Influence of Extrusion on Functional Properties of Flour from Selected Wheat and Barley Cultivars Grown in Croatia

The aim of this research was to evaluate the effect of extruder die temperature (90, 100, 110 °C) and flour moisture (25, 30, 35%) on properties of extrusion-modified flours from wheat (Kraljica, Olimpija) and hull-less barley (GZ-10, GZ-11) cultivars. Flours were extruded in laboratory single screw extruder and micro viscoamylographic, farinographic properties, sedimentation and falling number were determined. The results showed that viscosity values decreased and stability of flours increased after extrusion, both during shearing at high temperatures and regarding retrogradation. Although barley flours were in B2 and C1 quality category before extrusion, after extrusion all flours were within A1 or A2 category. Sedimentation values significantly decreased after extrusion, and falling number depended largely on extrusion conditions. By careful selection of cultivar, flour moisture, and extrusion conditions flours with desired properties may be produced.