Trace element concentrations in commercial gluten-free amaranth bars

Abstract

Gluten-free foods are specially designed to be consumed by people who suffer from celiac disease or some type of gluten intolerance. Few studies are currently available about trace element contents in gluten-free foods. This study aimed at analyzing the concentrations of 15 trace elements in commercial gluten-free amaranth bars by inductively coupled plasma optical emission spectrometry, after wet digestion by microwave system. The accuracy of the method was determined by the use of a standard reference material (NIST SRM 1570a Spinach Leaves) and recovery experiments, obtaining satisfactory values in all cases. The contents of the investigated trace elements in gluten-free amaranth bars were found to be in the range: Al (3.7–8.1 µg/g), Co (0.02–0.07 µg/g), Cr (0.05–0.25 µg/g), Cu (1.80–6.12 µg/g), Fe (7.0–14.5 µg/g), Mn (6.5–10.6 µg/g), Ni (0.30–0.78 µg/g), Pb (0.25–1.12 µg/g), Sr (1.4–2.7 µg/g), and Zn (4.7–9.8 µg/g). Some of the essential trace elements were found to have good nutritional contribution in accordance to daily nutrient recommendations for adults. The concentrations of non-essential elements such as Al, Ni and Sr, were very low in all samples. The levels of toxic elements such as As, Cd, Sb and Tl were not detected in any of the samples, and do not pose any threat to consumers. However, the Pb concentrations were above the safety limits in 8.9 % of the studied samples. Therefore, regular monitoring of this toxic metal should be conducted in the future, to ensure the quality of the gluten-free products for human health.