Practice Abstracts
Fermented foods have been a part of the human diet for millennia. Today, there are roughly 5000 varieties of fermented foods and beverages prepared and consumed worldwide, contributing to 5-40% of the human diet. Fermented foods and beverages were defined in 2021 by ISAPP as “foods made through desired microbial growth and enzymatic conversions of food components”. A broad range of fermented foods exist, being produced from diverse food substrates, such as vegetables, grains, milk, fish and meat. Fermentation can increase the shelf-life of foods and can add new tastes and textures to foods. Fermented foods often contain live microorganisms, e.g. yoghurt, cheese and kombucha. However, in several fermented foods, the microorganisms are not alive anymore, for example, in bread, pasteurised fermented vegetables, soy sauce and wine.
During fermentation, microorganisms transform the food matrix and synthesise new components. A wide diversity of microorganisms can be used to produce fermented foods. The most familiar fermented foods require lactic acid bacteria, acetic acid bacteria, bacilli or other bacteria, yeasts, or filamentous fungi. During fermentation, several food components, e.g., carbohydrates, proteins and fibres, are transformed into other products, such as organic acids, gas or alcohol. Furthermore, microbes can also synthesise new molecules, e.g., B vitamins or antioxidants. The microorganisms used in food fermentation can originate from the raw material or manufacturing environment or be added as starter cultures. Choosing specific starter cultures may enable the precise modulation of certain food properties.
Pulses are the edible seeds from a legume plant, including beans, peas, lentils, lupin and other protein grains. They have great benefits for food security, nutrition, health, climate change and biodiversity. According to the UN, the cultivation of pulses is an effective strategy for achieving its 2030 Agenda for Sustainable Development, as they can contribute to the development of sustainable food systems and the eradication of world hunger and poverty.
Fermentation is a promising strategy for producing value-added, nutritious, and palatable pulse-based foods. Culinarily speaking, the fermentation of pulses can enhance their texture, appearance, colour and flavour. Regarding human health benefits, the fermentation of pulses can enhance protein digestibility, vitamin content, and bioavailability of minerals and reduce the content of non-nutritive compounds like flatulence-causing oligosaccharides. In addition, fermented pulses can contain beneficial microorganisms that could promote gut health.
The production process of fermented foods is often environmentally friendly, requiring low inputs of water and energy and limiting waste production. The shelf-life can be increased, helping to reduce food waste and energy-intensive logistics. Finally, fermented pulses address the demand for more nutritious plant-based protein options, addressing the need to decrease reliance on animal-based proteins.
For the above reasons, faba bean and yellow pea have great potential. We use them as study objects in the HealthFerm project, which will investigate the molecular changes caused in various foods by designed fermentation processes and their effects on food quality and health.
Cereals are the primary source of energy, carbohydrates and protein in the human diet. They also supply most dietary fibre, especially when whole grain products are consumed. Dietary fibres are paramount for gastrointestinal and overall health but are deficient in European diets, leading to a fibre gap.
Among cereals, wheat is Europe’s most produced and processed crop. Oats are much less produced and consumed, but their high-quality protein and dietary fibre and their suitability for coeliacs make them unique among cereals.
Fermentation can positively affect the taste, texture and even health-related properties of wheat-based products. It could also represent a new way to expand the use of oats in emerging plant-based foods such as dairy alternatives and meat analogues. Indeed, while oats are increasingly used to make such products, some of these plant-based alternatives are poor in protein and fibres and must be improved in taste and texture. Fermentation could help to solve these issues.
For the above reasons, wheat and oats have great potential. We use them as study objects in the HealthFerm project, which investigates the molecular changes introduced in various foods by designed fermentation processes and their effects on food quality and health.
Every traditional food fermentation is a unique microbial ecosystem shaping flavour, texture, shelf life and nutritional value. Yet only a small fraction of this microbial diversity has been explored. As a result, many microorganisms with the potential to improve food fermentations remain undiscovered. At the same time, food producers are seeking fermentation cultures that make plant-based food fermentations more reliable, nutritious, sustainable and appealing to consumers.
HealthFerm addressed this challenge by partnering with over 1,000 citizen scientists across Europe. Home fermenters documented their practices and contributed samples of sourdoughs and other plant-based fermented foods, effectively transforming Europe’s home kitchens into a living laboratory for fermentation research. Together, they created one of Europe’s largest collections of traditional fermented foods, capturing diverse ingredients, recipes, environments and microbial communities that could never be achieved through laboratory studies alone.
Using this unique resource, HealthFerm identified microorganisms naturally associated with desirable fermentation characteristics, including robust fermentation with novel plant-based substrates such as oats and faba beans, flavour development and the production of health-beneficial compounds. The most promising strains are now being isolated and characterized, providing the foundation for next-generation starter cultures and redesigned fermentation processes.
The project also returned knowledge directly to participants. Personalised microbiome reports and the AI-powered Dough-Pro assistant enable users to explore the diversity of fermentations, compare practices and experiment with new approaches. Additionally, all collected data will be made openly available through a Fermented Food Atlas, enabling anyone to explore and reuse these unique data.
Current dietary shifts encourage more plant-based foods, but consumer studies show that flavour, texture and appearance remain major barriers to consumer acceptance of many plant-based foods. Faba bean and oat are well suited to Nordic conditions and can support regional food production, yet faba bean is still often directed to feed or low-value uses. This project within HealthFerm addressed a practical question: How can fermentation transform Nordic crops into higher-value foods? Tempeh, a traditional Indonesian food normally made from fermented whole soybeans that are bound together into a dense, firm cake, was used as an example to answer this question.
Faba bean–oat tempeh was developed using controlled soaking, boiling, inoculation and solid-state fermentation. The products were assessed for sensory quality, composition, antinutritional factors, structure and in vitro digestion.
In a consumer test with 107 participants from Finland and Sweden, tempeh made with 85% faba bean and 15% wholegrain oat had the highest overall liking score compared with faba bean-only tempeh. The faba bean–oat products also showed higher chewiness and more favourable sensory attributes, including umami, nutty, buttery and fermented notes.
Fermentation also improved nutritional functionality. It acted as a multifunctional process, influencing flavour development, protein hydrolysis, antinutrient degradation and food structure formation.
The project further showed that starter culture selection can be used to steer product quality. Co-fermentation with Rhodotorula babjevae increased gamma-aminobutyric acid (GABA), free amino acids and selected phenolic compounds while maintaining the compact tempeh structure.
The main outcome is a processing route for turning Nordic faba bean and oat into higher-value fermented foods. This creates opportunities for product diversification, regional food production and reduced dependence on imported soy ingredients.
Oats are increasingly used in plant-based foods such as drinks and yoghurt alternatives. However, fermenting oats is often challenging. Slow acidification and limited microbial growth can hinder product development.
Researchers from the HealthFerm project therefore investigated why some oat fermentations perform better than others. The study compared oat wholemeal flour produced from conventional kilned oat groats with flour from non-kilned oat groats. Kilning is a heat treatment commonly applied in the oat industry to improve storage stability and prevent rancidity. While effective for product preservation, this process is meant to inactivate some naturally occurring oat enzymes.
The results showed that fermentation of non-kilned oat flour by lactic acid bacteria proceeded considerably faster than that of kilned oat flour. This was reflected in more rapid acidification, increased microbial growth, and greater biochemical changes in starch, protein, dietary fibre, and phytate. These differences were attributed to the activity of endogenous oat enzymes that remain active in non-kilned oats and help release nutrients needed by fermenting microorganisms.
The findings demonstrate that processing steps applied before fermentation can have a major impact on fermentation performance and product characteristics. Active oat enzymes play a crucial role in supplying nutrients to lactic acid bacteria and enabling desirable biochemical changes during fermentation. While the use of non-kilned oats may offer opportunities to improve fermentation efficiency, further research is needed to address potential challenges related to lipid stability and rancidity. Alternative strategies could include supplementing fermentations of kilned oats with enzymes or specific nutrients to support microbial growth and activity.
Bread is one of the world's most widely consumed foods. Pulse ingredients such as faba bean and yellow pea are increasingly attracting interest because they are rich in proteins and dietary fibres that are different from those in cereals and in bioactive compounds. However, their incorporation into bread remains challenging because they can negatively affect bread quality.
Researchers within the HealthFerm project investigated how selected combinations of lactic acid bacteria and yeasts can improve sourdough fermentation of pulse-based ingredients. A total of 288 combinations of microbes as starter cultures in type-II sourdoughs were screened using faba bean flour, faba bean protein concentrate and yellow pea flour. The best-performing sourdoughs were further matured and used as starter cultures for wheat sourdough breadmaking.
The incorporation of pulse-based sourdoughs increased the protein content and quality of the breads and resulted in substantially higher levels of free amino acids compared with the control bread. The sourdough breads were also enriched in several bioactive phenolic compounds. In addition, specific sourdough formulations showed reduced levels of anti-nutritional compounds such as phytic acid, while the breads generally developed more complex volatile profiles. These findings show that selected pulse-based sourdoughs enhance the nutritional functionality of bread while supporting pulse incorporation into bakery products.
For bakers and food producers, these findings highlight the importance of selecting suitable microbial consortia for pulse-based sourdough fermentation. Screening a wide range of microorganisms made it possible to identify pulse-based sourdoughs with improved functionality for breadmaking. This study demonstrates the potential of tailored microbial consortia to support the development of breads with enhanced nutritional quality and more diverse biochemical characteristics.