Metabolomic profiling of beer by LC/MS has largely focused on the hops used or compositional changes that occur during storage. Here we profiled metabolomic differences in an amber ale that was fermented by White Labs with four different yeast strains. A 20-barrel batch of the ale was equally divided and fermented with Bedford British ale yeast, Dusseldorf alt yeast, Tennessee whiskey yeast and Abbey ale yeast. The yeasts imparted distinctly different flavor profiles that ranged from fruity to spicy, as determined by a sensory panel. Within two days post-fermentation, samples were received by JMU, sonicated, filtered and stored at -80 °C. Both positive and negative ion ESI q-TOF MS was used for metabolomic profiling. Principle component analysis (where P1 and P2 accounted for ~55% of the variance) revealed that the Tennessee whiskey yeast was least similar to the other strains in P1. The other three strains clustered together in P1 but were separated in P2. ANOVA with a Tukey post-hoc test was then used to identify up- and down-regulated (p&lt;0.05) molecular features (MFs, unique mass and retention time) across samples. These features were then searched against the Metlin database. Efforts moving forward will focus on more putative identification of differentially expressed MFs using MS/MS, spectral library searches and Agilent’s Mass Profiler Professional Pathway Analysis for <i>Saccharomyces cerevisiae</i> in order to better understand the role of yeast on a beer’s metabolome.

LC/MS metabolomic profiling of an amber ale fermented with four different yeast strains

251st National Meeting (2016)

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