Analytical methods for the determination of the geographic origin of Emmental cheese: mid- and near-infrared spectroscopy

摘要

Four different Fourier transform infrared spectroscopic techniques (near infrared diffuse reflection (NIR/DR), mid-infrared attenuated total reflection (mlR/ATR) using two different instruments and mid-infrared transmission (mIR/Tr) spectroscopy) in combination with multivariate chemometrics were investigated for their potential for discriminating Emmental cheese of various geographic origins. A total of 20 Emmental cheese samples produced in winter from Switzerland (n=6), Allgau (Germany) (n=3), Bretagne (France) (n=3), Savoie (France) (n=3), Vorarlberg (Austria) (n=3) and Finland (n=2) were analysed. The normalised spectra or their 2nd derivatives were analysed by principal component analysis (PCA) and linear discriminant analysis (LDA) of the PCA-scores. Despite the few samples in this preliminary investigation clear trends were observed. The mIR transmission spectra achieved 100% correct classification in LDA when differentiating the Swiss Emmental from the other samples pooled as one group. The NIR/DR spectroscopy allowed a classification by the six regions of cheese origin.