Dairy research boosts cheese technology

Prepared Foods, Nov, 1990 by Joseph O'Donnell

Recombinant DNA is an accelerating field with tremendous potential benefits. However, isolating and characterizing gene coding for specific proteins, followed by constructing appropriate DNA sequences and infusing them into an experimental system, such as a mouse, are aU steps that must precede any work in the cow. This will take time, but as genetic mapping and other techniques evolve so will the rate of progress.

Milk: Protein and quality critical

As researchers use the latest biotechnology to improve the protein and fat composition of the milk for cheese, aU is for naught if milk quality is not maintained through the understanding and application of improved farm practices and technology. It also is imperative that this fine of though through the cheese-making procedure itself. The value of the final product is the function of each channel in the system. For example, if a cheese-maker is going to pay a higher price for higher quality milk, that cheese-maker will have to invest in cheese-making technologies that take full advantage of the raw material.

The other half of the cheese-making industry is, of course, whey production. Whey products are sold in many different forms; however, those products with the greatest value and potential for application are the products rich in functional protein.

The endeavors of Dr. John Kinsella, Cornell University, are generating critical information on the physical and chemical properties of whey proteins. Of particular interest are the properties useful in today's food processing environment, including whipping, gelling emulsification properties.

Dr. John Brady, Cornell University, is developing this information further by using computer modeling to predict functional properties of these proteins or of proteins modified by recombinant DNA procedures. For example, if one wishes to alter the functionality of a protein, the computer model can recommend specific amino acid substitutions.

Also at Cornell, Dr. Carl Batt is working with the third piece of the puzzle: genetic engineering aspects of whey protein modification. Dr. Batt is making advances primarily in thee-lactoglobulin area.

Dr. Thomas Richardson, UCD, has taken a multifaceted approach to milk protein modification. The highly productive and innovative laboratory of UCD is developing the basic recombinant DNA work to modify the content of specific proteins in milk in order to improve the value of the milk for specific applications. Examples include lactotransferrin and lysozymes (to inhibit spoilage and pathogenic organisms) and caseins (to optimize cheese making, drying, condensing, etc.).

Once the level of a particular protein is elevated in milk, one may need to isolate or concentrate the protein before using it as a food ingredient. Thus, Dr. Richardson's recombinant work is balanced by efforts in fractionation technologies to isolate commercially those proteins in milk that are of special value as food ingredients.

Dr. Harold Swaisgood, North Carolina State University (NCSU), is taking other biotechnological approaches to modifying whey proteins. With his long experience in immobilized process reactors (enzymes or bacterial cells), Dr. Swaisgood is able to make selective modifications of proteins, measure the change in functionality, and develop a process system designed to make modifications that improve the market value of the protein. This system has the distinct advantage of conducting a biotechnical treatment with low quantities of catalysts and no residual contaminants.