Ambient Ionization Mass Spectrometric Detection of Aroma Released During Gummy Chewing

Importance of the Topic

The dynamics of retronasal aroma during eating strongly influence flavor perception, product acceptance and formulation decisions in food science. Objective, time-resolved chemical measurements of aroma release complement sensory panels by capturing fast changes in volatile emission tied to oral processing and texture. Methods that enable near-real-time monitoring without extensive sample preparation are particularly valuable for R&D, quality control and sensory science because they can link physical properties (e.g., gummy texture) to flavor delivery profiles.

Objectives and Study Overview

This study developed and evaluated a practical analytical workflow to measure retronasal aroma released during chewing using a single-quadrupole mass spectrometer (LCMS-2050) equipped with an ambient ionization source (Dark Current Discharge Ionization, DCDI). Two application cases were explored: (1) time-resolved aroma release from commercially available grape-flavored gummies that differed in texture (soft, hard, soft & bouncy), and (2) aroma changes during combined consumption of sake, sashimi and wasabi to illustrate flavor "marriage" effects. The method aimed to operate without chemical pretreatment and to provide second-scale temporal resolution of volatile signal changes.

Methods

The experimental approach combined an ambient ionization inlet (DCDI) and a sample injection unit (SIU) tube positioned to capture volatiles released during active chewing. Participants chewed individually while the DCDI–LCMS system recorded ion signals continuously. For the gummy tests, three texture variants were compared and total ion current chromatograms (TICC) were used to track overall volatile emission over time. For the food-pairing experiment, participants consumed sake according to a timed protocol (first sake intake at 60 s, repeated sips roughly each minute) and sashimi 30 s after drinking; signals were recorded throughout to capture interaction effects.

Signal processing included per-second data acquisition, weighted moving average smoothing (algorithm developed by AMR, Inc.) and visualization using heat maps and three-dimensional time-series plots produced with statistical software R, enabling pattern recognition of aroma dynamics.

Used Instrumentation

• Single-quadrupole mass spectrometer: LCMS-2050 (Shimadzu).
• Ambient ionization source: Dark Current Discharge Ionization (DCDI).
• Sample Injection Unit (SIU) tube configured to sample retronasal/orthonasal volatiles during chewing.
• Data processing and visualization: R statistical software and a weighted moving-average algorithm (AMR, Inc.).

Main Results and Discussion

The ambient DCDI–LCMS setup successfully recorded rapid changes in volatile ion intensity during active chewing without sample pretreatment. Key findings included:

• Distinct time-resolved TICC profiles for different gummy textures: soft gummies showed a gradual increase in aroma intensity with repeated chewing; hard gummies exhibited a slower but steady aroma emergence from the start; soft & bouncy gummies produced a rapid initial surge of aroma release with a prolonged aftertaste signal.
• Heat maps and three-dimensional time-series plots provided clear visualization of per-second signal fluctuations, facilitating comparison between samples and helping to link observed chemical signals to textural properties and presumed sensory impressions.
• In the food-pairing experiment, sequential consumption of sake and sashimi resulted in measurable changes in the number, intensity and temporal distribution of ion peaks. The visualization highlighted how alcohol and food combination can modulate retronasal volatile release—informally described as visualizing the "marriage" between food and alcohol.
• Overall, the method delivered rapid, time-resolved fingerprints of aroma release dynamics; however, the use of a single-quadrupole instrument limits confident molecular identification of individual volatiles. The study emphasized pattern recognition and temporal profiling rather than compound-level confirmation.

Benefits and Practical Applications

The described ambient ionization MS approach offers several practical advantages:

• Fast, near-real-time measurement of aroma release during natural eating behavior without solvent extraction or extensive sample prep.
• Ability to compare texture-dependent release dynamics to support formulation decisions (e.g., tuning gel hardness or elasticity to modulate flavor release profile).
• Utility for product pairing studies, sensory research and quality control where time-resolved volatile behavior matters.
• Visual outputs (heat maps, 3D plots) aid interdisciplinary communication between analytical chemists and sensory scientists or product developers.

Future Trends and Potential Applications

Building on this work, likely developments and opportunities include:

• Integration with higher-resolution or tandem mass spectrometry to enable compound identification and link specific volatiles to sensory attributes.
• Combining ambient MS data with sensory panels and chemometric or machine-learning models to predict consumer perception from volatile release patterns.
• Standardization of in-mouth sampling geometries and protocols to improve reproducibility across studies and labs.
• Automation and miniaturization for in-field or consumer-environment testing, enabling large-scale product screening and real-time feedback during product development.
• Coupling ambient MS with complementary capture methods (e.g., sorbent traps followed by GC–MS confirmation) to validate compound identities and sensory relevance.

Conclusion

The study demonstrates that a single-quadrupole LCMS equipped with DCDI ambient ionization can rapidly capture retronasal aroma dynamics during chewing without pretreatment. Time-resolved visualization reveals texture-dependent differences in aroma release among gummy samples and can illustrate interactions between food and beverages. While molecular identification remains limited on this platform, the method provides a valuable, pragmatic tool for linking oral processing to volatile emission patterns and for supporting formulation and sensory research.

Reference

Iida T., Nomura A., Sagawa T., Suzuki A., Shiota T., Kobayashi M. Ambient Ionization Mass Spectrometric Detection of Aroma Released During Gummy Chewing. Shimadzu Corporation; S&B FOODS Inc.; AMR, Inc. (authors and affiliations as provided in the source document).