Rat bioassay of the protein nutritional quality of soy-fortified sorghum biscuits for supplementary feeding of school-age children

Abstract

BACKGROUND: Protein-Energy Malnutrition (PEM) remains a major deficiency disease among children in developing countries. The protein nutritional quality of soy fortified sorghum biscuits was evaluated with respect to their potential as a protein-rich supplementary food. Three isonitrogenous diets based on: 50:50 ratio decorticated sorghum: defatted soy flour biscuits, 100% sorghum biscuits, casein, and a protein-free diet were fed to male Sprague Dowley weanling rats. RESULTS: Protein Efficiency Ratio (PER) for the sorghum-soy biscuit diet was equivalent to the reference casein diet, and zero for the 100% sorghum diet. Faecal bulk for 100% sorghum diet was 1.5 times higher than sorghum-soy and casein diets. True protein digestibility of the three diets was high, 88 to 95%, agreeing with previous rat studies with sorghum. Biological Value and Net Protein Utilization of sorghum-soy biscuit diet were similar to the casein diet, but lower that the 100% sorghum biscuit diet CONCLUSION: Not withstanding limitations of rat bioassay for assessing sorghum food protein quality, the higher PER of defatted soy flour fortified sorghum biscuits (sorghum: soy 50:50 ratio) indicates they have considerable potential as a supplementary food to young children to alleviate PEM.