A material made from crustacean shells could one day be used to replace petroleum by-products in food packaging.

With concerns growing over the amount of plastic waste littering the world's riverbanks and oceans, it's a timely discovery that could lead to an increase in the use of biodegradable packaging materials in the food processing industry.

At the moment, many food items are covered with plastic films to make them last longer and to protect them from microbes. In tests with packaged carrots, researchers in Spain and Ireland showed that chitosan films, which are less harmful for the environment in a range of categories, had a positive effect on the color and texture of the carrots and delayed microbial spoilage.

Chitosan is made from the shells of prawns, king prawns and other crustaceans.

"The environment benefits from the use of this waste material and, what is more, the resulting product, chitosan, is biodegradable," explained Itsaso Leceta, one of the researchers. "Chitosan also has antimicrobial properties, so it is highly suited to the food industry, as it reduces the microbial load — in this case — of carrots. That is why their properties have been preserved better."

However, there is still much work to be done before chitosan can be used on an industrial scale for packaging food. For example, the manufacturing of chitosan needs to be optimized in order to further reduce the material's environmental impact.

"We have to go on conducting research. Just as with renewable energies, it is better to have various options — to produce a mix — rather than just to have only one. You have to work with different polymers, to reduce the use of petroleum-based materials as much as possible," Leceta added.