Most food in the supermarket – from meat to bread – comes wrapped in plastic packaging. Not only does this create a lot of non-recyclable, non-biodegradable waste, but thin plastic films are not great at preventing spoilage.
To make matters worse, some plastics are suspected of leaching potentially harmful compounds into food.
To address these issues, scientists are now developing a packaging film made of milk proteins – and it’s even edible.
The researchers presented their work at the 252nd National Meeting & Exposition of the American Chemical Society (ACS), the world’s largest scientific society.
‘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.’
Current food packaging is mainly petroleum-based, which is not sustainable and does not degrade, creating plastic waste that sits in landfills for years.
To create an all-around better packaging solution, Tomasula and colleagues at the US Department of Agriculture are developing an 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.
The magic formula
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.