Two UNSW academics have proposed a new ingredient – banana plantation waste – for creating packaging plastic that is not only biodegradable, but also recyclable.
Associate Professor Jayashree Arcot and Professor Martina Stenzel were looking for ways to convert agricultural waste into something when they thought about a banana waste-based material.
According to Arcot, the banana growing industry produces large amounts of organic waste, with only 12% of the plant being used (the fruit) while the rest is discarded after harvest.
“What makes the banana growing business particularly wasteful compared to other fruit crops is the fact that the plant dies after each harvest,” says Arcot.
“We were particularly interested in the pseudostems – basically the layered, fleshy trunk of the plant which is cut down after each harvest and mostly discarded on the field. Some of it is used for textiles, some as compost, but other than that, it’s a huge waste.”
Using a reliable supply of pseudostem material from banana plants grown at the Royal Botanic Garden Sydney, Arcot and Stenzel set to work in extracting cellulose to test its suitability as a packaging alternative.
According to Arcot, the pseudostem is 90% water, so the solid material ends up reducing down to about 10%.
Once brought into the lab, the pseudostem is chopped into pieces, dried at very low temperatures in a drying oven, and then milled into a very fine powder.
The powder is finally washed with a very soft chemical treatment, notes Stenzel: “This isolates what we call nano-cellulose which is a material of high value with a whole range of applications.”
“One of those applications that interested us greatly was packaging, particularly single-use food packaging where so much ends up in landfill.”
According to the scientists, when processed, the material has a consistency similar to baking paper and can be used in a number of different formats in food packaging.
And unlike foam, the new material is completely non-toxic, biodegradable and recyclable.
Image and content: UNSW Sydney
