The aim of this study was to determine the different soy protein concentrate (0, 15, 30, and 45%), defatted soy flour (0, 10, 20, and 30%), and wheat flour (10, 20, and 30%) contents replacing fish meal on physiochemical properties of extruded aquatic feed by using twin screw extruder. The moisture content, barrel temperature, die diameter, and screw speed were adjusted to 45%, 137°C, 4 mm, and 250 rpm, respectively. With the higher amount of soy protein concentrate replacing fish meal, the expansion ratio, swelling ratio, and water stability significantly increased while specific length and water holding capacity significantly decreased. With increasing the defatted soy flour contents, expansion ratio significantly increased, but specific length, water holding capacity and water stability significantly decreased. With increasing in the wheat flour contents, the specific length significantly decreased while the water stability significantly increased. In conclusion, high-quality aquatic feed was achieved in this study and could be used in the future.

• Xuelian Ma(Department of Food Science and Technology, Kongju National University, Korea)
• Gihyung Ryu(Department of Food Science and Technology, Kongju National University, Korea)