The Ultimate Guide to Milk Protein Concentrate/Isolate

What is milk protein concentrate/isolate (MPC/MPI), how is it made, and for what purposes is it most useful? When you’re new to the world of milk protein products, it’s natural to have many questions, especially considering the diverse terminology involved. Not all these products are the same. It’s worth taking a few moments to contemplate some of the most common questions about these substances. Here’s our quick guide to understanding MPC/MPI.

  1. What is the Difference Between Milk Protein and Whey Protein?

In this case, when we talk about “milk protein,” we mean both casein and whey proteins as found naturally in cow’s milk. Casein typically accounts for about 80 percent of all the protein in any given portion of milk and whey protein the other 20 percent. Casein proteins exist as a molecule suspended within milk itself, and its chemical composition gives it a high affinity for forming bonds with calcium compounds — hence milk being so rich in calcium and considered good for bone health. Whey proteins, on the other hand, exist dissolved into solution within milk and comprise a wide variety of components. Whey protein denatures quickly with heat and contains more amino acids with an affinity for sulfur bonds.

  1. What About the Difference Between MPC and WPC?

Although both milk protein concentrate and whey protein concentrate undergo a similar production process known as ultrafiltration, the two products are quite different from one another. WPC is precisely what you’d expect from the name — 100 percent whey protein with absolutely no casein in the final product. When dissolved in water, the sulfurous amino acids give WPC products a slightly chemical or astringent flavor profile, requiring flavor masking agents. MPC, on the other hand, preserves the 80 to 20 percent ratio of casein to whey found in unprocessed milk. It yields a creamy mouthfeel when re-suspended and has a more-complete nutritional composition.

  1. Is There a Difference Between MPI and WPI, Too?

When we get into the terminology surrounding isolates, it’s important to remember there is no formalized definition for such products other than as defined by the American Dairy Products Institute which reads, “Milk Protein Isolate (MPI) is the substance obtained by the partial removal of sufficient non-protein constituents (lactose and minerals) from skim milk so that the finished dry product contains 90% or more protein by weight.” In general, isolates contain a higher percentage of protein than concentrates, but in practice, the two terms are often used interchangeably. The differences remain the same, with MPI containing casein and WPI using only whey proteins. 

However, the loose definition of MPIs means that many on the market today contain only a small amount of whey compared to natural milk. Some also use chemical processing to separate the casein, which has many trade-offs. Only isolates that undergo a filtration process at gentle temperatures will maintain natural protein ratios.

  1. What Effect Does Pasteurization Have on Milk Proteins?

Preserving the quality and neutral flavor of MPC/MPI is essential but preventing the proteins from denaturing (unfolding) is often a challenge. There is a reason why the high temperatures and alkaline additives of chemical processing are not a part of any filtration process. However, destroying pathogens potentially still contained within milk or the resultant concentrates requires pasteurization. Does this exposure to heat cause problems?

In short, no. While some proteins may denature during pasteurization, the typical process used — High Temperature Short Time, or HTST pasteurization — does not expose the product to elevated temperatures for too long. We use enough heat to kill and neutralize pathogens without negatively impacting the product.

  1. What Are Some of the Uses for Milk Protein Concentrate/Isolate?

The high protein concentration of MPC/MPI, combined with its neutral to mild flavor, make it well-suited for blending into the formulations of many other products. For example, athletes and bodybuilders often look for products created to suit the high protein demands of continually building new muscles. Including MPC/MPI in a product is a simple way to add healthy protein comprised of the nine essential amino acids without imparting a bad taste or odor to the product. Other nutritional applications abound, as do opportunities for using MPC/MPI as a stabilizer in foodstuffs such as ice cream.

  1. What is Ultrafiltration? How Does It Produce a Superior MPC/MPI Product?

Ultrafiltration involves physically trapping and extracting the larger protein molecules from the smaller molecular components of milk. Using a specially made filter, the milk passes through the medium under pressure. The entire process takes place at “cold” temperatures well below the point where proteins start to denature. The filtration media trap protein particles which then undergo a drying and refining process to create milk protein concentrates/isolates. Microfiltration efficiently traps both casein and whey proteins.

Exploring Additional Facts About MPC 

We hope this scratch on the surface of milk protein concentrates/isolates has been helpful. From understanding how whey proteins differ to busting myths about isolates and what is on the market today, there is always more to discover. To learn about purchasing MPC/MPI products or to explore the unique benefits of Idaho Milk Products and our own solutions, please contact us online or by phone at your convenience.