Development of a favor release analysis method on volatile compounds of citrus fruits by DART MS

Significance of the topic

The ability to monitor volatile flavor compounds in real time is key for linking analytical measurements to sensory perception. Conventional gas chromatography requires extensive sample preparation and long analysis times, limiting its use for dynamic studies of aroma release. Direct Analysis in Real Time mass spectrometry (DART MS) with a closed-chamber interface overcomes these constraints by enabling rapid, successive detection of volatile molecules within seconds.

Objectives and Study Overview

This work aimed to establish a rapid analytical method to profile the release of characteristic volatile compounds from citrus fruits using a DART MS/MS system. The focus was on optimizing multiple reaction monitoring (MRM) transitions for structural isomers and demonstrating real-time flavor release detection on intact and crushed fruit samples.

Methodology and Instrumentation

A set of five aroma-active compounds was selected for method development: limonene, gamma-terpinene, octanal, linalool and alpha-terpineol. A Shimadzu LCMS-8030 triple quadrupole mass spectrometer was employed under positive ion mode. Key components:

• Analytes: C10H16 and C10H18O structural isomers plus octanal
• Ionization: DART-OS source for all compounds; APCI used for octanal comparison
• Mass spectrometry: Ultra-fast scanning (15 000 u/sec), polarity switching and MRM capability (up to 555 transitions/sec)
• Interface: Volatimeship closed-chamber for enhanced sensitivity and real-time sampling

Main Results and Discussion

MRM transitions were established for each analyte based on characteristic fragment ions: terpinene at m/z 170→153, limonene at 135→107, linalool at 154→81 and alpha-terpineol at 137→81. Positive-mode DART mass spectra revealed abundant fragment peaks, enabling selective monitoring without chromatographic separation. Application to Shonan Gold and common orange fruits demonstrated that volatile release profiles could be captured within a five-minute window. Release intensity changed markedly upon fruit squeezing, with distinct patterns observed between cultivars.

Benefits and Practical Applications

This closed-DART MS/MS approach offers:

• Sub-second temporal resolution for flavor release studies
• Minimal or no sample preparation for intact fruit analysis
• High sensitivity and selectivity via optimized MRM transitions
• Potential use in breeding, quality control and product development

Future Trends and Potential Applications

Emerging directions include integration with sensory evaluation, development of portable DART setups for field use, expansion to diverse food matrices and coupling with chemometric tools for comprehensive flavor fingerprinting. Advances in ion source design and data processing will further enhance dynamic monitoring of aroma compounds.

Conclusion

The developed closed-chamber DART MS/MS method enables rapid, real-time detection of key volatile flavor compounds in citrus fruits. Optimized MRM transitions and a high-speed interface deliver sensitive, selective measurements that can support research and industrial applications in flavor analysis.

References

• No literature references were provided in the original text.