Effect of species on the distribution and oxidative stability of milk added of lead and cadmium

Abstract

The aim of this study was to evaluate the effect of species on added lead (Pb) and cadmium (Cd) content in cow, buffalo, and goat milk and their distribution in fat, casein, and whey fractions. In addition, the oxidative stability of the milk was evaluated. Most of the Pb and Cd were recovered in the skimmed milk (96.74 and 94.21%, respectively). The distribution of Cd and Pb in casein and whey fractions, obtained by enzymatic coagulation, highlighted that they were mainly associated with casein (on average 94.77 and 90.54% of Pb and Cd, respectively). The species significantly affected the distribution of Cd and Pb in the casein and fat fractions (p < 0.01). In particular, Cd and Pb levels in fat fraction were the highest in the buffalo milk, whereas casein fraction was the highest in bovine milk. Furthermore, the presence of metals negatively influenced the oxidative stability of the milk and the species influenced its response. The results showed that in the presence of Cd and Pb, bovine milk increased the content of Malondialdehyde (MDA), advanced oxidation protein products (AOPP) and dithyrosines compared to other species. In addition, there was a significant decrease in the thiol content, highlighting a reduction in the antioxidant capacity of the contaminated milk.