Propolis is a resinous product made by honeybees from plant-derived materials, with high content of polyphenols associated to beneficial bioactivities with potential use as a natural food additive for preservation and as a functional food ingredient.

Inadequate eating habits, among other factors, lead to nutritional deficiencies worldwide. Attempts have been made to control micronutrient deficits, such as biofortification of usually consumed crops, but the interaction between food components may affect the bioavailability of the nutrients. Thus, this study aimed to evaluate the effect of pro-vitamin A on the bioavailability of iron in biofortified cowpea and cassava mixture, compared to their conventional counterparts. The chemical composition of the raw material was determined, and an in vivo study was performed, with Wistar rats, using the depletion-repletion method. Gene expression of iron-metabolism proteins was evaluated. Results were compared by analysis of variance (ANOVA), followed by the Tukey test (p < 0.05). Biofortified cowpea (BRS Aracê) showed an increase of approximately 19.5% in iron content compared to conventional (BRS Nova era). No difference in Hemoglobin gain was observed between groups. However, the animals fed biofortified cowpea were similar to ferrous sulfate (Control group) regarding the expression of the hephaestin and ferroportin proteins, suggesting a greater efficiency in the intestinal absorption of iron. Thus, this study points out a higher efficiency of the biofortified cowpea in the bioavailability of iron, regardless of the presence of pro-vitamin A.

BACKGROUND Cowpea (Vigna unguiculata L. Walph) is predominantly consumed in the North and Northeast regions of Brazil, and its biofortification with iron seeks to reduce the high prevalence of iron deficiency anemia in these regions. It is commonly eaten cooked; however, in the germinated form, it can improve nutritional quality by reducing the antinutritional factors and consequently improving the bioavailability of elements. The present study aimed to determine the physico‐chemical characteristics, bioaccessibility and bioavailability of iron in biofortified germinated cowpea. RESULTS There was no statistical difference between the germinated and cooked beans with regard to centesimal composition. Germinated beans had phytates and tannins similar to cooked beans. The phytate‐iron molar ratio for all groups did not present a statistical difference (cooking 3.58 and 3.41; germinated 3.94 and 3.51), nor did the parameters evaluating in vivo iron bioavailability. Total phenolics was higher in the germinated group (cooking 0.56 and 0.64; Germinated 2.05 and 2.45 mg gallic acid kg−1). In vitro bioaccessibility of iron of germinated beans presented higher values (P ≤ 0.05) compared to cooked beans. There was higher expression of divalent metal transporter‐1 in biofortified and germinated beans. CONCLUSION The iron bioavailability from the biofortified and germinated beans was comparable to ferrous sulfate. Germination can be considered as an alternative and efficient method for consuming cowpea, presenting good iron bioaccessibility and bioavailability. © 2019 Society of Chemical Industry