Browsing by Author "Yusuph, Athumani"

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    Physico-chemical evaluation and optimization of extruded starchy foods fortified with soybeans and moringa oleifera leaves
    (University of Dar es Salaam, 2015) Yusuph, Athumani
    This study was aimed at developing extruded food snacks rich in micronutrients by fortifying starchy cereals with soybean and Moringa oleifera leaves as native sources of micronutrients. Specifically, the study examined the effects of barrel temperature, residence time and feed moisture content on selected properties of extruded snacks; evaluated the sensory properties of selected extrudates; and assessed microbial stability based on total plate counts and yeast/mould counts of the selected extrudates. Extrudates were obtained by blending ingredients including maize flour (MF), full fat soybean flour (FFSF), and Moringa oleifera leaf powder (MOLP) followed by extrusion cooking at selected experimental conditions. Extrudates obtained were analysed for β-carotene and iron contents, water activity (aw), expansion ratio (ER), water solubility and absorption indices and urease activities. Extrudates with good physical appearance were selected and analysed for proximate composition, total plate and yeast/mould counts and sensory evaluation. Incorporation of FFSF and MOLP in the starch cereals had significant effects on the expansion ratio, water solubility and water absorption indices of the extrudates. Increased MOLP level resulted in increased iron and β-carotene contents from 4.25 mg/100 g to 9.93 mg/100 g and 1.20 mg/100 g to 5.81 mg/100 g respectively. High barrel temperatures (100°C, 130°C, 160°C) resulted in low water activity (aw = 0.27- 0.38), undetectable microbial growth on the extrudates and low urease activity. Sensory evaluation of extrudates indicated that extrusion of FFSF flour and MOLP in combination with maize flour can produce acceptable extruded snacks. It is recommended to carry out further studies on the bioavailability of the β-carotene and iron from extrudes.