The objective of this study was to determine the effect of moisture content(45, 50, 55%), barrel temperature(140, 150°C), screw speed(150, 250 rpm) and two die configurations on the physical properties of extruded soy protein isolate(SPI). Water holding capacity(WHC), texture, integrity index and nitrogen solubility index(NSI) of extruded SPI were analyzed. The texture of extruded SPI was affected by the die configuration. The physical properties of extruded SPI was significantly influenced by barrel temperature, moisture content and die configuration. The increase in water injection rate and barrel temperature led to increase WHC and NSI. The higher water injection rate led to increase integrity index and texture(elasticity, cohesiveness, chewiness, cutting strength). The extruded SPI at 8 cm die configuration had higher integrity index than those of the 5 cm die configuration. Integrity index and NSI were negatively correlated. Thus, the die configuration can be useful to control quality of extruded SPI.

• Bon Yeob Gu(Department of Food Science and Technology, Kongju National University)
• Gi Hyung Ryu(Department of Food Science and Technology, Kongju National University)