Study of chromium and nickel content in white asparagus (Asparagus officinalis, L.)

The modifications in the chromium (Cr) and nickel (Ni) content and the distribution of these trace elements in white asparagus spears (Asparagus officinalis, L.) were investigated. Samples were taken of two varieties of white asparagus, Desto and Ciprés, and grouped in function of their thickness in spears of < 11 mm and of > 14 mm. All the asparagus samples were cut in lengths of 20 cm and divided into 10 portions of 2 cm each. The determinations of chromium and nickel were carried out by atomic absorption spectrophotometry with air-acetylene flame. The mean concentrations were 0.675 +/- 0.19 and 5.578 +/- 1.39 mg/kg dry weight for chromium and nickel, respectively. By means of three-factor analyses of variance (varieties, thickness and portions), statistically significant differences were determined between the concentrations of chromium and nickel and each one of the sources of variation established. The chromium content showed a variable distribution throughout the white asparagus portions as a result of the notable differences between varieties and thickness. In the case of nickel, its levels underwent a generalized decrease as the spear portions were further and further away from the apical area or tip of the white asparagus.