Chemometric Assessment of Volatile Fraction of Pesto by SPME Arrow GC Orbitrap Mass Spectrometry

Significance of the Topic

Pesto Genovese is prized for its aromatic signature, which derives from a complex blend of basil, cheese, pine nuts, garlic and olive oil. Industrial processing steps such as pasteurization or sterilization, while extending shelf life, can alter volatile compounds responsible for aroma and taste. A robust analytical approach to monitor these changes supports quality control, process optimization and product authenticity verification.

Study Objectives and Overview

This work aimed to profile the volatile fraction of commercially produced pesto samples prepared by different technologies. By combining headspace solid-phase micro-extraction (SPME) Arrow with high-resolution Orbitrap GC-MS and chemometric tools, the study sought to:

• Extract and identify key volatile organic compounds (VOCs).
• Discriminate samples based on production processes.
• Demonstrate the performance of SPME Arrow and Exactive GC Orbitrap in food volatolomics.

Used Instrumentation

• Thermo Scientific Exactive GC Orbitrap GC-MS with TriPlus RSH autosampler and SPME Arrow configuration
• DVB/CWR/PDMS Arrow fiber (110 µm coating, 20 mm length)
• TraceGOLD TG-1MS column (30 m × 0.32 mm × 1.0 µm)
• Compound Discoverer 3.1 and TraceFinder software for data processing and chemometrics

Methodology

Pesto samples (1 g each) were homogenized in 10 mL headspace vials. A 15-minute incubation/extraction at 60 °C with stirring enabled automated concentration of a broad VOC range. Chromatographic separation used a stepped GC temperature program (40 °C to 300 °C). Full-scan Orbitrap acquisition at 60,000 FWHM provided sub-1 ppm mass accuracy over 50–550 Da. Deconvolution and library matching (NIST17) in Compound Discoverer yielded putative identifications and retention indices. Multivariate statistical analysis including principal component analysis (PCA) highlighted compositional differences across sample groups.

Main Results and Discussion

The total ion chromatograms exhibited distinct patterns according to thermal treatment and vendor. Major monoterpenes like anethole and minor compounds such as γ-terpinene were quantified reproducibly. PCA separated samples by processing method; heat-treated pesto showed elevated γ-terpinene and linalool, while raw-style products were richer in β-caryophyllene and germacrene. Sulfur‐containing compounds (diallyl disulfide/trisulfide) marked garlic-intensive samples. High resolution and accurate mass data allowed clear discrimination of isobaric species and confident molecular ion assignment via electron impact (EI) and chemical ionization (CI) spectra.

Benefits and Practical Applications

• Rapid, solvent-free extraction with SPME Arrow reduces prep time and risk of artifact formation.
• Orbitrap resolution and mass accuracy enhance compound identification in complex matrices.
• Chemometric models enable authentication, process monitoring and supplier comparison.
• Workflow is adaptable to other food products requiring volatile profiling.

Future Trends and Potential Applications

Advances may include integration with real-time monitoring sensors and mobile GC-MS platforms for on-site quality control. Enhanced data analysis via machine learning could improve pattern recognition and predictive modeling of aroma changes. Coupling with sensory evaluation and metabolomic data will deepen understanding of flavor formation pathways.

Conclusion

This study demonstrates that SPME Arrow combined with high-resolution Orbitrap GC-MS and chemometric analysis constitutes a powerful strategy for volatile profiling of pesto. The approach offers high sensitivity, mass accuracy and statistical discrimination capacity, making it a valuable tool for food quality assessment and process optimization.

References

1. Salvadeo P., Boggia R., Evangeliti F., Zunin P. Analysis of the volatile fraction of “Pesto Genovese” by headspace sorptive extraction (HSSE). Food Chemistry, 105(2007):1228–1235.
2. Zunin P., Salvadeo P., Boggia R., Lanteri S. Study of different kinds of “Pesto Genovese” by the analysis of their volatile fraction and chemometric methods. Food Chemistry, 114(2009):306–309.