The application of Near-Infrared Reflectance Spectroscopy (NIRS) to detect melamine adulteration of soya bean meal

Soya bean products are used widely in the animal feed industry as a protein based feed ingredient and<br/>have been found to be adulterated with melamine. This was highlighted in the Chinese scandal of<br/>2008. Dehulled soya (GM and non-GM), soya hulls and toasted soya were contaminated with melamine<br/>and spectra were generated using Near Infrared Reflectance Spectroscopy (NIRS). By applying chemometrics<br/>to the spectral data, excellent calibration models and prediction statistics were obtained. The coefficients<br/>of determination (R2) were found to be 0.89–0.99 depending on the mathematical algorithm used,<br/>the data pre-processing applied and the sample type used. The corresponding values for the root mean<br/>square error of calibration and prediction were found to be 0.081–0.276% and 0.134–0.368%, respectively,<br/>again depending on the chemometric treatment applied to the data and sample type. In addition, adopting<br/>a qualitative approach with the spectral data and applying PCA, it was possible to discriminate<br/>between the four samples types and also, by generation of Cooman’s plots, possible to distinguish<br/>between adulterated and non-adulterated samples.