Edible Film Packaging Made From Milk Protein is Excellent Oxygen Barrier

22 Aug 2016 --- Scientists are developing a new kind of film packaging made from milk - and you can even eat it. The powerful protein-based films prevent food spoilage and could prove to be an alternative to plastic type packaging, some of which are suspected of leaching potentially harmful compounds into food. 

The team of researchers behind the milk protein wrapping presented their work at the National Meeting & Exposition of the American Chemical Society at the weekend.

“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,” says research leader Peggy Tomasula, of the U.S. Department of Agriculture. 

Improving food spoilage across the supply chain is one important issue, however the milk-based packaging has other crucial advantages. Current food packaging is mainly petroleum-based which is not sustainable, doesn’t degrade and creates tons of plastic waste that sits on landfills for many years.

Tomasula and her team at the U.S. Department of Agriculture are developing an environmentally friendly film made of the milk protein casein which are up to 500 times better than plastics at preventing oxygen getting into food. 

This is because they are derived from milk, are biodegradable, sustainable and even edible. 

Although some other edible films made from starch are already on the market, they are much more porous and allow oxygen to seep through its microholes. While the new milk-based packaging has smaller pores and can create a tighter network that keeps oxygen out. 

The researchers’ have perfected the packaging after the first attempt of using pure casein led to a strong and effective film but it was hard to handle and would dissolve in water too quickly. 

They added citrus pectin into the blend to make the packaging even stronger, more resistant to humidity and high temperatures, and after these improvements came up with the casein-based packaging that looks fairly similar to store-bought plastic wrap, although it is less stretchy. 

As the packaging is made almost entirely of proteins it is safe to eat although it’s relatively tasteless. The researchers say a wealth of nutritious additives like vitamins, probiotics and nutraceuticals, could be added in the future, as well as flavorings.

Co-leader of the study, professor Laetitia Bonnaillie says prototype film samples are being made for a small Texas-based company and there is possible interest from other companies as well. 

"The coatings applications for this product are endless," says Laetitia Bonnaillie, Ph.D., 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 them from getting wet or dirty.

There is also potential for the casein coating to be sprayed on food like cereal flakes or bars to replace the sugar coating that is currently used to make sure they keep their crunch in milk. Manufacturers could replace the sugar coating with casein to prevent soggy cereal.

Similarly, it could even line food boxes like pizza boxes to stop grease from staining the packaging or to serve as a lamination step for paper or cardboard food boxes or plastic pouches. This is especially interesting as the U.S. Food & Drug Administration recently banned the perfluorinated substance that used to coat these containers which means casein coatings could be a viable, safe and biodegradable alternative. 

The research team plans to keep working on the casein coating, making improvements and estimate the packaging will be used for meats, breads, cheese, snacks within three years.