Technique removes functional beta-casein from milk.

Beta-casein, a component of milk, is a potent emulsifier suitable for use in a variety of products. Although reducing the concentration of beta-casein in milk prior to cheese-making improves the meltability of cheese, no commercially feasible method of removing soluble beta-casein from milk has been developed. Beta-casein makes up one-third of the nutritionally important protein in cow's milk. As well as being a rich source of amino acids, beta-casein delivers minerals such as calcium.

Now, researchers at the University of Wisconsin have applied for a patent on a novel, low-cost separation technique for removing functional beta-casein from milk without adding unwanted by-products. This process allows a significant amount of highly soluble beta-casein to be extracted from milk, while also improving the cheese-making properties of the milk. The technique also provides enriched, highly soluble beta-casein for use as an emulsifier or foaming agent in various food products.

With this technology, beta-casein is separated from other milk serum components using non-ceramic, cross-flow polymeric microfiltration membranes that form a permeate enriched in beta-casein. The milk may be cooled prior to microfiltration to enhance the separation process.

Beta-casein is then purified from this enriched permeate through demineralization. The cheese formed from the milk partially depleted of beta-casein has better meltability and is less bitter. The purified beta-casein exhibits improved yield, purity and solubility; excellent foaming and emulsification properties; and is suitable for use as an additive.

The process, which is available for licensing, is substantially less expensive and more efficient than current techniques using ceramic membranes. The process removes beta-casein from milk without contaminating the milk or beta-casein and uses fewer steps than existing techniques for fractionating milk. The technique actually uses standard dairy processing equipment and allows dairy plants to continuously separate and purify beta-casein.

The technology will be useful in producing a new generation of whey protein products that contain beta-casein and milk protein concentrates with various casein ratios, which could be used as ingredients in nutritional products or as a substitute for casein and caseinate.

Further information. John Lucey, Department of Food Science, University of Wisconsin-Madison, A203A Babcock Hall, 1605 Linden Dr., Madison, WI 53706; phone: 608-265-1195; fax: 608-262-6872; email: jalucey@wisc.edu. Licensing: Paul Pucci, Licensing Associate, Wisconsin Alumni Research Foundation, 614 Walnut St., Madison, WI 53726; phone: 608-262-4924; fax: 608-263-1064; email: ppucci@warf.org.