Regular consumption of coffee has been reported to have positive effects on health and enhance quality of life. Coffee consumption habits are known to be impacted by the flavor quality such as the bitter taste attributes. Therefore, understanding the molecular underpinnings of bitter perception in coffee brew is of importance to tailor bitterness profiles for different consumer segments. The current study utilized an untargeted chemical profiling flavoromics approach to identify compounds that contribute to coffee brew bitterness. Fourteen coffee brew samples were chemical profiled by UPLC/MS-QToF and the bitter intensities were determined by a descriptive sensory panel. Significant differences in the perceived bitterness intensity (p &lt; 0.05) were noted among the fourteen coffee brew samples, ranging from 5.0 to 9.4, with no significant correlation observed to the quantified caffeine content (R2 = 0.07). The untargeted UPLC/MS-QToF chemical profiling obtained 1680 chemical features after data processing. A OPLS model for bitterness intensity and the chemical profile was established with good fit (R2Y &gt; 0.9) and predictive ability (Q2 &gt; 0.9). Ten chemical markers that were highly predictive of bitter intensity were subsequently purified by multi-dimensional preparative LC/MS for quantification, sensory recombination testing, and compound identification. Compounds negatively correlated to coffee bitterness were selected for sensory recombination testing and when added to a control brew significantly reduced bitter intensity by 1.5 points (p &lt; 0.05). Three compounds, namely 4-caffeoylquinic acid, 5-caffeoylquinic acid, and 2-O-β-D-glucopyranosyl-atractyligenin were identified as the main bitter modulators in coffee, and individually decreased the perceived bitterness intensity of the brew between 0.6-0.8 points. These results support the importance of bitter taste modulators to the flavor perception of coffee brew.

Identification of coffee compounds that suppress brew bitterness

ACS Fall 2021

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