Mineral content in legumes and nuts: contribution to the Spanish dietary intake

Abstract

We evaluated the levels of essential elements as Cu, Cr, Fe and Zn, and toxic elements as Al, Ni, Pb and Cd in a total of 40 samples of different legumes and 56 samples of different nuts, that are widely consumed in Spain. These elements were determined in the samples mineralized with HNO 3 and V 2O 5, using electrothermal atomic absorption spectrometry (ETAAS) as the analytical technique. Reliability of the procedure was checked by analysis of a certified reference material. No matrix effects were observed and aqueous standard solutions were used for calibration. In legumes, the levels ranged from 1.5–5.0 μg Cu/g, 0.05–0.60 μg Cr/g, 18.8–82.4 μg Fe/g, 32.6–70.2 μg Zn/g, 2.7–45.8 μg Al/g, 0.02–0.35 μg Ni/g, 0.32–0.70 μg Pb/g and not detectable—0.018 μg Cd/g. In nuts, the levels ranged from 4.0–25.6 μg Cu/g, 0.25–1.05 μg Cr/g, 7.3–75.6 μg Fe/g, 25.6–69.0 μg Zn/g, 1.2–20.1 μg Al/g, 0.10–0.64 μg Ni/g, 0.14–0.39 μg Pb/g, and not detectable—0.018 μg Cd/g. A direct statistical correlation between Cu–Cr, Zn–Al and Cr–Ni ( P<0.05), and Al–Pb ( P<0.001), has been found. The growing popularity of these products in recent years on the basis of its nutritional properties and beneficial effects, requires additional data and a periodical control. In addition, the present findings are of potential use to food composition tables.