WPC vs WPI – the differences between whey protein concentrate and whey protein isolate

In 1974, a paper was published in the "Journal of Dairy Science" on the composition and properties of whey protein concentrates produced using ultrafiltration. Prior to this, whey had been regarded primarily as a by-product of cheese production. Advances in filtration during the 1970s and 1980s made it possible to concentrate whey proteins and partially remove lactose, fat and minerals. It is from this technological development that modern products labelled as WPC and WPI originate.

1. Characteristics of whey
2. Differences between WPC and WPI
3. The use of WPC and WPI

Characteristics of whey

Whey is the liquid part of milk that remains after the curds have been separated during the production of cheese, quark or casein. It consists mainly of water, but also contains whey proteins, lactose, small amounts of fat and minerals.

Whey itself and whey protein

Liquid whey alone cannot be treated as a concentrated source of protein, as its protein content is low compared to ready-made supplements. It is only through technological processes such as filtration, concentration and drying that a powder with a high protein content in dry matter can be obtained.

What do whey proteins contain?

The main whey proteins include beta-lactoglobulin, alpha-lactalbumin, bovine serum albumin, immunoglobulins and lactoferrin. These proteins differ in structure, molecular weight and proportion within the total protein fraction, but in protein supplements, the most important thing is that they provide essential amino acids, i.e. those that the body does not synthesise in sufficient quantities. Whey protein contains significant amounts of so-called branched-chain amino acids, including leucine, isoleucine and valine.

"To optimise muscle protein synthesis, it is recommended to consume protein every few hours throughout the day; ensuring an intake of good-quality protein is crucial for breakfast, dinner and post-workout meals during the day." Tomasz Maciołek – Physiotherapist and Trainer

According to the approved health claim, protein contributes to the growth of muscle mass and helps maintain muscle mass. Whey is therefore primarily significant as a raw material for the production of high-protein ingredients.

Differences between WPC and WPI

Concentrate and isolate differ in the degree to which the protein is separated from the other components of whey.

WPC, or whey protein concentrate, is produced by concentrating the protein fraction, but the finished powder retains more lactose, fat and minerals than the isolate. In practice, whey protein concentrates often contain around 70–80% protein, although the exact figure depends on the raw material, technology and the manufacturer’s specifications. The remainder consists mainly of carbohydrates, primarily lactose, a small amount of fat, water and ash components.

WPI, or whey protein isolate, undergoes more thorough purification, which is why the protein content in dry matter is higher, whilst the lactose and fat content is lower. Isolates often provide around 85–90% protein or more, depending on the product.

The difference between WPC and WPI is therefore not that one contains a "different" protein, but that the proportions of protein to accompanying components vary within a single serving of powder. For the same serving size, WPI usually provides more protein and less lactose than WPC. For the same amount of protein, a serving of WPC will usually be larger and may provide more energy, carbohydrates and fat.

Comparison of typical nutritional values of WPC and WPI per 100 g of powder

 (without flavourings or functional additives)

The use of WPC and WPI

WPC and WPI are primarily used to increase protein intake in the diet. They can be used by those engaged in strength training, endurance training, or recreational activities, as well as by people who, for various reasons, do not consume sufficient protein through their meals. The supplement can be added to water, milk, plant-based drinks, yoghurt, porridge, omelettes, pancakes or desserts.

WPC is more often suitable as a versatile supplement for daily dietary supplementation, especially when small amounts of lactose and fat are not an issue.

WPI is more often chosen when a higher protein concentration per serving, lower lactose content, less fat, or easier integration of the product into a diet with precisely controlled energy and macronutrient intake is important. Some products contain a blend of whey proteins derived from both filtration methods. A typical serving of the supplement is usually 25–35 g of powder, which most often corresponds to around 20–30 g of protein.

Sources:

• Madureira AR, Pereira CI, Gomes AMP, Pintado ME, Xavier Malcata F. Bovine whey proteins – Overview on their main biological properties. Food Res Int. 2007;40(10):1197-1211. doi:10.1016/j.foodres.2007.07.005
• Morr CV, Ha EY. Whey protein concentrates and isolates: processing and functional properties. Crit Rev Food Sci Nutr. 1993;33(6):431-476. doi:10.1080/10408399309527643
• Morton RW, Murphy KT, McKellar SR, et al. A systematic review, meta-analysis and meta-regression of the effect of protein supplementation on resistance training-induced gains in muscle mass and strength in healthy adults. Br J Sports Med. 2018;52(6):376-384. doi:10.1136/bjsports-2017-097608