Isolating Valuable Whey and Lactose Constituents
Membrane filtration technologies enable proteins and lactose to be separated from whey and refined to produce high quality, specialty products that are much in demand as food supplements. Whey proteins are used widely in infant formula, for patients suffering from degenerative muscle wastage (sarcopenia), and by body builders.
Whey protein concentrates (WPC) and whey protein isolate (WPI)
Ultrafiltration can be used to remove proteins from whey. WPC 35 (35% protein) provides a cheaper alternative to skim milk in processing applications, while other protein concentrations are used in specialist nutritional products. Whey protein isolate (WPI 90) is 90% pure whey protein, and is obtained from whey using microfiltration to remove fat globule membranes and diafiltration to flush out remaining lactose and unwanted contaminants.
Isolating whey components and recycling water
Individual proteins, such as lactoferrin, lactoperoxidase and bovine serum albumin (BSA), can be isolated by using a combination of membrane filtration and chromatography. Whey protein hydrolysates (WPH) are manufactured from liquid WPC through the application of heat and the addition of enzymes. Lactose and minerals, such as calcium and phosphorous, can be harvested from the permeate stream from protein isolation using nanofiltration or reverse osmosis (RO) and heat treatment. Retained lactose can be further purified, using a process of evaporation and crystallization, to create edible or pharmaceutical grade lactose.
The permeate from RO provides a good source of soft water (FDA Category II) for reuse within the plant for cleaning. The water can be further purified by reverse osmosis polishing (ROP) to produce potable water (FDA Category I) that may be used in the plant, in accordance with FDA regulations.