Effect of mustard oil and process variables on extrusion behaviour of rice grits

Effect of process variables such as temperature, moisture and addition of mustard oil on extrusion behaviour of rice grits was studied, using single screw extruder. The extruder response of pressure and specific energy consumption (SEC) and product properties such as expansion, water absorption (WAI) and water solubility (WSI) indices were analysed. Iodine spectrum of the extrudates were determined to see the effect of mustard oil on amylose-lipid complex formation. Pasting properties of extrudates were measured, using Brabender visco-amylograph. Second order polynomials were computed to study the effect of process variables and mustard oil on extrusion parameters and product properties. Addition of mustard oil decreased die pressure and SEC of extruder and expansion, WSI and WAI. Peak viscosity, viscosity at 95°C, viscosity at 95°C after 15 min and viscosity at 50°C increased and λ max and absorbance ratio (630/520nm) decreased with the increase in mustard oil.