Protein Guide:

Understanding Dairy Proteins
A practical guide to whey protein, milk protein, casein, concentrates and isolates

Quick navigation

• What is milk protein?

• Casein and whey

• Caseinates

• Whey Protein Concentrates (WPC)

• Acid Casein Whey vs Cheese Whey 

• Milk Protein Concentrates (MPC)

• Whey Protein Isolate (WPI)

• Milk Protein Isolate (MPI)

• Native Whey Protein Isolate

• Which protein is right for your application?

Milk contains two major protein groups: casein and whey protein. Approximately 80% of the protein in cow's milk is casein, while the remaining 20% is whey protein.

The way milk and whey are processed can separate, concentrate and modify these proteins, producing a wide range of dairy protein ingredients with different protein levels, functionality and applications.

For food manufacturers, sports nutrition businesses and product developers, understanding the differences between casein, whey protein, milk protein concentrates and protein isolates can help when selecting the right ingredient for a formulation.

In this guide, we explain how these dairy proteins are produced, how they differ and where they are commonly used.

Casein & Whey Protein

Casein and whey are the two principal protein groups found in cow's milk.

Casein exists naturally in milk as casein micelles, which contain casein proteins associated with calcium phosphate. When milk is acidified to approximately pH 4.6, the casein precipitates and the casein micelle structure is disrupted.

The remaining proteins in solution are predominantly whey proteins.

The method used to separate and process these proteins has a significant impact on their final composition and functionality.

Casein

Casein is the predominant protein in milk and is widely used in food, nutritional and sports nutrition applications.

Whey Protein

Whey contains the proteins that remain in solution after casein separation. Modern membrane filtration technologies allow whey to be concentrated and further processed into ingredients such as whey protein concentrate (WPC) and whey protein isolate (WPI).

What Are Caseinates?

Casein can be further processed by adding an alkaline substance to redissolve the protein before drying it to produce caseinates.

Caseinates are available in different forms, including:

Calcium Caseinate
Sodium Caseinate

Calcium caseinate has historically been widely used in sports nutrition and nutritional products because of its high protein content and useful dispersibility.

Bacarel Express supplies a range of caseinate ingredients for different applications.

Click to explore our caseinate range 

Whey Protein Concentrate (WPC)

What is WPC?

Whey Protein Concentrate (WPC) is a dairy-derived protein ingredient produced by concentrating whey, the liquid remaining after casein is separated from milk during cheese or casein manufacture. It is widely used in food manufacturing and sports nutrition, offering different protein concentrations to suit a range of formulation requirements.

How is WPC produced?

Whey Protein Concentrate is typically produced using ultrafiltration, a membrane filtration process that concentrates whey proteins while allowing some smaller components, including lactose and minerals, to pass through. Further processing, such as diafiltration, can reduce lactose and mineral levels to achieve the required composition.

Understanding WPC Grades

WPC is available in different grades, with protein content and composition varying according to the processing method and product specification.

WPC 35: A lower-protein concentrate containing a greater proportion of lactose and other non-protein solids.

WPC 60: An intermediate-protein concentrate suitable for formulations requiring a balance of protein and other milk solids.

WPC 80: A high-protein concentrate commonly used in protein-rich food and sports nutrition formulations.

WPC 82: A higher-protein specification available from some suppliers, depending on the product range.

Protein percentages can vary by specification and whether they are stated on a dry-matter or as-supplied basis. Always consult the relevant product data sheet for exact values.

Click to explore our WPC range

Acid Casein Whey vs Cheese Whey: Key Differences

Whey protein is widely used in food manufacturing, sports nutrition and nutritional products because of its protein content, amino acid profile and functional properties. Whey is also a valuable co-product of the dairy industry, recovered from different milk-processing operations.

Two important sources are cheese whey and acid casein whey. Although both contain whey proteins, their manufacturing processes influence their composition, mineral content, flavour and functionality.

Understanding these differences can help manufacturers and product developers select the most suitable whey protein ingredient for their formulation.

Cheese Whey

Produced during cheesemaking

Cheese whey is generated when milk is coagulated using enzymes such as rennet or, depending on the cheese-making process, acidification. Conventional sweet cheese whey commonly contains glycomacropeptide (GMP), released through the action of chymosin on κ-casein.

Its composition and flavour profile vary according to the cheese and manufacturing process.

Acid Casein Whey

Produced during casein manufacture

Acid casein whey is produced when milk is acidified to approximately pH 4.6, causing casein to precipitate and leaving soluble whey proteins in the liquid fraction.

Acidification changes the distribution of minerals between the casein and whey fractions, influencing the resulting ingredient's composition and functional properties.

Why Does Whey Source Matter?

The source of whey can affect how an ingredient performs in a finished product.

Flavour profile: Cheese-derived whey may contribute characteristic cheesy notes, while acid casein whey can have a more acidic flavour. The impact depends on the ingredient specification and formulation.

Mineral composition: Acidification can dissolve calcium phosphate associated with casein micelles, changing the distribution of minerals between the separated fractions.

Functional properties: Differences in composition can influence properties such as gel formation, water binding and performance within a food formulation.

Protein composition: Cheese whey and acid casein whey can differ in their protein fractions and minor components, depending on the manufacturing process.

For manufacturers, these differences can be important when selecting ingredients for sports nutrition, food processing and other nutritional applications.

Milk Protein Concentrate (MPC)

Milk Protein Concentrates are produced by processing milk using membrane filtration.

MPC products can range from approximately 50% to 85% protein, with the protein consisting primarily of casein and whey in proportions broadly reflecting those naturally present in milk.

Milk Protein Concentrate 85% is widely used in nutritional and food applications where a high-protein dairy ingredient is required.

Click to explore Milk Protein Concentrate 

Milk Protein Isolate (MPI)

Milk protein can also be processed into a milk protein isolate with a protein content of more than 90%.

The casein remains in its native micellar form during appropriate membrane filtration processes, although the ratio of casein to whey protein can differ from that of standard milk.

Click to explore Milk Protein Isolate 

Native Whey Protein Isolate

What Is Native Whey Protein Isolate?

Native whey protein isolate is produced by processing milk in a way that allows the whey protein fraction to be separated while retaining its native characteristics.

Microfiltration can separate the whey proteins from the casein and fat fractions, with further processing used to produce a high-protein whey ingredient.

Native whey protein isolate is often differentiated from whey produced through cheesemaking because the production route can result in differences in composition and processing characteristics.