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Several products commonly found in grocery store dairy aisles could soon be coated in an edible and water-resistant milk protein, thanks to a new process developed by Agricultural Research Service (ARS) scientists that makes possible the continuous manufacture of casein film.
The process, created at the ARS Eastern Regional Research Center (ERRC) in Wyndmoor, Pa., uses the unique characteristics of casein, a milk protein that is the chief nutritional ingredient in cheese. Casein is also used in nonfood products including adhesives, finishing materials for paper and textiles, and paints.
Casein is first extracted from milk with high-pressure carbon dioxide (CO2), a method developed by Peggy Tomasula, the research leader at ERRC's Dairy Processing and Products Research Unit. She found that if this casein is mixed with water and glycerol and left undisturbed to dry, it results in a water-resistant, flexible, film-like material. ARS holds a patent on the method Tomasula developed.
The casein films could serve as stand-alone sheets or as thin coatings that form a barrier to outside substances while protecting a product from damage or contamination. The edible film locks in moisture, so it can coat dairy food products, such as cheese, or function as part of a laminate in packaging for cottage cheese or yogurt. Flavorings, vitamins or minerals could be added to enhance flavor and nutrition.
Michael Kozempel, a recently retired ERRC chemical engineer, developed a continuous pilot plant process to produce the film. He found a suitable belt material and feeding mechanism so that the solution can be uniformly spread and dried to form a film that is readily removed from the belt. The process can be modified for other proteins.
ARS has filed a patent application on the continuous production process Kozempel has developed, and is interested in finding business partners to move it to market.
Read more about this research in the November 2005 issue of Agricultural Research magazine:
ARS is the U.S. Department of Agriculture's chief scientific research agency.