The effect of operating parameters on physical properties of rice-based extrusion cooked food product of lentil and oat

The effect of operational parameters of extrusion cooking viz feed moisture content (8–16%), screw speed (60–100 rpm), barrel temperature (130–170°C) and die head temperature (180–220°C) on the physical properties (bulk density, sectional expansion index and water absorption index) of an expanded rice snack prepared with rice (70%), lentil (25, 20, 15, 10 and 5%) and oat (5, 10, 15, 20 and 25%) was investigated. The minimum value of bulk density was observed at 70: 10: 20 (rice: lentil: oat) blend ratio with 10 per cent feed moisture content (wb) extruded at 210°C die head temperature, 140°C barrel temperature and 90 rpm screw speed. The maximum value of sectional expansion index of extrudate was obtained for 70: 20: 10 blend ratio (rice: lentil: oat) with 14 per cent moisture content (wb), 210°C die head temperature, 160°C barrel temperature and 70 rpm screw speed. The maximum value of water absorption index was obtained at 70: 15: 15 blend ratio, 12 per cent moisture content (wb), 150°C barrel temperature, 200°C die head temperature and 60 rpm screw speed.