It's an unfortunate but common occurrence: you're sitting on the bus or the train — and someone pulls out reeking onions, garlic or some other pungent food.
Stinky foods can be problematic in many situations, especially transportation and storage. The durian fruit is an extreme example. In Southeast Asia, it is quite popular despite its stench, which many compare to the smell of garbage or dead animals. The fruit is banned from hotels, airplanes and mass transit in most cities in the region.
That's what inspired Lennart Bergström and his colleagues to develop an odor-neutralizing film for food. By infusing the film with nanoscale fibers of cellulose, the primary component of wood, they were able to create a thin material that effectively absorbs the odors of foods – including onions and durian – they report in a paper published in the journal ACS Applied Materials & Interfaces.
"A visit to Singapore made me aware that transport of foul-smelling fruits, such as durian, and vegetables is challenging and we decided to work out a solution to this problem," Bergström told Tech Times. "This is a cheap and easy way to make films and coatings that could easily be introduced in the food-packaging area."
The film is made from zeolite, a solid material with nanoscale pores that contains silicon and aluminum. This material is known to absorb gas molecules. Adding nano cellulose allowed it to do so more efficiently by acting as a scaffold, or matrix, and helping to bind the material together more strongly.
"By using nanocellulose as a matrix and binder, it is possible to prepare films with higher amounts of adsorbents – the zeolite – than before," Bergström said. "The films are also thin, strong, light and flexible."
Tests of the new odor-neutralizing material showed that it was able to effectively eliminate odors. The film absorbs stinky molecules like the sulfur-containing compounds that often make foods reek — reducing the levels of the offending molecules to below the level that humans can smell.
This new material could be used for disposable adsorbent pads in food packaging, Bergström said. The researchers also developed a way to apply the film as a thin coating on paper or cardboard.
Photo: Hafiz Issadeen | Flickr
