Whey products can vary greatly with regard to quality due to the variety of manufacturing techniques employed to turn raw milk into whey protein powders, some of which can denature the protein content.
The quality of a whey protein powder breaks down into two major factors:
- The quality of the raw milk from which the whey will be extracted; and
- The manufacturing process utilized to turn the raw milk into whey and then into whey protein powder.
Thus, the quality of whey protein powder depends on five critical steps in the production process:
- Production of raw milk (typically from cows);
- Pasteurization of the raw milk;
- Extraction of whey from the other components of the raw milk;
- Isolation of the protein from the carbohydrates, water, and fat in the whey; and
- Drying of whey protein isolate into a usable whey protein powder.
The entire process is illustrated below:
Each production step, including the factors that drive quality in the end-product, are discussed below in detail.
Raw Milk & Pasteurization
The quality of milk produced by cows can vary widely depending on the breed, diet, and environment of the cows. These factors can affect many attributes of the milk including the protein and fat content as well as numerous vitamins, minerals, and immune factors.
Most cows that produce milk are fed a diet of grains, particularly corn, not because it is best for the cows, but because it is the cheapest option. The result is cows that are overweight and more susceptible to illness; obviously, this has an effect on the quality of the milk they produce as well. A cow’s natural diet is primarily grass, as evidenced by the consumption habits of wild cows which will uniformly seek out grass pastures over grain. Raw milk from grass-fed cows is proven to contain higher levels of healthy fatty acids, such as conjugated linoleic acid, and is widely believed to have many other benefits as well.
Raw milk quality can be further impacted by the type of pasteurization used to remove harmful bacteria (a requirement for all milk products sold in the United States). Most industrial milk manufacturers use an Ultra-High Temperature (“UHT”) pasteurization method that removes bacteria by increasing its temperature to up to 280° F. This not only kills the harmful bacteria in the milk, but also destroys the structures of the proteins contained in the milk. Milk pasteurized using UHT can remain usable for more than 55 days because it is largely devoid of complex proteins and amino acids (which would naturally decay and spoil the milk, if they were present).
Alternatively, some milk manufacturers use a pasteurization process called Hot Temperature, Short Time (“HTST”) which brings the raw milk to a temperature of no more than 165° F – a temperature which eliminates harmful microbes while having a minimal effect on the proteins and amino acids in the milk. This process creates pasteurized milk that is safe to consume but maintains the beneficial proteins present in raw milk.
In summary, the two most important factors in the production of raw milk are the diet of the cows from which the raw milk is extracted and the method of pasteurization used. When given a choice, the best raw milk, especially for whey protein products, is milk from grass-fed cows that is pasteurized using the lowest temperatures necessary to kill harmful microbes.
Whey Extraction & Protein Isolation
Whey is frequently extracted from raw milk as part of the cheese production process, which involves the introduction of a complex of enzymes or a weak, edible acid to pasteurized milk. These methods cause certain milk protein to tangle into solid curds; what remains is a liquid serum, the whey. The enzymes and/or acids used in these methods can also affect the structure of the proteins contained in whey, reducing its nutritional viability.
Another method for extracting whey from raw milk is centrifugal skimming.
Whey extraction by centrifugal skimming requires the application of a persistent, uni-directional force to raw milk (usually accomplished by spinning) until it separates into casein, cream, and whey.
A small centrifuge
Centrifugal skimming works because the components of milk each have different densities. Since centrifugal skimming does not require the introduction of addition of enzymes or acids to the raw milk, and can be conducted a low temperatures, it results in whey that maintains the natural nutritional profile that it has in raw milk. Consequently, this method is the preferred solution for extracting high quality whey from raw milk.
Once extracted from raw milk, whey must be further processed to reduce it to its protein components, as whey naturally contains carbohydrates and fat in addition to protein.
The primary method by which the protein in whey is isolated from the carbohydrate and fat components is filtration, which has numerous variations including “cold”, “micro”, and “ultra” filtration. Filtration is generally considered superior to methods that use acids and/or other reactive compounds (i.e. ion exchange) because they cause damage to the proteins in whey.
Filtration methods force raw whey through barriers with small pores (as small as 250 nanometers). Proteins molecules are larger molecules than other (water, carbohydrate, and fat) molecules in contained in whey, so as whey is forced into the filtration barriers, the water, carbohydrate, and fat molecules fit through the small pores in the barrier and proteins are the only molecules left behind.
As stated above, the filtration method does not require chemicals or high temperatures and is, therefore, a fully organic process for isolating the protein components of whey.
The final step in turning raw milk into whey protein powder is the drying of the whey protein isolate yielded by whey filtration methods to remove any remaining water. Although the drying may seems like a trivial step, some industrial methods of drying can greatly diminish the quality of the whey protein powder. Specifically, if high temperatures are used to dry the whey, frequently applied by some manufacturers to quickly and cheaply dry industrial amounts of whey protein isolate, the heat will bend the proteins and break key bonds in the amino acid chains. Consequently, any drying method that relies on increasing the surface area of the whey protein isolate, versus using high temperatures, to encourage evaporation will result in a higher quality whey protein powder supplement.
Given the five critical steps in the production of whey protein powder (raw milk production, pasteurization, whey extraction, protein isolation, drying) and the factors in those steps that contribute to the highest quality proteins, the best whey protein powders are those that have as many of the following characteristics as possible:
- Milk from grass-fed cows;
- Pasteurized using the lowest temperatures possible;
- Whey extracted using centrifugal skimming;
- Whey protein isolated using filtration; and
- Whey protein isolate dried into whey protein powder using the least heat possible.
Visit our recommendations page to see the products we selected based on our investigation of the whey protein powders on the market based on these criteria.