Alexander Witt: "Using packaging deliberately protects valuable resources and can help to reduce hunger in the world"

In the second part of the interview, interpack Magazine speaks with Alexander Witt about packaging-based product protection, the SAVE FOOD Initiative and the relative importance of compostable packaging in the market.

Packaging-based protection is one of the issues taken up by the SAVE FOOD Initiative, which was founded in 2009. The alliance between Messe Düsseldorf, the FAO (Food and Agriculture Organization of the United Nations) and several other companies is aimed at reducing food losses and food waste around the world in order to combat hunger. What’s the significance of the SAVE FOOD Initiative for your work on product protection?

Product protection plays a key role for the Initiative. In my chart above, which I use to illustrate what optimal packaging means to me, I use SAVE FOOD as a synonym precisely for such optimal protection. One study has shown that some 1.3 billion tonnes of food are squandered worldwide every year because of careless waste, production losses or inadequate protection against external influences. I believe the right kind of packaging can drive down this shockingly large number.

Your work also explores whether a completely compostable packaging solution currently exists for cereal bars, one that can sufficiently protect the product while preventing food waste as described by the SAVE FOOD Initiative. In your view, what role does the compostability of packaging play in the market right now, and what are some of the associated challenges?

The SAVE FOOD Initiative pillories food waste, in part because of its hefty impact on the environment. Lots of natural resources and energy are required in food production; these are lost and the environment damaged when fruits, milk or meat spoil due to inadequate product protection.

That’s why it’s so important to find suitable packaging that’s as optimal as possible. In my illustration of how to find a compromise between the various demands made of optimal packaging, I juxtaposed product protection as envisioned by SAVE FOOD with the requirement that materials be as eco-friendly and natural as possible. The objective of my thesis was to find out whether a compostable packaging solution for the cereal bar might be the most sustainable compromise between a barrier composite and nature.

Several providers of compostable packaging materials operate in the market, and consumers can find such products on retailers’ shelves by looking for a compostability mark on the package. Nevertheless, its market share is still relatively small.

This could be because water vapour penetrates compostable materials more easily than many conventional plastics. Possible solutions might include adjusting the thickness of the film, adding another layer or shortening the best-by date.

Another major challenge, in my view, is disposal. Oftentimes, defined conditions must be met to enable the composting of the film. Depending on the packaging material, an industrial plant is required, which in turn presupposes that it’s reliably possible to differentiate between compostable and conventional plastics during the collection and processing of recyclables.

How can I recognise compostable packaging as a consumer?

Independent testing laboratories can certify compostable packaging. Certificates can be validated and awarded based on the DIN EN 13432, ASTM D6400 or GreeenPLA standards. Consumers can determine whether a package has been certified as compostable by looking for one of the logos depicted in the chart. The most popular marks in Germany are definitely the seedling and the OK Compost Logo.

How did you design your experiment, and what parameters did you have to take into account?

When developing plastics-based food packaging, one usually draws on empirical data from other products or infers the barrier requirements from the ingredients. One looks for guidance to existing packages already tested in the market. In addition, the development of the packaging is then verified in product-specific stress tests. This process generally yields a packaging concept that works for a given product.

I approached this task in a different way and tried to work backwards from the product to define the packaging requirements. To that end, I had to examine how the product reacts to possible influencing factors. That’s how I was able to establish threshold values.

I conducted my initial assessment of product sensitivity using literature research and by analysing and evaluating the main ingredients of a bar. Often it’s already know how several of the ingredients react to external influences. Peanuts, for example, react in a particularly critical way to atmospheric oxygen: they oxidise, which can lead to an unpleasant, rancid off-taste in the mouth.

The critical influencing factors I focussed on primarily were oxygen and water vapour. The best way to test how sensitive the entire cereal bar reacts to water vapour is to expose the product to different humidity levels. This is referred to as a sorption isotherm. Working with pacproject and the University of Applied Sciences in Hannover, I designed a series of experiments to implement this idea. Among other things, the results indicate what sort of conditions allow for the appearance of damaging reactions such as mould growth. When combined with sensory changes, e.g. bread crusts losing their crispiness, this process enables us to define threshold values for the absorption and release of water vapour.

In order to determine how the bar responds to oxygen, I calculated oxygen consumption by exposing the bar to stress conditions in an enclosed container and measuring the resulting change in oxygen content. The results enabled me to theoretically estimate oxygen sensitivity. In addition, validation necessarily requires sensory verification of the determined trends.

What were the findings of your thesis? Can compostable materials compete with conventional materials such as BOPP?

Compared one-to-one, compostable packing films cannot yet compete with conventional plastics. However, options exist that help to enhance the barriers. Functional coatings are available, and research institutes are currently working on promising new functional layers that are biodegradable.