Twin-Screw Extrusion Pink Salmon Muscle and Rice Flour Blends

Abstract

The effects of location and spacing of kneading elements on specific mechanical energy input and product attributes during twin-screw extrusion of pink salmon muscle and rice flour blends were investigated. Incorporation of kneading elements increased specific mechanical energy, expansion ratio and water solubility index, but decreased bulk density and Warner-Bratzler shear stress. The opposite trend was observed with increasing fish solids content except for shear stress, which was little affected by up to 30% fish solids concentration and in the expansion ratio range of 5 to 10. Water solubility index and Warner-Bratzler shear stress were linearly related to specific mechanical energy and bulk density, respectively. Results show that the magnitudes of the effects due to incorporation of kneading elements were different from that of reverse screw element and combination of reverse screw and kneading elements.