title: Chemical Imaging of Heterogeneous Muscle Foods Using Near-Infrared Hyperspectral Imaging in Transmission Mode.
abstract: Foods and biomaterials are, in general, heterogeneous and it is often a challenge to obtain spectral data which are representative for the chemical composition and distribution. This paper presents a setup for near-infrared (NIR) transmission imaging where the samples are completely trans-illuminated, probing the entire sample. The system measures falling samples at high speed and consists of an NIR imaging scanner covering the spectral range 760-1040 nm and a powerful line light source. The investigated samples were rather big: whole pork bellies of thickness up to 5 cm, salmon fillets with skin, and 3 cm thick model samples of ground pork meat. Partial least square regression models for fat were developed for ground pork and salmon fillet with high correlations (R = 0.98 and R = 0.95, respectively). The regression models were applied at pixel level in the hyperspectral transmission images and resulted in images of fat distribution where also deeply embedded fat clearly contributed to the result. The results suggest that it is possible to use transmission imaging for rapid, nondestructive, and representative sampling of very heterogeneous foods. The proposed system is suitable for industrial use.
authors.affiliation: Nofima, Norwegian Institute for Food and Fisheries Research, Tromsø, Norway jens.petter.wold@nofima.no.
authors.forename: Jens Petter
authors.initials: JP
authors.lastname: Wold
authors.affiliation: Norwegian Computing Center, Oslo, Norway.
authors.forename: Martin
authors.initials: M
authors.lastname: Kermit
authors.affiliation: Orkla Foods, Trollåsen, Norway.
authors.forename: Vegard Herman
authors.initials: VH
authors.lastname: Segtnan
mesh_terms: D000818:Animals; D004867:Equipment Design; D005223:Fats / Q000032:analysis*; D005396:Fish Products / Q000032:analysis*; D005504:Food Analysis / Q000295:instrumentation / Q000379:methods*; D016018:Least-Squares Analysis; D009132:Muscles / Q000737:chemistry; D000069466:Red Meat / Q000032:analysis*; D012474:Salmon; D019265:Spectroscopy, Near-Infrared / Q000295:instrumentation / Q000379:methods*; D013552:Swine
chemical_list: D005223:Fats
keywords: NIR; Near-infrared spectroscopy; chemical imaging; fat distribution; heterogeneous samples; hyperspectral imaging; multivariate regression; pork bellies; salmon fillets; transmission measurements