Enhanced Characterization and Comparison of Thyme Varieties from Different Geographical Origins

Significance of the topic

Analysis of volatile and semivolatile compounds in herbs is critical for flavor quality, authenticity, and supply chain integrity in the food and fragrance industries. Profiling aroma species supports raw material evaluation and ensures consistent product performance and consumer satisfaction.

Aims and overview

This study evaluates dried thyme varieties from France, Morocco, Poland, and Spain using a combined GC-TOFMS and automated data processing workflow. The goal is to identify and compare non-target volatile compounds to reveal geographic differences in aroma profiles and support quality control.

Used Instrumentation

• LECO Pegasus BTX GC-TOFMS with StayClean ion source
• ChromaTOF Sync software for deconvolution, alignment, and statistical analysis
• LECO L-PAL 3 headspace autosampler
• Tri-phase SPME fiber (PDMS/DVB/CWR)
• Rxi-5ms GC column (30 m, 0.25 mm id, 0.25 μm)

Methodology

• Sample preparation: 50 mg dried thyme in 20 mL vial, incubated at 40 °C for 2 min, extracted 5 min by HS-SPME
• GC method: inlet at 250 °C, split 20:1, helium carrier at 1.4 mL/min, temperature ramp from 40 °C to 250 °C
• MS detection: 35–500 m/z mass range at 10 spectra/s
• Retention index calibration using alkane standard

Main results and discussion

Non-target full mass-range acquisition yielded rich chromatograms enabling successful deconvolution of co-eluting species. Key compounds identified with mass spectral matching and RI support included thymol, carvacrol, β-myrcene, 2-pentyl furan, and 2-hexanone. Trends across origins:

• Thymol was most abundant in French and Polish thyme and lowest in Moroccan
• Carvacrol peaked in Moroccan samples
• β-Myrcene and 2-pentyl furan exhibited distinct distributions consistent with aroma note variations

PCA grouped France and Poland together, while Spain and Morocco formed separate clusters, reflecting compositional similarities and differences. Heat maps highlighted origin-specific marker compounds.

Benefits and practical applications

• Comprehensive non-target screening accelerates quality assessment and authenticity verification
• Automated deconvolution and statistical processing streamline data interpretation for routine analysis
• Insights into aroma profiles aid product development, supply chain monitoring, and regulatory compliance

Future trends and potential applications

• Integration with larger spectral libraries and machine learning for improved compound identification
• High-throughput workflows to support real-time quality monitoring
• Portable GC-TOFMS platforms for on-site authenticity testing
• Expanded non-target screening in complex matrices beyond herbs

Conclusion

The combined Pegasus BTX GC-TOFMS and ChromaTOF Sync workflow delivered robust non-target profiling of thyme varieties, revealing distinct volatile patterns linked to geographic origin. Automated deconvolution, alignment, and statistical analysis provided rapid insights that enhance aroma characterization and support quality control in the food and fragrance sectors.

References

1. Good Scents database