Essential oils obtained from Mentha species are extensively used as flavor ingredients. Peppermint oil, obtained from Mentha pipetita, and cornmint oil, obtained from Mentha aruensis var. piperascens, are two distinct, widely used, menthol-rich essential oils. Although the composition of these oils has been extensively studied, the contribution to the odor and flavor profile of the oil made by the individual volatile components has not been determined.
The techniques of gas chromatography-olfactometry (GC-O) and aroma-extract dilution analysis (AEDA) are used to determine which components contribute significantly to the organoleptic profiles of essential oils, food extracts and other materials.
GC-O, also known as GC-sniffing, is the evaluation of the effluent of a gas chromatography at an odor port. Compounds are separated on a GC column, and the gas stream is split into two components, one going to a detector and one to an odor port. At the odor port, odorants are smelled and described. Aroma extract dilution analysis then allows one to determine the relative importance of these odorants, and to distinguish potent odorants from volatiles that have low or no odor activity.