Effect of extrusion on protein quality, antinutritional factors, and digestibility of complementary diet from quality protein maize and soybean protein concentrate.

The nutritional quality of food transcends the availability of nutrients in food to being utilizable by the consumer. In this study, a complementary diet for infants was formulated with quality protein maize, soybean protein concentrate, and cassava starch. The formulated diet was extruded and the effect of extrusion on some antinutritional factors and in vitro protein and starch digestibilities of the meals were assessed. The amino acid profile of the samples was determined while other protein quality indices were calculated. The essential amino acid index of the formulated meal ranged from 87.3 in tryptophan to 133.7 in tyrosine-phenylalanine. Protein efficiency ratio of the formulated meal ranged from 1.20 to 2.45. The calculated biological value ranged from 92.57 to 95.20%. Extrusion cooking significantly improved the in vitro protein and starch digestibilities and significantly reduced some antinutritional factors of the formulated meals.