By Ben Coxworth
December 30,
2021
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Strawberries wrapped in the film lasted three days longer than a control group kept in baskets Photo credit: Nanyang Technological University
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Developed by
scientists at Harvard University and Singapore's Nanyang Technological
University (NTU), the material takes the form of a transparent film.
Made via
an electrospinning process, its base fibers
consist of a corn protein known as zein, along with starch, cellulose and other
naturally derived polymers. Those fibers are infused with natural antibacterial
compounds such as thyme, citric acid and acetic acid.
When the
film is initially placed around a food item like meat, fish or fresh produce,
the antibacterial compounds remain within the fibers. If the humidity rises or
if certain enzymes are produced by harmful bacteria, however, those compounds
are automatically released – they then proceed to kill the bacteria along with
any fungi that may be present, keeping the food from spoiling.
In lab
tests, fresh strawberries that were wrapped in the film lasted seven days
before developing mold, as compared to four days for strawberries which were
kept in regular fruit baskets.
Additionally,
as mentioned, the material fully biodegrades once discarded. It should also be
noted that the zein is obtained from corn gluten meal, which is a waste
by-product from the production of ethanol – this means that corn crops wouldn't
have to be grown solely for use in the film.
It is hoped
that the material may be commercialized within the next few years.
"The
sustainable and biodegradable active food packaging, which has inbuilt
technology to keep bacteria and fungus at bay, is of great importance to the
food industry," says NTU's Prof. Mary Chan. "It could serve as an
environmentally friendly alternative to petroleum-based polymers used in
commercial food packaging, such as plastic, which have a significant negative
environmental impact."
A paper on
the research was recently published in the journal ACS Applied Materials &
Interfaces.
Source: Nanyang
Technological University