Research Reveals How Microorganisms Can Enhance Nutritional Value of Plant-Based Foods

The study indicates that this approach allows researchers to extract greater nutritional benefits from the same quantity of plant-based products or animal feed. Associate Professor Christian Solem from the DTU National Food Institute stated that plant proteins often lack sufficient quantities of essential amino acids to serve as an ideal nutritional source. To address this, the researchers propose using microorganisms to enrich these foods with essential amino acids and essential vitamins.

Proteins consist of amino acids, which are vital for human health as some of them cannot be produced by the body. A protein is defined as "complete" when it contains all nine essential amino acids in adequate amounts. Many plant proteins, however, are deficient in one or more of these vital amino acids.

The study, titled "A Novel and Simple Fermentation Approach for Adjusting the Amino Acid Composition in Plant Biomasses to Enhance Nutritional Value for Humans and Animals," was published in the Journal of Agricultural and Food Chemistry. The researchers identified fermentation with specific microorganisms as a solution to improve the amino acid quality of plant ingredients.

By fermenting various plant proteins, they successfully enriched them with lysine, an essential amino acid. Solem explained that the use of microorganisms not only enhances the amino acid profile but also improves digestibility by partially breaking down plant proteins. This is particularly significant since many crops contain antinutrients that impede nutrient absorption.

The research is part of the NextOrganic project, focusing on animal feed, but the developed technology could also benefit human food production. The researchers believe this method may help combat malnutrition in low-income countries reliant on plant-heavy diets.

Their experiments have primarily involved faba beans and rapeseed press cake, which are widely produced in Denmark and Northern Europe. Faba beans are rich in protein and serve both human and animal dietary needs, while rapeseed press cake is a byproduct of oil extraction that can substitute for imported soy in animal feed.

In animal feed, a lack of essential amino acids can result in stunted growth and health issues in animals. The common solution is to provide excessive protein or to use fermented amino acids. Jan Værum Nørgaard, a professor at Aarhus University, noted that the organic production of pigs and poultry does not allow the addition of synthetic amino acids, making increased protein intake the only viable option. This practice contributes to environmental challenges due to higher nitrogen waste.

The researchers utilized a two-stage fermentation process, initially employing Bacillus subtilis subsp. natto to decompose faba beans and rapeseed press cake, thereby releasing nitrogen sources. Subsequently, they added Corynebacterium glutamicum, which converted these nitrogen sources into lysine. Following fermentation, the lysine content increased 3.4-fold in faba beans and 3.6-fold in rapeseed meal, measuring 37.5 grams and 29 grams of lysine per kilogram of dry matter, respectively. Further efforts are underway to enhance the levels of two additional essential amino acids.

The findings have significant implications for improving nutritional quality in both human and animal diets.