Spectral characterisation of dairy products using photon time-of-flight spectroscopy

Otto Hojager Attermann Nielsen, Arman Subash, Frederik Donbaek Nielsen, Anders Bjorholm Dahl, Jacob Lercke Skytte, Stefan Andersson-Engels, Dmitry Khoptyar

Research output: Contribution to journalArticlepeer-review


In this paper, we present, for the first time, the absorption and reduced scattering spectra of commercially available milk and yoghurt products, obtained using photon-time-of-flight spectroscopy. The ability of this technique to separate the contributions from absorption and scattering in the sample provides important information on the chemical composition and micro-structural properties, which are not available with the traditional techniques used in dairy production. The instrument operates in the spectral range from 500 nm to 1030 nm. The reduced scattering coefficient varies from 5 cm(-1) for milk with 0.1% fat in the near infrared range, to 60 cm(-1) for yoghurt with 3.0% fat in the green wavelength regime. The absorption is within the range of 0.05-0.5cm(-1), with only small variation in the absolute value between products. Our results show that the reduced scattering clearly distinguishes milk and yoghurt with the same fat content and can offer a reliable way of monitoring structural formation during milk fermentation.
Original languageEnglish
Pages (from-to)375-383
JournalJournal of Near Infrared Spectroscopy
Issue number5
Publication statusPublished - 2013

Subject classification (UKÄ)

  • Atom and Molecular Physics and Optics


  • optical properties
  • turbid media
  • photon-time-of-flight
  • dairy products
  • milk
  • yoghurt
  • fermentation


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