CREAM.
Cream varies in composition according to the circumstances under which it rises.
The composition of an average specimen as given by Letherby is:—
| Nitrogenous matter | 2.7 |
| Fat | 26.7 |
| Sugar of milk | 2.8 |
| Mineral matter | 1.8 |
| Water | 66.0 |
In the process of churning; the membranes of casein which surround each of the little globules constituting the cream are broken, and the fat of which they are composed becomes a compact mass known as butter. The watery looking residue containing casein, sugar of milk, mineral matter, and a small proportion of fat, comprises the buttermilk.
Skim-milk, or milk from which the cream has been removed, and buttermilk are analogous in chemical composition.
The composition of each, according to Dr. Edward Smith, is:—
SKIM-MILK.
| Nitrogenous matter | 4.0 |
| Sugar | 3.8 |
| Fat | 1.8 |
| Mineral matter | 0.8 |
| Water | 88.0 |