The molecular world of bitter compounds has so far only been partially explored. Researchers at 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) have now isolated three new bitter compounds from the mushroom Amaropostia stiptica and investigated their effect on human bitter taste receptors. In doing so, they discovered one of the potentially most bitter substances known to date. The study results expand our knowledge of natural bitter compounds and their receptors, thus making an important contribution to food and health research.