Shanghai – Polyurethane-encapsulated essential oils have been used to give food packaging films antibacterial properties. The films themselves are starch-based.
The films were created by a team of scientists at Shanghai Institute of Technology’s school of perfume and aroma technology. The idea was that the antibacterial essential oils could be added to a biodegradable film as an alternative for food preservation.
Three essential oils were blended together, and then encapsulated in PU via interfacial polymerisation to form microcapsule, which they named EOs@PU. The capsules had a uniform morphology, and an average size of about 3µm. A high loading capacity of 59% was possible.
The EOs@PU microcapsules were then incorporated into a potato starch film. This novel film was found to block more than 90% of UV light, and had low cell toxicity.
The long-term release of the microcapsules provided sustained antibacterial ability. The team found that fresh blueberries and raspberries had a shelf-life of more than a week at 25°C. The films were also biodegradable, with a 95% degradation in natural soil after eight days.
They suggest that the films could provide a natural and safe alternative for food preservation.
The work has been published in the International Journal of Biological Macromolecules.