Effects of extrusion process conditions on system parameters; physicochemical properties and cooking characteristics of extruded fortified rice kernels

Abstract

Fortified rice kernels (FRK) have emerged as innovative fortified product containing essential minerals and vitamins. Broken rice flour and micronutrient premix containing iron, folic acid and vitamin B12 were used to prepare FRK using a pilot scale twin screw extruder (TSE). Effect of extrusion parameters such as die head temperature (70–110 °C), extruder screw speed (40–80 rpm), feeder screw speed (20–60 rpm) and feed moisture content (26–34% wb) on the system parameters (torque, die head pressure and mass temperature), physicochemical properties (true density, water absorption index and water solubility index) and cooking characteristics (cooking time, cooking losses and water absorption ratio) of FRK were evaluated. Torque, mass temperature and die pressure varied from 12.77 to 15.23 Nm, 79.54–116.87 °C, and 25.98–41.46 bar, respectively, while the true density, water absorption index and water solubility index of FRK varied from 1.423 to 1.493 g/cc, 3.05–4.34 and 3.34–3.79%, respectively. Cooking time, cooking losses and water absorption ratio of FRK varied from 12.91 to 16.75min, 21.83–58.51%, 0.38–2.64, respectively. The results of response surface methodology (RSM) were compared with artificial neural network (ANN). ANN models were found to be best suitable for prediction of the responses than RSM.