Milk is a complex solution composed of water, solids, fat, proteins, lactose and minerals. Many of these components are compounds on their own, giving milk its very complicated chemical makeup.
Milk is very nutritious due to its high mineral and vitamin content, as well as the energy-giving fat content. The average glass of milk contains everything from calcium, to vitamins A, D, E and K. However, milk is mostly composed of water, with most milk having a water content of more than 85 percent. Lactose, or milk sugar, makes up more of milk's mass than fat or protein in most cases.
The other components of milk appear in varying content. For example, there is between 30 to 35 grams of protein per liter of normal milk. Casein by weight is between 76 percent to 86 percent of the molecules that comprise milk proteins.
The other components of milk, such as ions, colloids and emulsions, appear in different distributions. The distribution and concentration of components depend on environmental and herd management factors as well as multiple individual factors such as:
- Breed of the cow
- Stage of lactation