Iron and selenium speciation in enriched adzuki bean sprouts by graphite furnace atomic absorption spectrometry

The production of edible sprouts is a fast-growing segment of the food industry worldwide. Although several kinds of seeds may be eaten as sprouts, adzuki (Vigna angularis) and mung (Vigna radiata) beans are preferred and commonly used for sprout production.1 Studies have shown that grain germination increases the content of essential nutrients, such as minerals, vitamins, and proteins, and reduces the antinutritional factors, such as trypsin inhibitors, phenolic compounds, and nitrate,2 enhancing the quality and digestibility of the grains. Moreover, previous studies have clearly demonstrated that it is possible to enrich sprouts with essential elements to combat nutritional deficiencies, which is particularly important for populations in developing countries.3–6 The consumption of Se-enriched sprouts is a strategy to prevent the deficiency of this element in the human body, which is associated with various disorders including increased cholesterol levels, cardiomyopathy, muscular dystrophy, dysfunction of brain and liver, and Keshan disease, a disease affecting millions of people worldwide, particularly in China.7,8 The chemical form of dietary Se is important because it affects its bioavailability, toxicity, and chemoprotective activity. In nature, Se exists in the form of inorganic species, such as selenite [Se(IV)], selenate [Se(VI)], and selenides (e.g., HgSe), or as organic species.9,10 In general, the inorganic forms are more toxic11,12 and less bioavailable to humans than the organic species.13 On the other hand, the consumption of Fe-enriched can increase iron consumption, which helps cellular homeostasis, oxygen transport and energy metabolism, as well as a cofactor of enzymes for mitochondrial respiratory chain and nitrogen fixation.14,15 It is important to point out that legumes have low concentrations of Fe species potentially absorbed by the human organism due to interactions of inorganic Fespecies, mainly bivalent cations, with phytic acid, tannins and other anti-nutrients, not being able to supply nutritional deficiencies.8,14,15