Effect of the concentrations of corn starch and whey protein isolate on the processing parameters and the physicochemical characteristics of the extrudates

In this study, the effect of concentrations of corn starch and whey protein isolate was evaluated on the processing parameters and the physicochemical characteristics of the extrudates, using a Lattice simple mixture design. A variation from 10.02 to 68.81 g/min is observed in the residence time of the corn starch (CS)/whey protein isolate (WPI) blends and increased as WPI was higher, the torque ranged from 4.18 to 48.83 Nm/s, which decreases with the increase in WPI; the specific mechanical energy was between 247.85 and 882.92 J/g, and also the expansion index was between 0.92 and 1.40, which was decreasing with the rise in WPI, whereas the bulk density was between 0.14 and 0.42 g/cm3 presenting the same trend. The hardness ranged between 44.50 and 86.12 N. The results showed the importance of extrusion on the interactions that occur between CS/WPI concentrations and how these interactions influence the processing parameters and the physicochemical characteristics of the blends.