Nutritional and Functional Properties of Biofortified Cowpea (Vigna unguiculata (L.) Walp)

Cowpea (Vigna unguiculata (L.) Walp.) is a legume of great importance for food and nutritional security, especially in regions where malnutrition and climate change compromise agricultural production. Cowpea is an excellent source of protein, carbohydrates, vitamins, minerals, and dietary fiber, while also having low lipid content. This crop was included in a biofortification program in Brazil, aiming at increasing its iron content. Biofortified cultivars represent a potential strategy to reduce anemia and malnutrition, as their iron concentrations are approximately 60 mg/kg and protein levels approach 30 g/100 g. Studies have shown that the iron bioavailability of cowpea is higher or comparable to that of ferrous sulfate in animal trials. However, in Caco-2 cell culture, iron bioaccessibility is low, likely due to the presence of phenolic compounds. Biofortification, as well as the addition of foods biofortified with beta-carotene, such as cassava or sweet potato, did not significantly influence the iron bioavailability of cowpeas. Germination increased bioaccessibility but did not alter iron bioavailability. Iron bioavailability was also unaffected by a diet high in fat and sugar, although certain gut health benefits were more evident with biofortified cowpea compared to a conventional variety. Biofortified and conventional cowpeas contain a comparable quantity of protein, but little is known regarding whether biofortification can affect the protein quality of cowpea and limitations in sulfur amino acids (methionine and cysteine). Biofortified cowpea demonstrated potential anti-inflammatory effects in cell culture studies (RAW 264.7 macrophages) and a low glycemic index in humans. In summary, studies have shown promising results for biofortified cowpea as a source of protein and high bioavailable iron, comparable to conventional cowpea, with potential functional benefits for gut health.