Researchers at the U.S. Department of Agriculture have created a biodegradable alternative to plastic film wrapping for food products. While other kinds of plastic are often recyclable, plastic film can be hard to recycle and can contain harmful chemicals, according to recent studies. The research was co-led by Laetitia Bonnaillie, a USDA researcher.
The new packaging uses a milk protein, casein, to create a film wrapper for food that is not only biodegradable, but edible.
Additionally, the researchers found that the film is 500 times more effective than a plastic bag at keeping food protected from oxygen, as the network formed by proteins when they polymerize is even tighter than plastic. The casein-based packaging is also more effective than other edible food packaging made from starch, and has the added bonus of protecting food that is sensitive to light.
The issue of wasteful, and harmful, packaging has gained more primacy as items are increasingly sold in individual packaging. While convenient, this can generate a great deal of waste. In some cases, scientists have even found reason to doubt the safety of some plastic packaging. Packaging that is edible and biodegradable could potentially resolve such concerns.
The casein film is made by combining water with commercially available casein powder. The researchers added glycerol and citrus pectin to the film to increase its viability as a packaging choice. The glycerol softens the film, while the citrus pectin adds structure, allowing it withstand high temperatures and humidity. Bonnaillie pointed out that the pectin also adds health benefits to the edible film.
Vitamins and flavoring could also be added to the package to make it more appealing and nutritious. Bonnaillie emphasized that it will be more nutritious than starch-based versions.
The packaging could replace plastic for foods such as individually wrapped cheese sticks. Also, it could serve as an alternative for packets of dried coffee or soups, allowing the consumer to drop the packaging in the hot water without opening it, adding a boost of protein to the food.
One drawback is that the casein-based film dissolves easily in water, so an outer layer of protective packaging would still be required to keep food dry and safe.
Liquid casein can also act as food itself, potentially sprayed onto cereal as an alternative to the sugar now used to maintain a crunchy texture in many cereals.
Bonnaillie said it will be many years before the USDA researchers will be able to make it available, unless companies research their own applications for the packaging. She considers the team to still be at the beginning of a long process of finding applications for the potentially beneficial plastic alternative.