Fermentation is more than just trendy kombucha and kimchi – the ancient preservation method is being used to develop alternative protein sources. But how does it work? And what are the challenges?
The food system accounts for between 20-30% of total global greenhouse gas emissions. At the same time, the world's population is growing and so is the need for food. A protein shift, replacing animal proteins with plant proteins, has been identified as a possible solution to both challenges.
Fermentation is a natural process
Researchers are tackling the issue of protein metabolism in a variety of ways, including at RISE using a thousand-year-old technique that has historically been used to extend the shelf life of food and drink. Fermentation is a natural process in which microorganisms such as bacteria, yeast and moulds convert one substance into another. When 'fed' with sugar or other carbon sources, microorganisms can produce substances such as acid and alcohol (which affect flavour and preservability), or grow into a protein-rich biomass that can form the basis of novel foods.
"There are really three distinct strands to our work on fermentation and novel foods. The first is to process side streams from the industry. One example is rapeseed press cake, which is what remains after pressing rapeseed oil. It is high in protein and fibre, but has a bitter taste. Here, fermentation could be used to improve the flavour, by adding microorganisms that taste good themselves or that break down the bitter substances," explains Jenny Veide Vilg, Head of Microbiology and Hygiene at RISE.
"This is just one example of how it is possible to reduce waste and increase resource efficiency while creating new foods.
"Another track is called single cell protein. Here, it is the actual cells and proteins in a fungus or yeast that are targeted. By feeding the fungus or yeast with sugar and nutrients, they can grow rapidly and create a huge amount of biomass, which could, for example, replace soya in feed or food. "It's like growing protein in tanks instead of fields," says Jenny Veide Vilg.
We can actually do everything in fermentation, from the selection of suitable microorganisms to biotechnological and genetic adaptation to the finished product.
Living factories produce milk protein without cows
The third route is precision fermentation, in which microorganisms are genetically reprogrammed to produce specific substances or ingredients. For example, it is possible to program yeasts to produce the milk protein casein, which can be used to make vegan cheese and ice cream. In principle, microorganisms can be modified to produce exactly the protein you want.
"When we make these kinds of genetic changes, we have to find a way to keep them in the organisms. In the lab, we give organisms an evolutionary advantage if they carry a particular gene, so they keep it. Outside the lab, it's harder to have this control, so it's important to make the process robust and scalable," says Jenny Veide Vilg.
From the lab to the lunchbox
Fermentation is researched and tested on several fronts at RISE, not least at the food-approved facilities in Gothenburg and Örnsköldsvik. Food manufacturers come here with their challenges, ranging from flavours in new products to unused by-products, to take advantage of the technical infrastructure and knowledge.
"In fact, we can do everything in fermentation, from selecting the right micro-organism, through biotechnological and genetic adaptation, to the finished product. Thanks to the newly built facility in Örnsköldsvik, we can now also research and develop processes on a scale of up to 10,000 litres, which is important for creating the conditions for scalability," says Jenny Veide Vilg.
"Scaling up is one thing," she stresses, "but moving from research to a product that people want to eat is perhaps the biggest challenge.
"We have researchers at RISE working on the taste and texture of food, but also on neophobia, the phobia of trying new things. In the marine sector, a lot of work is being done to encourage consumers to eat seafood other than cod, salmon and herring. This work must also be done when it comes to fermented novel foods," says Jenny Veide Vilg.
How does it affect food safety?
Fermentation has been used to preserve and process food for thousands of years. When fermentative bacteria are allowed to grow in food, they produce acids that lower the pH and create an environment that inhibits harmful bacteria. This in itself contributes to food safety. Some lactic acid bacteria also produce bacteriocins, which directly inhibit the growth of pathogenic micro-organisms.
Fermentation for novel food development also takes place in closed and controlled environments.
If a new ingredient is produced using genetically modified micro-organisms - as is often the case with precision fermentation - the product is subject to rigorous testing before it can be approved for food use in the EU. In many cases, the micro-organisms are also removed before the product reaches the consumer - particularly in the industrial production of milk protein, for example.
