When milk is dried and the residue is burned, a white powder is obtained which is known as ash or mineral part of the milk. The major portion of ash is composed of the chlorides and oxides of potassium, calcium and phosphorus. It is of interest to note that these three elements are in greater concentration in milk than in blood, thus the mammary gland exerts a selective action to concentrate these elements.
The mineral content in milk is influenced by many factors ranging from environmental conditions during pasture, feeding, breeding, stage of lactation and climate to post-milking handling, transportation and processing.
The chemical form of mineral elements found in milk and dairy products is very important due to their absorption in the intestine and biological utilization (transport, assimilation in cells and conversion into biologically active form).
Milk contains more calcium than most foods because of the distribution of calcium in milk. About two thirds of the total calcium in milk is in colloidal form as calcium caseinate, citrate and phosphate; the remaining third is in true solution.
Phosphorus in milk is involved in the stabilization of caseins and is present in two forms: organic and inorganic. Organic P is bound to molecules such as proteins, organic acids, phospholipids and nucleotides, mainly in colloidal phase, and inorganic ionic P is mainly present in soluble fraction.
Minerals in milk
