ACS 2021: Combining GC with MS and Olfactory Detection for a Variety of Food, Flavor, and Fragrance Analyses

Significance of the Subject

The integration of gas chromatography (GC), mass spectrometry (MS), and olfactory detection (O) represents a vital advancement in the analysis of food, flavor, and fragrance samples. Volatile and semi-volatile compounds that define aroma and off-odor characteristics can be isolated, identified, and linked to sensory perceptions. This sensory-directed approach accelerates quality control, product development, and troubleshooting in industrial and research laboratories.

Objectives and Study Overview

This work aimed to demonstrate how GC-MS-O can:

• Separate complex mixtures into individual analytes
• Identify characteristic aroma-active compounds via TOF-MS
• Correlate chemical identity with sensory descriptors for targeted analysis

The study covers three application examples: nutmeg essential oil characterization, sensory differences in cilantro, and identification of a plastic off-odor in beer.

Methodology and Used Instrumentation

Samples including essential oils and beverage matrices were analyzed with a Pegasus BT GC-TOFMS coupled to a GL Science Phaser Pro olfactory detector. Key steps:

• GC separation for analyte isolation
• TOF-MS for full m/z range acquisition and library matching
• Olfactory port for real-time sensory detection
• Deconvolution algorithms to resolve coeluting compounds

Major Results and Discussion

Nutmeg Essential Oil:
Chromatographic analysis highlighted ten peaks with the highest signal-to-noise ratio; brown shading marked four distinctive aroma notes. Deconvolution separated coeluting features and linked them to characteristic nutmeg, citrus, and clove notes.

Cilantro Sensory Variability:
Four peaks perceived as soapy or fresh by different assessors were detected. MS and retention index matching tentatively identified these as specific aldehydes responsible for the soapy off-note in genetically susceptible individuals.

Beer Off-Odor Troubleshooting:
An unexpected plastic off-odor in a beer sample was traced to styrene formation. Spectral and retention index data suggested enzymatic decarboxylation of cinnamic acid during fermentation as the generation pathway, guiding corrective process measures.

Benefits and Practical Applications

The combined GC-MS-O platform enables:

• Targeted identification of aroma-active compounds
• Rapid sensory-directed screening for QC and R&D
• Efficient troubleshooting of off-flavors in complex matrices

Future Trends and Potential Applications

Emerging directions include:

1. Integration with chemometric models for predictive sensory profiling
2. High-throughput GC-MS-O workflows for rapid flavor screening
3. Online sampling interfaces for real-time process monitoring
4. Expansion into non-food sectors (e.g., fragrances, environmental odors)

Conclusion

This study illustrates that the synergy of GC separation, full-spectrum TOF-MS, and olfactory detection offers an efficient analytical toolkit. It isolates key aroma contributors, verifies their identities, and links them to sensory impacts, thereby enhancing flavor characterization, consumer acceptability studies, and quality assurance.

References

Elizabeth M. Humston-Fulmer, Joseph E. Binkley, Lorne M. Fell. Combining GC with MS and Olfactory Detection for a Variety of Food, Flavor, and Fragrance Analyses. LECO Corporation, Saint Joseph, MI USA.