The objective of this study was to determine the effect of moisture contents (40, 50, 60%) and CO2 gas injection (0 and 800 mL/min) on physicochemical properties of extruded soy protein isolate (SPI). The expansion ratio and the specific length increased, but piece density decreased with the increase in CO2 gas injection from 0 to 800 mL/ min at both 40 and 50% moisture contents. On the contrary, the expansion ratio and the specific length decreased, but piece density increased with the increase in CO2 gas injection from 0 to 800 mL/min at 60% moisture content. Extruded SPI with CO2 gas injection at 800 mL/min had small cell size and higher amount of cell than extruded SPI without CO2 gas injection. The water holding capacity and nitrogen solubility index increased, and the integrity index and the texture decreased with the increase in CO2 gas injection from 0 to 800 mL/min. In conclusion, extruded SPI with the CO2 gas injection at 800 mL/min showed better expansion properties and cell formation than extruded SPI without the CO2 gas injection.

• 김나영(공주대학교 식품공학과)
• 류기형(공주대학교 식품공학과) Corresponding author