Physical properties of extruded snacks enriched with soybean and moringa leaf powder

Abstract

This study was conducted to investigate the application of extrusion cooking in the production of snacks containing soybean (SB) and Moringa oleifera (MO) leaves as inexpensive sources of micronutrients.The specific objectives were to examine effects of barrel temperature, residence time and moisture content of feed on selected physical properties of extruded snacks (extrudates), namely water absorption index (WAI), water solubility index (WSI) and expansion ratio (ER).The extrudates were obtained by blending different levels of input ingredients of maize flour (MF) (55 to 80%), full fat soybean flour (FFSF) (10 to 30%), and Moringa oleifera leaf powder (MOLP) (5 to 15%).Extrusion process variables in a twin-screw extruder were at three levels for temperature (100, 130 and 160°C), feed moisture content (15, 22.5 and 30%), and residence time (60, 75 and 90 s).The performed study revealed that the level of incorporation of both FFSF and MOLP, and feed moisture content have significant effects on the expansion ratio, water solubility index and water absorption index of the extrudates.It was concluded that the role of processing conditions and blending levels have a significant contribution to the quality characteristics of the soy-moringa expanded snacks.