UNSW researchers are exploring how an Australian native coastal plant could help improve the strength and flexibility of biodegradable films.
An Australian native plant traditionally used by Indigenous communities for food and medicine could help scientists develop stronger, more flexible biodegradable film.
UNSW researchers have discovered that adding extracts from pigface, Carpobrotus glaucescens, a hardy coastal succent to seaweed-based films can significantly improve their strength and flexibility.
The findings, published in the Journal of Polymers and the Environment , could open the door for more sustainable materials that reduce our reliance on conventional plastics.
Led by Dr Rishi Ravindra Naik from UNSW School of Chemical Engineering, the research is part of a broader project supported by UNSW Societal impact Seed Funding, in collaboration with Indigenous-led nursery IndigiGrow.
Making biodegradable materials stronger
As the world deals with its growing plastic pollution, researchers are increasingly looking to natural materials as alternatives to conventional plastics.
One promising material is agar, a jelly-like substance extracted from seaweed that can be used to create thin, transparent biodegradable films.
While agar is renewable and biodegradable, films made from the material are often too brittle and sensitive to moisture for practical applications.
"If you just use agar by itself, it will just break in your hand, it will crumble," Dr Naik explains.
"If it's going to be used in the real world, it needs to be more durable."
To overcome this challenge, scientists typically add ingredients known as plasticisers, which help make materials more flexible.
Dr Naik and his team wanted to investigate whether natural compounds found in an Australian native plant could offer a similar benefit.
Their attention turned to pigface, a drought-resistant succulent commonly found along Australia's eastern coastline.
The plant's fleshy leaves contain a range of naturally occurring compounds, including sugars, organic acids and polyphenols, which the researchers believed could influence the properties of biodegradable materials.
The team extracted these compounds from pigface leaves and combined them with agar to create nine different film formulations. They tested each film's strength, flexibility, moisture resistance and antioxidant activity.
One formulation was about 38% stronger than the agar-only film and could stretch almost twice as far before breaking.
It also reduced the material's water vapour permeability by about 57%, allowing less moisture to pass through the material compared with films made from agar alone.
"Funnily, we thought if we added more pigface extract, it would improve our results - but it didn't," says Dr Naik.
"Films containing an intermediate amount performed best overall, while higher concentrations reduced their strength and flexibility.
"The findings suggest that pigface contains compounds that could help improve the performance of biodegradable films, although further research is needed to better understand exactly how they work together."
Could pigface help reduce plastic pollution?
While the findings are encouraging, Dr Naik says the research is still at an early stage.
One of the biggest challenges is the material's sensitivity to water. Although the pigface improved the film's ability to allow less water vapour to pass through, they still dissolved substantially when immersed in water.
This makes them unsuitable for many conventional packaging applications, particularly those requiring prolonged exposure to moisture.
However, Dr Naik says this property could also present an opportunity.
"For example, the material could potentially be developed into water-soluble packaging for products such as laundry detergent pods, where the film is designed to dissolve during use," he says.
"And it won't leave any traces of microplastic on your clothes or in the grey water.
"Another possibility is packaging for dry products, although further improvements and safety testing would be needed before the material could be used in contact with food."
The researchers also found that the films retained some of pigface's natural antioxidant activity, opening another avenue for investigating functional biodegradable materials.
Dr Naik emphasises that these are potential future applications rather than products ready for commercial use.
"At this stage, the research shows that natural compounds from pigface can improve certain properties of biodegradable films," he says.
"This is just like a stepping stone."
Discovering the potential of Australia's native plants
The idea to investigate pigface began with an unexpected encounter at a food conference in Coffs Harbour in 2025.
Dr Naik attended a dinner featuring native Australian ingredients presented by Mindy Woods, a proud Bundjalung woman and former MasterChef Australia participant.
Among the dishes was a salad containing pigface, a plant Dr Naik knew little about.
Curious about its properties, Dr Naik began investigating the plant and connected with IndigiGrow, an Indigenous-led nursery specialising in Australian native plants.
The collaboration led to a broader project exploring the chemical composition of pigface and its potential applications.
Their analysis identified a range of bioactive compounds, including antioxidants, polyphenols and other naturally occurring substances.
The researchers also identified an important safety consideration: pigface can accumulate contaminants from its growing environment, including heavy metals.
The study detected arsenic in the plant material, highlighting the importance of understanding where native plants are sourced and conducting appropriate safety assessments before developing food-related products.
"It's really important to understand the source," Dr Naik says.
"Higher levels of heavy metals were found in pigface that was sourced from areas with higher contamination."
Respecting the knowledge that came before
While modern scientific research can reveal new information about pigface's chemical composition, Dr Naik stresses that the plant's value has long been recognised by Indigenous communities.
For generations, Aboriginal peoples have used pigface for food and medicinal purposes.
Rather than claiming to discover the benefits, the researchers hope their work can contribute additional scientific understanding that communities can use to explore new opportunities.
The project was undertaken with Indigenous community approval, with the researchers committed to sharing their findings so communities can decide how the knowledge is used and developed.
"All the knowledge belongs to the Indigenous people so they can use it the way they want to," Dr Naik says.
"I hope these findings will inspire further research into Australia's native plants, while helping ensure communities remain central to decisions about how their knowledge and resources are used."
Peter Cooley, a proud Bidjigal man and CEO of IndigiGrow , says: "IndigiGrow is proud to partner with UNSW on this project. We as Aboriginal people have always known pigface has huge benefits as food and medicine which our people have used for thousands of years.
"We were keen to see if there could be other uses for this local plant that can be used and incorporated into modern times, which is why we got involved.
"There are huge opportunities with our native plants, however, Aboriginal people and communities must be integral to those opportunities and not sucked dry of knowledge and information and then left behind, which in many cases, happens a lot."
The researchers are open to collaborating on more projects to explore how other native plants could be processed into useful ingredients and materials, potentially creating new opportunities for small local Indigenous enterprises.
