An untargeted metabolomic method based on UPLC-QToF was used to identify potential markers in coffees brewed by boiled, pour-over and cold-brew methods, and a targeted method was used for marker identification and quantification. Caffeine content were compared as well. The results indicated that cold-brew could extract as much caffeine as the boiled method, while the caffeine content of the pour-over group was significantly lower (<i>p &lt; </i>0.05). Distinctive separation among the three groups could be seen from principal component analysis and hierarchical clustering analysis. Analysis of variance, fold change and orthogonal projection to latent structures discriminant mode were conducted to find the potential marker. Subsequently, nine potential markers were putatively identified from the MS/MS fragments, and five of them were confirmed with standards. Among the markers, the contents of norharman and harman were higher in the pour-over and boiled methods, compared to the cold-brew method. This method provides an effective approach for differentiating coffee samples brewed by different methods. And the result also suggested the non-thermal approach of cold-brew could offer healthier coffee, with no loss in caffeine.

Use of liquid chromatography quadrupole time-of-flight mass spectrometry and metabolomic profiling to discriminate coffee brewed by different methods

2019 Spring National Meeting

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