Characterization of key bitter compounds in Idesia polycarpa var. vestita Diels fruit by sensory-guided fractionation

Idesia polycarpa var. vestita Diels (I. vestita) has become a promising oil crop due to its easily digestible and highly nutritious fruit oil. However, the intense bitter taste of its fruit greatly limits its development and promotion in the food industry. Herein, five key bitter compounds from I. vestita fruit were isolated by sensory-guided fractionation and characterized using ultra-high performance liquid chromatography-quadrupole time of flight-mass spectrometer and nuclear magnetic resonance. The bitter taste of the identified compounds was subsequently validated by threshold tests and computational molecular docking. The bitterness threshold in water of idesin was the lowest (12.051 mg/L), and all bitter substances spontaneously bound to the bitter receptors hTAS2R16 and hTAS2R14, with a stronger affinity for the latter (approximately-6.5 --9.0 kcal/mol). This is the first systematic study of bitter compounds in I. vestita fruit, providing a scientific basis for revealing the mechanism of bitterness formation and bitterness control.