Researchers at the University of Helsinki have discovered an innovative and sustainable way to utilise by-products from the brewing industry, such as brewers' spent grain, and turn them into valuable food items.
The novel fermentation approach offers a sustainable solution for utilising brewing industry by-products and transforming them into functional foods.
Prabin Koirala from the Faculty of Agriculture and Forestry showed in his doctoral study that lactic acid bacteria (LAB) starters can effectively adapt to the complex spent grain. For example, adding fermented spent grain to wheat bread improved the bread's texture, moisture retention, and fiber content. Additionally, simulated digestion done in lab indicated that using fermented spent grain increased the production of beneficial substances for gut health, suggesting potential health benefits.
In practice, Koirala added sucrose to the spent grain during fermentation, which led to the production of beneficial substances dextran and oligosaccharides.
"The dual impact of dextran produced by LAB enhances both the texture and quality of food while supporting gut health. Also, the study aligns with the circular economy principles by reducing food industry by-products and waste, and promoting the development of healthy, fiber-rich food products," Koirala says.
Benefits for both consumers and food industry
In practice, food industry by-products can be transformed into valuable food ingredients through LAB fermentation. This provides food manufacturers with a sustainable ingredient that improves product quality and offers health benefits to consumers. Growing interest in sustainable food systems and gut health makes this research timely, as the brewing industry expands and the demand for sustainable, health-promoting foods increases globally.
Public examination:
Prabin Koirala, M.Sc. will defend the doctoral dissertation entitled "Upcycling of brewers? spent grain via in situ synthesis of dextran and oligosaccharides by lactic acid bacteria - Regulatory mechanisms and effects on gut microbiota metabolites" in the Faculty of Agriculture and Forestry, University of Helsinki, on 1 July 2025 at 12:00. The public examination will take place at the following address: Biokeskus 2, auditorio 2041, Viikinkaari 5. Associate Professor Felis Giovanna, University of Verona, will serve as the opponent, and Kati Katina as the custos.
The dissertation is also available in electronic form in Helda .
