Chemical characterization and sensory evaluation of a phenolic-rich melanoidin isolate contributing to coffee astringency

Abstract

The tactile flavor sensations of coffee are an important indicator of product quality, yet the stimuli contributing to these percepts remain insufficiently defined. In the present work, compounds that contribute to astringency in coffee were investigated. A multi-dimensional sensory-guided fractionation method was employed whereby preparative-scale liquid chromatography was leveraged to separate the coffee brew into subfractions, and then followed by sensory evaluation to identify fractions with perceptual impact. This process, paired with high-resolution chemical characterization via Fourier-transform ion cyclotron resonance/mass spectrometry, revealed a complex, phenolic-dominant, melanoidin fraction. Further sensory recombination testing confirmed this fraction imparted a perceptible astringent sensation at coffee-relevant concentrations in both water and coffee matrices. We hereby provide the first evidence of melanoidins contributing to the complex tactile flavor profile of coffee.