Analysis of aroma compounds in chocolate formulated from cacaos of different geographical origins using SPME Arrow-GC-MS

Significance of the topic

Assessing the aroma profile of chocolate is vital for understanding flavor quality and consumer preferences. Linking chemical composition to geographic origin supports authenticity verification and product differentiation in a competitive bean-to-bar market.

Study objectives and overview

This study aimed to profile volatile compounds in four single-origin 70% cocoa chocolates, each sourced from a different country, using SPME Arrow-GC-MS. Multivariate principal component analysis (PCA) was applied to correlate aroma profiles with characteristic sensory attributes.

Methodology and instrumentation

Five-gram samples of finely chopped chocolate were placed in 20 mL vials. Headspace volatiles were extracted at 36 °C for 30 min using a PDMS-coated SPME Arrow fiber, then desorbed at 250 °C into a GC-MS system. GC separation employed a Supelcowax10 column with a temperature program from 40 °C to 240 °C. Mass spectra were acquired in scan mode (35–350 m/z). Data processing and compound identification used GCMSsolution™ with NIST and FFNSC libraries. PCA was conducted in SIMCA to visualize sample clustering.

Instrumental setup

• GC-MS: Shimadzu GCMS-TQ8050 NX
• Autosampler: AOC-6000 with SPME Arrow capability
• Column: Supelcowax10 (30 m×0.25 mm i.d., 0.25 µm film)
• SPME Arrow fiber: PDMS (100 µm film, 20 mm length)

Key results and discussion

Total ion chromatograms displayed distinct peak patterns for each origin. PCA explained 48.6% of variance in PC1 and 33.6% in PC2, clearly separating the four samples. The nutty-aroma sample grouped with high pyrazine content, the fruity-aroma sample correlated with ester and alcohol peaks, the floral-aroma sample showed elevated aliphatic alcohols, and the spicy-aroma sample contained sulfur and nitrogen heterocycles. Triplicate analyses demonstrated excellent reproducibility.

Benefits and practical applications

• Comparative profiling of chocolate origins for quality control and authentication.
• Correlation of volatile markers with sensory descriptors to guide product development.
• Solvent-free, reproducible extraction suitable for routine QA/QC laboratories.

Future trends and potential applications

Integration with high-resolution mass spectrometry and data-driven approaches can enhance marker discovery. Advances in fiber chemistry and automated sampling will improve sensitivity and throughput. Extending this workflow to other food matrices and coupling with sensory or metabolomic data promises deeper insights into flavor science and traceability.

Conclusion

The SPME Arrow-GC-MS method combined with PCA offers a robust, sensitive, and reproducible approach for profiling cocoa origin-specific aroma compounds. This workflow effectively links chemical signatures to sensory attributes and supports quality assurance in specialty chocolate production.

Reference

• Christine Counet, Delphine Callemien, Caroline Ouwerx, Sonia Collin, Use of Gas chromatography-olfactometry to identify key odorant compounds in dark chocolate. Comparison of samples before and after conching, Journal of Agricultural and Food Chemistry, 50, 2385–2391 (2002).