Use of extrusion technology in instantizing a porridge flour formulation

Abstract

Production of instant flours provides a way to meet consumer demands for convenience porridge that require minimal preparation time. In addition, instant flours are energy saving, since they require low heat energy usage during preparation. This is a major factor to consider in low-income Ugandan households and relief situations where fuel is in short supply. The aim of the study was to optimize extrusion technology in instantizing a porridge flour formulation. Extrusion technology is a cost-effective way to produce instant flour, and also has numerous benefits associated with improving nutritional quality. The porridge flour was extruded at different moisture contents (4% and 7%), screw speeds (25 Hz and 30 Hz), and barrel temperatures (60℃, 70℃, 80℃, 90℃ and 100℃). The extrudates were then dried and milled using a hammer mill. The nutrient composition as well as functional and pasting properties for the extruded flours were determined. The means of fat, moisture and dietary fibre contents of the extruded flour sample were significantly higher (p˂0.05) than those of the non-extruded (control) flour samples, but no significant differences were (p˃0.05) observed between the means of crude protein, carbohydrate and ash contents of the extruded and non-extruded flour samples. The Bulk density of the extruded flour samples was significantly lower (p˂0.05) lower than in the non-extruded (control) flour samples, but the dispersibility, Water absorption Capacity, Water Solubility Index and Water absorption index of the extruded flour samples was significantly higher in the extruded flour samples than in the non-extruded sample, and these varied as the moisture content of the feed flour, screw speed, and barrel temperature of the extruder were varied. The pasting properties of the extruded flours were also significantly lower in than the non-extruded flour, and varied as the extrusion conditions were varied. In reference to the results of the flour properties, screw speed of 25 Hz, MC of 4% and a temperature of 60℃ is sufficient and ideal to produce an instant flour from the porridge flour formulation.