A newly developed line-scan Raman imaging system using a 785 nm line laser was used to authenticate powdered foods and ingredients. The system was used to collect hyperspectral Raman images in a wavenumber range of 102–2865 cm^–1 from three representative food powders mixed with selected adulterants with a concentration of 0.5%, including milk and melamine, flour and benzoyl peroxide, and starch and maleic anhydride. An acoustic mixer was used to create food adulterant mixtures. All the mixed samples were placed in sample holders with a surface area of 50 mm×50 mm. Spectral and image processing algorithms were developed based on single-band images at unique Raman peaks of the individual adulterants. Chemical images were created to show identification, spatial distribution, and morphological features of the adulterant particles mixed in the food powders. The potential of estimating mass concentrations of the adulterants using the percentages of the adulterant pixels in the chemical images was also demonstrated.

Date Published: 13 May 2015
PDF: 9 pages
Proc. SPIE 9488, Sensing for Agriculture and Food Quality and Safety VII, 94880F (13 May 2015); doi: 10.1117/12.2176562

Published in SPIE Proceedings Vol. 9488:
Sensing for Agriculture and Food Quality and Safety VII
Moon S. Kim; Kuanglin Chao; Bryan A. Chin, Editor(s)