Ricotta

How to breathe new life into cheese “leftovers”

Ricotta is Italian for “recooked”. It got this name by being made from the whey left over from other cheese making ventures, like Mozzarella and Parmesan.

As we’ve discussed before, casein is usually the most important protein in milk for cheesemakers since it forms the structure and body for many different cheeses. In this post we finally get to talk about the other major types of protein in milk—whey proteins!

The whey that ricotta is made out of contains copious amounts of whey proteins (duh). These proteins are very different than the casein proteins we think about in terms of cheesemaking. Whey proteins are much more susceptible to heat coagulation. For a quick reminder of coagulation, check out our old post on the subject.

Ricotta is usually made by mixing whey, milk, and acid together. This mixture is then heated to very high temperatures (~175°F). This combination of heat and acid cause the proteins in the whey mixture to coagulate. The high heat causes the whey protein to denature (i.e. unfold) and stick to each other and stick to any casein that might be present (like in the milk that was added). The acid that is added causes further whey protein denaturation as well as the caseins to begin to coagulate. The confluence of these processes creates the soft mixture we know as ricotta.

Native Heat Acid

Many manufactures add milk for two main reasons: better sensorial properties and better economics. The addition of milk adds more casein and fat. These components can improve texture, flavor, and the overall yield. Some manufacturers may add other ingredients to tweak the overall make, like calcium chloride.

For More Information

• International Dairy Journal - Effects of heat treatment and whey protein addition on the rheological properties and structure of acid skim milk gels