Microfiltration separates pure proteins from milk before cheesemaking.

Despite years of scientific advances in cheese-processing techniques, flavor systems and ripening, the first step in cheesemaking has always begun with liquid milk and ended with cheese and whey. Manufacturers considered cheese the desired product and whey a byproduct at best.

But dairy researchers have determined how to radically change this process for the benefit of both the dairy industry and food manufacturers. By reversing the cheesemaking process, a new product found in the cheese processing plant could be pure milk serum proteins separated from liquid milk before it is used to make cheese. Scientists based at Cornell University have refined a microfiltration process that separates the casein and milk serum proteins from liquid milk.

Investigators discovered that filtering these proteins from the liquid milk instead of the whey stream yields purified milk serum protein ingredients and concentrated native casein that contain none of the colorants, enzymes and cultures used during cheese manufacture. Approximately 9 lb of whey result from every pound of cheese produced. Cheesemakers then process the whey to create functional ingredients for food manufacturing, such as whey protein concentrates and isolates.

Using microfiltration, dairy scientists can filter liquid milk to remove serum proteins prior to using the milk for cheesemaking. The pore size of the filter determines the type and size of the molecule researchers retain. Whether the goal of the process is to make a concentrated milk-derived food ingredient, rich in protein, or to separate individual components from the milk, researchers can adjust the filters accordingly, yielding a customized fluid permeate and equally customized retentate. This process holds the potential to improve plant efficiencies, provide a premium product and, in turn, increase potential profit for dairy processors.

Microfiltration could improve the efficiency of the cheesemaking process through the production of customized concentrated retentate. Using low-concentration-factor retentates to fortify unfiltered milk improves cheese manufacturing efficiency and lowers manufacturing costs. Using a high concentration factor approach would create an even more efficient continuous cheesemaking process, with little or no whey drainage from the cheese.

In both cases, a milk serum protein concentrate (SPC) would be produced from the microfiltration permeate from the liquid milk. It would be a higher value co-product of cheesemaking than traditional whey products. This presents the dairy industry with a distinguishable new ingredient in the form of SPC. Functionally and nutritionally, this SPC differs from traditional whey products.

One key benefit of SPC is its consistency. Formulators can expect consistency and purity from SPC because it is extracted from milk before cheesemaking and is free of enzymes, colors and cultures. Food manufacturers, especially those concerned with maintaining kosher standards, need to be sensitive to the type of cheese from which a whey protein concentrate originates.

Further information. Syed Rizvi, Department of Food Science, Cornell University, 114B Stocking Hall, Ithaca, NY 14853; phone: [phone]; fax: [phone]; email: [e-mail].