Concentrate, Isolate, Hydrolysate…What’s the Difference?

This certainly is a relevant question and one that all of us at some point or another would have liked to have known a little more information about. I know when I first started looking at protein supplements; I was blown away by all of the different types of protein that was available. The question itself centers largely upon on the different types of processing methods available and not necessarily the differences between whey, casein, egg, beef and soy protein. My purpose here is to give you a basic understanding of the different types of basic processing techniques.

Interestingly, the question of different processing techniques is one that we recently tried to provide some clarity as we just completed a study investigating the impact of different types of whey protein supplementation for changes in strength, blood markers and body composition after eight weeks of resistance training in college-aged males. The results of that study haven’t been published yet, so more news on this later. I mention that study because Chris Lockwood, PhD(c), CSCS, the individual who used the project as his dissertation research also deserves credit for educating me a great deal on the unique and subtle differences that can exist and the health effects each form of protein may offer. Since a majority of these processing methods are performed on whey protein for sports nutrition products, just assume I’m talking about whey protein if it’s not clearly stated. Sure, the methods are also performed on other forms of protein such as casein protein, but again we’ll stick with whey protein.

Since I have decided to focus on whey protein, I should spend a little time talking about how whey protein is made before we get into the different types of processing methods performed on it. It’s often reported that whole milk is made up of around 87% water and 13% solids [1]. Of the 13% of whole milk that is solids, approximately 27% of this fraction is known to be protein, with ash and other minerals (6%), fat (30%) and lactose (27%). If we split it again, the 27% fraction of solids that is protein is made up of two protein sources: whey and casein protein [1]. Casein protein in cow’s milk comprises around 80% while whey protein comprises around 20%. Interestingly, these ratios in human milk is markedly different with the milk produced in early days of lactation consisting of 90% whey and 10% casein and changing later to around 60% whey and 40% casein [2]. Whey is made as part of the cheese making process. The casein or “curd” is separated from the whey to make cheese, the remaining liquid portion (the whey) goes through a series of filters which removes lactose, fats, etc. Microfiltration is a process that continually filter the proteins leaving more and more protein and getting rid of more and more lactose and fat. Another process, ion-exchange, exposes the product to a resin which is charged with electricity which bonds to selected proteins. This is removed, the charge is reversed and only protein remains. Overall, the process yields a high-level protein, but strong debate remains where this process leaves the bioactive components of a protein unadulterated.

By definition, a whey protein concentrate contains at least 30% and no more than 89% protein by weight. This means for every 100 grams of a product, at least 30% (or 30 grams) of it has to be protein to be called a concentrate. The other 70 grams (70%) could be anything from lactose, fat, ash, etc. Most of the whey protein concentrates used in the market range from WPC-50 (which literally means “Whey Protein Concentrate 50%”) to WPC-80, meaning they are 50% to 80% protein. A typical WPC-80 will often contain 80% protein, somewhere around 5-8% fat and around 4–10% lactose. As you can see, just because someone says they have a WPC doesn’t mean anything and unless it’s at the very least a WPC-70, it’s going to leave a lot to be desired.

Next, we move on to whey protein isolate (WPI). Isolate, by definition, is at least 90% protein by weight or 90 grams of protein for every 100 grams. As a result, this leaves a product that is largely void of fat and lactose, with most isolate containing around 0.5 to 1.0% of both fat and lactose. Additionally, WPI has extremely low amounts of cholesterol, oftentimes 5 milligrams or less. As you could imagine, the additional filtration process takes longer to produce WPI, thus making it considerably more expensive than WPC. Due to the added filtration and purity, WPI’s are highly sought after and viewed upon as some of the highest quality protein you can get.

Whey protein hydrolysates (WPH) are typically produced from some type of purified protein source, oftentimes a WPC that has its protein chains hydrolyzed or broken. Two predominant hydrolyzing methods exist: 1) acid hydrolysis in the presence of increased temperatures or cool temperatures or 2) adding a cocktail of proteolytic enzymes. What results is a complex mixture of peptides of different chain lengths together with free amino acids. The degree of hydrolysis (DH) is a variable commonly used to prescribe the extent to which hydrolysis has occurred, which is represented as a percentage of the peptide bonds that have been cleaved from the original protein. DH values for hydrolysate proteins typically range from 5% to 25%, but can range all the way to 100%. Even though DH values are intended to level the playing field of sorts, the native protein form and varying methods can still result in WPH with more or less oligo peptides, free amino acids, dipeptides and tripeptides, all of which will pass through the system at varying rates; in addition the size of the actual fragments is another influencing factor. One significant problem that has plagued the reputation and use of hydrolysates for years is their very poor, bitter or acidic taste. The reason is simply because of the high percentage of peptides and amino acids present. The higher the DH, oftentimes the more foul the taste. This is not always the case however, advancing processing technology and flavoring techniques has allowed for some forms of hydrolysates to be produced and used in finished goods with a pleasant taste.

Interestingly, the research surrounding hydrolysates has been slow to develop, but interest has been picking up. More has been completed in the last few years, and with the compelling evidence that exists to date, it’s likely much more research will surface. The initial research on hydrolysates stemmed from animal research that indicated amino acids from hydrolysates were better absorbed that intact proteins [3]. Regarding performance, enhanced cycling performance was found when a casein hydrolysate protein plus carbohydrate was ingested when directly compared to ingesting only carbohydrate and also suppressed increases in markers of muscle damage and minimized muscles soreness [4]. Furthermore, Cribb et al. used a hydroylyzed whey isolate (0.8 grams protein per kilogram body mass) as part of a regular resistance training program and found that those ingesting the hydrolysate experienced greater improvements in strength and body composition when compared to those ingesting an identical dose of casein protein [5]. Most recently, a study by Tang et al. found that after ingesting a whey isolate both at rest and after a single bout of resistance training led to greater increases in muscle protein synthesis when compared to a similar dosage of casein or a soy isolate [6]. Additionally, when a 25-gram dose of protein hydrolysate was ingested after a damaging bout of eccentric exercise and compared to a 25-gram of intact whey protein, those individuals who ingested the hydrolysate were able to completely recover their ability to maximally produce force and overall seemingly greater recovery [7]. Currently, research is lacking to tell us conclusively if ingestion of a hydrolysate is better than an isolate and whether either leads to better improvements in strength and body composition over even a highly purified concentrate. Until these studies are conducted, ingestion of hydrolysates, appears to invoke many favorably physiological responses, which can favorably alter many aspects of exercise, recovery and sport nutrition.

References

1. Kunz, C., et al., Nutritional and biochemical properties of human milk, Part I: General aspects, proteins, and carbohydrates. Clin Perinatol, 1999. 26(2): p. 307-33.
2. Kunz, C. and B. Lonnerdal, Re-evaluation of the whey/casein ratio of human milk. Acta Paediatrica, 2008. 81(2): p. 107-112.
3. Poullain, M.G., et al., Effect of whey proteins, their oligopeptide hydrolysates and free amino acid mixtures on growth and nitrogen retention in fed and starved rats. JPEN J Parenter Enteral Nutr, 1989. 13(4): p. 382-6.
4. Saunders, M.J., et al., Carbohydrate and protein hydrolysate coingestions improvement of late-exercise time-trial performance. Int J Sport Nutr Exerc Metab, 2009. 19(2): p. 136-49.
5. Cribb, P.J., et al., The effect of whey isolate and resistance training on strength, body composition, and plasma glutamine. Int J Sport Nutr Exerc Metab, 2006. 16(5): p. 494-509.
6. Tang, J.E., et al., Ingestion of whey hydrolysate, casein, or soy protein isolate: effects on mixed muscle protein synthesis at rest and following resistance exercise in young men. J Appl Physiol, 2009. 107(3): p. 987-92.
7. Buckley, J.D., et al., Supplementation with a whey protein hydrolysate enhances recovery of muscle force-generating capacity following eccentric exercise. J Sci Med Sport, 2010. 13(1): p. 178-81.

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