Mkronutrients in natural cow, ewe and goat milk

Abstract

The seasonal changes in concentrations of copper (Cu), iron (Fe), zinc (Zn) and manganese (Mn) present in the milk of the three main milk-producing species (cow, ewe and goat) were studied for one year by using flame atomic absorption spectrophotometry. The mean concentrations obtained for the four minerals studied, Cu, Fe, Zn and Mn, were: 0.16 ± 0.03, 0.44 ± 0.11, 4.21 ± 0.41 and 0.026 ± 0.006 mg/kg of fresh weight respectively for cow milk; 0.41 ± 0.14, 0.77 ± 0.32, 5.66 ± 2.20 and 0.089 ± 0.028 mg/kg of fresh weight for ewe milk; 0.40 ± 0.07, 0.67 ± 0.12, 4.76 ± 0.50 and 0.155 ± 0.059 mg/kg of fresh weight for goat milk. According to these concentrations the consumption of a cup (250 ml) of cow's milk contributes 40 μg of copper, 130 μg of iron, 823 μg of zinc and 6.4 μg of manganese; in the case of ewe's milk the contribution is 100 μg of copper, 192 μg of iron, 1415 μg of zinc and 22 μg of manganese; and a cup of goat's milk gives 100 μg of copper, 167 μg of iron, 1190 μg of zinc and 39 μg of manganese. Two-factor variance analyses were made on the milk products investigated for the four mineral elements and Scheffé multiple analyses (P ≤ 0.05) were also carried out for the formation of homogeneous groups per species for the mineral elements analysed.