Terpenes and fatty acid profiles of milk fat and "Bitto" cheese as affected by transhumance of cows on different mountain pastures.

The evolution of fatty acid (FA) and terpenoid profiles was studied in milk (n=20) and "Bitto" (n=3), a protected designation of origin cheese produced in a restricted Italian alpine area. Milk came from 25 Italian Brown cows successively grazing pastures at 1400, 2100 and 2200m during transhumance in June-September 2006. The fat matter was analyzed for FAs and terpenes by means of gas chromatography and purge & trap/gas chromatography-mass spectrometry, respectively. FA composition of milk fat varied significantly (p<0.0001) in relation to contents of conjugated linoleic acid (CLA), stearic, linoleic and trans-vaccenic acids. Similar monoterpene profiles characterized milk fat from cows grazing the different pastures and the highest amount of terpenes was measured in milk coming from cows grazing at 1400m. High levels of δ3-carene in milk fat were likely related to the important presence of Ligusticum mutellina in the pasture. Only negligible amounts of sesquiterpenes were detected in milk fat whereas they were the most abundant class in fodder. Both FA and terpene profiles of ripened (70 days) cheeses resembled those of the original milks. Overall, results confirm the influence of the botanical composition of mountain pastures both in enhancing the ruminal synthesis of CLA and in modifying the FA and terpenoid profiles of milk and "Bitto" cheese. Nevertheless, neither the FA nor the terpenoid profiles revealed here can be considered as "unique" to "Bitto" cheese and, for this reason, they can hardly be assumed to be biomarkers for defining a specific relationship among grazing area, milk and "Bitto" cheese. They better represent the chemical fingerprint of the cow feeding, adopted in mountain areas.