Chemistry Reference
In-Depth Information
9
Milk Salts: Technological Significance
J.A. Lucey and D.S. Horne
9.1.
Introduction
Mammalian milk contains all the essential components to sustain the growth
and development of the newborn suckling. Usually, this is taken to mean the
protein, fat and carbohydrate, but it must also apply to the mineral compo-
nents, the milk salts, including the citrates, phosphates and chlorides of H
+
,
K
+
,Na
+
,Mg
2+
and Ca
2+
, whether as ions in solution or as colloidal species
complexed with the caseins. These minerals are essential for bone growth and
development, for efficient cellular function or for maintaining osmolality in
the wake of carbohydrate (lactose) synthesis. Like the other components, all
these mineral species are there for a purpose and until weaning, milk may
often be the only source of these essential elements.
There have been a number of reviews on the topic of milk salts (Allen,
1931; Pyne, 1962; Jenness and Patton, 1976; Walstra and Jenness, 1984; Holt,
1985, 1997; Fox and McSweeney, 1998; Gaucheron, 2005). In this chapter,
the term salts will be used to represent substances that are, or can be, present
in milk as low molecular weight ions. This group includes both inorganic and
organic (e.g. citrate) substances. We can distinguish between the major salt
constituents and trace elements and the latter will not be considered in this
chapter. The approximate concentration of milk salts is shown in Table 9.1.
The milks salts have a crucially important impact on many properties of milk,
including the formation and stability of the casein micelles, acid-base buffer-
ing and various colligative properties, as well as its key biological role (i.e.
providing nutrition for the newborn). In addition, these salts have a powerful
