The protein-based films are powerful oxygen blockers that help prevent food spoilage. When used in packaging, they could prevent food waste during distribution along the food chain.
This film is environmentally friendly film made of the milk protein casein. These casein-based films are up to 500 times better than plastics at keeping oxygen away from food and, because they are derived from milk, are biodegradable, sustainable and edible. Some commercially available edible packaging varieties are already on the market, but these are made of starch, which is more porous and allows oxygen to seep through its microholes. The milk-based packaging, however, has smaller pores and can thus create a tighter network that keeps oxygen out.
Although the researchers’ first attempt using pure casein resulted in a strong and effective oxygen blocker, it was relatively hard to handle and would dissolve in water too quickly. They made some improvements by incorporating citrus pectin into the blend to make the packaging even stronger, as well as more resistant to humidity and high temperatures.
After a few additional improvements, this casein-based packaging looks similar to store-bought plastic wrap, but it is less stretchy and is better at blocking oxygen. The material is edible and made almost entirely of proteins. Nutritious additives such as vitamins, probiotics and nutraceuticals could be included in the future. It does not have much taste, the researchers say, but flavorings could be added.
In addition to being used as plastic pouches and wraps, this casein coating could be sprayed onto food, such as cereal flakes or bars. Right now, cereals keep their crunch in milk due to a sugar coating. Instead of all that sugar, manufacturers could spray on casein-protein coatings to prevent soggy cereal. The spray also could line pizza or other food boxes to keep the grease from staining the packaging, or to serve as a lamination step for paper or cardboard food boxes or plastic pouches. The U.S. Food & Drug Administration recently banned the perfluorinated substances that used to coat these containers, so casein coatings could be a safe, biodegradable alternative.
