Most foods come wrapped in plastic packaging, creating a lot of waste and sometimes food spoilage. That’s why research leader Peggy Tomasula and colleagues at the U.S. Department of Agriculture, Washington, D.C., are developing an environmentally friendly film made of milk protein casein.
These casein-based films are said to be up to 500 times better than plastics at keeping oxygen away from food. And, because they are derived from milk, they are biodegradable, sustainable and edible. The milk-based packaging also features smaller pores, thus creating a tighter network that keeps oxygen out.
“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,” she adds.
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 coatings applications for this product are endless,” says Laetitia Bonnaillie, co-leader of the study. “We are currently testing applications such as single-serve, edible food wrappers. For instance, individually wrapped cheese sticks use a large proportion of plastic — we would like to fix that.”
Because single-serve pouches would need to stay sanitary, they would have to be encased in a larger plastic or cardboard container for sale on store shelves to prevent from getting wet or dirty.
In addition to being used as plastic pouches and wraps, this casein coating could be sprayed onto food or to line pizza or other food boxes to keep grease from staining the packaging.
This research was presented at a meeting of the American Chemical Society, Washington, D.C.