Cooked weight (water uptake) decreased when barrel temperature
and screw speed were increased (Fig. 3C and D). Diosady,
Paton, Rosen, Rubin, and Athanssoulias (1985) reported that the
lower water uptake observed for extruded starch produced at higher
screw speed might be related to increased shear, resulting in
structural modification of the starch. Moisture content had no significant
effect on cooked weight (Table 3). However, Anderson,
Conway, Pfeifer, and Griffin (1969) reported that the water uptake
of extruded cereal products was higher when prepared from higher
moisture doughs. Cooked weight was negatively correlated with
expansion ratio (r = 0.74, p < 0.001) and percentage of gelatinised
starch (r = 0.80, p < 0.001) (Table 4).