Whey Protein Phospholipid Concentrate (WPPC), a low-value coproduct, is currently being examined as a source of nutritional and functional ingredients. WPPC contains high-value components, such as various types of proteins and phospholipids.

What is WPPC? When we make cheese, whey protein isolate (WPI) can be produced from the whey stream. WPI needs to have a fat content of less than 1% so, in addition to traditional fat separation technologies, WPI undergoes microfiltration to remove fat. The retentate in this microfiltration process is WPPC, which is also known as procream. WPPC is a high-fat, high-protein product (see table).

Currently, WPPC is low-value product mostly used in animal feed. However, there is interest in finding value-added uses for WPPC. For instance, here at the University of Wisconsin-Madison, there have been studies investigating the use of WPPC in various food applications, such as ice cream and caramels. One issue is the variability of WPPC due to differences in whey quality/composition from various cheese types (which alters the initial fat content of the cheese whey) and processing technologies used to produce WPPC.

More recently, there is growing interest in further processing or fractionating WPPC to extract its more valuable components like specific proteins (or bioactive peptides) and phospholipids. However, there are challenges with fractionating WPPC. One of the biggest challenges is that WPPC undergoes a lot of processing, including multiple heat treatments.

Currently, there are some options to break down WPPC and separate the fat and protein. Solvent extraction, which utilizes ethanol, can be used to remove the fat from the protein. This process can produce a product that is up to about 50-60% phospholipids. One downside is food safety concerns with the handling of ethanol that is used in the extraction process.

Some additional options to concentrate phospholipids are to hydrolyze the protein in WPPC and supercritical carbon dioxide extraction. Hydrolysis utilizes protease enzymes, which essentially break proteins up into smaller fragments, that can permeate ultrafiltration membranes. Supercritical CO₂ extraction will remove triglycerides to concentrate phospholipids from a powdered product. In both technologies, some protein is left in the product, so a pure lipid fraction is not obtained.

Here at the Center for Dairy Research, we have done some work utilizing chemical separation techniques to fractionate WPPC. We have been able to concentrate phospholipids several fold, but we were still unable to obtain pure phospholipids from WPPC.

Another challenge in working with WPPC is that since it contains high levels of fats, and more of the phospholipids that have a higher level of unsaturated fatty acids, oxidation and off flavors are a concern. In addition, the proteins (whey proteins and milk fat globule membrane proteins) in WPPC get denatured because of the additional heat treatments. These denatured proteins impact the functionality of WPPC and can impact the quality of the final food application.

So, what is the solution? One option may be to change how we process WPPC. Currently, WPPC powder is spray dried but during the atomization step there is some homogenization/encapsulation of fat with the proteins, which results in more fat getting trapped with the protein. Perhaps we could find a better solution to process WPPC if we want to use powders to do a further isolation process?

One of the potential products that we could extract from WPPC is a dairy version of lecithin, which is an emulsifier that is widely used by food manufacturers. With the conflict in Ukraine, there is a global shortage of lecithin, which is typically extracted from soy or sunflower sources.

The phospholipids found in WPPC are also of high nutritional interest. Potentially, the phospholipids from WPPC could be utilized to fortify high value products like infant formula and nutritional products. There are also minor bioactive components of WPPC that are worth exploring.

WPPC has a lot of potential to be utilized in high-value applications, however, it is challenging to work with, and further research needs to be conducted to develop better ways to process and fractionate it. Globally, as the amount of WPI increases, the amount of WPPC will also increase. So, we have plenty of WPPC to work with. Adding value to dairy is a top priority for researchers so let’s hope we can come up exciting new opportunities and uses for WPPC.

Typical Composition Ranges for Whey Protein Phospholipid Concentrate (WPPC)

Source: Levin, M.A.; Burrington, K.J.; Hartel, R.W. Composition and Functionality of Whey Protein Phospholipid Concentrate and Delactosed Permeate. J. Dairy Sci. 2016, 99, 6937–6947.