Current plastic films do a great job of keeping food fresh while it sits on the supermarket shelf, but lately we're seeing advanced forms of these materials that might play more than a passive role in preventing spoilage. A new "bioactive" material from researchers in Spain and Portugal serves as another compelling example, making use of extracts from mango leaves to fend off food pathogens and ultraviolet light.
The new bioactive plastic was developed by researchers at the University of Cadiz in Spain and the University of Aveiro in Portugal, who gathered mango leaves from pruning remains at a local farm. Mango leaf extract was then combined with nanocellulose from paper processing to form a novel film through a technique called supercritical solvent impregnation.
This technique proved to have advantages over conventional plastic fabrication, in that it allowed the mango extract to more effectively penetrate into the nanocellulose and promoted the migration of active compounds. The upshot of this is a film with a higher concentration of antimicrobial and antioxidant compounds, and therefore, an improved capacity to preserve food.
"As a result, the active properties of the mango remain intact after impregnation, which increases the film's ability to protect food," says Cristina Cejudo, researcher at the University of Cadiz.
The team put the film to the test through in vitro experiments against two food pathogens: Staphylococcus aureus and Escherichia coli. This revealed that the active compounds in the film took on an antimicrobial role and prevented the spread of the organisms. Furthermore, the mango extracts also served to increase the ability of the film to block UV light, which might otherwise accelerate food spoilage.
“Thanks to it, food wrapped in this film could be preserved longer without the addition of preservatives," says Cejudo. "The film itself replaces the chemical additive, since the active substance exerts its effect via the packaging without the need to add anything to the food."
From here, the team plans to conduct further experiments on the novel bioactive plastic, by studying how it performs actually preserving specific foods.
The research was published in the journal Food Hydrocolloids.
Source: Fundación Descubre via Phys.org
