In vitro gastrointestinal digestion to evaluate the total, bioaccessible and bioavailable concentrations of iron and manganese in acai (Euterpe oleracea Mart.) pulps

Acai pulp consumption has increased in Brazil and worldwide. Recently, a high average content of manganese (450 mg/kg) was observed in acai pulp, raising the hypothesis of toxicological effects associated to its ingestion. However, the total concentration of an element does not reflect the real benefits and risks of consuming a food. In this context, the total, bioaccessible and bioavailable concentrations of Fe and Mn were assessed in 9 acai pulps. Fe and Mn contents ranged from 27.6 to 73 and from 145 to 1197 mg kg(-1), respectively. Fe and Mn bioaccessibilities represented from 29 to 40 and from 39 to 55% of total amounts. Fe bioavailabilities were lower than LOQ and those of Mn varied from 8 to 17% of total. A daily consumption of 100 g of acai pulp exceeds by at least 1.5-fold the recommended Mn daily intakes for adults whereas poorly contributes to Fe intakes. Since the lowest Mn bioaccessible and bioavailable fraction corresponded to a Mn intake value higher than the tolerable upper intakes for children and that high amounts of Mn intake may impair Fe absorption, higher acai consumption may be worrisome. Future nutritional, toxicological and speciation studies must be undertaken.