Author(s):

Nalin Devrajan, Prem Prakash, Navdeep Jindal and Shashi Kala

Abstract: The present work was undertaken to study the utilization of corn flour (Zea mays) and germinated buckwheat (Fagopyrum esculentum) flour in preparation of extruded product using central composite rotatable design. The experiments were randomized in order to minimize the effects of unexplained variability in the observed responses due to extraneous factors. The effect of different extrusion parameters i.e. Feed rate (4 kg/h), Feed composition (Germinated Buckwheat: Maize:: 90:10, 80:20, 70:30, 60:40, 50:50 respectively), feed moisture (13–17%), screw speed (250– 350 rpm), and barrel temperature (100–140°C) on expansion, textural properties, water absorption index (WAI), and water solubility index (WSI) of an expanded buckwheat-corn snack was observed. Increasing feed rate results in extrudates with a higher hardness and lower energy to puncture the samples. Increasing feed moisture content results in extrudates with lower expansion, lower WAI, higher WSI, higher hardness and lower puncture energy. Increasing screw speed caused slight reduction in hardness of extrudate. Higher barrel temperature reduced WAI, and hardness, but increased the WSI and puncture energy of extrudate. Lateral expansion ranged from 130.36 to 189.39%, water absorption index from 3.73 to 9 g/g, water solubility index from 4.5% to 9%, hardness 29.49 to 36.83Nof extruded product. In experiment, optimization studies resulted in 129.69°C of barrel temperature, 275 rpm of screw speed, 14% of feed moisture and 34.52% of corn flour with 65.48% of germinated buckwheat flour.

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