Does heating whey protein affect the protein content of the powder itself? You will see many answers regarding this question, both yes and no. My personal opinion is yes The Maillard Reaction happens when you heat protein. The amino acid lysine breaks down into a chemical furosine, which is the cause of amino acid damage in protein. Excess heat causes the Maillard reaction to occur, which reduces the amount of energy and protein available. Whey protein can also be denatured by heat. Speaking from a biochemical standpoint, when heated the protein is denatured. This means the protein's shape starts to change in such a way that the chemical bonds start to break. High heat that is sustained at about 72 degrees Fahrenheit, which is the temperature associated with the pasteurization process, denatures whey proteins, destroying some bioactive compounds. When this happens, the whole chemical structure changes decreasing the protein content in your protein powder. What are the common pitfalls of baking, or cooking, with protein powder? Are there any dos and don'ts? When you cook with protein it tends to dry things out and even change the texture of what you are eating. So if you are cooking with it, be sure to measure it correctly. More isn’t always better in this case. Would the same denaturing issue hold true for heating casein protein? Yes the same denaturing issue holds true for casein. Being the major protein in milk, casein is one of the highest quality proteins. Unfortunately, inferior processing techniques can alter or denature this protein. Denatured caseins, such as sodium and potassium caseinate dominate the marketplace. So the “heating factor” has already taken place before it even hits the market place. Native casein however is a protein that is produced in the absence of high heat through a filtration method. So if you have this native casein and heat it, you will cause damage. Does the naturally occurring protein in things like steak, chicken and beans also denature when it's heated? Yes you can visually see this happen. It’s most noticeable in eggs when they change from runny to white and stiff. When talking about chicken or steak, the Maillard reaction occurs when the denatured proteins on the surface of the meat recombine with the sugars present. The combination creates the meaty flavor and changes the color.