engleski

Copper complexing properties, trace metal content and organic matter physico-chemical characterization of Greek beers

Complex formation is among the mechanisms affecting metal bioaccessibility, hence the evaluation of the extent of interactions between trace elements and organic matter in food items is of great interest. Sensitive electrochemical techniques, considered powerful tools for the study of such interactions, were applied for the first time in beer samples. The concentration of Cu complexing ligands (LT) determined in 30 Greek beers by Differential Pulse Anodic Stripping Voltammetry (DPASV) varied between 37.1 and 348 μM. In all beer samples examined total Cu concentrations were lower than the corresponding LT values, evidence that Cu is fully complexed. The concentrations of organic matter measured as total organic carbon (OC ; 30–56 g L−1) and total carbohydrates(CHOs ; 0.82–9.2 g L−1) were relatively high, their presence influencing metals speciation in beers. In an attempt to partially characterize the physico-chemical properties of organic material the surface active substances (SAS) and catalytically active compounds (CAC) were measured for the first time in beers by electrochemical techniques. A characterization of the beer samples examined, according to their elemental content was also carried out by determining 15 minor and trace elements with inductively coupled plasma mass spectrometry (ICP-MS). The median values of As, Cd, Co, Cs and Pb concentrations were determined at 0.04–3.4μg L−1, of Ba, Cr, Cu, Ni, V and Zn at 12–35 μg L−1 and those of Fe, Mn, Rb and Sr at 122–225 μg L−1.

Electroanalytical techniques, Copper complexation, Organic ligands, Metals, Beers

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