Influence of the Extrusion Shear Environment on Plant Protein Texturization

Abstract

The effects of total nominal shear strain, apparent shear rate, shear stress in the die and an integral temperature-time history function on textured soy protein properties were studied. These variables are independent of extruder size and can potentially serve as machine independent correlating factors. Correlation models showed that increasing shear strain and temperature-time in the screw tended to enhance cross-linking between protein molecules, while increasing shear through the die tended to disrupt the linkages. Moisture probably increases the mobility of the protein species which could improve cross-linking and reduced density while increasing water absorption.