AsianScientist (Feb. 16, 2022) – With shelves stocked with unsold goods, supermarkets throw out tons of spoiled or damaged food each day. To extend the shelf life of fresh produce, a Singapore-US research team developed new biodegradable packaging material that releases compounds to kill harmful microbes. The invention was described in ACS Applied Materials & Interfaces.
Globally, a third of food produced never makes it to the dinner table. It gets lost along the supply chain due to spoilage or logistical inefficiencies. Given these food safety and wastage concerns, developing sustainable packaging materials have been on the mind of industries and researchers to preserve the freshness of perishable goods.
On the other side of the coin, food packaging plastics are a problem in itself. They constitute the bulk of the plastic waste produced by industries. In Singapore alone, the National Environment Agency reported that packaging waste accounted for a third of the 1.76 million tons of trash disposed by households in 2018. Over half of it was plastic packaging.
To provide an alternative to synthetic plastics, a team from Nanyang Technological University, Singapore (NTU) and Harvard University in the US developed a packaging material that is biodegradable, non-toxic and antimicrobial. The main ingredient is a protein called zein, which is a waste by-product when corn oils are used to generate ethanol. Zein has antimicrobial properties.
The researchers combined zein with cellulose, which is a complex sugar found in plant cell walls, and acetic acid, the main component of vinegar. In addition, they infused the structure with more antimicrobial elements such as thyme oil and citric acid from Citrus fruits like oranges and lemons.
The novel material emits tiny amounts of antimicrobial compounds in the presence of bacteria or upon exposure to rising humidity. That smart timing of release provides protection only as needed to preserve the natural composition of the packaged goods.
In lab experiments, the packaging kept harmful bacteria like Escherichia coli and fungi at bay, minimizing contamination and delaying spoilage. For example, strawberries wrapped with the material remained fresh for seven days, whereas when packed in commercial fruit plastic boxes, they lasted just four days before developing mould.
Besides fresh fruit, the packaging can be used for a variety of products including raw meat and ready-to-eat food. When scaled up, the biodegradable material could serve as a sustainable alternative to plastic packaging, while ensuring food safety and quality. The researchers are already looking to partner with industrial collaborators to commercialize the material in the next few years.
“This invention would serve as a better option for packaging in the food industry, as it has demonstrated superior antimicrobial qualities in combatting a myriad of food-related bacteria and fungi that could be harmful to humans,” said Professor Mary Chan, Director of NTU’s Center of Antimicrobial Bioengineering.
The article can be found at: Aytac et al. (2021) Enzyme- and Relative Humidity-Responsive Antimicrobial Fibers for Active Food Packaging.
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Source: Nanyang Technological University Singapore; Photo: Shutterstock.
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