Unlocking the protein digestibility of Nordic tempeh

In recent years, intensive efforts have been made to support the green transition of diets, both in academia and industry. There is a need for new plant-based meat alternatives, that are rich in protein, sustainable to produce, and are so appealing in both taste and texture, that the consumers will buy them. One such product is tempeh – a sliceable, protein rich food typically made from fermented soybeans.

Over the past three years, the GUDP-supported project "Tempeh – a Solution for Healthy and Climate-Friendly Eating" has worked on developing variants based on Nordic raw materials instead of soybeans, produced by the company Contempehrary. Among other things, the project has produced tempeh from fava beans, and Associate Professor Iben Lykke Petersen from the Department of Food Science has studied the protein digestibility of these variants. 

“The product was actually very good, but the protein digestibility wasn’t as high as expected. It was only about 10% higher than raw fava beans. We had anticipated that the fermentation process, which creates the tempeh product, would have a more significant impact on protein digestibility. However, we discovered that just a small tweak in the fermentation process—a bit of extra heat and more time—is enough to significantly increase protein digestibility in fava bean tempeh,” says Iben Lykke Petersen. 

A happy little accident

Iben worked on the project together with Linea Hejgaard Thulesen, a master's student whose thesis focused on the topic. Part of the work involved analyzing tempeh samples in a lab setup that mimicked how food is broken down in the stomach and small intestine, measuring the extent to which it breaks down into amino acids and peptides. 

One day, they received a new batch of samples, and one of them showed a significant improvement in protein digestibility—51% higher than raw fava beans and 37% better than the other tempeh samples tested, without any change in taste or texture. 

“The difference between samples was clear, but we couldn’t figure out what had happened. So, Linea contacted Contempehrary, and it turned out that the sample with high protein digestibility had fermented longer than intended due to a power outage. It was an accidental discovery but a healthy one, that we’re happy to have gotten a hold of,” explains Iben Lykke Petersen. 

Subsequent controlled experiments varying in fermentation time and temperature confirmed the findings. These led to a new production process for the tempeh that improved protein digestibility by 25%, while maintaining the same great taste and texture. Their findings will be published in a scientific article very soon. 

Collaboration ensures impact 

The discovery means that just a small change in the production of fava bean tempeh can make the product significantly more nutritious without altering its flavor or texture.  And this quick impact is one of the aspects that Iben appreciates most when collaborating with businesses.

“These partnerships ensure that my research remains relevant and practical. Instead of staying within my own academic interests, I develop solutions that are directly useful to companies and consumers. It’s incredibly motivating to see our findings quickly applied in practice,” says Iben. 

At Contempehrary, the findings have already been implemented. Tobias Noe Harboe, one of the company’s two founders and leader of the GUDP project, explains that they have adjusted key parts of the production process of fava bean tempeh accordingly.

“We’re deeply passionate about everything related to tempeh and continuously develop our products and methods. Collaborating with researchers who can delve into new and unique aspects of our products helps us innovate,” says Tobias Noe Harboe. 

Tempeh as a food of the future

As a firm, sliceable product, tempeh has significant potential in the transition to a more plant-based diet. Increasing the digestible protein content is especially important, as the more protein we can absorb from our food, the less we need to consume. This has major implications, particularly for large-scale food production, explains Iben. 

“Tempeh is a product with great potential, and it’s important to see it as a product in its own right—not an imitation of something else. With its high protein content and fermentation process, tempeh offers nutritional benefits that align with growing research showing the health advantages of fermented foods for gut health and the microbiome,” she says. 

Tobias also sees this potential, which was a driving factor behind establishing Contempehrary in 2019 with the mission of creating innovative and flavorful plant-based foods. 

“We love tempeh for its taste and texture, which makes it versatile as the protein component of meals. But the hidden functional qualities resulting from our fermentation methods are just as fascinating,” says Tobias Noe Harboe and continues: “Our vision is to make tempeh a staple food in Denmark, as it’s a brilliant shortcut to incorporating more legumes into diets—with the added benefit of improved protein digestibility. That’s genius!”