Chemometric differentiation of PDO and non-PDO Italian and foreign hard cheeses using 1H NMR spectroscopy

The gargantuan sizes of food markets represents a constant challenge to control agencies. With the Protected Designation of Origin (PDO) in force, and with the ever-increasing diversity of food products, such as dairy products (in particular, cheese) robust and reliable analytical methods are required. Of many analytical techniques used for this purpose, Nuclear Magnetic Resonance (NMR) spectroscopy, specifically that utilizing 1H nuclei has been long been used for analysis, identification and authentication of various food products, such as wine, juice, coffee, edible oils and others. We have studied a selection of Grana Padano, Parmigiana Reggiano and foreign competitor cheeses by applying 1H NMR spectroscopic analysis to aqueous extracts and also additionally 13C NMR to lipid extracts. After the advanced data post-processing such as dynamic alignment and optimized bucketing, different multivariate statistics approaches such as PCA and PLS-DA were utilized. We addressed such group features as cheese variety, geographical origin, maturation time and year of production, as well as drawbacks and advantages of each of the approaches