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.

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 non-food products including adhesives, finishing materials for paper and textiles, and paints.

Peggy Tomasula, research leader at ERRC's Dairy Processing and Products Research Unit, found that if casein is mixed with water and glycerol and left undisturbed to dry, it results in a water-resistant, flexible, film-like material.

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 could be used to coat dairy food products, such as cheese, or function as part of a laminate in packaging for cottage cheese or yoghurt. Flavourings, vitamins or minerals could be added to enhance flavour and nutrition.

ARS is the US Department of Agriculture's chief scientific research agency.