Production of high quality expanded corn extrudates containing sesame seed using response surface methodology

Sesame seed, which possess exceptional nutritional and antioxidant properties, was incorporated into corn expanded extrudates to improve their nutritional quality. Expanded corn extrudates with 0, 15 and 30% sesame seed were processed in a twin-screw extruder at different screw speeds (140-220 rpm) and barrel temperature (120-160°C) levels. Response surface methodology was employed to investigate the effect of independent variables, independently or in combination, on the physical (expansion, density, hardness and colour parameters) and sensory properties of the extruded products. Results showed that increasing the sesame level produced less expanded, denser and harder extrudates with darker appearance (P<0.05) while higher screw speeds improved their physical attributes to some extent. Remarkable increases in expansion ratio, hardness and colour parameters were observed for products extruded at higher temperatures. According to sensory assessment, sesame seed could be used up to the level of 15% to produce high quality extrudates with acceptable sensory properties. The results recommended that sesame seed can be extruded with corn flour into an acceptable and nutritious snack.