Widely targeted metabolomics of 142 hydrophilic compounds in beer using liquid chromatography-single quadrupole mass spectrometer (ASMS)

Importance of the Topic

Beer is a complex beverage whose taste, aroma and health-related properties are determined by a wide array of hydrophilic metabolites. Comprehensive profiling of amino acids, organic acids, nucleotides and functional phenolics is essential to link analytical data with sensory quality and potential bioactivity.

Objectives and Study Overview

The study aimed to develop and validate a streamlined liquid chromatography–single quadrupole mass spectrometry (LC-MS) workflow capable of simultaneously targeting 142 hydrophilic compounds. This method was demonstrated by comparing the metabolite profiles of six beer types, including lager, ale, low-malt, soy-protein, and two non-alcoholic variants.

Methodology and Instrumentation

• Sample Preparation: All beer samples were diluted 1:10 with water and spiked with 1 µmol/L 2-morpholinoethanesulfonic acid as an internal standard.
• Chromatography: Separation was achieved on a Shim-pack GIST PFPP column (2.1 × 150 mm, 3 µm) using gradient elution with 0.1% formic acid in water (A) and acetonitrile (B), at 0.25 mL/min (increased to 0.5 mL/min late in the run) and 40 °C.
• Mass Spectrometry: Detection employed a Shimadzu Nexera XR system coupled to an LCMS-2050 single quadrupole mass spectrometer, operating in both positive and negative ESI modes with optimized gas flows and temperatures.

Main Results and Discussion

• Detection Coverage: Out of 142 targets, 82 metabolites were reliably detected across samples, including key amino acids, organic acids and nucleoside derivatives.
• Multivariate Analysis: Principal component analysis (PCA) and hierarchical cluster analysis (HCA) grouped the six beers into two distinct clusters consistent with ingredient composition and brewing processes.
• Purine Metabolites: Standard lager and ale beers exhibited the highest levels of purine nucleotides, whereas the low-malt, purine-free beer showed negligible purine content.
• Functional Phenolics: Beers with higher malt content and one non-alcoholic variant were enriched in antioxidant compounds such as ferulic, vanillic and sinapic acids, as well as GABA.

Benefits and Practical Applications

The established method provides a rapid, sensitive and accessible platform for routine quality control and research in brewing. It enables beverage manufacturers and laboratories to:

• Characterize flavor precursors and bioactive constituents in beer formulations.
• Monitor consistency between production batches and detect process-related changes.
• Support product innovation by linking metabolite profiles to sensory attributes.

Future Trends and Potential Applications

• Integration with high-resolution mass spectrometry for expanded metabolome coverage.
• Application of the workflow to other fermented beverages and food matrices.
• Development of predictive models correlating metabolite signatures with flavor and health outcomes.

Conclusion

The single quadrupole LC-MS approach successfully enabled simultaneous quantification of diverse hydrophilic metabolites in beer. Distinct clustering of samples underscores the method’s capacity to differentiate products based on ingredient and process variables. This workflow offers a practical solution for the brewing industry and analytical laboratories seeking comprehensive metabolomic insights.

Reference

No additional literature references were provided in the source document.