title: Aroma-impact compounds in dried spice as a quality index using solid phase microextraction with olfactometry and comprehensive two-dimensional gas chromatography.
abstract: A systematic experimental procedure is used to identify the aroma-impact compounds, leading to a shelf quality index based on head space solid-phase microextraction. Dried (ground) fennel seeds, having shelf life of 6 months (0.5Y) and 5 years (5Y), were used as a spice model for assessment of comparative aroma quality. Aroma-impact odorants were analysed by GC-olfactometry (GC-O) in parallel with comprehensive two-dimensional GC-flame ionisation detection (GC×GC-FID) using a polar/non-polar phase combination for the GC×GC column set. Tentative identification of aroma-impact odorants involved correlating data from the GC-O/FID system with GC×GC-time-of-flight mass spectrometry analysis by means of retention indices. Major compounds responsible for aroma perception were limonene, 1,8-cineole, terpinen-4-ol, estragole and trans-anethole, and showed an average decrease of 30-50% NIF from 0.5Y to 5Y. Monoterpenes which represent 'freshness', e.g. β-pinene and β-myrcene, exhibited identifiable aroma-impact only for the 0.5Y product. Sesquiterpenes and sesquiterpene oxides are suggested as an aging index, being present in increased amounts in 5Y. p-Anisaldehyde odour intensity for both samples remained the same (aroma perception sweet creamy, floral odour and Chinese seasoning powder).
authors.affiliation: Centre for Green Chemistry, School of Chemistry, Monash University, Wellington Rd, Clayton, Victoria 3800, Australia.
authors.forename: Bussayarat
authors.initials: B
authors.lastname: Maikhunthod
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Marriott
mesh_terms: D002849:Chromatography, Gas / Q000379:methods*; D009812:Odorants / Q000032:analysis; D064367:Olfactometry / Q000379:methods*; D011786:Quality Control; D052617:Solid Phase Microextraction / Q000379:methods*; D017365:Spices / Q000032:analysis*; D055549:Volatile Organic Compounds / Q000032:analysis* / Q000302:isolation & purification
chemical_list: D055549:Volatile Organic Compounds
keywords: Aroma; Comprehensive two-dimensional gas chromatography; Olfactometry; Solid-phase microextraction; Spices