Water ball, edible packaging

Plastics to save the planet: edible packaging

Image credit: Skipping Rocks Lab

Be it from seaweed, sugar cane or seafood, edible packaging is coming to a food outlet near you soon.

Nearly 10 years ago, Professor Nory Mulyono started making packaging from seaweed in a room in her fiancé’s house. Heavy rains in her home city of Jakarta had yet again highlighted the painful problem of plastic, with piles of waste swept away from municipal landfills and washed up on shorelines.

Now head of the Food Technology Department at the Atma Jaya Catholic University of Indonesia, Mulyono says: “The rains bring floods, huge economic losses and many health problems.

“I knew that if we could reduce the amount of plastic waste, heavy rains wouldn’t bring such serious problems,” she adds. “So my fiancé and I converted a room in his home into a mini laboratory and started to develop biodegradable packaging.”

Fast-forward to 2019 and Mulyono is now also co-founder and chief of research and development at Evoware, based in Indonesia’s capital Jakarta. Launched in 2016, the start-up has had significant success in selling edible cups called ‘Ello Jello’, as well as edible packaging including food films, burger wraps and coffee and noodle-flavouring sachets. The products are odourless, tasteless and, importantly, meet stringent food safety standards.

“Our coffee sachets are routinely ordered by Indonesia ‘coffepreneurs’,” says Mulyono. “Australia-based companies have also approached us, but they wanted the packaging in a roll and currently we only produce sheets and sachets. We are collaborating with them.”

Why seaweed? Indonesia is the second largest producer of seaweed in the world, next to China, with production rising by some 30 per cent a year. Evoware sources Eucheuma seaweed, which Indonesia farms in abundance and, as Mulyono points out: “By using this we can improve the livelihoods of local farmers.

“It is also a healthy food, has no allergy risk, is organic and cheap – we are optimistic that it is feasible to use on a mass scale,” she adds. “Seaweed cultivation is also really fast compared to terrestrial plants, with one cycle taking only 45 days.”

Crucially, package manufacturing is relatively straightforward; under controlled conditions the seaweed is hydrated and made into a slurry, which is then cast and dried. The end product delivers good properties, although, says Mulyono, the tensile strength of the films doesn’t yet match that of cling-films as she wants to avoid using additives such as the polypropylene elastomers that promote elasticity and toughness.

Soil tests indicate the plastic-alternative biodegrades within a week, while shelf life is around two years. And as Mulyono is keen to highlight: “Our packaging is also 100 per cent water-soluble so when it is used as a coffee or noodle-flavouring sachet, it dissolves in your hot water in less than 40 seconds.”

Mulyono and Evoware colleagues now expect to ramp up and automate production while reducing costs by some 30 per cent, so their edible packaging becomes more cost-competitive with plastics.

“I would like to see us with a seaweed-packaging manufacturing facility very soon, as well as a quality control and research and development laboratory for characterising the biopackaging,” she says. “Developing a bioplastic in Indonesia hasn’t been easy... but it will be more difficult to recover our entire ecosystem if this pollution isn’t stopped.”

‘The more we develop our technique, the more we see opportunities beyond our original plans.’

Indrawati Oey, University of Otago

Evoware is not alone in its designs to serve up edible alternatives to plastic packaging. Staying with seaweed, UK-based Skipping Rocks Lab has developed edible and compostable ‘Ooho’ drinks sachets, while in the US Loliware has introduced edible straws in several flavours including vanilla and rose.

Professor David Edwards from Harvard developed edible ‘Wikicells’ from isomalt or sugar cane several years ago; the packaging is now used with fruit snacks and frozen desserts from Incredible Foods.

Then last year, researchers led by Professor Indrawati Oey at the University of Otago, New Zealand, started tests on their biodegradable, edible wrapping whipped up from corn and seafood by-products, zein and chitosan. Food scientist Oey says toxicology results look promising, physical properties are sound, and she reckons many companies are keen to see what happens next.

“We have developed a hundred different formulations with different applications,” she says. “The more we develop our technique, the more we see opportunities beyond our original plans.”

Yet corn, seaweed, sugarcane and seafood aside, a host of researchers have long been tapping into the global dairy industry and developing milk-based edible food packaging.

For example, researchers from India’s National Dairy Research Institute in Bengaluru have developed films from the milk protein, casein, and whey protein concentrate (WPC) as a wrap for cheese.

In a similar vein, France-based Lactips recently unveiled a water-soluble film from casein that is produced as small pellets and can be processed on existing plastic lines.

The film takes just three weeks to biodegrade and as chief financial officer Jean-Antoine Rochette, says: “We can manage the product with [existing] industrial processes and do this at the same price [as oil-based plastics].”

However, just as one man’s meat is another man’s poison, not everyone is going to want to eat their packaging. What’s more, replacing petroleum-based products with biodegradable alternatives keeps plastic away from landfill, but what about the waste that is already out there?

Professor Julian Eastoe from the UK-based University of Bristol, Professor Rodrigo de Oliveira, State University of Paraiba, Brazil, and colleagues, might just have an answer. In a double-whammy, they take waste polystyrene and convert it into a ‘nanofoam’ that tackles water pollution.

Crucially, the nanofoam contains a photocatalyst that breaks down toxic dyes, such as rhodamine B, that leak into industrial wastewaters. Rhodamine B is banned in food production, but is widely used as a tracer dye in sewage treatment.

“This research suggests a promising approach to re-purpose some of the vast amounts of waste plastic into a resource for tackling environmental damage elsewhere,” says Eastoe. “The rhodamine B dye that we have used as an example here is a very real pollutant that comes out of many factories, and [our foam] could also work with many similar chemical structures.”

To create the nanofoam, the researchers first convert polystyrene into a porous solid by dissolving it with the solvent cyclohexane. The solution is then cooled until the cyclohexane freezes at around 6ºC.

“Polystyrene is, chemically, very tough, which is why it’s so good as a packaging material,” explains Eastoe. “But cyclohexane can actually dissolve it into a solution.”

On freezing, solid cyclohexane pockets are formed, just a few microns in diameter, which are separated by a mesh of interwoven polymer molecules. The cyclohexane is then removed at low pressure, leaving a foam-like structure of polystyrene that has the same mechanical properties as its original polystyrene block.

Eastoe and colleagues infuse the foam with a tin oxide nanoparticle photocatalyst that can break down toxic dyes on exposure to ultraviolet light. Indeed, experiments reveal their nanoparticle-foam can remove around 98 per cent of rhodamine B from contaminated wastewater samples. The nanofoams can be re-used up to five times.

“We then re-dissolve the polystyrene back into the cyclohexane solvent, the nanoparticles drop away as they aren’t soluble, and we can re-form the polymer all over again,” says Eastoe.

Where next for the researchers and their promising nanofoam? Unlike edible plastics, commercial interest hasn’t yet been forthcoming for this re-purposed polystyrene pollution treatment.

Still, Eastoe and colleagues are working with different structures and materials, such as silver and gold, to treat more pollutants. De Oliveira would also like to harvest waste polystyrene from cities across Brazil and convert it into a nanofoam to purify water in remote regions.

“The infrastructure is so poor in some parts of Brazil and people’s water can be contaminated by their own industrial activity,” says Eastoe. “But this could be developed into a portable water purification system that at the same time re-uses [discarded] polystyrene.”

“We welcome commercial interest... and our breakthrough [nanofoam] should be of interest to water companies worldwide,” he adds. “Developing processes to break down, recycle or re-use waste plastics is now of critical importance.”

Plastic passion

Packaging from milk

In a bid to exploit the over-production of milk in the US, Peggy Tomasula and Laetitia Bonnaillie from the United States Department of Agriculture (USDA) have been working on casein wraps for more than 10 years. They reckon their latest films are up to 500 times better at keeping oxygen out of food than petroleum-​based packaging, thanks to small pores that form an airtight network, keeping oxygen penetration at bay.

“These are powerful protein oxygen blockers that help to prevent food spoilage,” says Tomasula. “[And being edible] adds to the material’s appeal as it will reduce the amount of food-wrapping waste that goes into landfill.”

As the researchers point out, their original pure casein film wasn’t easy to handle and dissolved in water too quickly. However, they have now added an alkali compound, giving a stronger, stretchier material that is more resistant to humidity, temperature and moisture.

Tomasula and Bonnaillie are now refining the film’s process and formulation to make it more versatile.

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