Volatile nitrogen compounds are often important for the sensory properties of food flavors and natural isolates. Character-impact nitrogen compounds have been found, for instance, in the flavors of processed foods and drinks, such as bread, meat, coffee and cocoa. During the last decade, much attention has been paid to the identification and sensory properties of nitrogen compounds from natural isolates, such as headspaces and absolutes of flowers and essential oils.
Last year in the September/October issue of this magazine we studied the occurrence, identities and sensory properties of volatile nitrogen compounds emitted by flowers and isolated from flower absolutes and essential oils, Now we have investigated the threshold values and structure-activity relationships of natural volatile aliphatic and aromatic nitrogen compounds, substituted pyridines, quinolines, pyazines and thiazoles.
It is general knowledge that volatile nitrogen compounds are, from a sensory point of view, important constituents of flavors. Thorough reviews about this subject have been published. Researchers in the early 1970s tried to determine the sensory properties (i.e., odor and flavor qualities and threshold values in different media) of these flavor compounds. During the last decade, the identification and determination of the sensory properties of volatile nitrogen compounds from natural isolates have come more and more into focus. Interest arose from improvements in isolation and concentration of volatile trace constituents of natural products, and from modern chromatographic techniques. These techniques include, for instance, gas chromatography on high-resolution, high-precision fused silica capillary columns. An excellent review on headspace analysis by modern gaschromatographic methods was written by Bicchi.