Popcorn packaging: German scientists mimic polystyrene production to create compostable maize packs
06 Jul 2021 --- Researchers at the University of Göttingen in Germany are using popcorn to develop compostable packaging replicating the performance of polystyrene (PS).
The scientists take the inedible byproduct from corn flake manufacturing to crush and steam maize, which has the potential to create a light, air-filled material with similar properties to PS.
A license agreement with German maize producer Nordgetreide has been signed, and the research team is receiving funding from federal government ministries and other industrial partners.
Speaking to PackagingInsights, lead researcher Dr. Alireza Kharazipour, a professor of technical mycology at the university’s Büsgen Institute, says the project could lead to a common replacement for PS packaging free from virgin polymers and 100 percent compostable.
“I first got the idea on a visit to the cinema in Göttingen, which inspired me to produce feather-light granules based on crushed corn. In the dark, the popcorn felt just as light as styrofoam balls. The next day I bought corn and made popcorn at home in a pot.”
“After the whole house smelled like popcorn, I moved my experiments to the laboratory at the university.”
“In the meantime, my team and I developed around 40 products that consist of 100 percent crushed popcorn granulate with proteins used as binders. We aim to replace PS products with our popcorn-based products completely.”
A wine bottle case made from popcorn. Image credit: Carolin Pertsch
Maize mimicking fossil fuel
Kharazipour’s team mechanically shreds grain maize into so-called maize scrap. The crushed corn is then expanded into granulated popcorn using a steam-pressure process.
“The products are very light because popcorn granules are filled with air like honeycombs. When grain maize expands into popcorn, the volume increases by 15-20 percent. One cubic meter of popcorn granulate weighs approximately 65 kg.”
The methods employed in making popcorn-based products are very similar to the processes for PS products, he explains. Vapor-free processes such as radio wave frequency technology are used.
“This new process, based on technology developed in the plastic industry, enables the production of a wide range of molded parts,” continues Kharazipour.
“This is particularly important when considering packaging because it ensures products are transported safely, minimizing waste. And this has all been achieved using a material that will even be biodegradable afterward.”
Scale-up challenges
The team has faced a range of technical challenges in reaching its current development stage, explains Kharazipour.
The threat of humidity decomposing the packaging was a central challenge. “We solved this by covering the surface through a so-called coating process – for example, with polylactic acid – so the corn remains hydrophobic.”
The team is now in the process of transferring the results achieved in its laboratory from a technical to industrial scale.
“My industrial partner wants to manufacture various packaging products soon and hopefully not only market them across Europe but worldwide.”
Another industrial partner wants to produce insulation boards from popcorn to insulate houses’ interior and exterior walls, Kharazipour adds.
By Louis Gore-Langton
