Tracciabilità dell'origine del latte alpino mediante lo studio del profilo alcaloidico naturale

In 2015, 162.8 million tonnes of cow’s milk were produced in the EU-28, headed by Germany and France with 33 and 26 million tonnes respectively, while Italy was in seventh place with 11 million tonnes (Eurostat statistics explained), and world milk production is forecast to grow. In a globalised market, demand is growing for secure information about product traceability, and the consumer trend is increasingly moving towards conscientious purchasing, which avoids adulteration and fraud. Traceability is a powerful tool for pursuing different objectives: reinforcing consumers’ trust and loyalty to a product, peace of mind to promote product preference, and increasing confidence in the overall food chain quality system. As regards milk, in Italy the Decreto Interministeriale of 9 December 2016 made indication of the origin of raw milk materials on the packaging label mandatory, as stated by Regulation (EU) No. 1169/2011. In the same way, not only is the country of origin important, but also the differentiation between milk from highland and lowland areas, due to the evident implications for food quality. The different dietary regime of animals is the basis of the characteristics distinguishing alpine milk from intensive farming milk, and analytical controls usually exploit these properties. This work aimed to propose new markers for alpine dairy product traceability by focusing on one of the most abundant and ubiquitous groups of secondary metabolites in plants, namely alkaloids. In this work we developed a combined targeted and untargeted screening method for alkaloid profiling, using liquid chromatography coupled with high resolution mass spectrometry. Online SPE pre-treatment of herbal and milk sample extracts was proposed in order to reduce the impact of the matrix effect on instrumental response. Quantification of 41 analytes with reference to pure analytical standards, and putative identification of a further 116 alkaloids, confirmed on the basis of accurate mass, isotopic pattern, chromatographic retention time and fragmentation profile, were proposed. Moreover, the alkaloid profiles of over 60 alpine herbs sampled in two natural pastures in the eastern Italian Alps were defined, providing evidence that alkaloid composition represents an interesting tool for individually characterising plant families, with the most encouraging results for the Poaceae species. The composition and variability of alkaloids ingested by dairy cows grazing on the two grasslands was also investigated, verifying the possibility of discriminating animal diets from different pastures. Lastly, the variability of alkaloid profiles for milk samples produced by cows grazing on the two pastures was defined and the possibility of discriminating them with regard to pasture origin.