Caseins are a group of proteins commonly found in milk and dairy products, making up about 80% of the protein content in cow's milk. They play a crucial role in providing essential amino acids, calcium, and phosphorus, which are important for growth and development. Caseins are known for their ability to form a gel or curd when exposed to acid or enzymes, which is why they are often used in cheese-making. These proteins are also utilized in various food products and supplements due to their slow digestion rate, providing a sustained release of amino acids. Additionally, casein protein is popular among athletes and bodybuilders for muscle recovery and growth.