We analyze everyday articles and raw materials and also technological, physical, and chemical processes that lead to undesired/desired odor changes. We identify off-odors and characterize pleasant odors, such as the odor of wood. We compare different samples, both qualitatively and quantitatively. We identify possible reaction pathways and precursor molecules that contribute to odor formation. Advanced analytical methods enable us to detect and identify odors at a molecular level. We also are able to characterize and assess the expectations of consumers for specific products. This allows objective estimation of whether a specific product has a desired odor or an undesired off-odor. Using substantiated findings we can help you optimize the odor of your products to consumer wishes.
The characterization of individual odorants is typically achieved using high-resolution gas chromatography-olfactometry (HRGC-O) coupled to mass spectrometry (MS). The use of GC-O allows for odour-active compounds to be clearly distinguished from odourless molecules. As such, individual compounds that have an odor character resembling or relating to the off-odor can be isolated already during the analyses (cf. Fig. 1). This focussed analytical approach allows for a direct comparison between problematic samples and unaffected control samples.
Fig. 1: Chromatogram of a mineral water sample using GC-O, with examples of odour-active regions indicated by the text and arrows (© Fraunhofer IVV)
The identification of odor-active trace compounds is achieved using 2D-HR-GC-O/MS, which offers a high degree of compound separation (cf. Fig. 2). Odor compounds are thereby separated in two independent gas chromatographic columns, each housed in a separate oven that are coupled via a cryogenic trap, and are then analyzed on the basis of their mass spectrum and odour qualities as detected at an olfactory detection port by a trained sensory assessor.
We routinely align our chemo-analytical assessments with human sensory evaluations to maximise the likelihood that all of the odor-active compounds that are responsible for the off-odor of a sample are ascertained.
Fig. 2: Schematic of 2D-HRGC-MS/O systems (© Fraunhofer IVV)
Often, even minute traces of highly odoros substances can alter the flavor of a food. Combining analytical and olfactory assessment methods offers a highly accurate and directed analysis of odor-active compounds at trace concentrations. This has enabled us, for example, to identify the key compounds responsible for a plastic-like off-flavor, or similarly a medicinal off-flavor, in mineral water samples.
We have performed analyses on the odor attributes of diverse product groups and raw materials including (selected examples):