Effects of processing and addition of a cowpea leaf relish on the iron and zinc nutritive value of a ready-to-eat sorghum-cowpea porridge aimed at young children

While dietary diversification of monotonous cereal-based diets using legumes and vegetables can alleviate the high prevalence of iron and zinc deficiencies in sub-Saharan African children, laborious cooking times limit the use of particularly legumes. This study investigated the effects of high-temperature short-time (HTST) processing on sorghum (extrusion) and cowpea (micronisation), compositing sorghum-cowpea (70:30) (ESMC) in a ready-to-eat porridge and addition of cowpea leaves on iron and zinc bioaccessibilities compared to a commercial fortified maize:soy ready-to-eat porridge. HTST processing increased iron bioaccessibility from both grains and the zinc bioaccessibility from the sorghum. One serving of ESMC porridge with cowpea leaves could contribute ≈85 and 18% towards the iron and zinc RDA of preschool children, compared to the commercial product at ≈84 and 125%, respectively. However, the higher iron and zinc bioaccessibilities from the ESMC porridge with cowpea leaves, compared to the commercial product (11.8 vs. 5.0% and 18.9 vs 2.7%, respectively) means it would provide more bioaccessible iron (2.24 vs. 0.86 mg/100 g, db) and similar levels of zinc (0.35 vs. 0.32 mg/100 g) towards the absolute/basal requirements of preschool children. The ESMC porridge with cowpea leaves could improve the iron and zinc nutritive value of preschool sub-Saharan African children’s diets.