Impact of extrusion processing on physio-chemical and sensory attributes of broken rice - pearl millets and mushroom based extrudates
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Date
2023
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RPCAU, Pusa
Abstract
The extrusion cooking process is a high temperature and short time process in which material is feed to the extruder for desired temperature, pressure, and residence time. Broken rice, Oyster mushroom and pearl millet was used to develop Ready- To-Eat (RTE) snack through extrusion cooking. Composite mixed flour was prepared using Broken rice flour, Oyster mushroom powder and Pearl millet flour. Broken rice and oyster mushroom powder proportion were fixed and only pearl millet flour in varying proportions. Extrusion cooking was carried out using a Twin-Screw Extruder. Extrusion cooking experiments were conducted employing CCRD for four independent variables with five level each feed proportion- 90:10, 85:15, 80:20, 75:25, 70:30; feed rate-6, 8, 10, 12, 14 kg/h; screw speed- 300, 325, 350, 375, 400 rpm; Barrel temperature 105, 120, 135, 150,165°C. A total 30 combinations of these independent variables were formed to see the effect on different dependent variable like Moisture content, Expansion ratio, Bulk density (kg/m3), Total colour index (E), Hardness (N) and Overall acceptability (OA). During experiments the best combination was generated on the basis of optimization by response surface methodology (Liang et al., 2012). Second order multiple regression equations were developed for all the dependent variables which were optimized using response surface methodology. The best product was prepared at optimum solution such as feed proportion- Pearl millet flour percentage 24.99% Feed rate - 8 kg/h, Screw speed 307 rpm and Barrel temperature 150°C, produced the most acceptable extrudates. The experimental data for response were in close experiment with the optimized solution obtained from RSM. Moisture content 6.2 %, expansion ratio 3.6, bulk density 113.3 kg/m3, hardness 6.24 N total colour index 75.29 and 7.5 overall acceptability. The prepared optimized extrudates also had well balanced acceptable range of the nutrition (moisture content 6.20%, total carbohydrate 81.02%, protein 9.92, fat 0.87, fibre 2.10% and ash content 1.49%.