Material odor-odoractive compounds identified in different materials--the surprising similarities with certain foods, possible sources and hypotheses on their formation.

UNLABELLED: Increased efforts have been undertaken by manufacturers to reveal the secrets of material odors, the structure of the odorants responsible, with regard to finding out the source(s) of odor and possible starting points for odor reduction, and therewith product improvement, increased consumer satisfaction and improved indoor air quality. The identification of odor-active compounds in materials by means of gas chromatography-olfactometry (GC-O, also called GC-sniffing), performed at the Fraunhofer Institute for Building Physics (IBP) during the previous years, showed surprising similarities between certain odorants found in materials and those previously identified in certain kinds of food. Examples of important odorants found in different material samples and similarities with food odorants were analyzed. Odorant sources are indicated as regards materials, and possible conditions and mechanisms of formation suggested to show starting points for odor reduction and odor improvement in material development. PRACTICAL IMPLICATIONS: If technical materials are planned to be used indoors and if they spread a distinct odor, the analysis of the compounds contained and emitted by this material using gas chromatography-olfactometry is a means to help reveal the compounds being responsible for that odor. The exact knowledge of the structure of the odorants is the prerequisite for drawing conclusions on possible sources and formation mechanisms and to reveal starting points for odor reduction and product improvement, e.g. by changing ingredients or production conditions. This contributes to an improvement of indoor air quality. Furthermore, quite often the concentrations of certain single odorants found in materials can be very low and the same odorants can be part of other well-known food flavors. This information might be useful to reduce consumers' fears of a possible impairment of their health in the future.