The development of free amino acids and volatile compounds in cheese 'Oloumoucké tvarůžky' (PGI) during ripening

Summary Twenty-two free amino acid (FAA) concentrations were observed during manufacture (7 days) and ripening period (42 days follow-up) of Olomoucke tvarůžky (PGI, smear acid cheese). During the ripening period, the amounts of volatile compounds and selected sensory attributes were also analysed. The free amino acids were determined by means of ion-exchange chromatography, and the volatile compounds were detected and identified using HS-SPME coupled with GC/MS method. The development of the individual FAA content positively correlated with the ripening period (r = 0.7734–0.9229; P < 0.01). Forty-six volatile compounds (14 alcohols; 10 esters; 7 ketones; 5 acids; 4 aldehydes; 3 sulphur compounds; 2 phenol compounds; and 1 terpene) were identified. Concentrations of several compounds increased (e.g. 3-methylbutanal, 2-butanol, 2-butanone; P < 0.05) or decreased (e.g. dimethyldisulphide, methanethiol, 2-phenylethylacetate, methylbutyric acid; P < 0.05) over cheese ageing. The results gave information about the development of sensory active substances and its precursors in Olomoucke tvarůžky during ripening. In conclusion, we found that free amino acid concentrations and sulphur compounds are positive with improved flavour.