Het gevecht tegen plastic wegwerpverpakkingen


An empty bag of crisps in a ditch, thousands of cups trampled at a festival or a stray sandwich bag flying through the air, you’ve probably seen them all. These disposable packaging materials roaming the streets seem harmless, but they really aren’t. Disposable plastic is a major threat to our environment. At a neighborhood meeting in 2005, four neighbors decided that things had to change. They have developed a biodegradable coating for fruits and vegetables. With their company Liquid seal, they are not the only ones looking for alternatives to disposable plastic packaging. There are a variety of alternatives, and scientists have the topic high on their agenda as well.

This is desperately needed, as disposable packaging for our food and drink makes up the bulk – 82% – of the litter floating in the oceans. Just in Europe, between 307 and 925 million pieces of waste end up in the ocean every year. If this trend continues, around 1.3 billion tonnes of plastic will eventually drift into the oceans by 2040. Fortunately, there are scientists and entrepreneurs who are on a mission to stop it.

“Besides the fact that plastic is a threat to the environment, we also throw away a third of the food we produce around the world,” says Victor Monster, CEO of Liquidseal. The company is developing biodegradable coating technology for fruits, vegetables and flowers as an alternative to plastic packaging. “This allows us to reduce waste by thirty to forty percent and extend the shelf life of products. “

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Slow release system

Liquidseal is a spray or liquid in which fruits and vegetables are immersed. A thin layer about three to four microns thick is then formed. Inside this layer is a channel structure that affects not only the way the product handles the evaporation process, but also the exchange of oxygen and CO2. “Compare it to the vent on a barbecue. When fully opened, the coals burn quickly. If you leave the vent slightly open, the coals will burn much slower. This is also what our technology does; we extend the shelf life of the product by using a slow release system, ”continues Monster.

A complicated task, because each type of fruit and vegetable has a different need for oxygen. Therefore, Liquidseal must adjust the liquid formula and channel structure for each product.

Soaking and spraying Liquidseal. Image: Liquidseal

Legislation and regulations

At the moment, the company focuses only on the European market, in particular on the packaging of avocados, mangoes, citrus fruits, melons and papayas. “The packaging of bananas and pineapples is also in preparation, but our hands are bound by European legislation and regulations. There is a list of components that you are allowed to use for packaging. If you use other ingredients, you are officially breaking the law. For example, Liquidseal is currently only allowed on hard-skinned fruits and vegetables, and apples, pears, tomatoes and cucumbers are so far banned completely.

Still, Monster is confident that 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 field to fork

Another challenge for Liquidseal is that the coating should be applied to the product as soon as possible after harvest for it to perform optimally. “Therefore, we must be able to gain a foothold among producers in Ecuador, Mexico and Colombia. At present, Liquidseal is still performing numerous tests to demonstrate to importers and retailers the benefits of environmentally friendly packaging. “A number of importers have already signed up and we are in the process of bringing it to the market. Monster expects it will be another five years before there are fruits and vegetables on the shelves with the coating layer of Liquidseal.

Environmentally friendly alternative to aluminum layers

Scientists are also looking for alternatives to disposable packaging that is harmful to the environment. For example, the research group of Wiebe de Vos, professor of membrane technology at the University of Twente (UT), and the group led by Jasper van der Gucht, professor of physical chemistry and soft matter at the University of Wageningen (WU), are jointly developing a ecological alternative for the evaporated aluminum layer inside the packaging. The layer blocks oxygen so your crisps stay crisp and your coffee stays aromatic, “but all of these layers also make many food packaging very difficult to recycle,” adds Van der Gucht.

So there are actually two problems with current packaging: the aluminum layer is difficult to dissolve and difficult to separate from the other layers. In addition, plastic is tricky to recycle anyway because the polymer molecules are stuck together by permanent chemical bonds. “We are trying to do something on both aspects. Our polymer layer replaces aluminum and the layer includes bonds that you can expand. This makes recycling much easier, ”explains 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 deactivate the link. “That way you don’t need that aluminum layer anymore,” he adds.

What is important here is that the positive and negative polymers bind to each other and release at the right time. Van der Gucht cites a pot of paint as an example. “If you add negatively and positively charged polymers that bind prematurely, you end up with lumps in the paint bucket. If they bond too late, you won’t get a dense, solid coat of paint. This is why we apply a pH trick: at the beginning, the pH level is high and therefore the charges do not bond with each other. During the drying process, the base evaporates and the pH gradually decreases, so the polymers bind together. We do the same with the packaging.

Durable polymer packaging

The research is carried out in cooperation with UT, BASF and AkzoNobel. In the meantime, researchers from UT and WU have shown that it is thus possible to manufacture films of good quality, that the oxygen barrier meets the requirements and that it is more easily recyclable.

“The problem we always have is that this layer is not yet strong enough. You can solve this problem by using an extra layer, but in the end we want to move towards a single layer packaging. In addition, research is currently still focused on simple polymers made from fossil raw materials. In the future, Van der Gucht wants to move towards packaging made from sustainable raw materials. “The best thing would be to be able to use organic waste to make polymer packaging. “

According to Van der Gucht, the discovery is an important step towards a sustainable packaging industry. “The quality of this polymer-based coating is at least equivalent to that of aluminum-coated packaging, but the environmental gains are significant because polymer packaging is potentially much more recyclable.
Somehow, armed with polymer packaging and eco-friendly coatings, in the future the plastic soup will get smaller.

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