Effect of extrusion variable on physicochemical properties of extruded sorghum

Sorghum is a tolerant grain against droughtness and rich source of starch, protein (kafirin) and physicochemical components. Sorghum can be used in an extruded products because of its bland flavor, light color and good expansion. According to factorial design, whole grain sorghum was extruded to evaluation the effect of moisture (14, 16 and 19 %) and screw speed (140, 170 and 190 rpm) at constant temperature (150°C) on textural and physicochemical properties. The most value of porosity (56.24 %), expansion (3.39), water absorption (6.67 g g-1) and hardness and also the lowest value of bulk density (.344 g cm3) and oil absorption (4.77 g g-1) was obtained from 19% - 140 rpm. The most value of water solubility (32%) was obtained from 14% - 190 rpm and the lowest value of L* (68.22) was obtained from 19% - 170 rpm. Sensory analyses showed that sorghum flour extruded at 190 rpm with 14% feed moisture had most general acceptability.