Abstract
Odor-active compounds are commonly analyzed using gas chromatography–olfactometry (GC–O). However, there are only limited guidelines available for panelist training with this technique. In the current study, 29 volunteers were trained to detect, describe, and rate the intensity of odors. In addition, three GC–O methods, i.e., aroma extraction dilution method, detection frequency, and posterior intensity (PI), were used to evaluate the newly trained panelists’ ability to analyze key compounds of kvass (fermented nonalcoholic drink) aroma. A five-step approach is proposed for training as follows: (1) introduction of the method; (2) vocabulary training using standard compounds and learning the use of the scale; (3) training with the reference mixture A; (4) training with the real product of interest—the beverage kvass; and (5) monitoring and further training of the panel. Following these steps, all panelists learned how to perform GC–O analysis. Some variances among subjects were observed; however, the background of the trainees was found to be insignificant. Assessors for the “professional” GC–O panel were chosen for further training and included people with a sensory and food science background, but also ordinary consumers. The PI method, where subjects rate odor intensity after a peak eluted, was found to provide a sufficient amount of data for key compound analysis. The method enabled easy data handling, provided valuable feedback for panel monitoring, and aided in the selection process to decide which assessors would be suitable for further training and placement on a professional panel.
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Abbreviations
- AEDA:
-
Aroma extract dilution analysis. Dilutions are used to reveal the most intense flavor compounds in the extract. This results in D-values showing the highest dilution at which a substance can still be detected by olfaction.
- CHARM:
-
Combined hedonic response measurement. Differs from AEDA in that the duration of an odor is taken into consideration in calculations of odor unit values. Also, dilutions are presented in randomized order to avoid bias introduced by knowledge of the samples.
- DF:
-
Detection frequency method. Estimates the odor intensity based on recording-detected odors from a number of sniffers. To compare detection frequencies, both NIF and SNIF are used.
- FD:
-
Dilution factor
- FMTM:
-
Fragrance materials test mix
- GC–O:
-
Gas chromatography–olfactometry
- HS:
-
Headspace
- NIF:
-
Nasal impact frequency. This parameter indicates the peak height of a summed aromagram expressing the percentage of detection frequency of the odor. Nasal impact frequency of 100 % means that the odor was detected by all assessors.
- OT:
-
Odor detection threshold
- OID:
-
Olfactory intensity device. A technique that affords tracking odor intensity vs. retention time.
- PI:
-
posterior intensity method. The PI method involves recording the odor intensity on a scale after a peak has eluted from the column.
- SMM:
-
Single magnetic mixer
- SNIF:
-
Surface of nasal impact frequency. This parameter indicates the peak area of a summed aromagram expressing the percentage of detection frequency of the odor and the time duration of detection.
- SNIFF:
-
Program from Gerstel that summarizes olfactometry results of individual assessors into a group aromagram.
- TI:
-
Time-intensity method. The intensity of odor is rated with time-intensity device, providing an odor peak similar to a chromatogram.
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The authors wish to thank all the volunteers who participated in the study. The financial support for this research was provided by the Enterprise Estonia project EU29994.
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Vene, K., Seisonen, S., Koppel, K. et al. A Method for GC–Olfactometry Panel Training. Chem. Percept. 6, 179–189 (2013). https://doi.org/10.1007/s12078-013-9156-x
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DOI: https://doi.org/10.1007/s12078-013-9156-x