The production of concentrated whey protein (WPC) uses ultrafiltration technology, which is also a membrane separation technique. Unlike electrodialysis, ultrafiltration separates particles of molecular size and completes the separation under pressure. Ultrafiltration separation is capable of retaining any insoluble materials and solutes having a molecular weight greater than 20,000 Da. The material left by the ultrafiltration membrane is termed "retentate"; the substance that passes through the ultrafiltration membrane under pressure is called "permeate". The permeate contains most of the lactose, minerals and water of the whey. The retentate accounts for about 1-4% of the volume of the raw whey, and the retentate can be spray-dried as needed to prepare a concentrated whey protein powder having a protein content of 35-85%.
The concentrated whey protein powder is spray dried using a medium-low temperature process, thus maintaining the natural form of the protein with excellent solubility properties. New Zealand is the world's largest producer of concentrated whey protein powder, with an ultrafiltration membrane of tens of square kilometers.
Whey protein concentrate is widely used in the food processing industry, such as ham, custards, candies, crab sticks, cakes, infant formula, sports drinks, formula nutritious feeds, and the like.
Most concentrated whey protein powders contain 5-7% milk fat, which cannot be removed by a cream separator. Therefore, the most advanced concentrated whey protein production process uses a microfiltration (particles with a molecular weight greater than 200,000 Da) to separate the cream before ultrafiltration to produce a concentrated whey protein that is almost free of milk fat. This high quality protein is ideal for formulating sports drinks, such as those consumed by bodybuilders.