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Effects of raw material composition, feed moisture and die temperature on chemical, physical and sensory properties of extrudates produced by a single-screw extruder from the mixtures of rice flour, isolated soy protein and file fish were evaluated through response surface methodology (RSM). Nitrogen solubility index (NSI), integrity index (Ⅱ), rehydration ratio (RR), density, lightness and the external appearance of extrudates were measured as indices of the changes of physicochemical properties of extrudates. Rehydration ratio was negatively correlated with density (R=-0.742, P<0.01). Increased amounts of rice flour in feed mixtures resulted in increased rehydration ratio, but decreased density. The extrudate prepared from the mixtures of isolated soy protein (ISP), rice flour and file fish showed the highest sensory score at which die temperature was 130℃ or above.
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