Evaluation of functional properties of extruded snacks developed from brown rice grits by using response surface methodology

Extrusion behavior of brown rice grits was investigated using twin screw extruder. Feed moisture of the grits was adjusted between 14% and 18%, and extrusion cooking was done at barrel temperature of 130–170 °C and screw speed of 400–550 rpm. The brown rice grits differed significantly with respect to extrusion behavior and extrudate characteristics. Water solubility index (WSI) of extrudates varied from 5.43% to 14.32%, water absorption index (WAI) from 4.72 to 7.81 and bulk density (BD) from 0.065 to 0.188 g/ml. With increase in moisture, BD, WAI and hardness increased, while WSI and SME decreased. Increase in screw speed resulted in lower BD, WAI and WSI whereas resulted in a higher SME. With increase in temperature decrease in SME, BD, WAI and hardness was observed. All responses were most affected by changes in feed moisture, temperature and to a lesser extent screw speed.