Fluorescence and infrared spectroscopies: a tool for the determination of the geographic origin of Emmental cheeses manufactured during summer

Abstract

-Mid-infrared (MIR) and front-face fluorescence spectroscopies, coupled with chemometric techniques, were investigated for their potential for discriminating Emmental cheeses originating from various geographic origins. A total of 74 Emmental cheeses, produced during summer, from six countries, i.e., Denmark (n = 2), Finland (n = 4), Germany (n = 6), Austria (n = 8), France (n = 27) and Switzerland (n = 27) were analysed. Within the 1500-900 cm -1 spectral region, a good classification of samples was obtained for 83.7 and 77% of the calibration and validation data sets, respectively. Within the 3000-2800 cm -1 the classification was considerably worse (only 57.4 and 29.7% for the calibration and validation spectra, respectively). Protein tryptophan and vitamin A fluorescence spectra were recorded directly on cheese samples. Considering tryptophan fluorescence spectra, a good classification was observed for 76.4 and 63.5% of the calibration and the validation samples, respectively. A better classification was obtained from the vitamin A fluorescence spectra since 93.9 and 90.5% of the calibration and validation spectra, respectively, were correctly classified. Cheeses from Finland and Denmark were well separated using the 1500-900 cm -1 spectra and tryptophan or vitamin A fluorescence spectra. Considering cheeses from Germany, 100% of good classification was only obtained with vitamin A spectra. Cheeses from France and Switzerland were generally discriminated, but several samples were incorrectly classified. It was concluded that vitamin A fluorescence spectra may be considered a promising probe for the reliable evaluation of Emmental cheese origin.Emmental cheese / geographic origin / authenticity / infrared / fluorescence / chemometry Résumé -Les spectroscopies infrarouge et de fluorescence frontale : un outil pour la détermi-nation de l'origine géographique des fromages Emmental de productions estivales. La spectroscopie moyen infrarouge et la spectroscopie de fluorescence frontale couplées aux techniques chimiométriques ont été utilisées pour discriminer des fromages Emmental provenant de diverses origines géographiques. Un total de 74 fromages Emmental, de productions estivales et provenant de six pays : Danemark (n = 2), Finlande (n = 4), Allemagne (n = 6),

Potentiality of front-face fluorescence spectroscopy to determine the geographic origin of milks from the Haute-Loire department (France)

“…These results, which were not obtained by FDA performed on each of the tryptophan, AAA+NA, vitamin A or riboflavin fluorescence spectral data sets, showed that the concatenation methodology allowed the use of all the spectroscopic information given by the four intrinsic probes in a very efficient way. The current study is in agreement with previously published data, indicating that fluorescence spectra can be used for the determination of the geographic origin of Gruyère PDO and L'Etivaz PDO cheeses [15] and of European Emmental cheeses [23,24].…”

“…Indeed, Wold et al [41] have demonstrated that fluorescence properties of riboflavin can be used to measure the degree of degradation of riboflavin in dairy products. Finally, it has been shown that front-face spectroscopy allows the determination of the geographic origin of Gruyère and L'Etivaz PDO cheeses [15,24] and of Emmental cheeses from different European geographic origins [23,25,26].…”

Development of a portable spectrofluorometer for measuring the quality of cheese

“…As shown in Figure 2b, there was a good discrimination between farmhouse cheeses and the others, which was not observed for cheese samples obtained by using the laboratory spectrofluorometer. The obtained results partially confirmed the findings of Karoui et al [9,13], reporting that a maximum located around 345 nm was observed for different cheese varieties and was attributed to tryptophan residues. The difference observed between the shapes of the spectra recorded on the investigated cheese samples could be due to the different molecular environments of tryptophan residues.…”

Mid-infrared spectrometry: A tool for the determination of chemical parameters in Emmental cheeses produced during winter

“…The absorption bands observed in the MIR range of 4000-600 cm -1 are associated with fundamental valence vibrations of functional groups of the molecule. For a given cheese, a good repeatability is obtained from the three spectral measurements [19,20].…”