Edible milk-protein packaging to prevent food spoilage
Edible food packaging made of milk protein could replace petroleum-based plastic wrappings in future, offering a more sustainable but also healthier alternative for the food industry.
The technology was developed by a team from the US Department of Agriculture, which believes the biodegradable packaging could improve shelf life of foods and reduce waste.
"The protein-based films are powerful oxygen blockers that help prevent food spoilage,” said research leader Peggy Tomasula. “When used in packaging, they could prevent food waste during distribution along the food chain."
Production of conventional plastic packaging currently used by the majority of global food manufacturers requires the use of fossil resources. During manufacturing, a higl levels of emissions are generated, contributing to global warming. Moreover, only a fraction of plastic waste can be reused or recycled.
The case against petroleum-based plastic wrappings is made even stronger by the fact that some of these materials can contaminate the foods with toxic compounds.
The new packaging film developed by the American team is primarily made of the milk protein casein, which, according to the researchers, is 500 times more efficient at keeping oxygen away from the foods than the petroleum-based variant. The protein easily degrades and can even be eaten.
The milk-based packaging is also reportedly better than other biodegradable alternatives, which are usually made of starches. Being more porous by nature, these starch-based products allow more oxygen in, which in turn results in faster spoilage.
"We are currently testing applications such as single-serve edible food wrappers,” said Laetitia Bonnaillie, co-leader of the study. “For instance, individually wrapped cheese sticks use a large proportion of plastic - we would like to fix that."
The journey towards the ultimate edible packaging wasn’t exactly straightforward. The first experiments with casein resulted in a hard-to-handle material, which, although an efficient oxygen blocker, was dissolving in water way too fast.
The researchers later discovered that adding some citrus pectin into the mixture improves the water dissolvability problem and provides resistance against high temperatures.
The final product, which is currently being tested in cooperation with a Texas-based company, looks very similar to traditional plastic wrappers.
The research team, which hopes the material could be commercially available in three years, plans to further enhance the product by adding vitamins, probiotics or minerals. This way, the packaging would have nutritional value in its own right. Adding flavourings to the currently tasteless film should also be possible.
In addition to making single-serve pouches and wrappers, the material could also be used as a spray to provide protection to cereals. Currently, cereals remain crunchy thanks to a coating of sugar but the team believes the casein-based film could provide a healthier alternative.
Furthermore, a layer of the milk-based coating could be sprayed inside pizza boxes to prevent the food from staining the box. The researchers believe the solution could be a handy replacement for perfluorinated substances, previously used for these purposes, which have been recently banned by the US Food and Drug Administration.