Chemical composition of Italian Coffee knowledge Milk

Milk is made up of protein, fat and sugar. Protein is a foaming agent. When air is pumped into milk, protein forms a thin film around the air, enveloping the air to form bubbles. Fat inhibits and disrupts the foaming process, although whole milk produces a softer foam than skim milk, and fortified milk froths more easily and expands to a larger volume than unfortified milk, which is why low-fat milk with added protein has a larger volume after foaming because it has more protein and less fat.