Ionic Calcium in Milk and Whey

Simultaneous determination of free calcium, magnesium, sodium and potassium ion concentrations in simulated milk ultrafiltrate and reconstituted skim milk using the Donnan Membrane Technique

“…The calcium and magnesium ions were mostly complexed by anions in the serum, whereas the potassium and sodium ions were largely free. Both the DMT and calcium electrode gave repeatable and comparable values for Ca 2þ concentrations, which are within the typical range 1-3 mM (Demott, 1968;Holt, 1985). The concentrations of Ca 2þ , Mg 2þ , Na þ and K þ that were determined by DMT were generally consistent with the calculated ions concentrations in milk diffusate by Holt et al (1981).…”

The effect of free Ca2+ on the heat stability and other characteristics of low-heat skim milk powder

“…It is well accepted as a general principle that Ca 2þ plays an important role in determining the physicochemical and functional properties of milk and consequently of milk products (Augustin and Clarke, 1990;Demott, 1968;Geerts et al, 1983;Jeurnink and de Kruif, 1995;van Kreveld and van Minnen, 1955), but there is little direct experimental evidence reported supporting this statement in relation to the heat stability of reconstituted SMP. The fact that there are limited experimental data concerning the role of free Ca 2þ can be explained by both the practical difficulties that have been experienced in measuring Ca 2þ concentration, or by the complexity of the distribution of minerals in milk.…”

Dairy Chemistry and Biochemistry

“…(b) Calcium by titration with EDTA or by atomic absorption spectroscopy on 12 % TCA filtrates. (e) Ionized calcium is usually determined by the method of Smeets (1955), as modified by Tessier and Rose (1958), or using a calcium ion (Ca 2+ )-selective electrode (Demott 1968). (d) Citrate by the colorimetric method of Marier and Boulet (1958), as modified by White and Davies (1963), by complexation of citrate with copper ions (Pierre and Brule 1983) or by enzymatic assay involving the use of citrate lyase, malate dehydrogenase, lactate dehydrogenase and NADH (Mutzelburg 1979).…”