Aroma Investigation of Chios Mastic Gum ( Variety ) Using Headspace Gas Chromatography Combined with Olfactory Detection and Chiral Analysis.

Chios mastic gum ( var. ) exhibits intensely sourish, green, resinous, and woody odor notes with hints of citrus and pine. Despite its attractive flavor, no description of its aroma properties by molecular sensory techniques has been published thus far. A total of 25 odor-active compounds with flavor dilution (FD) factors of 1-512 were identified by gas chromatography-mass spectrometry-olfactometry (GC-MS-O) combined with headspace solid-phase microextraction (HS-SPME) and stir bar sorptive extraction (HS-SBSE). Quantitative analyses performed by multiple HS-SPME and calculation of odor activity values of 10 odorants with high FD factors revealed an essential role of several minor components (e.g., β-myrcene, limonene, β-linalool, and perillene) for the overall aroma of mastic gum, besides the dominating compound α-pinene. The indispensable contribution of the minor odorants to mastic gum was further confirmed by aroma recombination and omission tests. Varying enantiomeric excess values of the key odorants were observed by multidimensional GC-MS.