Expanding information on the bioaccessibility and bioavailability of iron and zinc in biofortified cowpea seeds

•The new biofortified cowpea cultivars have a high Fe and Zn content compared to common beans.•Biofortified cowpea seeds also provide more Fe and Zn for absorption in the gastrointestinal tract.•The interaction Fe–Zn was synergistic in bean cultivars.•50 g of biofortified Aracê cowpea contributes 27% and 48% of the Fe and Zn DRI for 1–3-year-old children. This work presents new findings on the nutritional quality of recently introduced biofortified and non-biofortified cowpea cultivars as well as some common beans. ICP-MS was used for the measurements. Biofortified cowpea cultivars showed high levels of Fe and Zn, greater than 60 and 40 mg kg−1 dry weight, respectively. The in vitro digestion protocol enabled simultaneous evaluation of bioaccessibility and bioavailability. Fe levels in cowpea cultivars were ca. 2.5-fold higher than in common beans. Cowpea seeds also had higher Zn levels, reaching 50.1% bioaccessibility and 44.2% bioavailability. Cooking improved the availability of micronutrients in bean seeds. The cooked biofortified Aracê cowpea showed a high Zn bioavailability above 60%. Consumption of 50 g of Aracê would contribute 27% and 48% of the Fe and Zn DRI for 1–3-year-old children. The new cowpea cultivars biofortified are a potential vehicle for improving the Fe and Zn status in groups in which the micronutrient deficiency is prevalent.