Whey Protein

Posted in: Sports Nutrition  on Thursday, August 7, 2008
by Dorian Yates

In this final installment on whey protein, we look at the impact of various processing techniques on the end product. Along the way, we also dispel some of the myths being fed to you by various supplement and dairy companies.

Today, the big word in protein supplement technology is undernatured. This means that the protein has not been subjected to treatment resulting in conformational, structural changes. Exactly what kind of treatment results in this type of damage? In simple terms, any process that involves pH changes and/or heat pasteurization.

In the first two parts of this series on whey, we have looked at the amazing immuno-supportive and growth-promotional properties of whey’s bioactive fractions. Now we look at what damages these fractions and how this relates to processing methods.

Amino Acids

Adjustment of pH and heat treatment (pasteurization) is also known to denature some amino acids—in particular, cysteine and methionine. If we refer to the various protein rating systems covered in the first part of this series, the common denominator with the top scoring proteins is cysteine. Along with being a precursor to the powerful antioxidant glutathione, cysteine is believed to be a regulator of nitrogen balance and body cell mass. In various catabolic conditions, the cysteine-mediated regulatory circuit is compromised, further underlining the key role that this amino acid plays (1).

Whey protein supplements utilize material that has been produced by one or sometimes both of the following processing techniques.

Filtration & Ionic exchange

Let us look at what is involved in these techniques in order to determine what is lost or damaged by each process.

Ionic exchange
This process involves separating proteins on the basis of their electrical charge. Hydrochloric acid and sodium hydroxide are the chemical reagents normally used to achieve this. The electrical charge on the proteins attaches them to resins in the reaction vessel. Obviously, these reagents damage pH-sensitive fractions and denature some amino acids. Going back to our table above, it becomes clear that we can say goodbye to glycomacropeptides, the immunoglobulins, lactoferrin, the growth factors, and a big percentage of the alpha-lactalbumin content. Cysteine and methionine will also be denatured (lost).

If some fractions have been eliminated or reduced, the resultant shift in the balance will mean that other fractions represent a higher percentage of the material. Beta-lactoglobulin, a reasonably stable fraction, can account for up to 75% of the fractions present in ion-exchange material.

Is there a problem with this? As we saw in part two of this series, beta-lactoglobulin can cause severe allergic reactions in humans. This fraction, not found in human milk, has even been responsible for the deaths of several individuals over the past ten years.

Another damaging factor with this type of processing is that it is known to form lysinoalanine, a bonded amino acid compound that results in losses of the following amino acids:

Cysteine (73-77%)
Threonine (35-45%)
Serine (18-30%)
Lysine (19-20%)

High amounts of lysinoalanine can be found in ion-exchange whey and may produce adverse effects on growth, protein digestibility, protein quality, and mineral bioavailability and digestibility (2).

Why did this material ever become popular? Heavy marketing from the dairy companies is the answer, but then you have to ask yourself why they developed it in the first place. Before ion-exchange came along, ultrafiltration was the only practical operation. However, a French patent on this process meant that all companies had to pay to use it. This expensive inconvenience led them to look for alternatives.

When the ion-exchange process was developed, it provided these companies with a lot more freedom. Even when micro-filtration came along, the ion-exchange process still remained popular, as the set-up cost is around one-fifth that of microfiltration.

So the development of ion-exchange whey had little to do with any benefit to the consumer. Long after several nutrition companies became aware of the disadvantages of ion-exchange whey, dairy companies kept on promoting it, as they sat on a mountain of this material.

The marketing ploys used to promote ion-exchange whey centered on its being higher in protein and lower in fat and lactose than ultrafiltrated material. High  levels of BCA As were also regularly mentioned in advertising campaigns. All of these points are true, but we also need to be concerned with the other, more important factors found in dairy proteins.

The biggest boost to sales of ion-exchange whey into the sports-nutrition industry came about through a combination of ignorance and questionable marketing. Most of us remember the first meal-replacement product (MRP) to hit the market and that it used filtrated materials in its formula. Both the supplier of those materials and the inventor of the product knew that this was central to any effectiveness.

However, the inventor dissolved his business partnership and felt secure in the knowledge that the patent on his product protected it. When ion exchange whey came along, his ex-partner had the opportunity to use a material made by a process sufficiently different so as not to violate the patent. Whether the partner missed the point with the original product or just didn’t care, I can’t tell you. What I can tell you is that the ex-partner owned the most hardcore bodybuilding magazine of that era, and its open format was used as the ideal vehicle to promote the new product.

The ex-partner teamed up with another of the industry’s "bigwigs" to promote the ion exchange whey found in both of their products, leading the public to believe that this was an entirely unrelated venture. This double-barreled assault on the market was the most influential campaign ever put together. Personally, I feel that no company will get away with this kind of marketing practice again.

Filtration
Whey Protein Concentrates (WPCs) are materials with a protein percentage of less than ninety. Once we go over this figure, we are talking about Whey Protein Isolates (WPIs), which are produced by ion exchange, microfiltration, or, as mentioned earlier, a combination of both.

Microfiltration is a process that uses much finer filter membranes and removes far more fat and lactose.

Since we know that ion exchange material is not the "whey to go," this must surely mean that there is only one real alternative, right? Now the plot really thickens! Remember that ultrafiltrated material is higher in fat; therefore, concentrates produced by this process are more likely to have growth factors present. Even without any heat or pH adjustment, the growth factors will not be retained to any significant degree in microfiltrated material.

Cross Flow Microfiltration is the current flavor of the month. This is generally described as a natural, low-temperature process employing high-tech ceramic filters that filter out fat, lactose, cholesterol, and denatured proteins. The dairy companies that specialize in this material will also tell you that it has the highest levels of undenatured protein possible, the high solubility of the material serving as evidence of how undenatured it is.

Sorry, but I’m going to have to burst another bubble here. Some dairy companies are misleading the consumer by equating solubility with levels of denaturation, when it is quite simply only a milk QA test. One can test the degree of damage that heat has done to whey proteins by determining their centrifuged water solubility. This test does not determine denaturation from any other conditions (like pH changes); it determines only heat damage. Neither was it ever intended as a denaturation test; it is a heat-damage test only!

If a whey protein has been destroyed by heat exposure (not just a structural denaturing change, but absolutely destroyed), it coagulates and settles out as sediment when the whey is centrifuged. The higher the level of centrifuged sediment, the higher degree of heat destruction. The test result is expressed as a percent of the total whey protein present.

This test was developed to be run on milk powders to determine the degree of heat damage and was never intended to be run on whey protein concentrates/isolates. In milk powders, a low-heat milk powder will have a result of 1% or less (when the milk powder contains only about 6% whey protein in total … so a low-heat-damaged milk powder has up to 16% of the whey protein destroyed). A medium-heat milk powder has a result of 1%-3% … meaning that up to 50% of the whey proteins can be destroyed by heat and still the damage is considered only medium.

The whey protein processors run this test on their whey protein and show that their final product whey protein powder is 99% soluble in water, and therefore is not denatured. What they do not tell anybody is that they have already processed out all of the denatured whey protein before they concentrate down the remaining undamaged protein.

Heat-damaged whey protein just plugs ultrafiltration, microfiltration, and nanofiltration membranes, causing the processor all sorts of problems. A long time ago, people found out that filtration ran easier if they first centrifuged the whey to remove all of the heat- and pH-damaged whey proteins. They then concentrate down only the non-heat-destroyed part of the protein. That does not mean that they have concentrated down all of the protein fractions; they have concentrated only the most heat-stable parts.

After processing, they can show that the final product has little evidence of heat damage (because they already removed the heat-damaged parts). This is why these folks claim that their whey protein is "undenatured. " That is not a correct statement! The correct statement should read, "The whey protein powder that we are selling exhibits low denaturation because the denatured whey proteins were removed during processing." The best fractions of whey protein have been destroyed by the required pasteurization and removed during processing!

That is why most of the whey proteins commercially available do not contain the levels of the bioactive protein fractions that the textbooks list. Yet almost all of them can show 99% water solubility. Water solubility does not equate to denaturation! Water solubility shows only that the process did a good job of removing the denatured whey proteins during processing.

What the consumer gets from the "undenatured" whey proteins from cheese and casein is not even strictly a whey protein. In a whey protein, all of the protein fractions have to be represented in the ratios and amounts that would be expected in unprocessed milk. Such is not the case with the whey proteins coming out of the cheese and casein factories. The best fractions are gone or significantly destroyed and removed.

References

(1). Droge, W., Holm, E.; Role of cysteine and glutathione in HIV infection and other diseases associated with muscle wasting and immunological dysfunction. FASEB Journal, 1997 Nov; 11 (13): 1077-89.

(2). Sarwar, G. et al.; Influence of feeding alkaline/heat processed proteins on growth and mineral status of rats. Advances in Experimental Medicine and Biology, 1999; 459: 161-77