Process optimization of extrusion variables and effects on some quality and sensory characteristics of extruded snacks from whole pearl millet-based flour

Abstract

Abstract This study investigated the effects and optimization of the respective feed compositions of pearl millet flour (PMf), African walnut flour (AWf), and corn starch (CS) [FC, (100:0:0, 90:5:5, and 80:10:10)], feed moisture content [FMC, (10, 15, and 20%)] and barrel temperature [BT, (60, 70, and 80 °C)] on some quality characteristics of extruded snacks using Box-Behnken design. The AWf and CS were substituted at 0, 5, and 10% in PMf and evenly mixed with sterile water to attain the required FMC. The resultant dough was processed in a twin-screw extruder into whole pearl millet-based snacks. The results showed that the extrusion variables significantly influenced (p 0.90), absolute average deviation (≤ 0.05), accuracy factor (≤ 1.05), and bias factor (≤ 1.01). The optimization of the combined interactive effects on an extruded snack prepared using 80% PMf, 10% AWf, and 10% CS cooked with 15% FMC at 60 °C BT gave desirable crude protein, fat, fibre contents with complementary low residence time, increased expansion ratio, and was liked moderately by the sensory panellists. Pearl millet-based snacks could be a worthy alternative to gluten-free snacks. Article Highlights 1. The extrusion variables’ interactive effect significantly influenced the pearl-millet snacks’ quality changes. 2. High feed composition and lower feed moisture resulted in high protein, fibre, & fat. 3. The response models were affirmed favourably by the adequacy of the indices examined.

Keywords

• Pearl millet-based flours
• Extrusion
• Optimization
• Quality characteristics
• Gluten-free snacks