In terms of nutritional content, which component of milk is primarily responsible for its protein content?

The component of milk that is primarily responsible for its protein content is casein. Casein accounts for about 80% of the total protein in cow's milk and plays a crucial role in forming curds during cheese production. This protein exists in the milk in the form of micelles, which are complexes that keep casein soluble and provide structural stability.

Lactose, the sugar found in milk, although important for energy, does not contribute to the protein content. Fat provides energy and essential fatty acids but is not a source of protein. Whey proteins do contribute to the overall protein content of milk, but they only make up about 20% of the total protein. Casein’s predominant presence and its specific properties make it the main protein component in milk, which is crucial for various functions, including nutrition and the manufacturing of dairy products.