Development and Process Optimization of a Ready-to-Eat Snack from Rice-Cowpea Composite by a Twin Extruder

Abstract

A central composite rotatable design with four independent variables viz. blend ratio (broken rice flour and cowpea flour): 90:10–70:30, moisture content (10–18% wet basis), barrel temperature (110–150 °C), and screw speed (280–360 rpm) were varied in the development of ready-to-eat snacks using a twin extruder for a broken rice–cowpea product. The effects of the independent variables on specific mechanical energy, water absorption index, water solubility index, total color, hardness, bulk density, expansion ratio, and overall acceptability of the extruded snack were investigated using regression analysis. The results showed that the physical qualities of the ready-to-eat snacks were significantly affected by the extrusion parameters (i.e., blend ratio, barrel temperature, moisture content, and screw speed). From the findings, it was observed that screw speed and moisture contents affected hardness, while water absorption index was affected by all the extrusion parameters. However, the water solubility index and overall acceptance were majorly affected by the moisture content; extrudate produced with barrel ratio of 85:15, 12% moisture content, barrel temperature of 140 °C, and screw speed of 300 rpm was the most acceptable, at 6.73 on a 9 point hedonic scales. The blend ratio and barrel temperature influenced the expansion. Furthermore, the combination of cowpea and broken rice to produce nutritious ready-to-eat snacks has high acceptability and is a promising panacea for food security.