Effects of Iron Enrichment of Adzuki Bean (Vigna angularis) Sprouts on Elemental Translocation, Concentrations of Proteins, Distribution of Fe-Metalloproteins, and Fe Bioaccessibility

Aline De Oliveira,Juliana Naozuka

doi:10.21577/0103-5053.20170034

Aline De Oliveira, Juliana Naozuka

Open Access

https://doi.org/10.21577/0103-5053.20170034

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Abstract

Iron (Fe) is an essential element for human nutrition, and its deficiency or low hemoglobin levels are a global health issue. Strategies aimed at increasing the amounts of essential elementals in agricultural products, as sprouts of adzuki bean (Vigna angularis), can be a way to minimize deficiencies, mainly in the populations of developing countries. Therefore, in this work was evaluated: production of Fe-enriched adzuki bean sprouts; Fe accumulation and translocation in plants in different culture media enriched with different Fe masses (500, 1000, 2000, and 3000 µg); and effects of the enrichment by means of 3000 µg FeIII-ethylenediaminetetraacetic acid (FeIII-EDTA): on the distribution of Ca, Cu, Fe, K, P, Mg, S, and Zn in different parts of the plant; on protein concentrations (albumins, globulins, prolamins, and glutelins) and their association with Fe in edible parts of the plant (stems); and on Fe bioaccessibility in the edible part of the plant (stems). The enrichment via FeIII-EDTA favored the translocation and increased Fe content of sprouts (75%), besides promoting interactions of Fe with albumins (141%), globulins (180%), and glutelins (93%). In the bioaccessibility assays, Fe was 83% bioaccessible in Fe-enriched sprouts.

Highlights

Iron (Fe) is an essential element for cellular homeostasis, oxygen transport, DNA synthesis, and energy metabolism as well as a cofactor for enzymes of the mitochondrial respiratory chain and nitrogen fixation
The Fe enrichment of adzuki bean sprouts depends on the chemical species used in the cultivation
The inclusion of adzuki bean sprouts enriched with Fe in the daily diet is a promising way to meet the daily intake recommendations of essential elements, especially Fe

Summary

Introduction

Iron (Fe) is an essential element for cellular homeostasis, oxygen transport, DNA synthesis, and energy metabolism as well as a cofactor for enzymes of the mitochondrial respiratory chain and nitrogen fixation. For the Fe quantification in water, NaCl (1.0 mol L−1), ethanol (70% v/v) and NaOH (1.0 mol L−1) extracts, a ZEEnit 60 model atomic absorption spectrometer (Analytikjena AG, Germany) equipped with a transversely heated graphite atomizer, pyrolytically coated graphite tube, and transversal Zeeman-effect background correction were used. A solution containing 1.0 mg L−1 Mg (Merck, USA) was utilized to assess the robustness of the spectrometer.[23] Titrisol standard solutions of 1000 mg L−1 for Ca (CaCl2), Cu (CuCl2), Fe (FeCl3), K (KCl), Mg (MgCl2), P (H3PO4), S (H2SO4), and Zn (ZnCl2) (Merck, USA) were applied to prepare the reference analytical solutions, after dilution in HNO3 0.1% (v/v) for elemental analysis by inductively coupled plasma optical emission spectrometry (ICP OES) and FeCl3 for determining the Fe content by graphite furnace atomic absorption spectrometry (GF AAS). Fe salt solutions [FeCl3⋅6H2O, FeSO4⋅7H2O, or ethylenediaminetetraacetic acid ferric sodium (NaFeIII‐EDTA)] (Sigma-Aldrich, USA)] were prepared for the enrichment procedure

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Results and Discussion

Conclusions