A/Prof Arcot said depending on the intended thickness, the material could be used in a number of different formats in food packaging. “There are some options at this point, we could make a shopping bag, for example,” she said.
“Or depending on how we pour the material and how thick we make it; we could make the trays that you see for meat and fruit. Except of course, instead of being foam, it is a material that is completely non-toxic, biodegradable and recyclable.”
A/Prof Arcot said she and Prof Stenzel have confirmed in tests that the material breaks down organically after putting ‘films’ of the cellulose material in soil for six months. The results apparently showed that the sheets of cellulose were well on the way to disintegrating in the soil samples.
“The material is also recyclable. One of our Ph.D. students proved that we can recycle this three times without any change in properties,” Professor Arcot said.
Tests with food have also reportedly proved that the product poses no contamination risks.
“We tested the material with food samples to see whether there was any leaching into the cells,” Professor Stenzel said. “We didn’t see any of that. I also tested it on mammalian cells, cancer cells, T-cells and it’s all non-toxic to them. So, if the T-cells are happy – because they’re usually sensitive to anything that’s toxic – then it’s very benign.”
Other areas of agricultural waste that the duo has looked at are the cotton and rice-growing industries – they have extracted cellulose from both waste cotton gathered from cotton gins and rice paddy husks.
“In theory, you can get nano-cellulose from every plant, it’s just that some plants are better than others in that they have higher cellulose content,” Prof Stenzel said.
“What makes bananas so attractive in addition to the quality of the cellulose content is the fact that they are an annual plant,” A/Prof Arcot added.
The researchers say that for the banana pseudostem to be a realistic alternative to plastic bags and food packaging, it would make sense for the banana industry to start the processing of the pseudostems into powder which they could then sell to packaging suppliers.
“If the banana industry can come on board, and they say to their farmers or growers that there’s a lot of value in using those pseudostems to make into a powder which you could then sell, that's a much better option for them as well as for us,” Prof Arcot said.
And at the other end of the supply chain, if packaging manufacturers updated their machines to be able to fabricate the nano-cellulose film into bags and other food packaging materials, then banana pseudostems stand a real chance of making food packaging much more sustainable.
“What we’re really wanting at this stage is an industry partner who can look into how this could be upscaled and how cheap we can make it,” Prof Stenzel said.
A/Prof Arcot agreed. “I think the packaging companies would be more willing to have a go at this material if they knew the material was available readily.”