Aroma Profiling and Detection of Off-Odors
Food analysis has long been important in order to evaluate its composition, monitor changes upon cooking or processing, and identify the components that provide them with desirable or undesirable characters. There are a wide range of food components, including volatile organic compounds (VOCs). VOCs are perhaps the most important components, as they give rise to aroma, which means they are essential in making food enjoyable to eat.
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Aromas often contain many VOCs at varied concentrations, which make it difficult for analysts to profile these VOCs that give rise to food aroma. The distinct aroma of a specific foodstuff results from one or two trace-level compounds with a disproportionately high odor-activity.
However, in recent years, advanced analytical methods have opened up the area of food volatiles to in-depth investigation, and major advancements are being made to better understand the role of VOCs in food. Present activity – both in industry and research – is focused in three key areas:
- Aroma profiling – Understanding the factors that promote aroma differences between similar foods, including how these are controlled by genetic differences
- Food consistency and quality – Ensuring production-line consistency of products from one batch to another
- Food safety – Understanding the origin of VOCs that give rise to taints or off-odors, and also those that can be employed as indicators of food deterioration (shelf-life) or contamination from the materials used in packaging
In the above situations, it is important to optimize each aspect of the sampling and analysis protocol to detect and identify the broadest range of analytes. Markes provides a host of solutions for the analysis and sampling of volatiles from food.
What Markes can Offer
Thermal Desorption Systems
Sampling vapors onto sorbent tubes, with analysis by thermal desorption (TD), provides the high level of concentration enhancement required for complete chemical analysis by standard analytical tools, and complements sensory information acquired by olfactometry. As a result, this method is extensively used for food aroma profiling and off-odor detection.
In addition, it requires minimal sample preparation, can be readily automated, and is an easy alternative to sample preparation techniques.
Markes’ UNITY-xr and TD100-xr thermal desorbers are suitable for food aroma and odor analysis for the following reasons:
- The cryogen-free focusing trap enables selective elimination of unnecessary, high-concentration interferents such as acetic acid, ethanol, and water, which may affect the detection of trace-level target compounds
- The short and inert flow path ensures compatibility with reactive compounds such as amines, mercaptans, and oxygenated species, which usually have very low odor thresholds
- The backflush operation of the focusing trap permits the use of multi-bed sorbent tubes, allowing simultaneous analysis of highly volatile and semi-volatile compounds from just a single sample
Sampling Equipment
In addition to the above-mentioned analytical systems, Markes provides a wide range of TD-compatible options for sampling:
- Near-real-time sampling and on-line sampling for monitoring changes in aroma profile with time
- Dynamic or static headspace analysis for extracting representative aroma profiles from food samples
- Alternatively, when the analytes are adequately concentrated, pumped sampling using Markes’ ACTI-VOC or grab-sampling of small sample volumes using Markes’ Easy-VOC is both fast and easy
Detecting Compounds in Complex Matrices
Generally, aroma profiling of foods needs in-depth examination of complex chromatograms in order to confirm the presence or absence of key target components, such as trace-level odor-active or taint compounds. It is equally important to determine the non-target compounds present, for example, when similar products are being compared.
Markes also provides TargetView software that can considerably reduce the time spent on these tasks. Using a combination of ‘intelligent’ background compensation, library matching, and compound deconvolution, it eliminates the need to manually process complicated GC–MS profiles and creates a simple report that lists the analytes detected in the sample.
This information has been sourced, reviewed and adapted from materials provided by Markes International Limited.
For more information on this source, please visit Markes International Limited.