Clay-nanotube film keeps foods fresher for longer
Run-of-the-mill plastic cling wrap sure is better than nothing when it comes to keeping food fresh, but that doesn't mean there isn't room for improvement. Scientists have now developed a new material promised to offer greater protection, by incorporating nanoscale clay tubes that apply the brakes to bacteria growth and over-ripening.
Contamination from bacteria and permeability to water vapor and oxygen are among the drawbacks of current cling wraps, as is the accumulation of a compound called ethylene around the food. This is naturally released by the fruits and vegetables, but when it is trapped beneath the plastic wrap it accelerates ripening and causes the food to rot faster.
Solving these issues has been far from straightforward. While scientists have been able to address particular flaws at a time, like developing films that prevent produce drying out so quickly, for example, coming up with a one-size-fits all solution has proven difficult to achieve.
Now researchers from the Sabanci University in Turkey have come up with a form of packaging that appears to tick quite a boxes. It starts with polyethylene film, the most common form of plastic and that used for things like bags and bottles. But the material's secret weapon comes in the form of nanoscale, hollow tubes made from clay that are hidden within.
The scientists say these serve the purpose of better preventing oxygen from permeating the film, while also preventing water vapor and other gases from escaping. Meanwhile, they stop ethylene from building up by absorbing it, and the addition of an antibacterial oil called carvacrol conveniently kills off microbes.
In putting its new film to the test, the team wrapped up tomatoes, bananas and chicken and then did the same with plain old polyethylene to see how they performed alongside one another. After 10 days, the tomatoes packaged in the new film were better preserved than their conventionally-wrapped counterparts. The bananas remained firmer and maintained a healthier yellow color, while the chicken showed significantly less bacterial growth after 24 hours of refrigeration.
The team says there is still a bit of work to be done before we see its new film on the supermarket shelf, but buoyed by its early success, it will now move onto the next stage of testing to make sure it is safe and non-toxic. It is presenting the research at the 254th National Meeting & Exposition of the American Chemical Society in Washington this week.
Source: American Chemical Society
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