Amino Acid and Protein Dispersibility Index (PDI) of Mixtures of Extruded Soy and Sweet Potato Flours

Selected samples of defatted soy flour, sweet potato flour, and their blends were extruded in an Almex-150 single screw extruder. Effects of extrusion cooking were verified with respect to amino acid profile and protein dispersibility indices of the samples. Amino acid contents of soy flour as well as that of sweet potato flour were more drastically reduced by extrusion than those of their mixtures. Protein dispersibility indices of the samples increased with increase in sweet potato proportion in the blends.