18C-12 |
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D. M. BOHN, Diageo Global Supply, 903 W. 143rd St., Plainfield, IL 60544, A. R. Schmidt, Univ. of Illinois at Urbana, Champaign, Urbana, IL 61801, and S. J. Schmidt, Univ. of Illinois at Urbana-Champaign, Urbana, IL 61801. A Dynamic Vapor Sorption-fast Gas Chromatography-Flame Ionization Detection (DVS-fast GC-FID) method was recently developed to rapidly and continuously measure the extent of volatile release that occurs from encapsulated glassy matrices as a function of humidification and temperature. A vital, but often overlooked aspect of method development is determination of measurement uncertainty. Thus, the objective of this study was to assess the variability of the DVS-fast GC-FID method by performing uncertainty analysis. Artificial cherry Durarome®, containing approximately 5 to 10% (w/w) benzaldehyde, was used as the model system. Triplicate samples progressed through a 2-step method in the DVS. In step one, samples were allowed to equilibrate to the target temperature (15, 25, or 35°C) at 30% relative humidity. In step two, samples were exposed to a target relative humidity (40, 50, 60, 70, 80, or 90%) for 600 minutes during which the amount of volatile released was measured. Uncertainty analysis showed that DVS-fast GC-FID method uncertainty was significantly smaller than sample uncertainty, indicating that the variability in the sample's physical properties had a dominant impact on the overall uncertainty of the volatile retention results obtained. Uncertainty analysis also indicated that, in the early part of volatile release, when the cumulative mass of benzaldehyde measured is small, the variance associated with the mass of benzaldehyde measured by the DVS-fast GC-FID is the largest source of variance in the calculated benzaldehyde retention. However, as the mass of volatile released (and measured) increases, as the experiment progresses, the initial mass of benzaldehyde in the sample becomes the largest source of variance in the calculated benzaldehyde retention. The uncertainty associated with the DVS-fast GC-FID method itself was found to be very small, which is an important finding that further supports the reliability and usefulness of this new method.
Session 18C, Food Chemistry: Food composition, analysis and volatiles
2005 IFT Annual Meeting, July 15-20 - New Orleans, Louisiana |