Concentration and seasonal variation of calcium, magnesium, sodium and potassium in raw cow, ewe and goat milk

The seasonal changes in concentrations of calcium (Ca), magnesium (Mg), sodium (Na) and potassium (K) present in the milk of the three main milk-producing species (cow, ewe and goat) were studied for 1 year by using flame atomic absorption spectrophotometry. The mean concentrations obtained for the four minerals studied, Ca, Mg, Na and K, were: 1.20 ± 0.11, 0.105 ± 0.007, 0.58 ± 0.07 and 1.68 ± 0.07 mg/g of fresh weight respectively for cow milk; 2.06 ± 0.27, 0.194 ± 0.040, 0.51 ± 0.12 and 1.57 ± 0.20 mg/g of fresh weight for ewe milk, 1.55 ± 0.12, 0.142 ± 0.014, 0.44 ± 0.08 and 1.63 ± 0.08 mg/g of fresh weight for goat milk. 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.