ISOLATION AND IDENTIFICATION OF FLAVOR VOLATILE COMPOUNDS IN MILK ANDA DERIVED MOUNTAIN CHEESE

The study of the volatile fraction of cheese plays an important role i n evaluating aroma. Two varieties of Quartirolo, a typical Italian mou ntain cheese, during 5 processing steps (milk, curd, mould, salting an d 45 d of ripening) were examined in order to isolate and identify fla vour volatile compounds. Simultaneous distillation extraction was carr ied out using methylene chloride added with n-nonadecane as internal s tandard. After 2 h, the procedure was stopped and the extract dried ov er anhydrous sodium sulphate. Aroma compounds were analysed by gas chr omatography and detected by mass spectrometry. About 70 compounds were identified by comparing GC retention times with those of known standa rds and by mass spectra; they included 12 aldehydes, 13 ketones, 19 fr ee fatty acids (FFA), 11 alcohols, 6 hydrocarbons, 1 sulfur compound a nd 5 furans. These compounds increased during the cheese making proces s and reached their maximum at the end of ripening. These changes were evaluated and discussed.