Introduction
Comparisons of food and beverage products can be useful for screening to identify samples and/or aroma analytes that differ from a target condition. This can be a quality control tool to monitor for adulterants, off-flavors, or the presence of desired analyte characteristics. Utilizing a non-targeted analytical approach allows the analyst to reliably determine what is in their samplewithout being limited towhat is already known or expected.GC-TOFMS is a powerful tool for performing non-targeted volatile analyses of aroma and flavor analytes in food and beverage products that uncovers what a targeted analytical approach may have been missing.
LECO's ChromaTOF brand software with True Signal Deconvolution (TSD) provides the analyst with automated peak finding and sample comparison tools, such as “Reference”, to take the analysis further. Here, these tools are demonstrated to determine differences between commercially available craft beers, specifically a stout and coffee-flavored stout. Samples were collected with headspace solid-phase micro-extraction (HS-SPME) and subsequently analyzed byGC-TOFMS. As demonstrated, this information builds brand awareness, but the workflow is readily transferrable to other analyte screening approaches for off-flavors, adulterants, or desired aroma characteristics.
Figure 1. Representative TIC chromatograms for a stout and coffee-flavored stout are shown. The TIC chromatograms are quite similar and few, if any, analytes stand out as differing between the two from visual comparison of TIC data alone. Data processing tools, such as ChromaTOF's Reference, help identify analyte differences that are hidden in the TIC, but visible in XIC chromatograms. For example, 2-furfurylfuran that has rich and roasted odor properties and is known to naturally occur in coffee is observed in the coffee stoutwithXICm/z 148 and not the stout.Experimental
Sample Preparation: Two commercially available stout beer samples were analyzed. Aliquots of 4.0 mL were pipetted into 10 mL SPME vials and sealed with septum caps. HS-SPME sampling was performed with a 50/30 μm DVB/CAR/PDMS fiber (Supelco, Bellefonte, PA, USA) at 50 C. Samples were incubated for 10min prior to 10min of o extraction.Data analysis: Data were analyzed with LECO’S ChromaTOF brand software. True Signal Deconvolution, peak identification, and relative quantification for individual analytes within the samples were performed with automated data processing. ChromaTOF’s Reference feature calculated relative concentrations of analytes between samples and was used for sample comparisons. Analytes that were present in both the user-specified reference and sample were tagged “Match” or “Out of Tolerance” depending on the relative concentrations compared to a user-specified threshold. “Not Found” and “Unknown” indicated analytes that were only present in the reference or the sample, respectively.
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