Comprehensive Evaluation of Pesto Aroma Profiles Using SPME-GCxGC-TOFMS

Importance of the Topic

The sensory attributes of pesto are driven by complex volatile compounds that determine consumer appeal and product quality. Comprehensive aroma profiling supports recipe optimization, ensures batch consistency, and enhances brand differentiation in the competitive food market.

Objectives and Study Overview

This study evaluates headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (HS-SPME-GC×GC-TOFMS) for non-target analysis of commercially available pesto. Four distinct pesto products were profiled to demonstrate the method’s ability to resolve, detect, and identify low-level aroma compounds that coelute in conventional one-dimensional GC-MS.

Methodology and Instrumentation

Sample Preparation:

• One-gram aliquots of each pesto were sealed in 10 mL vials.
• Incubation and extraction at 60 C for 15 min using a DVB/CAR/PDMS fiber.
• Thermal desorption in GC inlet at 220 C with a 20:1 split.

Chromatographic Conditions:

• Primary column: 30 m×0.25 mm Rxi-5SilMS, 0.25 µm film.
• Secondary column: 0.6 m×0.18 mm Rxi-17SilMS, 0.18 µm film.
• Oven program: 40 C (2 min), 5 C/min to 210 C, then 20 C/min to 280 C.
• Modulation period: 2.7 s with +5 C and +15 C offsets for secondary oven and modulator.

Instrumentation Used

• LECO Pegasus BT 4D GC×GC-TOFMS system.
• LECO GC×GC QuadJet thermal modulator.
• Helium carrier gas at 1.2 mL/min.
• MS range: 40–550 m/z, acquisition at 200 spectra/s.

Main Results and Discussion

Complex contour plots revealed over 400 peaks (S/N > 20, similarity > 75 %) in a single pesto sample. GC×GC enhanced resolution separated coeluting terpenoids and fatty acids, enabling deconvolution of peaks only 25 ms apart. Examples include β-pinene vs hexanoic acid and 2-octenal vs γ-terpinene separations. LECO’s spectral deconvolution algorithms provided high-quality mass spectra for confident library matching and non-target discovery. Semi-targeted visualization of terpenoid bands (m/z 93) and 3D surface plots allowed direct comparison of α-pinene intensity across samples. The ChromaTOF software Reference feature automated differential analysis, classifying analytes as match, out-of-tolerance, not-found, or unknown relative to a selected reference sample.

Benefits and Practical Applications

• Enhanced detection of trace aroma compounds obscured in 1D GC.
• Improved confidence in compound identification via retention indices and spectral matching.
• Automated comparative profiling across product variants for quality control.
• Time-efficient workflow combining HS-SPME, GC×GC, and automated software tools.

Future Trends and Potential Applications

Advances may include integration of tile-based statistical approaches such as Fisher ratio mapping to accelerate discovery of significant aroma differences in large sample sets. Machine learning-driven deconvolution and real-time data processing could further streamline non-target workflows. Expansion to other complex matrices in foodomics and environmental analysis is anticipated.

Conclusion

HS-SPME-GC×GC-TOFMS on the Pegasus BT 4D platform, coupled with ChromaTOF software, offers a robust non-target method for comprehensive aroma profiling of complex food matrices like pesto. Superior chromatographic resolution and rapid TOFMS acquisition enable identification of hundreds of volatile species that remain unresolved by conventional approaches. Automated comparative tools support rapid differential analysis, enhancing product development and quality assurance.

References

• LECO application note 203-821-642 on tile-based Fisher ratio statistical comparison of pesto products.