ICE Whey Technical Bulletin

Not all Whey Protein Isolate (WPI) is created equal. There are several different types processes employed by dairy manufacturers to produce WPI.  In all cases, ultra-filtration processes are first used to manufacture whey protein concentrates (WPC's). Once dried, WPC powders can contain up to 80% protein, but typically still contain 5-7% fat and similar quantities of lactose. Further processing is required to produce whey protein isolates with over 90% protein content and little or no lactose and fat.

The commonly used commercial processes are:

• Cation Exchange
• Anion Exchange
• Microfiltration

Ion Exchange

In ion-exchange processes the overall electrical charge on the whey proteins is manipulated by adjusting the pH of liquid whey protein concentrate. The pH manipulation does not charge lactose, fat and other unwanted substances present in the whey. The charged whey is passed through ion exchange columns of the opposite charge, which bind the whey proteins, but not uncharged lactose and fat etc. These are washed away leaving a very pure whey protein product that is virtually fat and lactose free.

Subsequent pH adjustment reverses the charge on the protein and releases it from the ion exchange columns. It can then be evaporated and dried to produce a high quality powder containing over 90% protein.

In Cation Exchange processes, the protein becomes positively charged and is bound to negatively charged columns. In Anion Exchange the reverse happens.

Microfiltration

As the name suggests this is a filtration process. Unwanted milkfat is retained on a microfiltration membrane, while the valuable whey proteins pass through. This is a similar process to ultra filtration but employs a coarser filter.

Whey Protein Composition

Whey contains a number of distinct proteins (see below). These vary in size, nutritional value and biological activity. Both the source of the whey used (cheese, lactic casein, rennet casein etc) and the method of manufacture employed (cation exchange, anion exchange, microfiltration), determine the relative proportions of the various microfractions present in a WPI.

Typical Microfraction Composition of Different Whey Protein Isolates

The biggest variation between isolates produced by different manufacturing processes is seen the content of ß-Lactoglobulin, a-Lactalbumin and Glycomacropeptide. Cation exchange processes preferentially isolate ß-Lactoglobulin and do not retain significant amounts of GMP.  Anion exchange and microfiltration processes retain significant amounts of GMP, but much less ß-Lactoglobulin.

As the branch chain amino acid content of the microfractions varies (refer table below), the BCAA content of WPI varies with the process employed to produce it. As ß-Lactoglobulin has the highest BCAA content (18% more than a-Lactalbumin), WPI produced by cation exchange technology has the highest BCAA content.

Branch Chain Amino Acid (BCAA) Content of Major Whey Microfractions

Research has determined BCAA’s to be the key amino acids involved in the synthesis of muscle protein and the provision of energy during exercise. Horleys believe that the high BCAA content of cation exchange WPI, as used in Horleys ICE Whey, is preferential for athletes and body builders looking to maximise their muscle mass gains.