Bioaccessibility of iron and zinc content of a traditional pearl millet gruel acidulated with extracts of roselle calyces and tamarind pulp

Iron and zinc deficiencies are a public health concern in the Far-north region of Cameroon, where diets are based on cereals containing inhibitors of minerals’ absorption. This work investigated the effect of acidulating a traditional pearl millet gruel with extracts of roselle calyces and tamarind pulp on iron and zinc bioaccessibility. We first determined pH, titratable acidity, phytates and polyphenols content of decoction and maceration extracts. Phytates, polyphenols and minerals content of the acidulated gruels as well as the bioaccessibility of iron and zinc using a simulated in vitro digestion method were then assessed. Finally, we evaluated the acceptability of the acidulated gruels. The pHs of roselle calyces extracts (2.59 – 2.71) were the lowest (p < 0.05) while phytates (114.61 – 115.72 µg.mL−1) and polyphenols (100.80 – 116.32 µg.mL−1) were more abundant (p < 0.05) in tamarind pulp extracts. There were no significant differences (p ˃ 0.05) in the titratable acidity of all extracts (0.20 – 0.24 g .100 mL−1). Gruels acidulated with decoction and maceration extracts of tamarind pulp were more concentrated (p < 0.05) in phytates (469.66 mg .100 g−1 DM), polyphenols (70.91 mg .100 g−1 DM) and Iron (5.70 mg .100 g−1 DM), respectively. All the acidulated gruels exhibited higher (p < 0.05) bioaccessible minerals with the greatest increases (22.28% for iron and 61.41% for zinc) being found in decoction and maceration extracts of roselle calyces, respectively. No acidulated gruels had a general acceptability score inferior to that of the control. The acidulation of pearl millet gruels with roselle calyces and tamarind pulp extracts could be an efficient and affordable food-based strategy to fight against iron and zinc deficiencies in at-risk populations.