Aroma Release Monitoring of Complex Flavors by Mass Spec

Food and Flavor Analysis with PTR-MS

Buying decisions can be influenced by aroma and its perception. So, it is crucial for the industry to establish what we taste and smell when enjoying a fresh strawberry or drinking a cup of coffee for example, at the exact moment the flavor molecules hit our receptors. Over time, the taste and flavor of food can also alter, depending on production processes and raw materials etc.

However, for a brand image which is consistent, the aroma quality of food should remain the same. For traditional analytical methods, handling requirements like extremely high time resolution, real-time and direct air sampling can pose challenges. IONICON provides real-time VOC analyzers and is the market leader in Proton Transfer Reaction – Mass Spectrometry (PTR-MS), to provide the industry and scientists with a clearer understanding of sensory perception.

Key Reasons for Using PTR-TOFMS

  • Direct mouth- and nose-space air analysis
  • Rapid screening of complex aroma systems
  • Monitoring of real-time variations in aroma
  • Suitable for chemometric datamining
  • Head-space analysis without sample preparation

Real-Time Food and Flavor Release Analysis with PTR-TOF 6000 X2

Science researchers are frequently confronted with highly complex matrices when it comes to food and flavor. So, in order to separate compounds of interest from other compounds sharing the same nominal m/z but possessing a different chemical composition (isobars), extremely high mass resolution is critical.

Mass resolution of trichlorobenzene peak, detected by a PTR-TOF 6000 X2 instrument: over 6200 m/∆m (FWHM).

Figure 1. Mass resolution of trichlorobenzene peak, detected by a PTR-TOF 6000 X2 instrument: over 6200 m/∆m (FWHM).

The benchmark for the highest mass resolution for substance separation is the IONICON PTR-TOF 6000 X2 which reaches over 6200 m/∆m (see Fig. 1). PTR-TOFMS can separate isobars well, unlike quadrupole based analyzers, so it is ideally suited for the measurement of complex aroma systems.

High Mass Resolution

The nosespace of a person who had consumed some freshly brewed coffee was analyzed to show the benefit of this excellent resolution. It is widely known that vanillin and 4-ethylguaiacol are key isobaric aroma compounds at nominal m/z 153 (protonated molecules). Yet, by observing the mass spectrum around m/z 153 in Fig. 2 it can be observed that there are actually four ions which share this nominal mass (black line).

Nose-space air analysis of coffee flavor demonstrates high mass resolving power of PTR-TOF 6000 X2.

Figure 2. Nose-space air analysis of coffee flavor demonstrates high mass resolving power of PTR-TOF 6000 X2.

For a low resolution instrument (e.g. quadrupole-based), all four of the ions would be merged into one broad mass spectral peak and only the intensity of the sum of them could be calculated. The high mass resolution of the PTR-TOF 6000 X2 permits separation of all four ions.

Intensities are deconvoluted automatically (grey and blue lines; the orange line is the sum of the deconvoluted peaks, which perfectly reproduces the original data) using IONICON's sophisticated data processing software. Vanillin and 4-ethylguaiacol can be independently quantified, without parasitic influence of the two additional isobars.

High Sensitivity and Throughput

When compounds of extremely low abundance have to be quantified with high time resolution high sensitivity is crucial. Using the high sensitivity PTR-TOF 6000 X2 the nosespace of a person before (blank) and after drinking freshly brewed coffee were analyzed.

Quantification of 3-mercapto-3-methylbutyl formate at m/z 149.063 with a time resolution of 700 ms and a concentration < 1 ppbv.

Figure 3. Quantification of 3-mercapto-3-methylbutyl formate at m/z 149.063 with a time resolution of 700 ms and a concentration < 1 ppbv.

In Fig. 3, concentration values of a flavor compound at m/z 149.063 are exhibited during this experiment with a time resolution of 700 ms. Although this key aroma compound is observed only in trace concentrations below 1 ppbv, the high sensitivity and low limit-of-detection of the PTR-TOF 6000 X2 permit online quantification of the aroma development over numerous breath cycles after swallowing the coffee in real-time.

IONICON Analytik

This information has been sourced, reviewed and adapted from materials provided by IONICON Analytik.

For more information on this source, please visit IONICON Analytik.

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