The fight against single-use plastic packaging

An empty bag of chips in the ditch, thousands of trampled cups at a festival or a stray sandwich bag flying through the air – you’ve probably seen them all before. Those stray disposable packaging materials on the street seem harmless, but they are not. Single-use plastic is a major threat to our environment. At a neighborhood meeting in 2005, four neighbors decided that something had to change. They developed a biodegradable coating for fruits and vegetables. Not only are they seriously looking for alternatives to disposable plastic packaging with their company Liquidseal. There are a multitude of alternatives and scientists have the topic at the top of their agenda.

This is urgently needed, because disposable packaging for our food and beverages make up the largest proportion of the garbage floating in the oceans, at 82 percent. In Europe alone, between 307 and 925 million pieces of garbage end up in the sea every year. If this trend continues, around 1.3 billion tons of plastic will eventually be floating in the oceans by 2040. Fortunately, there are scientists and entrepreneurs who have made it their business to put a stop to this.

“Apart from the fact that plastic poses a threat to the environment, we also throw away a third of the food we produce worldwide,” says Victor Monster, Managing Director at Liquidseal. As an alternative to plastic packaging, the company is developing a biodegradable coating technology for fruit, vegetables and flowers. “This enables us to reduce waste by thirty to forty percent and extend the shelf life of the products.”

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Slow release system

Liquidseal is a spray or liquid that fruits and vegetables are dipped in. A thin film layer is then formed that is approximately three to four micrometers thick. Inside this layer there is a channel structure that not only influences the evaporation process of the product, but also the oxygen and CO2 exchange. “Compare it to venting a grill. When it is fully open, the coals will burn up quickly. If you leave the hood slightly open, the coals burn much more slowly. Our technology does that too; We extend the shelf life of the product by using a slow release system, ”explains Monster.

A complicated task, because every type of fruit and vegetable has a different oxygen requirement. As a result, Liquidseal has to adapt the formulation of the liquid and the channel structure for each product.

Dipping and spraying Liquidseal. Image: Liquidseal

Laws and regulations

Currently, the company focuses exclusively on the European market, in particular on packaging for avocados, mangoes, citrus fruits, melons and papayas. “We are also preparing packaging for bananas and pineapples, but our hands are tied by European laws and regulations. There is a list of the components that you are allowed to use for the packaging. If you use other ingredients, you are officially breaking the law. ”For the time being, Liquidseal is only allowed on hard-skinned fruit and vegetables; apples, pears, tomatoes and cucumbers have so far been completely taboo.

However, Monster is confident that this will change in the future. “People want less plastic packaging, environmentally friendly packaging, less chemicals on products and less food waste. Liquidseal fulfills all of these conditions. “

From the field to the fork

Another challenge for Liquidseal is that the coating must be applied to the product as soon as possible after harvest in order for it to function optimally. “That’s why we have to be able to gain a foothold with producers in Ecuador, Mexico and Colombia.” Liquidseal is currently still carrying out a lot of tests to demonstrate the advantages of environmentally friendly packaging to importers and retailers. “A number of importers have already committed themselves and we are in the process of bringing it to market.” Monster assumes that it will be another five years before fruit and vegetables with the Liquidseal coating are on the shelves.

Environmentally friendly alternative to aluminum layers

Scientists are also looking for alternatives to environmentally harmful single-use packaging. For example, the research group of Wiebe de Vos, Professor of Membrane Technology at the University of Twente (UT), and the group of Jasper van der Gucht, Professor of Physical Chemistry and Soft Matter at the University of Wageningen (WU), are working together to develop an environmentally friendly alternative for the vapor-deposited aluminum layer on the inside of the packaging. The layer blocks oxygen so your chips stay crispy and your coffee stays aromatic. “However, all of these layers also make recycling a lot of food packaging difficult,” adds Van der Gucht.

So there are actually two problems with today’s packaging: The aluminum layer is difficult to dissolve and difficult to separate from the other layers. In addition, plastic is difficult to recycle anyway because the polymer molecules are glued to one another through permanent chemical bonds. “We’re trying to do something about both aspects. Our polymer layer replaces aluminum and the layer is made up of compounds that you can expand. That makes recycling so much easier, ”says Van der Gucht.

Negatively and positively charged polymers

This special polymer layer is the result of an experiment with positively and negatively charged polymers. Together they form a dense and protective layer against oxygen. But it is also possible to switch off the binding. “That way you don’t need that aluminum layer anymore,” he adds.

It is important that the positive and negative polymers bind to each other and release at the right time. Van der Gucht mentions a paint pot as an example. “If you add negatively and positively charged polymers that combine prematurely, then you end up with lumps in the paint pot. If they bind too late, you won’t get a thick, solid layer of paint. Therefore we use a pH trick: At the beginning the pH value is high and so the charges do not bind. During the drying process, the base evaporates and the pH value gradually drops, so that the polymers bind. We do the same with the packaging. “

Sustainable polymer packaging

The research is carried out in cooperation with UT, BASF and AkzoNobel. In the meantime, the researchers from UT and WU have shown that high-quality films can be produced in this way, the oxygen barrier meets the requirements and is easier to recycle.

“The problem we still run into is that this layer is not yet strong enough. You can solve that with an additional layer, but ultimately we want to move on to packaging that consists of a single layer. ”In addition, research is currently still concentrating on simple polymers made from fossil fuels. Van der Gucht wants to switch to packaging made from sustainable raw materials in the future. “The best thing would be if you could make polymer packaging from organic waste.”

According to Van der Gucht, the discovery is a significant step towards a sustainable packaging industry. “The quality of this polymer-based coating is at least as good as that of aluminum-coated packaging, but the environmental benefits are great as polymer packaging is potentially much more recyclable.”
Either way, armed with polymer packaging and environmentally friendly coatings, the plastic soup will be smaller in the future.

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