Development of Extruded Senegalese Infant Formula from Mixtures of Pearl Millet and Grain Legumes

Abstract

Instant compound flours were developed from local Senegalese plants, using a single-screw extruder (Technochem brand) previously designed for soybean processing. Adapting the parameters of the equipment to our local cereals (sorghum, millet, and maize), legumes and oleaginous plants was the first technical step performed. We modified the parameters of the extruder and then carried out several tests to determine the best blend obtained from several combinations of co-extruded raw materials that led to compound flour (70% millet, 15% peanut, and 15% cowpea) of high nutritional value. Prior to this step, analyses were run on each compound of the blend to determine their selected macro (moisture, ash, acidity, protein and lipid) and micro composition (iron, magnesium, and zinc). For a good result, the extruder parameters were set at a frequency of 48.2 Hz and a temperature of 280°F. Three shear rings of 1.47 mm of diameter each, followed by a bigger one (1.59 mm), were respectively inserted along the end of the screw; the rotational speed of the screw was set at 900 rpm and total liquid content was 30%. The final instant flour obtained was composed of 13.99% protein, 9.37% fat, 4.10% moisture, 1.64% ash and 0.08% acidity. The flour was split in four different batches and each was flavored with one of four powders (mango, papaya, baobab fruit or carrot). On a hedonic scale from 1 to 9, the results of the organoleptic tests performed by 21 trained panelists showed that all four samples received a score higher than 5 in all three categories (taste, color, and texture). However, taste wise papaya flavor received a better score followed by mango, carrot and baobab fruit flour. In conclusion, changing the parameters of the extruder helped obtain a well-accepted instant blend from local plants when local fruits were used to enhance flavors.