Aroma Profile of Pet Food by GC-TOFMS and GCxGC-TOFMS

Importance of the Topic

The aroma profile of pet food plays a crucial role in product consistency, quality control and consumer acceptance. Volatile and semi-volatile compounds define characteristic flavors in complex matrices, yet their odor impact often does not correlate with concentration. High chromatographic resolution and wide dynamic range are therefore essential to detect, identify and quantify individual aroma compounds.

Objectives and Overview

This study aimed to isolate and characterize volatile and semi-volatile flavor compounds in seafood-, turkey- and beef-based pet food samples. Headspace solid-phase microextraction (HS-SPME) was used to pre-concentrate analytes, which were then analyzed by GC-TOFMS and comprehensive two-dimensional GC (GCxGC)-TOFMS. The goal was to compare flavor profiles, resolve coeluting constituents and demonstrate the advantages of each technique.

Methodology and Instrumentation

• Sample Preparation
  1.5 g of pet food mixed with 1.5 g saturated salt solution in a 20 mL headspace vial and sealed.
  Incubation at 53 °C for 10 min followed by 40 min extraction with a 50/30 µm DVB/Carb/PDMS SPME fiber.
  Thermal desorption in a 250 °C GC inlet for 2 min.


• Instrumentation
  GC-TOFMS: LECO Pegasus HT with Agilent 6890 GC and GERSTEL MPS2 autosampler.
  GCxGC-TOFMS: LECO Pegasus 4D with Agilent 7890 GC, dual-stage quad-jet thermal modulator and secondary oven.
  Data processing via ChromaTOF software with automated True Signal Deconvolution.


• GC Conditions
  Column 1: Rxi-5Sil MS, 30 m × 0.25 mm × 0.25 µm; Helium carrier.
  Temperature program: 35 °C (4 min), 5 °C/min to 100 °C, 25 °C/min to 250 °C (4 min hold).
  Mass range 30–400 m/z at 20 spectra/s; source 250 °C.


• GCxGC Conditions
  Primary column as above; secondary column Stabilwax, 1.5 m × 0.25 mm × 0.25 µm.
  Modulation every 6 s; primary ramp 10 °C/min to 250 °C (10 min hold); secondary oven +10 °C; modulator +15 °C.
  Mass range 30–400 m/z at 100 spectra/s; source 250 °C.

Main Results and Discussion

GC-TOFMS analysis and deconvolution resolved coeluting compounds based on unique m/z traces. In a seafood-based sample, an unresolved GC peak contained three overlapping analytes: 2-ethyl hexanoic acid, 3-methyl-2-thiophene carboxaldehyde and 2-propionylthiazole. Deconvolution algorithms separated pure spectra for identification and quantification. In cases of incomplete separation, GCxGC introduced a second chromatographic dimension, enabling full resolution of coeluting analytes. For instance, 2-propionylthiazole was distinguished from 2-acetyl-3-methylpyrazine with improved library match scores (from 660 to 891 and 860, respectively).

Comparative flavor profiling detected 491, 421 and 598 peaks (S/N ≥ 200) in seafood, turkey and beef samples by GC-TOFMS. GCxGC-TOFMS increased these counts to 1199, 957 and 1069 respectively, demonstrating enhanced peak capacity and sensitivity. Distinct chromatographic patterns highlighted flavor differences among formulations.

Benefits and Practical Applications

• High-throughput flavor fingerprinting for pet food quality control and product development.
• Deconvolution of overlapped peaks without extensive sample preparation.
• GCxGC dimension offers superior peak capacity and trace-level detection through thermal modulation.
• Comprehensive datasets facilitate comparative analysis across formulations.

Future Trends and Applications

Advances may include integration of multidimensional separations with tandem mass spectrometry for structural elucidation, machine-learning algorithms for automated pattern recognition, real-time aroma monitoring in production lines, and expansion into profiling of emerging flavor additives and bioactive compounds in complex food matrices.

Conclusion

HS-SPME coupled with GC-TOFMS and GCxGC-TOFMS provides a robust platform for profiling complex aroma mixtures in pet food. Deconvolution and two-dimension separations enable accurate identification and quantification of coeluting volatiles. These techniques support quality control, flavor optimization and comparative studies in food analytics.

References

• No external literature references were provided in the original text.