Cellulose leads the way for new produce coating and edible straws

Despite the fact that it is vilified today in many quarters plastic packaging is generally understood to protect fruits and vegetables from spoilage in grocery stores. However it also creates significant amounts of waste. Together with the retailer Lidl Switzerland, Empa, the Swiss Federal Laboratories for Materials Science and Technology have now developed a protective cover for fruit and vegetables based on renewable raw materials. For this project, Lidl chose Empa for its research experience with cellulose products.

In Empa's Cellulose & Wood Materials laboratory, researchers spent more than a year developing a special protective cellulose coating that can be applied to fruits and vegetables. Coated fruits and vegetables stay fresh significantly longer, they claim. In tests, the shelf life of, for example, bananas was extended by more than a week. "The big goal is that such bio-coatings will be able to replace a lot of petroleum-based packaging in the future," says Gustav Nyström, head of the Empa lab.

The cellulose material is extracted from squeezed fruit and vegetable peels. The idea is to process so-called pomace into fibrillated cellulose. Pomace is the solid residue left over after extracting the juice from fruit, vegetables or plants. Previously, this plant leftover was disposed of in biogas plants or directly on the field. Now it can be used to create a protective coating for fresh fruit. The coating is either sprayed onto the fruit or applied to the produce as a dip and is easy to wash off.

As it is harmless to the consumer, it can also be eaten. The potential of cellulose coatings is by no means exploited yet, the researchers believe. There is the possibility of adding additives such as vitamins or antioxidants.

In another advance in cellulose materials for packaging and related components Chinese researchers have developed a new type of eco-friendly edible straw without microplastic. Says an article in Industry Intel.

Disposable plastic straws can take hundreds of years to fully degrade it is claimed, potentially causing serious environmental problems. So in recent times paper straws have been used by the foodservice industry, but they bring poor taste to users and are generally easy to deform.

Also China recently released an ambitious plan to ban or significantly reduce the production and use of environmentally-unfriendly plastic products in the next five years to contain pollution. So the researchers have developed this new edible and microplastic-free straw made from bacterial cellulose by biosynthesis.

The straw achieves better mechanical performance than paper straws and avoids additional adhesives, according to the research article published in the journal Advanced Functional Materials. The bacterial cellulose-based straws can be made thinner than paper straws with the same performance requirements. With edible colouring or natural plant extracts loaded on a 3D nano-fibre network of bacterial cellulose, a variety of colours and flavours can be absorbed into the straws to provide a better taste.

The straws can degrade quickly in the environment without causing any negative environmental impact, China Science Daily reported. Experiments showed that they would break into pieces in 15 to 45 days, or even almost disappear. The edible character claims to provide a better user experience, making the straw a healthier and better eco-friendly substitute for plastic straws.

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