Protein quality evaluation of cowpea-based extrusion cooked cereal/legume weaning mixtures

Abstract

The protein nutritional quality of cereal/legume mixtures developed with theoretically optimal nutrient profiles was assessed by determining the indices; Protein Efficiency Ratio (PER), Net Protein Ratio (NPR) and Protein Digestibility Corrected Amino Acid Score (PDCAAS). Two formulations (generated by computer-assisted successive approximation) were prepared with 45–50% maize, 35–40% cowpeas, and either peanuts or soybeans to improve the amino acid balance and to raise the energy level of the diet. Isonitrogenous diets prepared from these weaning formulations and casein were fed to 21–28 day old Sprague Dawley rats according to the Official PER protocol. Acceptable PERs of 2.1–2.4 were obtained for the diets when casein was adjusted to 2.5. The True Protein Digestibility of these food formulations ranged from 87.4–92.1% (that of casein was 96.4%) and the NPR ranged from 3.0–3.3; NPR of the casein diet was 3.5. PDCAAS for the formulations ranged from 0.72–0.82.