Nutritional, physical and sensory quality of extruded instant white sorghum-pigeon peas gruel flour

Master Dissertation, 2018Five varieties of white sorghum consumed in Tanzania namely, Pato, Hakika, Tegemeo, Macia and Wahi, non-complemeted and complemented with pigeon peas at ratios 75:25 and 70:30 were extruded to produce instant porridge flour. The physical, nutritional, and sensory quality of the flour was evaluated. The physical quality parameters were: bulk density 0.5-0.7 gcm -3 , viscosity 0.5-0.8dpas, water absorption index 0.04-0.6 g/g, water solubility index 24.1-41.2%; the nutritional composition was: crude fibre 3.3-8.9 g/100 g dry matter (DM), crude fat 0.5-3.6 g/100 g DM, ash 0.6-2.6 g/100 g DM, crude protein 9.5-14.1 g/100 g DM, carbohydrates 67.7-83.8 g/100 g DM, energy 323-397 kcal/100g. The addition of pigeon peas to sorghum increased the bulk density, viscosity and water solubility index in all varieties, while the water absorption index decreased. Complementation of sorghum with pigeon peas improved the nutritional quality of the composites flour. The digestibility of the instant flour ranged from 7.4 to 11.8 g/100 g DM. Complementation of sorghum flour with pigeon peas increased the mineral levels. The content of calcium, magnesium, potassium, copper, zinc and iron was 258-395, 255.1-336.2, 365.1-915.2, 0.1-0.4, 1.8-3.8 and 3.0-8.5 mg/100 g DM, respectively. The sensory evaluation of instant gruel prepared from all the formulations indicated that all formulations were acceptable. Therefore, the inclusion of pigeon peas improved the quality of sorghum instant porridge flour for young children and infants