Analysis of Aroma Compounds in Cheese

Significance of the Topic

Accurate profiling of volatile and aroma compounds in cheese is essential for quality control, product development, and ensuring consistent sensory profiles across production batches. Volatile sulfur compounds, in particular, play a major role in cheese flavor but are often difficult to detect with conventional sampling techniques.

Objectives and Study Overview

This study aimed to evaluate a novel combination of a hybrid silica-carbon adsorbent (MonoTrap RGC18 TD) with thermal desorption gas chromatography–mass spectrometry (TD-GC/MS) for comprehensive aroma profiling in Parmesan and Blue cheese varieties. The goal was to demonstrate efficient capture and analysis of a broad spectrum of volatiles, including low-abundance sulfur species.

Methodology and Instrumentation

Ten grams of cheese were sealed in a 40 mL vial with a MonoTrap RGC18 TD adsorbent held above the sample. The headspace was agitated at 60 °C for 3 hours to collect volatile compounds. The MonoTrap device was then introduced directly into the OPTIC-4 multi-purpose injector for thermal desorption at 200 °C for 5 minutes under splitless conditions. Desorbed analytes were cryo-trapped at –150 °C before transfer onto an InertCap Pure-WAX capillary column (60 m × 0.25 mm I.D., df = 0.25 µm). GC–MS analysis was performed on a GCMS-QP2010 Ultra system equipped with OPTIC-4 and an AOC-5000 Plus auto-sampler. The oven program ramped from 40 °C (5 min hold) to 250 °C at 6 °C/min. Mass spectra were acquired in scan mode from m/z 29–600.

Key Results and Discussion

Total ion chromatograms revealed over 30 distinct volatiles in each cheese type, encompassing aldehydes, ketones, alcohols, acids, esters, pyrazines, lactones, and sulfur compounds such as dimethyl disulfide and dimethyl sulfone. The MonoTrap-TD approach enabled reliable detection of sulfur species that are often lost or suppressed in conventional thermal desorption systems. Compound identification was confirmed by spectral library matching.

Benefits and Practical Applications

• Solvent-free sampling with minimal background interference due to pre-conditioned MonoTrap devices.
• Enhanced sensitivity for trace sulfur and other low-abundance volatiles critical to flavor perception.
• Direct desorption into the GC inlet reduces sample handling and risk of compound loss.
• Applicability to routine quality control, batch comparison, and flavor development in dairy research and industry.

Future Trends and Opportunities

Advancements may include coupling MonoTrap sampling with multidimensional GC or high-resolution mass spectrometry to improve separation and identification of complex aroma matrices. Integration with sensory analysis and chemometric methods could establish stronger correlations between chemical profiles and sensory attributes. Automation of headspace sampling workflows may further increase throughput for industrial applications.

Conclusion

The combination of MonoTrap RGC18 TD adsorbent and OPTIC-4 TD-GC/MS provides a robust, sensitive platform for comprehensive aroma profiling in cheese. This approach overcomes limitations in detecting key sulfur volatiles, offering significant benefits for quality assurance and flavor research.

References

Shimadzu Corporation. LAAN-J-E062 Application Data Sheet: Analysis of Aroma Compounds in Cheese. First Edition, June 2012
GL Sciences, Inc.