Structural, physicochemical and technofunctional properties of corn gluten meal modified by extrusion

This study aimed to evaluate the influence of sample moisture, extrusion temperature, and extruder screw speed on the hydration properties of corn gluten meal (CG), optimize process condition for the highest protein solubility at pH 7 (PS7) and WAC, and assess the effect of the optimized extrusion process on the structural, chemical, physical, and technofunctional properties of CG proteins. Extrusion was carried out at different sample moisture (20%-40%), temperatures (120-160 degrees C), and screw speeds (33-117 rpm) using a complete factorial design with two central points. All extrusion conditions resulted in reduced hydration properties. Extrusion with 20% sample moisture, 120 degrees C and 117 rpm resulted in the lowest loss of water absorption capacity and protein solubility at pH 7 (optimized condition). After optimized extrusion, the GC became darker and showed greater activity and protein emulsifying capacity and lower foaming capacity. Furthermore, CG proteins had reduced solubility at different pHs. Changes in technofunctional properties resulted from changes in protein structure after extrusion. The new protein structure is stabilized by non-covalent bonds (hydrogen bonds and hydrophobic interactions) and disulfide bonds. Extruded corn gluten has the potential to be used as an ingredient in bakery, emulsified meat products, salad dressings, vegetable pates, and desserts.