Mineral contents and distribution between the soluble and the micellar phases in calcium-enriched UHT milks

A study concerning the content of mineral elements (calcium, magnesium, sodium, potassium and phosphorus) and the distribution between the soluble and the micellar phases has been carried out on mineral-mainly calcium-enriched UHT milks. Total calcium contents were 1371-1793 mg l-1 in the 10 brands examined. Percentages of calcium in the soluble phase varied from 23.6 to 37.2%, whereas ionic calcium concentrations found were within a very wide range (44-91 mg l-1). The different forms of phosphorus were studied by 31P-NMR. Spectra indicated that the majority of the brands employed polyphosphates as stabilizers. Ingredients used to fortify these products consisted of dairy fractions and calcium salts. The modifications in salt balance as consequence of these practices are discussed.