Nielsen, Otto Højager Attermann1; Subash, Arman Ahamed6; Nielsen, Frederik Donbæk4; Dahl, Anders Bjorholm1; Skytte, Jacob Lercke5; Andersson-Engels, Stefan6; Khoptyar, Dmitry6
1 Department of Applied Mathematics and Computer Science, Technical University of Denmark2 Image Analysis & Computer Graphics, Department of Applied Mathematics and Computer Science, Technical University of Denmark3 Lund University4 Department of Photonics Engineering, Technical University of Denmark5 National Food Institute, Technical University of Denmark6 Lund University
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.
Journal of Near Infrared Spectroscopy, 2013, Vol 21, Issue 5, p. 375-383