Can you picture breathing through a reusable face mask that is made from the discarded husks of seeds?
Now can you imagine that these masks are not only kinder to the environment, but have bacteria-killing properties as well?
Researchers at the Nanyang Technology University (NTU) have recently announced that they had found a way to repurpose food waste to create an antibacterial fabric for reusable masks.
Conservationists have warned that the coronavirus could spark a surge in plastic pollution, as disposable masks and gloves used to prevent the spread of Covid-19 had been found littering streets, beaches and green spaces.
Single-use masks cannot be recycled and take a staggering 450 years to decompose in nature. Masks that are not adequately disposed of will likely end up in marine waters through sewers and rivers, adding to the millions of tons of debris already polluting our oceans. Over time, they will break down into microplastics which will be ingested by marine animals, find their way into the food chain and eventually endanger our own lives.
Yet masks play a critical role in the fight against Covid-19.
To provide a more sustainable solution, Professor William Chen and his team at NTU’s Food Science and Technology (FST) programme developed a process to extract antimicrobial compounds from the discarded husks of seeds. The compound can reportedly kill 99 % of harmful bacteria by disrupting their cell walls, and may be used in the fabric finishing of reusable masks.
Typical antimicrobial solutions require the use of harsh chemicals such as solvents or ions obtained from various metals such as silver. Prof Chen’s method, in contrast, is entirely natural – a timely eco-friendly innovation in response to Covid-19.
“In this case, our antimicrobial compounds extracted from plant waste streams, initially aimed at reducing food waste, have found an unexpected application in reusable antimicrobial masks to prevent the spread of Covid-19”, Prof Chen tells The Pride.
His team has since partnered with apparel and textiles company Ghim Li Group to manufacture and distribute the reusable masks.
As the natural compound is considered non-toxic for humans, it also has the potential to be applied in a range of other products, including personal protective equipment, sports apparel, paints and disinfectants.
Biodegradable packaging from prawn shells and fruit waste
And that’s not the only sustainability innovation Prof Chen and his colleagues are involved in.
With their research focused primarily on the circular food economy, the team is also working on upcycling crustacean shells and discarded fruits into chitin, a biopolymer which can be used in food thickeners and stabilisers, or in antimicrobial food packaging.
This low-cost, environmentally friendly alternative to single-use packaging is part of the team’s drive to reduce food waste and combat plastic pollution in Singapore and across Asia.
According to the National Environment Agency (NEA), plastic and food waste make up about 23% of total waste generated in Singapore.
Unlike many of the chemical-based bioplastics on the market, which are both expensive to produce, and require a special industrial facility to break down, Prof Chen claims that his packaging material will biodegrade within a month when placed in soil because it’s made of natural ingredients only.
Chitin is typically extracted from marine waste using chemicals, which is costly, energy-intensive and may lead to toxic by-products being discharged via industrial wastewater.
“Our new method takes crustacean waste and discarded fruit waste and uses natural fermentation processes to extract chitin. This is not only cost-effective, but also environmentally-friendly and sustainable, and helps to reduce overall waste”, Prof Chen tells The Pride.
Fruit waste contains high sugar content which powers the fermentation process, and helps break down the crustacean shells, producing higher quality chitin compared to the chemical method, he adds.
Earlier this month, the eco-friendly packaging material won two prizes at The Liveability Challenge, an annual contest by Temasek Foundation and Eco-Business, which seeks innovative solutions to some of Southeast Asia’s most pressing problems.
Whilst working on commercialising the biodegradable food wrap, NTU is also in discussion with insect farms in Singapore to use insect husks as an alternative to prawn shells. Bugs have the potential to revolutionise global food supply as a sustainable source of protein, and are more abundantly available compared to prawns, which increases the scalability of the innovation, shares Prof Chen.
Although the food waste-based packaging might be cheaper to produce compared to commercial bioplastics, bringing it to market will require beating the price of incumbent products, including single-use plastics – a common hurdle faced by most sustainability solutions.
Fermentation as a low-cost method to combat food waste
The NTU team tested the fermentation process with various sources of fruit waste, including white and red grape pomace, mango and apple peels, pineapple cores, and even durian husks and seeds.
They had also experimented with fermenting okara, or soy pulp, an insoluble waste product from soy milk and tofu production, to grow a protein-rich microalgae which is considered a sustainable and economical source of food ingredients, health supplements and biofuels.
Fermentation forms a critical part of the FST programme’s experiments, because it’s a low-cost method that helps increase the nutritional value of by-products that would otherwise be discarded during food processing, including seeds, stems and husks.
“This research also echoes NTU’s translational research focus, which aims to develop sustainable innovations that benefit society and industry and create a greener future.”