Contents lists available at ScienceDirect Journal of Trace Elements in Medicine and Biology journal homepage: www.elsevier.com/locate/jtemb Nutrition In vitro gastrointestinal digestion to evaluate the total, bioaccessible and bioavailable concentrations of iron and manganese in açaí (Euterpe oleracea Mart.) pulps Silvana Ruella Oliveira a, ⁎ , Katherine Chacón-Madrid b , Marco Aurélio Zezzi Arruda b , Fernando Barbosa Júnior a a Faculdade de Ciências Farmacêuticas de Ribeirão Preto, Universidade de São Paulo - USP, Avenida do Café s/n, Monte Alegre, 14040-903, Ribeirão Preto, SP, Brazil b Spectrometry, Sample Preparation and Mechanization Group - GEPAM and National Institute of Science and Technology for Bioanalytics - INCTBio, Institute of Chemistry, Department of Analytical Chemistry, University of Campinas - Unicamp, PO Box 6154, Zipcode 13083-970, Campinas, SP, Brazil ARTICLE INFO Keywords: Açaí (Euterpe oleracea Mart.) In vitro gastrointestinal digestion Bioaccessibility Bioavailability Iron Manganese ABSTRACT Açaí pulp consumption has increased in Brazil and worldwide. Recently, a high average content of manganese (450 mg/kg) was observed in açaí 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 açaí 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 açaí 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 açaí con- sumption may be worrisome. Future nutritional, toxicological and speciation studies must be undertaken. 1. Introduction Açaí is a native South American tropical palm (Euterpe oleracea Mart.), which occurs primarily in the Amazon region [1,2]. This multi- stemmed palm tree produces edible spherical fruits, which are dark purple when fully ripe (about 175 days) and reach 10–12 mm of dia- meter [1,3–4]. Usually, açaí fruits are consumed as pulps, liquids with thick, soft, and smooth texture obtained by macerating the pericarp with different amounts of water [5]. In the last years, açaí had a remarkable growth in its popularity being acclaimed as a “superfruit” and its consumption has been in- creasing all over the world due to its unique flavor and nutritional properties such as high energy, antioxidant, anti-inflammatory and cardioprotective [2,6–8]. Açaí is valuable in human nutrition as source of energy, fiber, polyphenols in the form of flavonoids and anthocya- nins, minerals and fatty acids. The main constituents found in dry matter are lipids (50%), fibers (25%) and proteins (10%) [7]. Açaí is also a good source of macro and micronutrients, such as phosphorus, sodium, zinc, iron, manganese, copper, boron, chromium, calcium, magnesium, potassium and nickel [1,2,9–13]. An earlier study carried out by our group [13] observed relatively high contents of es- sential elements, especially manganese, in açaí pulps. Manganese is essential for most life on earth, including human beings. Various enzymes have Mn in their composition, for example superoxide dismutase, pyruvate carboxylase and glutamine synthetase. Additionally, Mn is fundamental for proper brain function and for normal bone structure [14,15]. However, elevated exposure to Mn is associated to neurological impairments which cause several symptoms, and, although the inhalation is the primary route of concern, the main source of exposure is the diet [16]. Therefore, the high amounts of Mn in açaí pulps may contribute to a considerably level of exposure. For instance, the northern Brazilian population, which usually consume reasonable amounts of açaí every day (may reach 500 mL/person/day or more) may be exposed up to 28 mg per day of Mn [13]. Another crucial point is that Mn may interfere with Fe absorption, due to similar physicochemical properties, and shared absorptive pathways [17]. Manganese may affect on Fe absorption, circulating transporters like transferrin, and regulatory proteins, then influencing https://doi.org/10.1016/j.jtemb.2019.01.016 Received 23 November 2018; Received in revised form 14 January 2019; Accepted 28 January 2019 ⁎ Corresponding author. E-mail address: silvanaruella@gmail.com (S.R. Oliveira). Journal of Trace Elements in Medicine and Biology 53 (2019) 27–33 0946-672X/ © 2019 Elsevier GmbH. All rights reserved. T