A lot of classic dishes cannot do without cheese – from pizza to panini and from queso to quesadilla. But why do some cheeses melt, turning into a viscous mass, while others simply cannot give in to melting? This question has a molecular explanation related to the behavior of Casein protein.
Casein, found in milk, forms a network of weak links, water, and fat during the cheese-making process. When cheese is heated, this network gradually breaks down. First, fats begin to melt, and then at around 70 degrees Celsius, proteins start to compress, making the cheese soft and viscous. At 160 degrees, the cheese fully melts.
Nevertheless, not all cheeses behave identically. For instance, Mozzarella stretches and spreads thanks to the flexibility of its casein network, while Ricotta doesn’t melt at all due to a structure based on whey proteins. The amount of calcium in casein also affects the cheese’s texture: too much calcium results in overly hard cheese, while too little causes it to melt too quickly.
The key factor affecting the structure of casein is acidity. The addition of acid breaks some calcium and phosphate bonds, making the cheese more prone to melting. However, excessive acidity can lead to the formation of overly dense connections among proteins, hindering the cheese’s stretchiness. The aging process is crucial too: enzymes break down protein molecules over time, making the cheese melt more easily but less viscous.
Vegan cheeses, lacking casein, do not exhibit the same characteristics. They remain soft even at low temperatures and lose their shape when heated, resembling hot jelly.