Physico-chemical characteristics,nutritional quality and shelf-life of pearl millet based extrusion cooked supplementary foods

The process variables for extrusion cooking of pearl millet were standardized and some of the physicochemical characteristics of the millet extrudates and also the nutritional qualities of the millet and legume-based extruded supplementary foods were determined. The millet grits less than 355 µm in size, equilibrated to 18±1% moisture content, extruded at 150±5°C temperature and at 200±10 rpm of the barrel of a twin-screw extruder yielded the extrudates of 1.75±0.21 expansion ratio and 7.5±1.5 kg breaking strength. The cold and cooked paste viscosity, the melt energy and also the carbohydrate digestibility of the extrudates indicated that the products were pre-cooked and were of ready-to-eat nature. The millet was blended with grain legumes (30%) and also with defatted soy (15%) separately and extruded to prepare ready-to-eat nutritious foods suitable as food supplements to children and mothers. The foods based on the millet and legumes and also the millet and soy contained 14.7% and 16.0% protein with 2.0 and 2.1 protein efficiency ratio values, respectively. The shelf-life of the foods was about 6 months in different flexible pouches at ambient storage conditions. The study showed that applications of extrusion cooking technology to pearl millet have promise for preparation of diversified and value-added food products from the millet.