title: Near-Infrared Spectroscopy Using a Supercontinuum Laser: Application to Long Wavelength Transmission Spectra of Barley Endosperm and Oil.
abstract: The supercontinuum laser is a new type of light source, which combines the collimation and intensity of a laser with the broad spectral region of a lamp. Using such a source therefore makes it possible to focus the light onto small sample areas without losing intensity and thus facilitate either rapid or high-intensity measurements. Single seed transmission analysis in the long wavelength (LW) near-infrared (NIR) region is one area that might benefit from a brighter light source such as the supercontinuum laser. This study is aimed at building an experimental spectrometer consisting of a supercontinuum laser source and a dispersive monochromator in order to investigate its capability to measure the barley endosperm using transmission experiments in the LW NIR region. So far, barley and wheat seeds have only been studied using NIR transmission in the short wavelength region up to 1100 nm. However, the region in the range of 2260-2380 nm has previously shown to be particularly useful in differentiating barley phenotypes using NIR spectroscopy in reflectance mode. In the present study, 350 seeds (consisting of 70 seeds from each of five barley genotypes) in 1 mm slices were measured by NIR transmission in the range of 2235-2381 nm and oils from the same five barley genotypes were measured in a cuvette with a 1 mm path length in the range of 2003-2497 nm. The spectra of the barley seeds could be classified according to genotypes by principal component analysis; and spectral covariances with reference analysis of moisture, β-glucan, starch, protein and lipid were established. The spectral variations of the barley oils were compared to the fatty acid compositions as measured using gas chromotography-mass spectrometry (GC-MS).
authors.affiliation: Spectroscopy & Chemometrics, Department of Food Science, University of Copenhagen, Frederiksberg, Denmark tine.ringsted@food.ku.dk.
authors.forename: Tine
authors.initials: T
authors.lastname: Ringsted
authors.affiliation: Department of Chemistry, Aarhus University, Aarhus, Denmark.
authors.forename: Sune
authors.initials: S
authors.lastname: Dupont
authors.affiliation: Department of Chemistry, Aarhus University, Aarhus, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Ramsay
authors.affiliation: Spectroscopy & Chemometrics, Department of Food Science, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Birthe Møller
authors.initials: BM
authors.lastname: Jespersen
authors.affiliation: Spectroscopy & Chemometrics, Department of Food Science, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Klavs Martin
authors.initials: KM
authors.lastname: Sørensen
authors.affiliation: Department of Chemistry, Aarhus University, Aarhus, Denmark.
authors.forename: Søren Rud
authors.initials: SR
authors.lastname: Keiding
authors.affiliation: Spectroscopy & Chemometrics, Department of Food Science, University of Copenhagen, Frederiksberg, Denmark.
authors.forename: Søren Balling
authors.initials: SB
authors.lastname: Engelsen
mesh_terms: D056625:Endosperm / Q000737:chemistry*; D004867:Equipment Design; D001467:Hordeum / Q000737:chemistry*; D007834:Lasers; D008055:Lipids / Q000032:analysis; D010938:Plant Oils / Q000737:chemistry*; D010940:Plant Proteins / Q000032:analysis; D025341:Principal Component Analysis; D012639:Seeds / Q000737:chemistry*; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation / Q000379:methods*; D013213:Starch / Q000032:analysis; D047071:beta-Glucans / Q000032:analysis
chemical_list: D008055:Lipids; D010938:Plant Oils; D010940:Plant Proteins; D047071:beta-Glucans; D013213:Starch
keywords: Barley seed; NIR; NIT; beta-glucan; food; near-infrared spectroscopy; near-infrared transmission spectroscopy; single seed; supercontinuum laser