Light scattering properties of ghee (a form of clarified butter) and vanaspati (partially hydrogenated vegetable oil) have been investigated in order to explore the use of optical techniques for detection of adulteration of vanaspati in ghee. Significant differences in the diffuse reflectance spectra of ghee and vanaspati were observed. The estimates for the reduced scattering coefficient (μs′) and the absorption coefficient (μa) for ghee and vanaspati were also obtained from integrating sphere measurements. These suggest that the differences in the diffuse reflectance spectra of ghee and vanaspati are primarily due to the differences in their absorption characteristics in the spectral range of 400 to 550 nm. Further, the results obtained show that the ratio of diffuse reflectance at 460 nm to that at 410 nm could be used to detect adulteration of vanaspati in ghee.
N. Ghosh, A. Datta, and P. K. Gupta, "Diffuse Reflectance Studies of Edible Fats," Appl. Spectrosc. 56, 1094-1097 (2002)