Microorganisms Enhance Nutritional Value of Plant-Based Foods

Research from the DTU National Food Institute and Aarhus University reveals that microorganisms can be used to specifically modify the amino acid composition of plant-based foods, improving their nutritional value for both humans and animals. This technique allows for increased nutrition from the same quantity of plant products or animal feed.

Associate Professor Christian Solem from the DTU National Food Institute stated, "Plant proteins do not contain the right amino acids in sufficient quantities to be an ideal source of nutrition for humans. Our solution is to use microorganisms to enrich plant-based foods with essential amino acids and important vitamins."

Proteins consist of amino acids, with humans requiring essential amino acids that the body cannot produce. A protein is considered 'complete' when it contains all nine essential amino acids in adequate amounts; many plant proteins fall short in one or more of these.

The researchers utilized fermentation with specific microorganisms to enhance the essential amino acid lysine in various plant proteins. Christian Solem noted, "We can use microorganisms to improve the amino acid profile of plant-based ingredients while also making them easier to digest by partially breaking them down. This is particularly beneficial as many crops contain antinutrients that hinder the absorption of nutrients."

The project demonstrates this method's effectiveness with lysine and aims to enhance crops with two additional essential amino acids. While targeting animal feed, the technology can also improve plant-based foods for human consumption and may help combat malnutrition in low-income countries reliant on plant-heavy diets.

The research primarily focused on faba beans and rapeseed press cake, both of which are widely produced in Denmark and Northern Europe. Faba beans serve as a protein-rich crop for both animal and human food, while rapeseed press cake is the byproduct after oil extraction.

In animal feed, essential amino acid deficiencies can slow growth and lead to illness. Current practices often involve overfeeding animals protein or adding synthetic amino acids, which is not permitted in organic production, creating environmental concerns due to nitrogen waste. Professor Jan Værum Nørgaard of Aarhus University emphasized that enhancing protein composition would improve feed efficiency and mitigate waste.

The researchers employed a two-stage fermentation process wherein they first treated faba beans and rapeseed press cake with Bacillus subtilis subsp. natto to break down proteins and release nitrogen sources. Subsequently, they introduced Corynebacterium glutamicum to convert these nitrogen sources into lysine. Post-fermentation, lysine content increased by 3.4 times in faba beans and 3.6 times in rapeseed meal, yielding 37.5 and 29 grams of lysine per kilogram of dry matter, respectively. Researchers are now working on solutions for additional essential amino acids.

The findings, titled "A Novel and Simple Fermentation Approach for Adjusting the Amino Acid Composition in Plant Biomasses to Enhance Nutritional Value for Humans and Animals," were published in the Journal of Agricultural and Food Chemistry. This research forms part of the NextOrganic project, funded by ICROFS under the Green Development and Demonstration Programme (GUDP).