Differential analysis of fermented beverage using fast polarity switching TOFMS acquisition with high mass accuracy and multivariate analysis

Significance of the Topic

This study addresses the need for comprehensive metabolite profiling in fermented beverages, which is crucial for product quality assessment, flavor optimization, and process monitoring in the brewing industry.

Objectives and Study Overview

The primary goal was to establish a rapid, high-throughput liquid chromatography–time-of-flight mass spectrometry (LC-TOF MS) method with fast polarity switching. This approach aims to capture a broad spectrum of polar metabolites in various beer samples, differentiate beer types based on metabolic fingerprints, and monitor chemical changes during thermal degradation.

Methodology and Instrumentation

Beer samples (n=25) were selected to represent different malt contents and origins. Chromatographic separation used a reversed-phase Phenomenex Synergi Hydro-RP 80Å column (150×2.0 mm, 4 µm) at 40 °C, employing a gradient of water and acetonitrile (both containing 0.1% formic acid) at 0.2 mL/min. Mass spectra were acquired on an LCMS-IT-TOF system with fast polarity switching, achieving external calibration mass accuracy below 3 ppm across m/z 85–1000. Both positive and negative electrospray ionization modes were used. Multivariate statistical analysis, including principal component analysis (PCA), was performed using SIMCA-P+ software.

Main Results and Discussion

• Detection of ~1 072 positive and ~480 negative ion features within a 20 min run.
• High mass accuracy enabled confident molecular formula predictions for numerous polar metabolites.
• Key compounds identified included amino acids (tyrosine, phenylalanine, proline, pyroglutamic acid), organic acids (fumaric, citric acid), nucleosides (adenosine, deoxyadenosine), and hypoxanthine.
• PCA separated samples into groups correlating with malt content: low-malt, standard, high-malt beers, and distinctive styles such as Belgian ales. Marker ions m/z 205.0976 (tryptophan) and m/z 191.0199 (citric acid) characterized high-malt beers.
• A thermal degradation model (up to six days at 60 °C) revealed progressive decline of deoxyadenosine (m/z 252.1091), demonstrating the method’s sensitivity to product deterioration.

Benefits and Practical Applications

The developed LC-TOF MS workflow enables rapid, high-sensitivity profiling of polar metabolites for quality control in brewing. It supports discovery of chemical markers for beer differentiation, authenticity verification, and monitoring of storage or processing-induced changes. The approach is adaptable to other beverages and biofluids for industrial and research applications.

Future Trends and Potential Applications

Future developments may include integration of higher-resolution mass analyzers, automated data-processing pipelines, and expanded spectral libraries for deeper metabolome coverage. Real-time fermentation monitoring, combined omics approaches, and application to a wider range of fermented foods and beverages are promising directions. Advanced machine learning techniques could further enhance marker discovery and predictive quality modeling.

Conclusion

Fast polarity-switching LC-TOF MS provides a robust platform for untargeted metabolite profiling in fermented beverages. High mass accuracy combined with multivariate analysis yields detailed metabolic fingerprints for product classification and quality assessment, making this method well suited for both research and industrial QA/QC workflows.

Reference

• I. Duarte et al., Journal of Agricultural and Food Chemistry, 2002, 50, 2475–2481
• C. Almeida et al., Journal of Agricultural and Food Chemistry, 2006, 54, 700–706
• S. Yamaki et al., Proceedings of the 59th ASMS Conference, 2011, WP 354