Dairy

Whey Protein Isolate (WPI) is a high-quality product requiring protein levels of more than 90% in the total solids. Because the whey proteins are concentrated to a very high level, removal of fat is required to achieve these final target protein concentrations, in addition to the pretreatment separation, which leaves 0.05% fat in the whey.  

Good quality brine is often used to “salt” and cure many different varieties of cheese, typically soft cheeses that still contain a certain amount of whey proteins. The brine and curing process is essential to cheese flavor, taste, rind and the appearance of the cheese.

Ultrafiltration is applied to either skim milk or whey to concentrate the dry matter to the required total solids (TS%). The commercially available powders’ names are based on the protein type: milk protein (named casein) or whey protein. Their protein content (percentage of protein in the dry matter) ranges from 34-80% (e.g. Whey Protein Concentrate “WPC60” has 60% protein in the dry matter or Milk Protein Concentrate “MPC60” has 60% protein in the dry matter).

Whey has a fairly high salt content, about 8-12% of the dry matter. Demineralization (also known as desalination or de-ashing) enhances the nutritional value of whey products by removing salts and reducing the content of organic ions, such as lactates and citrates.

Product recovery using reverse osmosis has increasingly become an option as dairy production facilities attempt to reduce waste and increase the production output. Reverse osmosis systems can treat wastewater streams to minimize disposal costs and to recover water for reuse. In some cases, the concentrate from the waste stream is a valuable consumer product.

Permeate streams from reverse osmosis or nanofiltration processes as well as condensates from evaporators are essentially water. With additional cycles of reverse osmosis, this water can be purified or “polished” to a level where it may be reused again for cleaning purposes. With further heat or UV treatment, this water may even be used as process water.