Membrane filtration systems for whey - Food and Beverage
No useful discussion of membrane filtration can begin without a look at the filtration spectrum. As you move from the right to the left of the spectrum you are following from coarse to fine filtration. Coarse particle filtering starts the spectrum and can most easily be associated with screen or sock filters. These separate the rocks from the water. The next is microfiltration. Here is where we can separate the large components that are in milk. Fat, for example, can be removed by using a pore size that restricts only the cream from milk but allows the skim milk to pass. You can also use yet another, even smaller pore size to allow a separation of the casein from the milk serum or 'Whey' proteins. Moving further along we get to Ultrafiltration where we reject all the large milk components, proteins and fat, but allow the lactose, minerals and water to pass. It is here that with the addition of water, or diafiltration, we can wash even more lactose from the milk. Nanofiltration is the next membrane used for dairy. This membrane rejects all components except for select salts and water. The final membrane used for dairy applications is Reverse Osmosis. This membrane allows only water to pass through the membrane, thus acting as pure concentration membrane.
Cross-flow membrane filtration has opened the doors to a variety of new and innovative dairy products. You don't have to look back to far to the days of the mechanical separator being the only means of harvesting a component of milk. Today, not only can we separate the cream; we can separate virtually every major component of milk through membrane filtration. Membrane filtration technology has rapidly gained prominence in the processing of dairy ingredients. Microfiltration, Ultrafiltration, Nanofiltration and Reverse Osmosis, is making it possible to produce products with very unique properties and functionalities.
Note 1: The membrane filtration technology is used for concentration, purification, separation, clarification, separation and filtration.
Note 2: WPC = whey protein concentrate, WPI = whey protein isolate.
Note 3: Whey is the milk serum that is produced during the manufacture of cheese after separation of casein and fat during milk coagulation.