Chris Roberts, technical director of Versaperm, asks can edible or biodegradable packaging pass the test?
As the F&B industry looks for ways to cut packaging waste, the spotlight is turning onto edible and biodegradable packaging. A nice idea but it has to be good enough to protect and preserve pack contents and that’s difficult due to the special ingredients and coatings needed for such wraps.
The biggest challenge comes from contaminants such as water vapour, oxygen or CO2 which can affect the packaging or its contents. These can accelerate chemical and biological reactions, spoil the material and limit product-life, stability as well as edibility.
Go with the flow
This vapour-flow through packaging, or vapour permeability, effects the strength, appearance, edibility and printability of packaging and the contents’ life.
Vapour permeability varies – cellulose is an excellent barrier against liquid water for example but an extremely poor one for water vapour. Seaweed proteins, polysaccharides lipids, essential oils, and emulsifiers can offer excellent mechanical, hydrophobic and structural properties for edible packaging but these are affected by the flow of oxygen and moisture as well as flavourings such as icing or chocolate. Vapour permeability is also affected by processes such as baking or cooling.
The solutions involve using layers of materials which combine properties’ one a good barrier against oxygen, another the flow of CO2, or to provide strength. This is complicated by manufacturing processes, and it is impossible to predict the precise barrier properties of a finished package, so you have to test and optimise the results to suit specific edible or biodegradable needs.
It’s complex for sure but not impossible and we’ve had years to perfect it. The earliest edible coating was probably that on a blood sausage’ mentioned over 2,500 years ago in Homer’s Odyssey!