Whey Protein Concentrates: Production and Applications

Every time cheese is made, a yellowish-green liquid is left behind – that liquid is whey. For decades, whey was treated as waste, often dumped into waterways or used as animal feed. Today, it is recognised as one of the most valuable by-products of the dairy industry. Among the many products derived from whey, whey protein concentrates (WPCs) stand out for their exceptional nutritional profile, functional versatility, and wide range of food applications. From infant formulas to protein bars, WPCs have become an indispensable ingredient in modern food manufacturing.

What are whey protein concentrates? 🔗

Whey protein concentrates are dried powders obtained by removing a significant portion of non-protein components – primarily lactose, minerals, and water – from liquid whey. The result is a product with a protein content typically ranging from 35% to 80% on a dry weight basis. The two most common commercial grades are WPC 34 (containing around 34% protein) and WPC 80 (containing around 80% protein).

The key proteins present in WPC include beta-lactoglobulin (the most abundant, accounting for roughly 50-55% of total whey protein), alpha-lactalbumin (20-25%), immunoglobulins, bovine serum albumin, lactoferrin, and glycomacropeptide. Each of these fractions contributes specific nutritional and biological benefits, making WPC a complex and valuable ingredient rather than a simple protein powder.

How whey protein concentrates are produced 🔗

The production of WPC begins with liquid whey obtained during cheese or casein manufacture. This raw whey undergoes several processing steps to concentrate its protein content while removing lactose, fat, and minerals. The choice of processing method determines the final protein concentration and functional quality of the WPC.

Ultrafiltration 🔗

Ultrafiltration (UF) is the most widely used industrial method for producing WPC. It is a membrane-based separation technology that selectively retains whey proteins based on molecular size while allowing smaller molecules – lactose, minerals, and water – to pass through as permeate. UF membranes typically have a molecular weight cut-off ranging from 3 kDa to 10 kDa, which effectively blocks the passage of whey proteins (which are larger) while letting through low-molecular-weight solutes.

A key advantage of ultrafiltration over older thermal methods is that it operates at relatively low temperatures, preserving the native structure and functional properties of the proteins. Thermal evaporation, the conventional approach, consumes far more energy and can damage heat-sensitive proteins, reducing both their nutritional and functional value.

To produce higher-protein WPC (such as WPC 80), ultrafiltration is often combined with diafiltration (DF). In this step, water is added to the UF retentate and the filtration process is repeated. This additional washing helps remove more lactose and minerals from the concentrate, effectively increasing the protein-to-total-solids ratio. Research has shown that adding small volumes of diafiltration water multiple times is more effective at purification than adding a large volume all at once.

Gel filtration 🔗

Gel filtration, also known as size-exclusion chromatography, separates whey components based on their molecular size as they pass through a column packed with porous gel beads. Larger protein molecules move through the column faster because they cannot enter the pores, while smaller molecules like lactose and minerals are delayed as they diffuse into and out of the beads. While gel filtration can produce highly purified protein fractions, it is less commonly used at large industrial scales compared to membrane filtration due to lower throughput and higher costs. It is more commonly employed in research settings or for producing specialised protein fractions.

Heat precipitation 🔗

Heat precipitation takes advantage of the fact that whey proteins denature (unfold and aggregate) when exposed to elevated temperatures, especially under specific pH conditions. By carefully controlling the heating temperature and acidity, proteins can be made to precipitate out of solution, after which they are separated from the remaining liquid by centrifugation or filtration. This method is relatively simple but can alter the functional properties of the proteins since heat-denatured proteins behave differently from their native forms – they may lose solubility and emulsifying capacity, for instance. Heat precipitation is therefore best suited for applications where protein denaturation is acceptable or even desirable.

Post-concentration processing 🔗

After concentration by any of the above methods, the WPC is typically further processed through evaporation to increase the total solids content, followed by spray drying to convert it into a stable, storable powder. According to a USDA technical report, ultrafiltration, evaporation, and drying together are the standard industrial sequence used to produce commercial WPC ingredients with 34% to 80% protein content.

Nutritional profile of WPC 🔗

One of the primary reasons WPC has gained such importance in the food industry is its outstanding nutritional quality. Whey proteins have a high biological value (BV) – a measure of how efficiently the body can use the protein consumed. The biological value of whey protein exceeds that of egg protein and other high-quality protein sources including meat, soy, and casein.

Whey protein is a complete protein, containing all nine essential amino acids. It is especially rich in branched-chain amino acids (BCAAs) – leucine, isoleucine, and valine – which together make up over 20% of the protein by weight. These amino acids are considered important metabolic regulators involved in protein synthesis, glucose homeostasis, and lipid metabolism. Whey also provides significant amounts of the sulphur-containing amino acids cysteine and methionine, which contribute to antioxidant functions in the body.

The protein efficiency ratio (PER) of whey protein is among the highest of any food protein. PER measures the weight gain of a growing animal per gram of protein consumed, and whey consistently outperforms casein, soy, and other common protein sources on this metric. This superior PER is attributed to its excellent amino acid profile and high digestibility, making WPC a preferred protein source in formulations where protein quality matters most.

Functional properties of WPC in food systems 🔗

Beyond nutrition, WPC is valued for a range of functional properties that influence the texture, appearance, and stability of food products. These properties arise from the physicochemical characteristics of whey proteins – their solubility, surface activity, gelling behaviour, and water-binding capacity.

Solubility 🔗

Whey proteins are highly soluble across a wide pH range, which makes them suitable for use in clear beverages, acidic drinks, and other liquid applications. This high solubility also underpins many of their other functional roles – a protein must dissolve properly before it can emulsify, foam, or gel effectively.

Emulsification 🔗

WPC acts as an effective emulsifier, helping to stabilise oil-in-water emulsions in products like salad dressings, soups, and sauces. The whey proteins migrate to the oil-water interface, forming a protective layer around fat droplets that prevents them from merging. Beta-lactoglobulin, in particular, shows strong emulsifying and surface-active properties.

Gelation 🔗

When heated above a certain temperature (typically around 70°C), whey proteins denature and form a three-dimensional gel network. This gelling ability is useful in products like processed meats, baked goods, and desserts where a firm or semi-solid texture is desired. The gel strength and characteristics can be modulated by adjusting protein concentration, pH, and the presence of salts.

Foaming and whipping 🔗

Whey proteins can stabilise foams by forming flexible films at the air-liquid interface. This makes WPC a useful ingredient in products like meringues, mousses, whipped toppings, and aerated confections.

Water and fat binding 🔗

WPC can bind water and fat, improving the moisture retention and mouthfeel of food products. This is particularly useful in baked goods, yoghurts, and processed meat products where improved water holding capacity, gel firmness, and viscosity are desirable.

WPC as a substitute for non-fat dry milk 🔗

In many food formulations, WPC serves as a partial or complete substitute for non-fat dry milk (NFDM). There are several reasons for this substitution. First, WPC often costs less per unit of protein than NFDM. Second, WPC provides a higher protein-to-lactose ratio, which is advantageous in formulations where high protein but low lactose is desired. Third, the functional properties of WPC – particularly its superior emulsification, foaming, and gelation – can actually improve the quality of the finished product compared to NFDM.

In applications like bakery products, frozen desserts, and processed cheese, WPC can replace NFDM while maintaining or even enhancing texture, moisture retention, and protein content. Its superior PER compared to the casein-dominant protein in NFDM also makes it a better choice in nutritionally targeted products.

Applications of WPC in the food industry 🔗

The combination of nutritional quality and functional versatility has led to the use of WPC across a remarkably wide range of food products.

Infant formula 🔗

One of the most critical applications of whey protein is in infant formula manufacturing. Human breast milk contains roughly 60% whey protein and 40% casein, whereas cow’s milk has the reverse ratio. To make infant formula that more closely resembles human milk, manufacturers add whey protein ingredients to adjust the casein-to-whey ratio. WPC provides essential amino acids that support infant growth and development, while its high digestibility ensures that nutrients are efficiently absorbed. Partially hydrolysed whey protein formulas are also produced for infants at risk of allergic reactions.

Sports nutrition and protein supplements 🔗

WPC is one of the most popular protein ingredients in the sports nutrition market. Its high BCAA content – especially leucine – supports muscle protein synthesis, making it a preferred choice for protein shakes, bars, and ready-to-drink beverages. WPC 80 is particularly favoured in this segment because it delivers high protein density while remaining more affordable than whey protein isolate.

Bakery and confectionery products 🔗

In baked goods, WPC improves moisture retention, crumb structure, and browning. It also contributes to the protein content of the product without significantly affecting flavour. In confectionery, WPC can replace portions of other dairy solids while enhancing texture and providing a clean flavour profile. According to the American Dairy Products Institute, WPCs are commonly used in bakery products, confections, frozen desserts, and prepared dry mixes.

Beverages 🔗

The high solubility of whey proteins, especially at acidic pH, makes WPC suitable for clear and opaque beverage applications. It is used in protein-enriched waters, smoothies, and meal-replacement drinks. The growing popularity of whey-based functional beverages – including probiotic drinks, electrolyte drinks, and ready-to-serve protein drinks – represents a significant and expanding market segment.

Dairy products 🔗

WPC is used to enrich the protein content and improve the texture of yoghurts, ice cream, and processed cheese. In yoghurt production, adding WPC can improve gel firmness, reduce syneresis (whey separation), and boost the protein content to meet consumer demand for high-protein dairy products.

Processed meats 🔗

In processed meat products like sausages and deli meats, WPC acts as a binder, improves water retention during cooking, and enhances the overall texture of the product. Its ability to form heat-set gels makes it particularly effective in this application.

Specialised nutritional products 🔗

Beyond mainstream food products, WPC plays an important role in clinical and therapeutic nutrition. It is used in enteral feeding formulations, products for elderly nutrition, and weight management products. The bioactive peptides derived from whey proteins have demonstrated antioxidant, anti-inflammatory, and blood pressure-lowering effects, which further enhances the appeal of WPC in health-focused product development.

Grades and classification of WPC 🔗

WPC is commercially available in several grades, classified primarily by protein content on a dry weight basis. The most widely produced and traded grades are WPC 34 and WPC 80.

WPC 34 contains approximately 34-36% protein and retains more lactose and minerals. It is more affordable and commonly used in baked goods, confections, and processed foods where extremely high protein density is not required.

WPC 80 contains approximately 80% protein with significantly reduced lactose and fat content. It is used in sports nutrition, infant formula, clinical nutrition, and any application where a higher protein payload is necessary. Production of WPC 80 typically requires ultrafiltration combined with diafiltration to achieve the necessary level of protein purity.

Beyond WPC, further processing can produce whey protein isolate (WPI) with over 90% protein content. WPI undergoes additional purification steps, including microfiltration, to remove virtually all fat and lactose. However, WPC remains more cost-effective and retains more of the naturally occurring bioactive compounds found in whey.

Challenges in WPC production 🔗

While WPC production technology has matured considerably, several challenges persist. Membrane fouling is a major operational issue in ultrafiltration – whey proteins and other components gradually deposit on the membrane surface, reducing filtration efficiency over time. Research has documented that permeate flux can decrease by over 50% during extended ultrafiltration runs, necessitating regular cleaning cycles and membrane replacement.

Variability in the composition of incoming whey – which depends on the type of cheese produced, the milk source, and processing conditions – can also affect the consistency of the final WPC product. Maintaining tight control over diafiltration volumes, transmembrane pressure, and concentration factors is essential for producing WPC that meets the required specifications.

Storage stability is another consideration. WPC powders must be stored in cool, dry conditions to prevent moisture uptake, caking, and protein degradation. Proper packaging – typically multi-wall kraft bags with polyolefin liners – is important for maintaining product quality throughout the supply chain.

The future of whey protein concentrates 🔗

The global demand for whey protein continues to grow, driven by increasing consumer interest in high-protein diets, sports nutrition, and functional foods. Advances in membrane technology are making WPC production more efficient, with newer membrane materials offering higher flux rates and better fouling resistance. There is also growing interest in fractionating individual whey proteins – particularly alpha-lactalbumin and lactoferrin – for use in specialised nutritional and pharmaceutical applications.

From an environmental perspective, the shift from treating whey as waste to converting it into high-value WPC represents a significant achievement in dairy sustainability. Converting the liquid by-product of cheese manufacturing into a commercially valuable food ingredient reduces pollution while adding economic value to dairy operations.

What do you think? Given the growing demand for plant-based protein alternatives, do you see whey protein concentrates maintaining their dominant position in the protein ingredient market? And could advances in membrane technology make WPC affordable enough to replace conventional protein sources in developing countries?

References

1. https://pmc.ncbi.nlm.nih.gov/articles/PMC4662358/
2. https://www.sciencedirect.com/science/article/abs/pii/S0011916411004681
3. https://pmc.ncbi.nlm.nih.gov/articles/PMC11433986/
4. https://www.ams.usda.gov/sites/default/files/media/Whey%20Protein%20Concentrate%20TR.pdf
5. https://www.adsa.org/Portals/0/SiteContent/Docs/Membership/GSD/Pioneers-in-Dairy-Science/PP1_Modler.pdf
6. https://pubmed.ncbi.nlm.nih.gov/36725371/
7. https://www.sciencedirect.com/science/chapter/edited-volume/abs/pii/B9780128121245000138
8. https://adpi.org/ingredient-resources/whey-protein-concentrate/
9. https://pmc.ncbi.nlm.nih.gov/articles/PMC4744604/