The characteristic carbohydrate of milk is lactose, commonly called “milk sugar”.
Lactose is present in the milk of most mammals in various amounts from approx. 1.9% (horse) to approx. 18.3% (rabbit). The average lactose content is 4.8% anhydrous lactose, while human milk contains 7% lactose.
The lactose content of dairy products depends on the processing. In concentrated and dried products it increases proportional to the dry substance, while it is lower in fermented products.