Most Bitter-Tasting Substance Ever Revealed – ryan

Scientists have identified the most bitter-tasting substance ever discovered—a potent chemical compound found in a “bitter bracket” mushroom.

The discovery comes from a collaborative project between the Leibniz Institute for Food Systems Biology at the Technical University of Munich in Freising and the Leibniz Institute of Plant Biochemistry in Halle (Saale).

Their research sheds new light on how the human body detects and reacts to intensely bitter compounds, some of which are not harmful despite their taste.

As part of the study, the team focused on the extremely bitter fungus, Amaropostia sigte, which develops a soft, white and shelf/bracket-like fruiting body with a rough surface and small pores.

A. stiptica can be found on hardwoods and conifers across the Northern Hemisphere.

Using modern analytical methods, researchers led by Norbert Arnold were able to isolate three previously unknown compounds and determine their molecular structures.

Follow-up testing by researchers in Freising showed that the compounds activated at least one of the approximately 25 known human bitter taste receptors.

One compound stood out: oligoporin D, which stimulates the receptor TAS2R46 at incredibly low concentrations—approximately 63 millionths of a gram per liter.

To illustrate the potency, that’s equivalent to one gram of oligoporin D dissolved in 106 bathtubs of water, where one gram is roughly the weight of a knife tip of baking soda.

“The more well-founded data we have on the various bitter compound classes, taste receptor types and variants, the better we can develop predictive models using systems biology methods to identify new bitter compounds and predict bitter taste receptor-mediated effects,” said food systems biologist Maik Behrens of the Leibniz Institute in Freising in a statement.

This includes both ingredients in food and natural substances in the body that can trigger bitter taste sensors found outside the mouth, like in the stomach or other organs.

The findings help expand the BitterDB database, which currently contains more than 2,400 bitter molecules. Of those, around 800 are linked to specific human bitter taste receptors. However, the majority of these known compounds are either synthetic or derived from flowering plants.

Bitter substances from fungi, bacteria, or animals are still rarely included, making this study a significant step in broadening our understanding.

Researchers note that bitter taste receptors likely evolved as a defense mechanism to prevent the consumption of harmful substances.

Yet not all bitter substances are toxic, and not all toxins taste bitter. For instance, the lethal death cap mushroom contains a toxin that is virtually tasteless.

Adding to the mystery, bitter taste receptors are found not just in the mouth, but also in the stomach, intestines, lungs, heart, and even on certain blood cells. Since we do not “taste” with these organs, scientists are still exploring the wider physiological roles of these receptors.

“Comprehensive data collections on bitter compounds and their receptors could help us to find answers to these open questions,” added Behrens.

“Our results contribute to expanding our knowledge of the molecular diversity and mode of action of natural bitter compounds.”

He concluded: “In the long term, insights in this area could enable new applications in food and health research, for example in the development of sensorially appealing foods that positively influence digestion and satiety.”

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Reference

Schmitz, L. M., Lang, T., Steuer, A., Koppelmann, L., Di Pizio, A., Arnold, N., & Behrens, M. (2025). Taste-Guided Isolation of Bitter Compounds from the Mushroom Amaropostia stiptica Activates a Subset of Human Bitter Taste Receptors. Journal of Agricultural and Food Chemistry, 73(8), 4850–4858.