The future of packaging: curbing food waste

Whether for juice boxes, potato chip bags or plastic trays for minced meat: Packaging is indispensable in the food industry. The Fraunhofer Institute for Process Engineering and Packaging IVV is working to develop new recycling processes and alternative packaging materials so that packaging not only protects food but also the environment.

Packaging ensures that pre-baked dinner rolls stay fresh for weeks and that chips are still crispy months after purchasing. These and many other foods would quickly become inedible without protective packaging. According to the Environment Programme of the United Nations (UNEP), 17% of all food available to consumers ends up in the waste bins of households and retailers. Another 14% is lost between harvest and retail. This is a huge waste of water, land and other resources. Furthermore, it is associated with enormous quantities of greenhouse gas emissions — all completely unnecessary.

Packaging should ensure that food ends up on the plate and not in the bin. It prevents produce from becoming bruised and protects against mechanical damage as well as against mold, bacteria and other pests. Packaging keeps out moisture and dirt, contaminants and off-flavors. When food products are correctly packaged, oxygen and light cannot penetrate the protective barrier, ensuring that fatty food does not become rancid and that vitamins and other nutrients are not lost.

However, packaging does not just protect food from external factors. It prevents water-containing products from drying out and stops protective gases escaping in the case of highly perishable foodstuffs, such as raw meat and pre-baked dinner rolls, that are packaged in a protective atmosphere. Furthermore, packaging is an information medium and marketing tool — particularly for processed foods, from yoghurt to frozen pizza.

At Fraunhofer IVV, scientists are also researching active packaging. This type of packaging contains oxygen scavengers or substances that bind to the ripening gas ethylene, for example. Antimicrobial packaging also extends the shelf life so that the amount of preservatives added to the food can be reduced.

Sustainable packaging should not only minimize food waste but also conserve other resources. The aim is to therefore reduce material usage, particularly plastic, and replace fossil-derived raw materials with renewable ones. However, completely ditching plastic is ineffective because it can in fact be superior to other materials — as the life cycle assessment of reusable drinks bottles made of polyethylene terephthalate (PET) shows.

The key to greater resource efficiency and minimum waste lies in closed material cycles. This applies in particular to food packaging, where the use of recycled materials is strictly regulated. Researchers at Fraunhofer IVV are developing laser-based waste sorting systems to separate food packaging from other waste materials that are unsuitable for food contact. Such systems are based on fluorescent tracers printed on the packaging, which contain a material-specific code.

Recycling composite materials, for example those made of cardboard, plastic and aluminum (such as traditional juice boxes) or those made of plastic and aluminum (such as potato chip bags and vacuum packaging for coffee), is an ongoing challenge. The different materials are strongly bonded together and cannot be separated using conventional recycling methods. Fraunhofer IVV has developed a solution to this problem with the CreaSolv Process, a physical process that uses non-hazardous solvents to separate plastics from composites. One CreaSolv pilot plant in Indonesia is recovering polyethylene for Unilever, while a plant at the premises of our industrial partner Lömi in Germany is recycling other plastics. There is currently an additional CreaSolv plant at Fraunhofer IVV in Freising.

In addition, Fraunhofer researchers are working on easily detachable composites. These contain a protein-based coating that acts as an oxygen barrier. They can be delaminated using special enzymes that break down the protein coating. Composites with adhesives that lose their adhesive strength when heated, for example, are also under development at Fraunhofer IVV.

At first glance, many composites are not recognizable as such. There are some particularly gas-tight plastic films used for packaging raw meat, for example, which comprise up to 11 layers of different plastics. One objective of the research is to replace such composite films with a monomaterial. This single-material packaging comprises either a bulk plastic such as polyethylene or a bioplastic such as polylactic acid (PLA) to which ultra-thin barrier coatings are applied to achieve a better protective function. In terms of coatings, Fraunhofer researchers prioritize natural materials, for example plant oils and waxes, or algal polysaccharides. Nanoscale clay minerals in the form of ten-nanometer-thick coatings comprising inorganic materials such as aluminum oxide or cellulose particles are also used. They close the gaps in the plastic’s molecular network, thereby preventing water vapor and gases from permeating the film. As the barrier coatings are extremely thin, they do not hamper the recycling process. Their proportion is lower than that of standard plastic additives.

Coating shrink films is particularly challenging. When heat is applied during the packaging process, shrink films contract by up to 30% to tightly cover the foodstuff. The barrier coating must not flake or chip in the course of this. To achieve transparent, UV-resistant shrink films, Fraunhofer IVV is using special silicon compounds that have several binding sites. At one site, they have a UV absorber and, at another, they dock to the film. During the shrinking process, the UV absorbers can move closer together without affecting the bonds with the film.

Fraunhofer IVV is also working on bioplastics for food packaging. Algae-based barrier coatings and standalone films are being developed to this end. Researchers are also trialing various methods to improve the properties of bioplastics. For example, electron beam treatment is increasing the mechanical stability of the bioplastic PLA and improving its impermeability to water vapor by crosslinking the polymer. Enzymes incorporated into the bioplastics in turn ensure more effective composting.

In addition, Fraunhofer researchers are developing edible casings and coatings made from plant, algae or fungal proteins that prevent food from going off. The initial focus is on casings for vegan sausage products. The concept will then transferred to other foodstuffs.

Whether food packaging is recyclable, easily compostable or even suitable for consumption: Researchers at Fraunhofer IVV are always thinking about sustainability during the development process. They want to not only curb food waste but also protect the environment.