Characterization of Important Odorants from Shell Ginger Rhizomes, Alpinia zerumbet

Shell ginger, Alpinia zerumbet (Pers.) B.L. Burtt & R.M. Smith, is a plant species native to Southeast Asia and is grown as an ornamental plant in Europe and the United States. Shell ginger rhizomes and leaves are commonly used to prepare herbal teas and as a seasoning for foods, including rice and noodles, owing to their purported health benefits and pleasant, distinctive flavor. Despite widespread consumption, the molecules responsible for the flavor of shell ginger remain unknown. This study identified 26 odorants in shell ginger rhizomes using solvent-assisted flavor evaporation (SAFE), gas chromatography-olfactometry (GC-O), and gas chromatography-mass spectrometry (GC-MS). Additionally, flavor dilution (FD) factors were determined using aroma extract dilution analysis (AEDA), and selected odorants were quantitated via stable isotope dilution assays (SIDAs). Odor activity values (OAVs) were calculated based on the quantitation, and 11 odorants had an OAV of ≥1. Notable odorants included linalool, α-pinene, (2E,4E)-nona-2,4-dienal, 1,8-cineole, and (E)-isoeugenol. The aroma simulation model closely matched the sensory attributes of an aqueous infusion of dried rhizomes. This study provides the first insight into the aroma chemistry of shell ginger rhizomes and establishes a foundation for future research into other understudied culinary spice plants in the Alpinia genus.