Chemical characterisation of European Emmental cheeses by near infrared spectroscopy using chemometric tools

This study examines the use of near infrared (NIR) spectroscopy for the determination of chemical parameters of Emmental cheeses from different geographic origins of Europe. A total of 91 Emmental cheeses produced during the winter in Austria (n=4n=4), Finland (n=6n=6), Germany (n=13n=13), France (n=30n=30) and Switzerland (n=38n=38) were investigated. Fat, total nitrogen (TN), water-soluble nitrogen (WSN), non-protein nitrogen (NPN), sodium chloride (NaCl) and pH were analysed by reference methods. The diffuse reflection of different cheeses was measured by a Büchi NIRLab N-200 spectrometer using a rotating measuring cell between 1000 and 2500 nm. The best results for fat content (R2=0.92R2=0.92; ratio of standard deviation to root mean square error of prediction (RPD)=3.61) and NaCl (R2=0.39R2=0.39; RPD=1.28) were obtained after maximum normalisation and smoothing, whereas the best results for TN (R2=0.82R2=0.82; RPD=2.34), WSN (R2=0.77R2=0.77; RPD=2.08), NPN (R2=0.80R2=0.80; RPD=2.17) and pH (R2=0.43R2=0.43; RPD=1.32) were obtained when the spectra were subjected to the first derivation between maximum normalisation and smoothing. It can be concluded that NIR spectroscopy can be used for the determination of fat, TN, WSN and NPN of European Emmental cheeses with varying degrees of accuracy. However, the NIR failed to determine NaCl and pH parameters.