Characterization and Comparison of Basil Before and After Drying Using GC, GCxGC, and TOFMS

Importance of the topic

Basil is a widely used culinary herb whose aroma profile significantly affects flavor quality and consumer perception.
Understanding compositional changes during drying or curing processes is critical for quality control, product development, and sensory consistency in food and beverage applications.

Objectives and overview of the study

This study aimed to compare the volatile composition of fresh versus cured basil.
Comprehensive two-dimensional gas chromatography (GCxGC) combined with time-of-flight mass spectrometry (TOFMS) and advanced data analysis were applied to uncover subtle chemical differences that are not apparent in one-dimensional GC.

Methodology

Fresh basil was dried at 60 °C until moisture content reached 5–10 %, as measured by a moisture analyzer.
Samples were prepared by headspace solid-phase microextraction (HS-SPME) and injected into a GC and GCxGC-TOFMS system.
Triplicate analyses were performed on equivalent dry mass (11–12 mg) to ensure comparability between fresh and cured samples.

Applied instrumentation

• HS-SPME extraction: LECO L-PAL3 autosampler, triphase fiber, 2 min incubation/5 min extraction at 40 °C
• GCxGC modulator: LECO GCxGC QuadJet thermal modulator (1.5 s modulation, +15 °C offset)
• Columns: Rxi-5ms (30 m×0.25 mm×0.25 µm) and Rxi-17Sil MS (0.6 m×0.25 mm×0.25 µm)
• GC oven: 40 °C (2 min), ramp 10 °C/min to 250 °C, hold 2 min; secondary oven +10 °C offset
• Carrier gas: Helium at 1.40 mL/min constant flow
• MS detector: LECO Pegasus BT 4D TOFMS, 35–500 m/z, acquisition 10 spectra/s (GC) and 100 spectra/s (GCxGC)
• Moisture analyzer: LECO TGM800

Main results and discussion

GCxGC markedly increased peak capacity and resolved coeluting compounds that were indistinguishable in one-dimensional GC.
Using ChromaTOF Tile software, key volatiles such as 3-hexen-1-ol, estragole, γ-hexanolactone and various terpenes were identified and quantified in both sample types.
Several analytes increased or decreased significantly upon curing, reflecting changes in the sensory profile.

Benefits and practical applications

• Enhanced resolution and identification of minor and coeluting aroma compounds
• Non-targeted profiling enables discovery of previously obscured analytes
• Toolset supports batch comparison, quality assurance, and product formulation studies
• Methodology transferable to other herbs, spices, and food matrices

Future trends and possibilities for application

Integration of GCxGC-TOFMS with chemometric analysis and machine learning for predictive aroma profiling.
Development of high-throughput screening workflows for industrial quality control.
Coupling multidimensional GC with sensory analytics or online detection for real-time monitoring of processing effects.
Expansion to broader classes of botanicals and complex food systems.

Conclusion

Comprehensive GCxGC-TOFMS analysis coupled with advanced data mining revealed significant volatile differences between fresh and cured basil.
The approach enhances the depth of aroma profiling, providing valuable insights for quality control and product development in the food and flavor industries.

Reference

No specific literature list was provided in the original text.