title: Volatiles obtained from whole and ground grain samples by supercritical carbon dioxide and direct helium purge methods: observations on 2,3-butanediols and halogenated anisoles.
abstract: Volatile compounds were obtained from whole and ground grain samples by two methods. In the supercritical fluid extraction (SFE) method, volatiles were extracted from the grain with supercritical carbon dioxide, trapped at -78 degrees C, and then transferred via a purge-and-trap instrument to a gas chromatograph with mass and infrared detectors (GC-MS/IR) for separation and identification. In the direct-helium-purge method (DHP), volatiles were purged directly from the grain into the purge-and-trap instrument for subsequent transfer to the GC-MS/IR system. With SFE, extraction of volatiles was favored by ground grain, low pressures (</=13.8 MPa), and high temperatures (50-90 degrees C). DHP gave more low molecular weight compounds, while SFE was better for aldehydes, enals, 2, 3-butanediols (dl and meso forms), acetic acid, and chloro- and bromomethoxybenzenes apparently associated with musty odors in sorghums. The diols were present in both musty and normal-odor sorghums.
authors.affiliation: USDA-ARS, U.S. Grain Marketing Research Laboratory, Grain Marketing and Production Research Center, 1515 College Avenue, Manhattan, Kansas 66502, USA. larry@usgmrl.ksu.edu
authors.forename: L M
authors.initials: LM
authors.lastname: Seitz
authors.forename: M S
authors.initials: MS
authors.lastname: Ram
authors.forename: R
authors.initials: R
authors.lastname: Rengarajan
mesh_terms: D000840:Anisoles / Q000032:analysis*; D002072:Butylene Glycols / Q000032:analysis*; D002245:Carbon Dioxide; D002523:Edible Grain / Q000737:chemistry*; D005511:Food Handling; D008401:Gas Chromatography-Mass Spectrometry / Q000379:methods; D006371:Helium; D013055:Spectrophotometry, Infrared / Q000379:methods; D014908:Triticum / Q000737:chemistry; D014835:Volatilization; D003313:Zea mays / Q000737:chemistry
chemical_list: D000840:Anisoles; D002072:Butylene Glycols; D002245:Carbon Dioxide; D006371:Helium; C026978:2,3-butylene glycol