Study reveals impact of fava bean proteins on sensory cells in the mouth

Researchers at the Leibniz Institute for Food Systems Biology at the Technical University of Munich have for the first time investigated how protein structures derived from fava beans affect a cellular model of human oral tactile cells. These sensory cells respond to mechanical stimuli such as pressure and play a key role in the perception of texture and mouthfeel of food and beverages. The new findings could help improve our understanding and ultimately optimize the sensory acceptance of plant-based foods, promoting a more sustainable and healthier diet.

For many consumers, aspects of environmental sustainability, health and/or animal welfare are important reasons to increasingly choose a plant-based diet. According to Statista, global sales of plant-based foods already reached 29.4 billion US dollars in 2020. By 2030, this figure is expected to rise to as much as 161.9 billion US dollars.

It is therefore not surprising that there is a strong demand for biomaterials that can improve the mouthfeel of plant-based food alternatives."

Sanjai Karanth, first author and research associate in the Mechanoreceptors junior research group at the Leibniz Institute

Protein nanofibrils derived from fava beans are one such biomaterial.

Special protein molecules

Protein nanofibrils are special protein molecules organized into tiny structures. They have unique physicochemical properties that can have a lasting effect on the texture and thus the mouthfeel of foods.

While much is known about their formation and physical properties in liquid media, little research has been done on how these fibrils affect cells under physiological conditions. For example, there is a lack of studies on cellular model systems that would allow future conclusions to be drawn about the texture perception of protein nanofibrils.

This is exactly where the research of the Leibniz team, led by junior research group leader Melanie Köhler, comes in. Her team focuses on the mouthfeel of food. Using state-of-the-art technologies, the research group has for the first time investigated how protein nanofibrils from fava beans affect cells of a human cell line of so-called mechanoreceptor cells.

Investigated under physiological conditions

When studying the model cells under physiological conditions, the researchers first found using atomic force microscopy that the nanofibrils roughened the surface structure of the cells without changing their overall elasticity. "Since the biophysical effect was not very pronounced, we further investigated what was happening at the molecular level," explains principal investigator Melanie Köhler.

The tests showed that adding the nanofibrils to the cells' culture medium altered the activity of receptor genes that play a role in the perception of food texture. These included mechanosensitive ion channels such as piezo receptors, as well as receptors that detect fatty acids. Further studies on artificial cell membranes also showed that the fibrils interact with the membranes via lipids, which affects membrane elasticity in this test system.

"Although our research is still in its early stages, our biophysical and biochemical results already suggest how nanofibrils can influence the perception of texture and fat," says Melanie Köhler. "Therefore, we want to deepen our new findings in future experiments and sensory studies. In the long run, we want to find new applications for plant-based nanofibrils to develop sensorially appealing foods with improved texture."