TAGS: Environmentally Friendly Coatings
Researchers at the Fraunhofer-Gesellschaft have developed an environmentally friendly coating for paper packaging in the “BioActiveMaterials” project. This not only saves plastic, the coating of plant-based proteins and waxes also extends the shelf life of the food. After use, the packaging is disposed of in the waste paper bin.
As with conventional packaging, the shelf life of the food is extended. But the new packaging dispenses with plastic. After use, it can be easily recycled.
Proteins, Waxes and Antioxidants Extend the Shelf Life
In the project BioActiveMaterials, the researchers use paper as a basic material for the production of typical and functional packaging materials: sealable bags with sealed edges or wrapping paper. The paper is given a special coating using standard processes. The researchers use proteins and waxes with bio-based additives for this coating. The special formulation of the long-term stable coating fulfills several functions at the same time.
“On the one hand, the proteins serve as an oxygen barrier and the waxes as a water vapor barrier, so fruit, for example, does not dry out so quickly. On the other hand, the bio-based additives provide antioxidant and antimicrobial effects. Meat and fish do not spoil as quickly then. Overall, the shelf life of the food is significantly extended,” explains Dr. Michaela Müller, Functional surfaces and materials at the Fraunhofer IGB.
The proteins in the coating also perform certain tasks. They prevent mineral oil from the paper being transferred to the food. Waste paper in particular contains residues of printing ink containing mineral oil.
The coated papers developed as part of the “BioActiveMaterials” project represent an alternative to current packaging for all kinds of food, regardless of whether it is fruit and vegetables, meat and fish, cheese or even confectionery. The consumer can store and handle the paper-packed food in the same way as food packed with plastic.
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Our paper-based packaging is also suitable for food that needs to be cooled, such as meat. The protective function against oxygen is retained,” adds Dr. Michaela Müller. You can even pack frozen food in it. "After use, the packaging goes to the waste paper bin, the coating is biodegradable and does not interfere with paper recycling," says Dr. Cornelia Stramm, head of department at Fraunhofer IVV.
The Fraunhofer institutes pushed the project forward in close teamwork. While the scientists at Fraunhofer IGB took care of the complex formulation and manufacture of the coating, the researchers at Fraunhofer IVV tested how well the coating works in practice.
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For example, we tested how effectively the respective coating protects the food from external influences such as water vapor, oxygen and mineral oil," explains Dr. Cornelia Stramm. In addition, the team at Fraunhofer IVV was responsible for applying the coating to the papers using the roll-to-roll process. This is done by means of a machine on which the paper is guided over rollers. The coating is applied as an aqueous dispersion.
Proteins from Residues, Waxes from Brazil and Northern Mexico
When choosing the raw materials for “BioActiveMaterials”, the Fraunhofer team relied on natural substances approved by food law. For the protein component, for example, they experimented with rapeseed, lupins, whey and sunflowers. In practice, farms could deliver unused residues from production to the packaging industry.
When it comes to waxes, the researchers are using beeswax and waxes obtained from the candelilla bush found in northern Mexico and the Brazilian carnauba palm. "
We chose these waxes because they are biodegradable, approved for use with foodstuffs and are readily available on the market," explains Dr. Michaela Müller.
Classic laboratory technology is used in production, i.e. chopping, heating, stirring and mixing. "
The art consists in the mixing ratio and in the order in which the individual substances are added. The flexibility in the mixing ratio of the substances also enables us to optimize the coating for certain applications, ”says Dr. Michaela Müller.
For example, packaging for meat could develop a particularly strong antimicrobial and antioxidant effect with more antioxidants, while the lettuce in the bag is particularly well protected against drying out by a wax coating.
Advantages for Manufacturers, Retailers and Consumers
The researchers have also thought of very practical aspects. In addition to paper, cardboard can also be equipped with the bioactive coating. Printing on the packaging is not a problem. A manufacturer could print their logo or information on ingredients required by food law. Discounters and grocery retailers also benefit from Fraunhofer packaging. Resource-saving and biodegradable packaging without plastic is a trend among consumers.
The project partners from Fraunhofer IVV and Fraunhofer IGB are already experimenting with concepts in which the coating is applied directly to food such as fruit or vegetables, thus increasing the shelf life. From a health point of view, the edible coating is harmless anyway.
Source: Fraunhofer