This might be due to the synergy of extrusion shear and enzymatic hydrolysis, which improved the digestion of protein. De Mesa-Stonestreet, Alavi,and Gwirtz (2012) reported that sorghum protein concentrates were produced by extrusion-enzyme liquefaction. Enzymatic extrusion yielded protein concentrates with higher protein yield and digestibility, since extrusion promoted starch and protein degradation.