The potential of combined infrared and fluorescence spectroscopies as a method of determination of the geographic origin of Emmental cheeses

The potential of near-infrared (NIR), mid-infrared (MIR) and front-face fluorescence spectroscopies combined with chemometric methods was investigated for discriminating Emmental cheeses from different European geographic origins. A total of 91 Emmental cheeses produced during winter in Austria (n=4), Finland (n=6), Germany (n=13), France (n=30) and Switzerland (n=38) were investigated. Cheese samples were classified by factorial discriminant analysis. From NIR, a good classification of cheeses was observed for 89% and 86.8% of the calibration and validation spectral data sets, respectively. The MIR results were comparable to those observed with NIR. Within the 3000-2800 cm−1 region, 84.1% and 85.7% of the cheeses were correctly classified for the calibration and validation data sets, respectively. The classification obtained with the tryptophan fluorescence spectra was considerably lower (only 67.6% and 41.7% for classification and validation spectra, respectively). But tryptophan fluorescence spectra allowed a good discrimination of Emmental cheeses made from raw milk or from thermised milk. Common components and specific weights analysis were performed on the physico-chemical, infrared and tryptophan fluorescence data sets. These results showed that spectroscopic techniques may provide useful fingerprints and allow the identification of Emmental cheeses according to the geographic origin and production conditions.