Effects of acid concentration and extrusion variables on some physical characteristics and energy requirements of cassava starch

Abstract

Some physical characteristics of cassava starch extruded using a single-screw extruder, varying acid concentration, feed moisture content and barrel temperature were evaluated using surface response methodology. The combined effects of different concentrations of sulphuric acid and extruder parameters provided unique physical functionality to the extruded cassava starch. Product hardness and torque value was highly significant for three variables. The addition of sulphuric acid (0.06N) during extrusion cooking gave the highest values for expansion and softness of the extruded samples. The highest torque values (60-70 Nm) were for the samples extruded at the lowest moisture content, while the lowest torque values (23.0-26.0 Nm) were for the samples extruded at the highest values of feed moisture and barrel temperature

Physical characteristics of extruded cassava starch

“…At very high temperature, however, the vaporization occurs in a violent way and may cause breakage of the structure, hampering expansion (Hashimoto & Grossmann, 2003). Chang & El-Dash (2003) reported similar results for extruded cassava starch. Moisture (26 -24%), followed by barrel temperature (120-200°C), affected the expansion at constant speed of 100 rpm.…”

“…High feed moisture and high barrel temperature conditions decreased expansion. Expansion is related to the starch gelatinization degree (Chang & El-Dash, 2003). Low moisture content in the material may restrain its flow inside the extruder, increasing shear and residence time, which could increase the gelatinization degree.…”

Optimization of extrusion conditions for defatted soy-rice blend extrudates

“…Protein content in the developed snack was 9.9%, which was 46.7-70.7% higher than the market snacks. Chang and EI-Dash (2003) studied some physical characteristics of extruded cassava starch using a single-screw extruder, by varying acid concentration, feed moisture content and barrel temperature and evaluated using surface response methodology. Singh et al (2006a) optimized the processing parameters of extruded food prepared from Bengalgram broken and sorghum blends.…”

The influence of expansion control device used during production of different extruded sea bass feeds on pellets quality

“…The amount of soluble protein and starch in feed ingredients exerts positive influence on the expansion process, whereas the amount of fat -negative (Onwulata et al, 2001;Chang and El-Dash, 2003;Rokey and Plattner, 2004;Glencross and Hawkins, 2007;Sørensen, 2007). Various plants products, such as soyabean meal, maize and wheat flour, are used during the production of fish feed as protein sources.…”