Edible films made from the proteins of whey -- the waterybyproduct of cheese processing -- appear to hold great potential asfood coatings, according to a UC Davis food scientist. The whey protein films have the potential to rival the qualities of synthetic packaging materials, reports John M. Krochta, a professor of food science and technology who is investigating edible food films as a way to optimize food quality, lengthen shelf life and limit packaging waste. When products with high fat content like nuts, cereals, crackers and chips are exposed to oxygen, they tend to become rancid. On the other hand, fresh fruits and vegetables require packaging with just the right amount of permeability to limit, but not exclude, the intake of oxygen and expulsion of carbon dioxide, thus maintaining ripeness for as long as possible. Whey proteins offer a particularly attractive source of material for edible films, because 50 percent of the whey from cheese manufacturing currently goes to waste, according to Krochta, whose work is funded by the California Dairy Foods Research Center.