parameters like the internal friction, angle of sliding friction and angle of repose of different wet basis moisture content and different particle size of wheat flour were respectively measured by direct shear apparatus, self-made bevel instrument and the angle of repose for measuring device. To study the variation of gelatinization for the material during processing, rapid viscosity analysis (RVA) were performed to research the pasting properties of the materials, then analyzed the variation of testing results.The experimental results showed that under these conditions the angle of repose was 39.8°~46.7°, the angle of sliding friction between the wheat powder and plastic board, glass plate, galvanized plate, stainless steel plate were respectively 37.1°~55.3°, 36.3°~47.3°, 34.5°~46.5° and 32.5°~48.3°; the internal friction was 22.5°~33.6°. The higher the moisture content was in wheat meal and the smaller the particle size of the wheat meal was, the bigger the friction between the meal grain of wheat was, the poorer the liquidity was, the bigger the internal friction, angle of sliding friction and angle of repose was. The smaller the particle size of the wheat meal was, the higher the final viscosity was. This study can provide basic data support for the use of wheat meal, especially the physicochemical characteristics in related equipment in feed industry.