Fraunhofer Institute fights food waste through active packaging innovation project

24 May 2021 --- Fraunhofer Institute’s Process Engineering and Packaging IVV division is reporting progress in its international project to develop packaging solutions effective against food waste.

Food retailers discard up to half of their fruit and vegetables due to premature ripening, often triggered by the plant hormone ethylene or microbial infestation in the form of mold. 

The three-year FreshInPac project began in 2019, designing food-grade packaging that prolongs fresh produce shelf life by inhibiting ethylene-induced ripening and microbial spoilage. 

Half way through the project, PackagingInsights checks in with Fraunhofer materials development scientist Dr. Phil Rosenow, who details how the project is progressing.

FreshInPac has already identified several promising active components to suppress microbial growth, such as essential oils. 

In the form of clay particles loaded with catalytic metals or potassium permanganate, ethylene scavengers serve to bind or break down the ethylene released from fruit and vegetables, thereby delaying the ripening process.

“These substances have been applied as additives in films or coatings and shown to have the desired effects in laboratory trials,” Rosenow highlights.

Antimicrobial protection
The FreshInPac consortium combines the expertise of different partners in Belgium, Poland and Germany to develop and characterize new active materials. The partners are researching two issues in food waste prevention: antimicrobial growth and ethylene control.

In the first research tract, FreshInPact uses antimicrobial substances to inhibit the growth of bacteria (bacteriostatic) and fungus (fungistatic). Fitting the model to literature data in IVV shelf life modeling software.

Various combinations of essential oils and other substances are currently being investigated, which can be either directly incorporated in plastic foil or applied in the form of a special coating. Here, the recyclability of the packaging materials is also taken into account.

Innova Market Insights highlighted how the COVID-19 pandemic has heightened consumer hygiene concerns and given rise to antimicrobial technologies in its fourth top packaging trend for 2021, “Hygiene Heroics.” 

According to the market researcher, 59 percent of global consumers believe packaging’s protective function is more important since the virus outbreak (2021).

Equilibrium modified atmosphere packaging
The FreshInPac packaging requires materials allowing the contents to breathe but also preventing fermentation under anoxic conditions. Therefore, packaging with an overly strong gas barrier is deemed unsuitable. 

Instead, perforated packaging is used to create a protective atmosphere, which is known as equilibrium modified atmosphere packaging (EMAP). Here, an elevated concentration of carbon dioxide serves to suppress microbial activity. 

“We are looking to supplement the existing EMAP technology with additional active packaging approaches. EMAP keeps the produce alive while slowing down both its metabolism and the growth of microorganisms,” Rosenow elaborates. 

“The interplay of produce respiration and gas exchange with the environment leads to a stable, dynamic equilibrium atmosphere in the headspace. By tailoring the packaging appropriately, the equilibrium conditions can be optimized to achieve the desired effect.”

Mathematical headaches
The Fraunhofer Institute for Process Engineering and Packaging IVV has developed mathematical models to describe the packaging’s physical, chemical and biological processes. Some equations are general while others provide the parameters specific to a given case. 

“Of course, a mathematical model is always an approximation that might not cover all the intricacies of reality. However, as long as the main processes are captured and described well enough, the resulting simulations are meaningful,” Rosenow points out. Schematic representation of the model for breathing and ethylene-producing fruit and vegetables.

Challenges can arise from the availability and variability of parameters and from interactions between different processes.

“Using ethylene production as an example, measurements are available for most fruits. However, reported values can vary strongly, depending on the growth conditions and storage conditions of the fruits,” continues Rosenow.

The project takes this into account by running the simulations several times with varied parameters and statistical analysis of the results. 

“The payoff of having established a mathematical model for any given fruit or vegetable is the ability to simply switch out other parts of the whole system,” continues Rosenow.

Virtually testing different components also greatly reduces the need for storage tests.

Commercialization plans by 2022
FreshInPac aims to demonstrate a fully functioning product by early next year. “Currently, we have most of the components in place and now need to assemble everything into a working whole,” explains Rosenow.

“Once that is finished, we will conduct storage tests with selected fresh produce in the demonstrators to quantify the effects of the active packaging on shelf life.” 

The project is supported by the German Ministry of Economy and Energy. The following bodies are also involved:

• Industry Association for Food Technology and Packaging (Germany) (project coordinator)
• CELABOR (Belgium)
• Materia Nova (Belgium)
• West Pomeranian University of Technology (Poland)
• Leibniz Institute for Agricultural Engineering and Bioeconomy (Germany)

“Of course, the members of the project consortium are research institutions,” notes Rosenow. “While we can certainly offer consultation to this effect, it will be necessary to find a manufacturer to produce the actual material.” 

By Anni Schleicher