Abstract
Defatted-dried rice flour and untreated rice flour were extruded with a twin-screw extruder, and the characteristics of the extrudates were compared with each other. The defatting and drying treatment was effective for improving the expansion ratio and the degree of gelatinization of the rice-flour extrudate. Microscopic observation showed that the extrudate of the defatted-dried flour had a large number of minute cavities, while that of the untreated flour had a small number of larger cavities. Before extrusion-cooking, both the specific surface area and the micropore volume of the defatted-dried rice flour particles were larger than those of the untreated rice flour particles. After extrusion-cooking, both the specific surface area and the micropore volume of the defatted-dried flour extrudate were smaller than those of the untreated flour extrudate.
