THE PROPERTIES OF CASEIN MICELLES .5. THE DETERMINATION OF HEAT-INDUCED CALCIUM-PHOSPHATE PRECIPITATIONS IN MILK

Although the amounts of colloidal Ca, Mg and inorganic PO4 in cows' milk were only slightly affected by heating at 128-degrees-C for 5 min, their appearance was not unaffected. This could be concluded after adding 10% (w/w) NaCl, 10 mM Na3 citrate and 0, 5 or 10 mM EDTA (pH less-than-or-equal-to 5.8) to sterilized and unsterilized milk and subsequently measuring the transfer of the minerals to the serum fraction. In the sterilized milk samples about 6, 1 and 5 mM less colloidal Ca, Mg and inorganic PO4, respectively, were transferred as compared to the corresponding unsterilized samples. Thus a considerable part of the native micellar calcium phosphate was transformed into more stable mineral phosphates upon the heating procedure.