title: Gas chromatography-mass spectrometry method optimized using response surface modeling for the quantitation of fungal off-flavors in grapes and wine.
abstract: An optimized method for the quantitation of volatile compounds responsible for off-aromas, such as earthy odors, found in wine and grapes was developed. The method involved a fast and simple headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) for simultaneous determination of 2-isopropyl-3-methoxypyrazine, 2-isobutyl-3-methoxypyrazine, 3-octanone, fenchone, 1-octen-3-one, trans-2-octen-1-ol, fenchol, 1-octen-3-ol, 2-methylisoborneol, 2,4,6-trichloroanisole, geosmin, 2,4,6-tribromoanisole, and pentachloroanisole. The extraction of the temperature and time were optimized using response surface methodology in both wine base (WB) and grape base (GB). Low limits of detection (0.1-5 ng/L in WB and 0.05-1.6 in GB) and quantitation (0.3-17 in WB and 0.2-6.2 in GB) with good recoveries (83-131%) and repeatability [4.3-9.8% coefficient of variation (CV) in WB and 5.1-11.1% CV in GB] and reproducibility (3.6-10.2 in WB and 1.9-10.9 in GB) indicate that the method has excellent sensitivity and is suitable for the analysis of these off-flavor compounds in wine and grape juice samples.
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Navideh
authors.initials: N
authors.lastname: Sadoughi
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Leigh M
authors.initials: LM
authors.lastname: Schmidtke
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Guillaume
authors.initials: G
authors.lastname: Antalick
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: John W
authors.initials: JW
authors.lastname: Blackman
authors.affiliation: National Wine and Grape Industry Centre, School of Agricultural and Wine Sciences, Charles Sturt University, Locked Bag 588, Wagga Wagga, New South Wales 2678, Australia.
authors.forename: Christopher C
authors.initials: CC
authors.lastname: Steel
mesh_terms: D005421:Flavoring Agents / Q000737:chemistry* / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis; D005658:Fungi / Q000378:metabolism; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods*; D027843:Vitis / Q000737:chemistry / Q000382:microbiology*; D014920:Wine / Q000032:analysis* / Q000382:microbiology
chemical_list: D005421:Flavoring Agents
keywords: Botrytis cinerea; Colletotrichum acutatum; design of experiment; fungal off-flavor; optimization