Bioavailable Iron and Vitamin A in Newly Formulated, Extruded Corn, Soybean, Sorghum, and Cowpea Fortified-Blended Foods in the In Vitro Digestion/Caco-2 Cell Model

Fortified-blended foods (FBFs), particularly corn-soybean blend (CSB), are food aid products distributed in developing countries. The US Agency for International Development food aid quality review recommended developing extruded FBFs with the use of alternative commodities such as sorghum. The objective of the study was to determine bioavailable iron and vitamin A content from newly developed extruded corn, soybean, sorghum, and cowpea FBFs compared with the nonextruded traditional food aid FBFs, corn-soy blend 13 (CSB13) and corn-soy blend plus (CSB+). Eleven extruded FBFs—sorghum-cowpea (n = 7), sorghum-soy (n = 3), and corn-soy (n = 1)—along with 2 nonextruded FBFs—CSB13 and CSB+, and Cerelac (Nestlé), a commercially available fortified infant food, were prepared. Bioavailable iron and vitamin A contents were assessed by using the in vitro digestion/Caco-2 cell model. Dry FBFs, aqueous fractions, and Caco-2 cell pellet vitamin A contents were analyzed by HPLC. Dry FBF and aqueous fraction iron contents were measured by atomic absorptiometry, and bioavailable iron was assessed by measuring Caco-2 ferritin contents via ELISA. Iron and vitamin A concentrations in Cerelac and dry FBFs ranged from 8.0 to 31.8 mg/100 g and 0.3 to 1.67 mg/100 g, respectively. All of the extruded FBFs contained 4- to 7-fold significantly higher (P < 0.05) aqueous fraction iron concentrations compared with CSB13 and CSB+. However, there were no significant differences in Caco-2 cell ferritin and vitamin A concentrations between extruded FBFs, nonextruded FBFs, and or the basal salt solution negative control. Results support the theory that the consumption of newly developed extruded sorghum-cowpea, sorghum-soy, and corn-soy FBFs would result in iron and vitamin A concentrations comparable to traditional nonextruded CSB13 and CSB+ FBFs.